bs 00350-1꞉1974

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BS 350 : Part 1 :

1974

UDC

611.i

8,3

:

13.081

CONFIRMED OCTOBER

1983

e

Conversion

factors

and tables

I

Part I . Basis of tables. Conversion factors

i.

British Standards Institution

ritish Standards Institute on ERC Specs and StandardsPYRIGHT British Standards Institute on ERC Specs and Standardscensed by Information Handling Services

7/17/2019 BS 00350-1꞉1974


7/17/2019 BS 00350-1꞉1974


B S

350

: Part I ; M a r c h 1974

UDC

51 1.168.3

:

3.081

Conversion

fac tors

and tables

Part

i.

asis

of

tables.

Conversion

fac to rs

CONFIRMED

OCTOBER

1983

Amendments issued since publication

Amd. No. Dateof ssue Text affected

4153

July 1983 Incorporated in this standard

British Standards Institution

2

Park Street

.

LondonW1

A

28s

Telephone O1-629

9000

Telex

266933


7/17/2019 BS 00350-1꞉1974


BSI B S * 3 5 0 : P A R T * L

BS

350 :

Part

1 :

1974

Contents

Page

Co-op erating organizations Inside front cover

Acknowledgements

2

Foreword 3

Basis

of

tables.

Conversion

factors

Subject table(s)

Associated

1. Number la, l b

2. Leng th 2

3.

Area 3a, 3b

4. Volum e and capacity 4a, 4b, 4c, 4d

5. Modulus

of

section, first

mom ent of area (see 4a)

6. Second moment

of

area,

or

geometrical mom ent

of

inertia

6

7. Plan e ang le 7

8 .

Solid angle

-

9. Time -

10. Linear velocity (speed) 10

11. Angular velocity 11

12. Frequency (see 11)

13. Acceleration 13

14. Mass 14a, 14b, 14c

15. Mass per unit length

15

16. Mass per unit area

16

17.

Sc

surface, or area

per

unit mass 17

18. Area per unit capacity 18

19. Density 19

20. Con centration 20

21. Specific volum e 21

22. Mass rate of flow

22

23. Volume rate of f low

23

24. Traffic factors 24a)

246

25.

Moment

of

inertia

25

26. M omentum (he ar )

-

27. Angular momentum

-

28. Force 28

29. Weight (see 14a, 14b, 14c and 28)

4

5

7

9

15

15

16

17

17

17

19

19

20

20

25

27

30

32

32

34

36

38

38

40

42

42

42

43

45

74 S Lb24bbî O L L b L 2 û O W

Page

30, Moment of force, or torque 30 46

32. Pressure

32a,

326, 32c 48

33. Stre ss (see 32a, 32b, 32c) 54

35.

Viscosity, kinem atic 35 56

36. Energy (work, heat , etc,) 36a, 36b 58

37. Power 37 62

38. Tem perature, including temperature

difference or interv al

38

64

39, Specific energy 39 65

40.

Heat content, volume basis

4Oa,

4ûb,

40c

67

41,

Speciñc heat capacity 41 70

42. Speciñc entro py (see 41) 72

43. Heat capacity, volume basis 43 72

44.Heat

flux

density

44

73

45. Therm al conductan ce 45 74

46. Th erm al conductivity 46 75

47. Th erm al resistivity 47 76

48. Hea t release rate 48 77

49. Th erm al diffusivity (see 35) 77

31, Force per unit length

-

48

34. Viscosity, dynam ic 34

54

Appendices

A. Commentary

on

mperial and metric

78

B. References

B.l

Detailed conversion tables 81

B.2 Gen eral information

83

B.3 Some other British

systems

of

measurement and units

Standards containing

conversion information 83

Figure

1. Fuel consum ption

41

Indexes

1. Alphabetical list of symbols for units

and prefixes 84

2. Gen eral index 88

Acknowledgements

Th e Com mitt ee responsible for this revision acknowledges with th ank s the assistance provided by Mr.

A. C. Hutchinson, C. ng., in the form ative stages of the planning and drafting, and later by Mrs. Pam ela

Anderton of the National Physical Laboratory who gave expert advice and personally checked the tables

of factors.

2


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BS 350 Part 1

:

1974

Foreword

This standard deals withinterconversion from one unit

of

measurement o another for

a

num ber of quantities

which are

in

general use in engineering, industry and trade. The subjects covered are, broadly, metrology,

mechanics

and heat; th e standard does not d eal with purely electrical units.

BS 350

was first published in 1930, and was revised in

1944

an d again in 1959.

It

was then that the standard

was split into two parts, P art

1

dealing with the basis of tables an d conversionfuctors, and Part 2, w hich

first appeared in 1962, giving

detailed

conversion

tubles

for the more frequently used conversions. From

those tables in Par t 2 conversions could be read off direc t ly or asse ssed by i n t e rpo l a t i on , and t he onus o f i t u j m d l u

mul t ip l ic a t i on by a

six

f igure fac tor was removed. In I967

a

S u p p l e m e n t

(PD

6203) was i ssued

to

Par t

2,

giving

addi t ionat de ta i led tables for

SI

conversions.

BS

350 : P a r t 2 was wi thdrawn in 1981 s ince many o f t he tab l e s

.ilfrfificf/

calcula tors was considered to have m ade suc h tables, which of ten requi red interpo la t ion, obsole te. P D 6203 is,

how ever, sti l l valid and has been retained.

This , then, i s a revision (confirmed on the i ncorpora t i on

of

A m e n d m e n t No.

i

in 1983) of

BS

350

:

Par t 1 : 1959

and provides a compre hensive l is t of conversion fac tors and notes on the i r use . Th e uni ts i n about f i fty quant i t ies

of

me asu rem ent a r e given, together wi th such def ini t ions, and informat ion on th e der iva t ion of conversion fac tors, as

are considered necessary fo r th e purpos e .

The experience gained with th e earlier editions ha s been a reliable guide to the choice of quantities to be

treated

in

this revision. Only information now considered obsolete has been discarded, and the quantities

dealt with

liave

remained su bstantially unehaiiged. There have, however, been consid erable additions made

to

the units, and consequently to the conversion factors, and t he standard has been funda men tally re-

arranged for the reason which follows.

In this edi t ion, wh i le interconversio n fac tors be tween a l l the imp ortant uni ts t rea ted are given, the standpoin t

i ~ . I t i ~ t ~ ~ n s

from which th e var ious uni ts an d conv ersion fac tors a re discussed i s the

SI.

T h i s m a r k s a n i m p o r t a n t d e p a rt u re

ii-Oni the ear l ie r edi t ions which or iginal ly argued from the im peria l system an d la ter perforce adopted a mixed

imperia l -m etr ic s tandpoint . Imperia l uni t s a re be ing progressively discarded an d the i r re tent ion as the stan dpoint in

this s tandard w ould have ac ted as a brak e t o t he p rogre ss o f m e t r i c at i on . Fur the rmore , t he

SI,

unde r t he cus tody of

the Gene ra l Conference of Weights and Measures, forms the prec ise and na tura l basis for conversion informat ion

on uni ts , and on crs f i rm prospects of an interna t ionat harmo niza t ion in uni t prac tice , a f te r which co nversion fac tors

wili no long erbe requi red.

stated accuracy. The other important but extraneous information in it

is

there to help the general user

when he is faced with the need to make conversions. BS 350 does no t pur port to define quantities o r units,

or to standardize the letter symb ok or abbreviations used for units. These matters are dealt with

elsewhere, bu t their m ention

is

necessary here an d has been m ade up-to-date with the latest international

Where factors are given in bold print it is to show that they are exact; in general, factors have been

rounded to include six signiíicant figures, thus perm itting accuracies satisfactory for most p ractical purposes.

The computation of each factor ha s a s far a s possible been m ade from first principles, using eight or m ore

signiñcant figures to m inimize the possibilities of errors in roundin g. By co mp ariso n with previous editions

(including

BS 350 :

Part

2)

deviations by one digit

in

the last signifìcant figure of factors involving the

UK

gallon may sometimes be noticed. These have arisen because the computation in the previous editions was

based on

I

ü K g a l = 4 . 5 4 6 09 dm3. S ince Novem ber 1976 the de f ini ti on o f t h e ga l l on i n t he We igh ts an d Measure s

. A W I ~ I ~ A ~ ~ /

Act 1963 has been

4.546

(19

dm3. Before tha t d a te th e def init ion in t h e w e i g h t s a n d M e a s u r es A c t 1 9 63 w a s s u c h t h at

the ga l lon cou ld be caIcula ted

to

be 4.546 O91 8 79 dm 3 to ten signi f icant f igures and , on advice f ro m the N at ionaI

Physica l Labora tory , a more accu ra te fac tor was used as

a

bas is fo r t he computa t i on i n t he p re sen t ed it ion . T he

re tu rn , i n Novem ber 1976, by p rec i se de f ini t ion t o wha t had ea r l i e r been used a s a n approx im a t ion fo r the va lue o f

th e galion (Le. 4.546 O9 dm3 ) clearly im plies changes, in s om e cases, in the final figure of fac tors inv olving the U K

gal lon and in par t icular , the reversa l of the chan ges as described tha t occu rred be tween the pres ent and th e previous

edi t ions of the standard . Ta ble 23 h as however n ow been correc ted in th is respect. T he six signi ficant f igures given

for conversion fac tors involving the

15 "C

calor ie ace no t warranted by th e accuracy of def init ion of tha t par t icular

un i t , bu t have been re t a ined for t he sake

of

consistent ly in the lay out of the tables.

Six-figure factors are unnecessarily precise for many practical purposes, and will be rounded to fewer

significant figures as appropriate. T he Departm ent of Tra de a nd Industry h as asked users of these tables

to be reminded that conversions for trade purposes should be based

on

the s tatutor y deñnitions of units

in the Weights and Measures Act, 1963. Section

24

of that Act makes

it

an offenoe to

give

sho rt weight or

measure

(or

to

overcharge for t he goo ds supplied if they are offered a t the stated price

per

unit weight or

measure). The conversion factors shou ld therefore always

be

chosen

so

that the rounding

is

in t he customers'

favour, regard being paid to a ny statutory requirement (such as M arking of Goods Regulations) there

may be

in

this respect.

Jirii ifi.i.+

inc luded in it had become in consistent wi th th e Interna t ional System of U n i t s

(SI)

and the increasing use of pocket

Ji r l t iYh3

i $ i t i ) i c . t I f i l f

Ji r i i iWt3

Ji i l i

i W 3

Th e standardiza t ion funct ion of this s tandard I ies in the provision of conversion factors reliable to a

f r u i r l c i i i l t w

J i r l i iW 3

I

\

d t h v i

and

national

decisions, dil l1

I W

Jir l i iY33

3


7/17/2019 BS 00350-1꞉1974


BS 350 Part

I

:

1974

Brit ish Standard

Conversion factors and

tab les

Part 1 . Basis of tables. Con versio n factors

i . Number

1.1

The following preíkes, w ith significance, iianie, and symbol as shown below, are used to d enote decimal

multiples or submultiples

of

(metric ) units. T hese prefixes developed

in

conjunction with the metric system,

and are now authorized as

' SI

prefixes '.

Table

la .

Prefixes denoting decimal multiples or submultip les

To

indicate multiples

To

indicate

submultiples

x 10-1

x

10-2

x 10-6

x 10-12

x

10-18

x 10-3

x 10-9

x 10-15

deci

centi

milli

micro

nano

pico

femto

~

atto

d

m

P

n

P

f

a

C

1.2 Regarding the meaning of million, biilion, etc. the convention shown in Table lb, accords with the

decision of th e 9th General Conference of Weights and Measures, Paris 1948, and is in use in European

countries including the United K ingdom.

Table

ib .

Meaning of million, billion, trillion , etc.

Tenn

million

biiiion

t a o n

quadrillion

Significance

thousand

x

thousand

million x million

million

x billion

million x triilion

Corresponding

decimal factor

106

1012

1018

1024

A different convention is

in

use in the United States of America, where ' miliion signiíies

a

thousand

times a thousand (109, billion ' signifies a thousand times a million

(log),

' rillion ' signifies a million

times a million (1012),and

'

quadrillion

'

signifies a million times a US billion (1015).

In view

of

the differences between European and

USA

practice, ambiguities can easily arise with the

words

'

billion ', rillion

'

and ' quadrillion ', therefore their use should b e avoided.

4


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e

O

B S

350

Part I : 1974

Length

2. Length

2.1 The

SI

unit of length is the met re (symbol m). I t is one of the base units of the S1 and is now defined in

terms of a specified number of wavelengths of a particular a tom ic radiation, a s given in

BS 3763,

NOTE. The titles of BS

3763

and all other British Standards referred to in this text

are

listed

on

the inside back cover.

2.2 Multiples and submultiples of the metre are formed by using any

of

the

SI

prefixes given a t 1.1;kilometre

(km), decimetre (dm), centimetre (cm), miliimetre (mm) and micrometre (pm) are common examples. An

alternative term for the micrometre, abrogated by the CGPM but

s t i l l

in common use, is ‘micron

’.

The

symbol

p,

associated in the past with the micron,

is

incorrect; pm should be used.

2.3

Some units of length having associations with the metric system but not forming part of the S I are:

i

angström (A) = 10-lOm Refer to

note

1 international nautical mile (n mile) = 1852 m

1

astronomical unit (AU)

= 1.496

x 1011 m 1

1 parsec (pc) =

3.0857

x 1016m 2

1 light year

(1

y.)

= 9.4605 x 1015m

3

2.4 The definitive

U K

(or imperial) and US unit of length

is

the yard, legally deíined (since

1959

in the

USA and since

1963

in the UK) as follows:

2.5 The connection between m ultiples and submultiples of t he yard is indicated in the foliowing traditional

table of named UK and US units of length, defined (for the UK) in the Weights and Measures Act, 1963.

Refer

to

note

4

1

yard = 0,9144 m

(1 in

=

0.0254

m)

= 0.3048m)

(1 yd

= 0.9144

m)

1 foot (ft) =

12

inches (in) (1

f t

1

chain == 22 yards (yd) (1 chain =

20.1168

m) 5

1

yard (yd)= 3 feet (ft)

I furlong = 10 chains

(1

furlong = 201.168 m)

1 mile =

8

furlongs (1 mile = 1609.344 m) 6

1 micro-inch (pin)

Refer

to

note

1

thou = 10-3 in = 25.4 pm = 25.4 x 10-6 m 7

1 mil = 10-3 in = 25.4 pm = 25.4

x 10-6 m

8

1

point

- in

(approx)

= 0.351 mm

(approx)

9

1

iron

-

Ain = 0.529 167 itîm 10

1

line

- 1

in

=

0.635

11

1

line or ligne

-

& i n

=

2.116 671111i11

12

2.6 Some less usual, or mo re specialized,

UIC

and

US

named units of length are:

=

10-6

in =

0.0254

pm =

25.4 x

10-9 m

-

1em

-

1

in

=

4.233 33

mm

13

1hand

=

4 i n

=

10.16

cm 14

=

0,201 168 mlink

1

US survey foot _ - . iDA9B f t

e

38.87

8

= 0.304 801

m

1

fafhom

y =

6 f t

=

1.8288 m

1 rod, pole, or perch

= 5+

yd

= 5.0292

m 15

1 engineer’s cha in = l oo f t = 30.48 m

1 cable-length

- -

16

1

U K

nautical mile

=

6080

ft

=

1853.18m

17

1 telegraph nautical mile = 6087 ft

chain = 0.66 ft

-

= 1855.32 m

Notes on section 2

I. Approximalely th e mean distance between the S un and the Earth.

2.

The distance at which

1

AU subtends an angle of

1

second

(1‘7.

3.

Approximate distance travelled by light in

1

year.

4.

An exception is the US survey foot, shown in 2.6.

5. Th e legally defined chain, commonly called Gunter’s chain in the US A.

6.

Also known as

a

statute mile. There

is

no recognized abbreviation for mile and the complete word ‘ mile ’ s used as the

7.

Colloquial, for one-thousandth of an inch,

8.

Colloquial, for one-thousandth

of

a n inch.

For

ot ier

meanings

of mil see 3.54.4 and (Note

2) of

section 7.

9. Printing trade. (Originally defincd by 83 picas- 83 x 12 points = 35 cm).

10. Boot and shoe trade.

11. Button trade.

12. Watch trade.

13.

Printing trade.

14.

Height

of

horses.

15.

Obsolete.

16. A

nautical term not precisely defined

in

the

UK. In

ifs most general concept

it

isequal to on e-tenth of a n unspecified nautical

mile, but other values have been used, including the value 120 fathoms (720 ft).

17.

Obsolescent as the interiiational nautical mile becomes adopted

in

the

UK.

Foreonversion factors for a number of widely-used units of

length

see Table 2.

iinit symbol.

5


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B S I

B S * 3 5 0 :

P A R T r L 74 m

L b 2 4 b b î

O L L b L 2 4 B m

BS 350 Part I

:

1974

Length

I

9,

o

7 4

a

2

t-

2

a

w

1

II

6


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3.

Area

(length squared)

3,1

The coherent SI unit of area is the square metre (symbol m2), a derived unit.

3,2

Areas are also expressed in terms of the squares

of

any

of

the multiples and submultiples of the metre

formed by the use of the Si prefixes, e.g. squa re millimetre (mm2), square centimetre (cmz), square decimetre

(dm2), square kilom etre (km2),

i n

accordance with the rule concerning prefixes attached to units raised to

a

power, the relationship

between each of these and the square metre

is

as follows:

l d m * -

(z)

=

10-2

in*

I

km2

=

( i O 0 0 n 1 ) ~

=

106m*

1 a = 100m2

This, an d m ore especially its multiple the hectare (symbol ha), are used fo r land m easurem ent of area.

Ano ther specially named m etric unif is the barn, used

in

atomic physics in the measurement

of

cross

1 barn

= 10-28

m?

3.3 A

metric unit with a special name is th e are (symbol

a),

1

ha =

1ûOa =

1OO00m2

sections.

3.4

The connection between various traditional UK aiid US units of area, and their relationship to the

square metre, are as foüows:

Refer to note

I

square fo ot (ft2)

=

144 square inches (in21 (1 in2

1

square yard (yd2)

=

9 squ are feet (1 ft2 =

0.092

903 O m2)

1 rood

=

1210 square yards (1 yd2

= 0.836

127 m2)

1

1 acre

= 4

roods = 4840 square yards

(1

rood = 1011.71 m2)

(1 acre

=

4046.86 m2)

1

square mile (mile2)

= 640

acres

(1

mile2

=

2.589 99 x 106

m*)

=

6.4516

x 10-4 m2)

3.5

A specialized UK and U S unit of are a (used in connection with sections of wire) is the

'

circular inil '.

1

circular

mil

=--=

7.853

98

x 10-7 in2

= 5.067 07 X

10-10 m3

Refer to note

2

Notes

on section 3

I , The

rood is

obsolescent in the UK and rarely used in the

USA.

2.

The circular mil has an are a equal to tha t of a circle one-thousand th of an inch in diameter.

For

other meanings of mi l see

2.6, 4.4

and section

7 ,

Note 2.

For

conversion facto rs for

a

number

of widely-used

uni ts of area

see Tables 3a and 36.

7


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BS

350

Part 1 :

1974

A’rea

P

s

8

a

X

VI

c.l

m

f

W

51

m

X

O

2

m

-

m

o,

2

3

d

X

JaA

-

I

E

57%

SI

8


7/17/2019 BS 00350-1꞉1974


B S

350 Part 1

1 circular mil* _ _

_

1 square millimetre =

1

square inch -_

mm2

-_

in2

Volume and

circular mil

square

millimeíre

square inch

mm*

in*

1

5.067 07

x

10-4 7.853 98

x

10 -7

1973.53

1

1.550

0 0 ~ 1 0 - 3

1.273 24 x

106

645.16 1

: 1974

Area

capacity

4. Volume and capacity (length cubed)

4.1

The coherent

SI

un it of volum e is the cub ic metre (symbol m3),

a

derived unit.

4.2

Volumes are also expressed in terms of the cub es of any of the multiples and submultiples of the metre

formed

by

the use of the

SI

prefixes; of these the cubic decimetre (dm 9, the cubic centimetre (cmj), and the

cubic millimetre (mm3) are c om mon examples.

The relationship between each of these and the cubic metre is as follows:

3

1

mm3

=

6)10- 9m3

4.3

Iii the SI no distinction is drawn between units of volume and units of capacity. However, a metric

uni t with a special name, used in conjun ction with the SI and com monly used for the measurement of liquids

and fluids, is the litre (symbol i?).

1

litre

= 1

dm3

= 10-3

m3

(This definition has applied in the SI ince 1964, but see

4.3.1

below.)

The

SI

prefixes are used with the litre, leading for example to t he hectolitre (hl), cen tilitre (ci), millilitre

(mi) and micro litre (pi).

1

hl

=

100 litre =- 10-1

ni3

1 ci -=

(&)litre

= 10-srm3

i ml =

(&)litre =

10-6

m3 = i

cm3

I

pl

- - (&)litre -=

10-9

ln3 --

1

mm3

4.3.1

Units of capacity for the measurement of liquids (and sometimes of dry go ods also) have been treated

as

base units at various times in th e past, an d have

been

defined independently of length. Thu s in the m etric

system f rom 1901 to 1964 the litre was defined as the vo lume occupied by a mass of on e kilogra m of water

tAlfhough in this standard the symbol used for the litre is the lower case letter

‘I’,

it has long been recognized that

in

some Asamende

typefaces it was difficult to distinguish between the lower case letter ‘1’ and numeral

1.

Th e 16th General Conference of Weights

Jtrb19*3

and Measures (1979) accordingly recognized the use of the upper case letter ‘L‘ as an alternative symbol for the litre. In British

Standards

‘L‘

s now the preferred symbol but

‘I’,

which is still widely used, is recognized as acceptable. See

also

BS

5 5 5 5 .

9


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BS 350 Part I : i974

Volume

and

capacity

under specified conditions (at its temperature

of

maximum density and uiider a pressure of one standard

atmosphere). Since 1964. however, the litre has been re-defined within the SI as a special name for the

volume of one cubic decimetre (which is

as

it was before I901). Since

1

November

1976,

the 1964 definition has

been embodied within the law of {he United Kingdom. Because

of

these changes, where

a

very

high

degree of

/ Y , t I

precision is called for,

it

is necessary

to

establish which definition

of

the litre is intended.

In

the tables which follow

in

this standard

a

litre

as

defined according to the 1901 definition

is

described

as

the 'litre

(ISOI)',

and the litre

as

it is

now defined according

to

the SI is described simply

as

the 'litre'.

1 litre (1901)

=

1.ooO 028 litre

4.4

In the French timber trade the volume of one cubic metre goes under the obsolescent name ' stère

'

(symbol st). Similarly,

in

the timber trade in Ge rman y the cubic metre has been described as the

'

Festmeter

(Fm) or

'

Raummeter

'

(Rm), nd these two special name s are als o obsolescent.

Another obsolescent metric-based volume unit

is

the

'

mil

',

used

in

the

UK in

pharmaceutical work,

particularly for prescriptions, to denote a millilitre (see British Phormncopoeia, 1953). For other meanings

of '

mil

'

see

2.6,

3.5, and section

7,

Note 2.

4.5

The connection between the traditional UK and

US

iiiiits

of

volurne and their relationship to the

cubic metre are as follows:

Syml>ol

Unit Metric equivalent

yd3 I cubic yard =: 27 cubic feet = 0.764 555 m3

ft3 1 cubic foot

=

1728 cubic inches

=

0.028 316 8 m j

in

3

1 cubic inch

= 1.638 71 x 10-5

1113

4.6

As with th e litre in the metric system, it is customary to regard certain U K and

US

volumetric units as

units

of

capacity. These include the

UK

gallon and its multiples and submultiples, and the US gallon and

US

bushel, with their multiples and submultiples. The

UK

and U S units of capacity differ markedly

from

each other* an d it is therefore imp ortant to avoid confusion in their use. The prefixes U K and

US

are

used

for purpose of their identification in this standard but the qualifications

U K

o r

U S

are frequently omitted

in practice. Care is particularly necessary with conversions of the gallon in order to identify which gallon

is concerned.

4.6.1 UK

units qf cnpacity. These are all based on the UK gallon (UKgal), defined in Schedule

1

of the

Weights and M easures Act, 1963, as the space occupied by

10

pound s weight of distilled water under certain

conditions specified in the schedule.

Key conversion factors are

:

YX.J

1 UKgal = 4.546 09 dm3

=

4.546

O9

litre

=

4.545 96 litre (1901)

WKmin

U K

f l

d r

UK fl oz

UKpt

UKqt

UKgal

-

The connection between the U K gallon and its various multiples and sub niultiples is shown

in

the I'ollowing

list:

Symbol if any) Unit Metric equivalent

minim t

= 0.059

193

9 cm3

fluid drachm t

= 60

minim

L 3.551

63 cm3

fluid o unce

=

8 fluid drachms

=

28.4131 cm3

gill

= 5

fluid ounces

=

0.142 065 dm 3

pint = 4 gills

(= 20

fluid ounces) = 0.568 261 dm3

quart

=

2 pints

=

1.13652dm3

gallon

=

4 quarts

(= 160

fluid ounces)

=

4.546

O9

dm3

- 1 peckf = 2 gallons

1

busheit

=

4pecks

=

9.092 18 dm3

= 36.3687dm3

4.6.2

U S

units ofcapaci ty .

The US units of capacity are defined

in

terms of

a

specified number

of

cubic

inches. The U S gallon is equal in volume to 231 cubic inches and

is

used for the measurement of liquids

only. The US bushel is equal

in

volume to 2150.42 cubic inches and is used for the measurement of dry

commodities only.

* For a direct comparison of U K and U S units of capacity see Table 4d

and it

is now

llegal to use these units for trade purposes.

I The m inim, fluid drachm,

peck

and bushel are

now

deleted from Schedule

1

to the

UK

Weights and

Measures

Act,

1963;

10


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BS

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Volume and

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Volume and capacity

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1974

Volume and capacity

Modulus of sect ion

Second moment o f area

Table 46.

Relationship.between UK (imperial) and

US

units of capacity

1

UK minim

=

0.960

760

US minim

1

UK luid drachm

= 0.960 760 US

luid* dram

1

U K

fluid ounce

=

0.960 760

US

luidf ounce

1 U K gill

=

1.20095US gill

1

UK pint =

1.20095

US

iquid pint

I UKq u a r t

= 1.200

95 US iquid quart

1 UK

gaiion

=

1.200 95 US gaiion

1

UK pint

=

1,032

6 US

dry pint

1 UK quart

=

1.03206US dry quart

1 UK

bushel

=

1.032 06

US

bushel

1

US minim

= = 1.040

84

UK

minim

1

US fluid' drain

=-z 1.040 84UK

fuid drachm

1 US fluidt ounce = 1.040 84 UK luid ounce

1

US gill

=

0.832 674

UK

ill

1 US

liquid pint

=

0.832 674

UK

int

1 US iquid quart

=

0.832 674 UK uart

1

US gaiion 0.832 674 UK gallon

1

US

dry pint = 0.968 939 UK int

1

US

dry quart

=

0.968 939

UK

uart

1 US

ushel =

0.968 939 UK

bushel

1 UKp e c k

=

1.03206

US

peck

1 US peck

=

0.968 939 UK eck

* Sometimes also known as the liquid dram in the USA.

t

Sometimes

also known as

the liquid

ounce n

the

USA.

1 m 4

=

l c m 4

=

1 ft4

=

--

o

m4

1

1 x 10-8

0.863 097 x 10-2

5.

Modulus of section, f irs t moment of area

5.1

These quantities have the sam e dimensions as volume; the coherent

SI

unit

is therefore the metre

cubed (m3).

5.2

They may also be expressed in terms of thetcu be of any suitable submultiple of the metre; the

centi-

metre cubed (cm3) and millimetre cubed (mm3) a re comm only used.

5.3 In imperial units the foot cubed (ft3) or inch cubed (in3) are usually used.

The relationship between

the

above-mentioned uniís can be seen or inferred

from

Table 4a.

6. Second moment of area, or geometr ical moment of inertia

The coherent

SI

unit for this quantity is the metre

to

the fourth (m4). Other commonly

used units

are the

centimetre to the fourth (cm41 and millimetre to the fourth (mm4) and, in imperial units, the foot to the

fourth (ft4) and inch to the fourth (in4). See Table 6 or conversion factors for these units.

Table

6.


1 in4 = I 41.6231 x 10-8

NOTE. 1 mm4

=

10-4

cm4 = 10-12

m4.

I 1

1 x 108 115.862 2 402 510

1.15862

x

10-6

863

097

41.6231

I

4.822 53

x

10-5

I

1

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.

BSI

BS*350: P A R T * i I 74 1624669

OiI16134

O

BS 350 Part

I : 1974

Plane angle

7. Plane angle

7.1 The coherent SI unit of plane angle is the radian (symbol rad), a supplementary" unit. It

is

the angle

between two radii

of

a circle which c ut off on the circumference an a rc equal in length to the radius.

Thus a complete circle subtends an angle of 2n: rad at its centre, and a riglit angle (L) equals

2x

x

-rad = - ad.

4 2

7.2 Angular units

of

such practical importance that they a re retained for general use in conjunction with

the SI are the traditional units degree

( O ) ,

minute ('), second (").

The full circle subtends an angle of 360 degrees (360') a t its centre,

and

thus the right angle

(L)

=

90

degrees (90 O).

x

1 degree (1

O)

= 60 minutes (60') = -rad

180

rad

60

i<

180

minute

(I')

= 60 seconds

(60") =

1

second

(1")

I C

-

3600

x

180

rad

It is often convenient to express sub-divisions of the degree in decimal form, rather than to use minutes

and seconds.

7.3

A unit of plane angle used in so me continental countries is the grade (3 or, as it is called in Germany,

the gon. This is a one-hundredth of a right angle.

x

lo (or 1

gon)

= 0.9" - rad

-

200

Notes

on section 7

1. Note the possibility of confusion between the hundredth part of a grade in angular measure and the terni Centigrade (cor-

rectly called Celsius) in connection with temp erature,

2. The unit

'mil

' s sometimes used

in

connection with angular measure. For sonie purposes the angular mil is taken

to be

one thousandth of a radian

(10-3

rad), which is equivalent to

3'26.25".

There is, however, anuther concept i i i which an angular

mil is equa l t o 3 60/6400 degrees ¡.e.

3' 22.5".

For other meanings

of

'

mil

'

see

2.6, 3.5,

and

4.4.

3.

In English there

is

no com monly used expression for the

'

ull angle

'

siihiended by

a

circle.

In

German the terni

'

Vollwinkel

'

is used.

For interconversion factors for the units mentioned in 7.1,7.2 and

7.3

see Table

7.

Table

7. Plane

angle

Exact values are printed in bold type.

radian

rad

1

radian -

rad

i ight angle

= 1.570 80

1 degree

=

0.017453 3

0

1minute = 2.908 88 X 10-4

1

second

=

4.848 14x10-6

1

grade

(or

gon)

= 0.015 708

O

P gon

right angle

L

0.636 620 57.2958

I

I l

.011 111 1

1.851 85 x1 0- 4 0.016 666 7

I

3.0 86 42 ~1 0- 6 2.777 78x10 -4

0.01 0.9

minute

,

~ I

437.75

5400

6 0 .

1

0.016

666

7

54

second

,,

206 265

324 O0 0

3600

60

1

3240

grade (or gon)

P gon

63.6620

..

____

100

1.111

11

1.851

85

x 10-2

3.086 43 x 10

-4

1

In

October

1980

the International Co mmittee of Weights and M easures decided to interpret the class of suppleme ntary units in

he Intemational System

as

a class of dimensionless derived units for which th e General Conference of Weights and Measures

leaves open the possibility of using these or not in expressions ofderived units of the International System.

16


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8. Solid angle

BS 350 Part

1 :

1974

Solid angle

Time

Linear velocity

The coherent unit

of

solid angle, the only unit in common use for

solid

angle, is the steradain

(symbol sr), a su pplem entary * unit. I t is the solid angle which, having its vertex a t the centre of a sphere,

cuts

off

an a rea of the surface of the sphere equal to that of a square with sides of length equal to the radius

of the sphere.

9. Time

9.1 The SI uni t of time is the second (symbol s), a base unit.

It is

now defined as the du ratio n of a specified

nuniber of periods of a particular atomic radiation; for details see BS 3763.

9.2 Prior to 1967 the second was defined as a speciiìed fraction of the time taken by the Ea rth to comp lete

a particular orbit of the Sun. (This second, the ' ephemeris second ', is retained fo r use as a special unit

in astronomy, and is as nearly equal to the SI unit as the highest precision of measurement could permit

in 1967.)

9.3 Other units

of

time

of

such practical im portance tha t they are retained for general use in conjunction

with the

SI

are:

minute (min)

hour (h)

I

h

=

60

min

= 3600

s

A

comp lete sphere subtends a solid angle

of 4n

sc

at its centre.

1

min = 60

day (d) I d

= 2 4 h = 8 6 4 0 0 ~

9.4 Longer du rations of time are conveniently expressed in terms of the week, month

or

year, but the last

two

of these cannot in general

be

explicitly related to the second (of time).

l we e k

=

7 d

=

604800s

1 Month = 28, 29, 30 or 31 days (according to calendar)

1 yearf

= 12 months

= 365 or 366

days (according t o calendar)= 8760

h

or

8784

h (according to calendar).

.qrnJllt. il

J11[r IYX3

Notes

on section 9

1.

Th e only tim e unit commonly used in conjunction with the

SI

prefixes is the second;

e .g

the submultiples millisecond

(nu),

inicrosecond

(cis)

and nanosecond (ns) which are in wide technolog ical use.

2. The symbol a ' s used for year.

3.

Th e scale of International Atomic T ime

(TAI),

based directly on the atomic radiation defining the second, is maintained by .+

U < / M

the Bureau International de l'Heure (BIH) in Paris. Legal time in the U K, as in most countries, is based on

a

related scale, that of J d i . I 5 8 3

Co-ordinated Universal Time (UT C), broadcast by an international network of radio stations. U TC is defined in such a manner

that it differs from TA I by a whole number of seconds. Th e difference UTC -TA I was set equal to

-

IO s

on

1

January

1972,

the

date ofapplication of th e reformulation of UT C (which previously invoived a frequency offset).

Th is difference can be changed in steps of

1

s, but the use of a positive

or

negative leap second at the end of a month of UTC,

preferably in the first instance at the end of December or of June, and in the second instance at the end

of

March or ofSeptember,

to keep U TC in agreement with th e time defined by the rotation of Earth with an ap proximation better than

0.9

s. On 1 January

1981 the difference UT C-T AI was

-

19 s. in fact, the legal times ofm ost countries are offset from U TC by a whole number of

hours (because of time zones and 'daylight saving' arrangements).

I . Linear velocity (speed) (length/t ime)

10.1 Th e coherent SI unit of linear velocity is the metre per second (symbol m/s), a derived unit.

10,2

Multiples and submultiples

of

the metre per second are formed

by

using any of the

SI

prefixes in

conjunction with the metre.

10.3 A metric unit often used for speed is the kilometre per hour (km/h).

1

km/h = 0.277 778 m/s

10.4

Va rious speed units used

in

the imperial system are:

foot

per

second

1

ft/s

= 0.3048

m/s

inch per second

1

in/s

0.0254

m/s

foot per minute

mile per ho ur i

The international knot (kn) is metric-based, being equat to o ne international nau tical mile per hour.

1

kn

= 1852

m/h

= 0.514444

m/s

The

UK

knot is imperial-based and obsolescent, k i n g equal to one

UK nautical

mile per hour.

1

UK knot = 6080 t/h =

0.514

773 m/s

1

ft/min =

0,005 O8

m/s

1 mile/h

=

0.447 04 m/s

10.5 The knot, one nautical mile per hour, is a unit used for speed in nautical and aeronautical contexts.

Por

interconversion factors

for

the above units see fable 10.

*

In October 1980the International Co mmittee

of

Weights and M easures decided

to

interpret the crass

of

supplementary units in

.Jslmettdtv/

the In ternational System as

a

class of dimensionless derived units for which t he G eneral Conference of Weights and Measures

Jir i . IY*3

leaves open th e possibility ofusing these or no t in expfessions ofderived un its of th e International System.

t

The

year

referred t o here

is

the ' d e n d a r

y

Calendar adjustments are based on he ' ropical

year

', the t iT e interval

between two consecutive passages (in the sam e direction) of the Sun hrough the Earth's equatorial plane, In

1900

the duration

of

the

'

ropical year 'was

365.242 198

78 d a nd it is decreasing at the rate of

6.14

x

10-6

days

per

century.

$ Traditionally indicated by

the

abbr eviati on m.p.h.

17

ritish Standards Institute on ERC Specs and Standards

Services

PYRIGHT British Standards Institute on ERC Specs and Standardscensed by Information Handling Services

7/17/2019 BS 00350-1꞉1974


B S I

B S * 3 5 0 : P A R T * &

74 m L b 2 4 b b 9

O l L b i 1 3 b 4

m

S

350

Par t I : 1974

velocity

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B S I L S * 3 5 0 { PAR T 8 3~

~ 74

m

3624669

0336137

=-

~

BS 350 Part

I :

1974

Angular velocity

Frequency

11.

Angular velocity" (angle/time)

11.1

The coherent

SI

unit of angular velocity is the radian per second (rad/s), a derived unit.

11.2 Other units used are:

radian per minute (rad/min)

revolution per minute

revolution per second

degree per minute ( Imin)

degree per second

Is )

(revlmin) o r (r/min)

(revis)

or

(rid

For interconversion factors for the above units see Table 11.

Table 11. Angular velocity and veloci ty of rotation

Exact values ar e prinfed

i i i

bold type

second minute

rev/min

60

9.549 30

_l l

1

0.002 652 58 0.159 155

radian per

second

md/s

- - -

- - - _

1

radian

pcr

sccond

1

radian per

miiiiice

= 0.016

66U 7

=

=

~

1

radis

radlniin

I

57*2958

I

1


= 6.283

i9

376.991

1

rcv/s

rev/niin

1 rcvolution

per

minute = 0.104 720

6.283 19

0.016666

7

I degree per

secoiid

= 0.017 453 3 1.047 20 0 002777 78 0.166

667

Is

2.908

8 8 x 1 0 4 0.017 453 3 4.629 63

XlO-5

2.777

78x10-3

0.016 666

7

=I l

l

I

degree

per minute

"/ni in

12. Frequency

(numberJtime)

degree

per

minute

'/min

3437.75

57.2958

21

600

360

60

1

12.1 The

coherent SI unit

of

frequency (of

a

wave or periodic phenomenon)

is

the hertz (symbol Hz ,

a

derived unit with a special name. Formerly in this cou ntry th e h ertz was called the cycle per second (CIS).

Expressed in terms of base units of the SI both the hertz and th e cycle per second are the inverse second

i.e,

- or s

-1).

12.2 Th e coliereiif

SI

unit of rotational frequency (e.g. a frequency associated with th e mechanical rotation

of a shaft) is also th e inverse second, i.e.

-

or s

-1). It

is commonly known as the revolution per secoiid

(re;/s or

r/s).

12.3

Another very commoiiíy used unit

of

rotational frequency

is

the revolution

per

minute (revlmin or

r/min, b ut traditionally indicated by th e abbrev iation r.p,m.).

1

S

1

S

1

60

iev/min

= -

ev/s

1 1

60s 60

(in SI terms) - r - -1

12.4

Corresponding angular velocities are obtainable from Tab le 11using 1 rev,ís as corre spon ding to

1

Hz,

1

-

or s-1.

S

NOTE. See also the note under secfion

11,

Angular velocity.

*

Thc terms

'

otational velocity',

'

otational speed

'

and

'

peed of rotation ' ar e commonly used as alternative terms for

aiigulat velocity, but are

also

often thought of as a frequency, particularly when being expressed in revolutions per minute,

or

per

second. When frequency is

meant,

the revolution should not

be

identified with an de

as

it is

9 0

identified

in

Table

11

(1

revolution

= 2

IC radians = 360 O), but should be thought of as

a

number, and a clearer

f e r n

for expressing

this

concept

is

'

otational frequency

.

(See also section

12,

Frequency,)

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P A R T * L

74 m Lb24bbî O L b b & 3 8

8

m

BS

350

Part 1 : 1974

Acceleration

M a s s

13. Acceleration

(length/time squared)

13.1 The coherent

SI

unit of acceleration is the metre per second squared (symbol m/s2), a derived unit.

13.2 The centimetre per second squared (cm/s2), a submultiple of the above, is also called the galileo or

gal (symbol Gal).

1 Gal = 1 cm/s2 = 10-2 m/s2

A unit tha t has been comm only used in geodesy is the milligal (mGal).

1 mGal

= 10-3

Gal = 10-5 m/s2

1 ft/s2 = 0.3048 m/s2

13.3 The most-used unit

in

the imperial system for acceleration is the foot per secoiid squared (ftls2).

13.4 The standard acceleration

of

9.806

65

m/s2 plays an important part in the definition of certain

iinif

in the olde r technical systems. When the acceleration of free

fall

has

this

value the terin ' standard gravity '

is used, the associated sym bol for this qua ntity being g .

The acceleration due to gravity is sometimes used as a unit of acceleratioii, an d called ' g , particularly

in

aeronautical engineering and centrifuge technology. For the sake of precision the standard value

9,806

65

m/s2 should be taken

for

this unit,

A

close approx ima tion in imperial units

is

32.1740 ft/s2. These

are frequently rou nded to 9.81 m/s2 and 32.2 ft/s2.

Interconversion factors for the above

units

can be

seen

or inferred

from

Table

13.

Table

13.

Acceleration

Exact

values are

printed

in

bold

type

i metre per second squared

=

m/s2

metre

per

second

squared

m/s2

-

-_-

1

foot per second squared =

0.3048

ft/s2

standard acceleration

due to gravity

=

9.806 65

gn

I

NOTE.

1

Gal =

1

m/s2 = 10-2 m/s2

1

mGal

- 10-5

m/s2 (see 13.2).

foot

per second

squared

ft/s2

3.280 84

.- - . .

-

-

1

32.1740

standard accelera tion due

to

¿?n

gral l i tY

~.

-

. . . . -. -

0.101

972

_______

- .

....

0.031

081 O

1

14. M a s s

14.1

The coherent

SI

unit of mass is the kilogram (symbol kg), a base unit. It is defined as equal to the m ass

of the international pro totype

of

the kilogram (which

is

in the custody

of

the International Bureau

of

Weights

and M easures at Sèvres near Paris).

14.2

Because the nam e

of

the base unit of mass already contain s the SI prefix

'

kilo

',

multiples and sub-

multiples are formed by adding

S I

pr eb es to the word ' ram

'.

Examples are megagram (Mg), gram

(g),

milligram

(mg)

nd microgram (pg), as follows:

Refer

to

note

1 M g = 1000kg -

lo00

g =-kg

1

mg

= 10-6kg

i pg

=

10-9kg I

In practice the megagram is usually referred to by the special name

'

onne

'

(symbol

t), and is often

called the

'

metric ton

'

n the

UK

and

in

the

USA.


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BS 350 Part 1 : 1974

M a s s

14.3 Som e other units

of

mass having associations with the m etric system are:

1 metric car at = 200 milligrams = 2 x 10-4 kg

1

quintal (q) = 1ûOkg

1atomic mass unit (u) = 1.660 53 X 10-27 kg

Refer

to

note

2

-

14.4

The primary unit

of

mass

in

the imperial system and in t he

USA

s

the pound

(Ib).

In

the

UK

Weights

and Measures Act, and in similar legislation

in

the USA, it is defined precisely and exactly

as

f d o w s :

14.5 T he connection between multiples an d submultiples of the pound

is

indicated in t b ollowing traditional

lists

of

named UK and US units of mass,

1

lb

= 0.453

592 37

kg

Avoirdupois units

(a) UK

nd US

nits

1 pound

=

16 ounces

(OZ) (1

OZ

=

28.3495 g)

= 1 6x 16 drams (dr)

(1 dr

=

1.771 85 g)

= 7000 grains (gr)

(1

gr

=

0.064

798 9 1 g)

(b)

UK

nits only

1 stone = 14pounds (= 6.350 29 kg)

1

quarter (qr)

=

28 pounds

(=

12.7006

kg)

1 cen tal (cfl)

=

100pounds (= 45.3592 kg)

1

hundredweight (cwt) =

112

pounds (= 50.8023 kg)

1 ton (ton) = 2240pounds (= 1016.05 kg)

(c) US nits only

1 shor t hundredweight (sh cwt) = 100 pounds (= 45.3592 kg)

1

short ton (sh ton) = 2000pounds (= 907,185 kg)

(In the USA the word ton refers to the ' hort

ton

' of 2000 lb unless oth erwise specified. The terms ' ong

ton ' or ' gross ton ' are sometimes used, referring to the ton of 2240 lb. T he hundredweight of 112 lb is

often called the ' ong hundredweight '. The use of the ' ong

units is decreasing in the

USA.)

Apothecaries' unifs (used in the U K * and the USA)

1 scruple"

=

20 grains (= 1.295 98 gram)

1

drachm* (in

UK)

=

3 scruples

(=

3.887

93

gram)

1

dram (in

USA) = 3

scruples

(=

3.887 93 gram)

1

ounce* = 24 scruples

=

480grains (= 31.1035 gram)

(oz

apoth in

UK

oz

ap in USA)

Troy units (used

in

the UK and the USA)

1

ounce troy = 1 apothecaries' ounce = 480 grains

(= 31.1035 gram)

(oz

tr in UK

oz

t in USA)

(Th e apothecaries' ounce* and the ounce troy ar e identical in mass and differ from the a voirdupois

ounce.

Unless otherwise qualified, the term ounce and ifs abbreviation oz signify the ayoirdupois ounce. The

pound troy

has

110 legal basis in the UK but i s legalized in the USA, where it is defined as a m ass equal to

5760 grains.

1

pound troy (U SA only)

=

12 ounces troy

=

5760 grains

(=

0.373 242 kg)

The grain has the same value in the avoitáupois,

troy, and

apothecaries' systems, and is abbreviated to

gr

in the UK.)

14.6

S o i e more specialized UK and/or USA iianied

units

of mass are:

=

32.667 g

=

29.166 g

I assay toi1

(UK)

1

assay ton (US)

1 slug

=

32.1740 lb (= 14.5939 kg)

1 international corn bushel = 60 lb

(=

27.2155 kg)

Refer to

noíc

3

4

5

6

For interconversion facto rs

for

inany

of

the Unitsof mass mentioned above see Tables

14u,

146 and 14c.

*

The apothecaries' uiiits (scruple, drachm, and apothecaries' oance) have been illegal since

1

January

1971

for

use

in

the

United

Kingdom.

21


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BSI B S * 3 5 0 :

P A RTUL 7 4 L b 2 4 6 6 9 O L L b L 4 0 b

BS

350

Part I

1974

Mass

Notcs

on

section

14

1. Th e alternative name

'

gamma ' symbol y)

is

somctimes

uscd

to indicate a micrograin.

2.

The m etric carat has international sanction for

use n

trade in diamonds, fine

pearls,

and

precious

stones.

Iii

tlie UK tlie

Icgiil

abbreviation for this unit is CM.

3.

The number o f milligrams in

a

UK ssay ton is equal to the number of ounces troy in a UK ton.

4. The number of milligrams in a US assay ton is equal to the number of ounces troy in a US

(short)

ton.

5 . The

slug

is

tlie British technical unit

of

mass. One pound-force acting on this

mass

produces

an

accelcratioii of

I

foot per

second squared.

6.

Used

for

the salc

of

wheat iindcr internatioiial Whent Agrecment,

1949.

Table i 4 a .

M a s s


1

kilogram

kg

I 2.204 62

I

o.o68

521

1 pound

Ib

I l

0.453

592

37

I

08'

O

I

slug =

I

14.5939 32.1740

22


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B S 350

Par t

I : 1974

M a s s

U

W

\o

Q\

W

in

8

oo

2

U

U

9

O

m

G

8

Q\

F

s

I

O

00

d.

ril

G

W

m

8

O

3

Y

e

u

Li

._

2

io

o\

Q\

m

a

O

c?

2

x

n

U

23


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B S 350 Part

I

: 1974

M a s s

e4

v

8

M


7/17/2019 BS 00350-1꞉1974


B S I

B S 3 3 5 0 :

P-ART*i

74 E

1624669 O l L b i 4 3

i

E

_ _ _ _ _ _ _ _ _ _ -

~

__ ~

_ ~ ~ --

BS

350 Part I :

1974

M a s s per unit length

15. Mass

per un it ength (or linear density) (masdlength)

15.1 The coherent SIunit of mass per un it length is the kilogram per metre (sym bol kg/m), a derived unit.

15.2 Two specialized units of linear density used in the textile industry and which have an association

with th e metric system are :

1

tex

=

1

gram

per

kilometre

=

10-6

kg/m

1 denier = 1 gram per 9 ilometres = 0.111 112 x 10-6 kg/m

1 pound pe r inch (lb/in)

1 pound

per

fo ot (lb/€t) (=

1.488

16kg/m)

1 pound per ya rd (lb/yd) (= 0.496

055

kg/m)

1

pound

per

mile (lb/rnile)

1 UKton per loo0 yards (ton/lûûû yd)

1 UK ton per mile Cton/mile) (= 0,631 342kg/m)

15.3 A selection of imperial units used in industry , often fo r Wires, rods etc. is:

(= 17.8580 kg/m)

(= 2.818 49 X

10-4 kg/@

(= 1.11

1 16kg/m)

Interconversion factors for the

units in

15.1 and 15.3 are given in

Table

15.

For further information on

15.2

reference should be m ade to BS 947 which gives tables for calculating the tex values of nu mbe rs or counts

in other systems, including denier.

e

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BSI B S * 3 5 0 : P A R T * L

BS 350

Par t I

:

1974

74 811 Lb24bb ï OLlb144

3

=

M a s s per uni t length

t

I

E:

x

o\

i.1

o

-

8

z

6

m

r

N

w

m

æ

9

E;

r

m

m

m

m

m

2

io

m

io

m

io

m

8

m

m

m

m

03

cc

F

s

8

in

W

8

3

II

2

R

I4

a

fia

g - h

ns

d

1

Li

B

E

B E

n r "

E

O0

3

d

-

II

k

F

a

fi

g $

n f

d

26


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BS 350

Par t

I

: 1974

M a s s per unit area

16. Mass

per

unit area

(mass/length squared)

(applicable for example to sheet metal, plating etc., and in agriculture)

16.1

The coherent

SI

unit is the kilogram per square metre (kg/m2), a derived

unit.

16.2 Other comm only used metric units are:

gram per square metre (g/m2)

milligram per square c entime tre (inglcm2)

milligram per square millimetre (nig/mm*)

kilogram per hectare (kg/ha)

16.3 A selection of imperial units

is:

pound per thousand square feet (lb/lûûO ft2)

ounce per squ are yard (ozlyd2)

ounce per square foot (oz/ft2)

pound per acre (lb/acre)

UK on per square mile (ton/milez)

(=

0.001

kg/m2)

(= 0.01 kg/m2)

(= 1 kg/m2)

(= O.ûûO1 kg/m2)

(= 4.882 43 X 10-3 kg/mz)

(= 3.390 57

x

10-2 kg/m2)

(= 0,305 152 kg/m2)

(= 1.120 85

x 10-4

kg/m2)

(=

3.922

98 x

10 -4

kg/m*)

For interconversion factors for the above see Table 16.

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B S

350 Part I 1974

M a s s per unit

area

O0

o\

M

2

iA

u O0

?

T:

a

4 CI

i

3

r.

O0

9

2

d

2

m

I

O

X

O0

iA

m

O0

c'

CI

e4

E

I

I

5

.

x

-

n

f

5

II

Fi

2 i

28


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-~

S I~-S U 3 5 0 : PART-*& 7 4 l b 2 4 b b ï O L Lb l4 7

9

BS 350 Part

I

: 1974

Area

per

unit mass

17. Specific surface, or area per

unit

mass

(applicable to sheet metal, plating, etc., an d in agriculture)

17.1 The coherent SI unit is the square metre per kilogram (m2/kg), a derived unit.

17.2 Other commonly used metric units are:

square metre per

gram

(m2/g)

(=

loo0 m2/kg)

square centìmetre per milligram (cm2/mg) (=

100

m2/kg)

square d m e t r e per milligram (mm2/rng) (=

1

mz/kg)

hectare per kilogram (ha/kg)

(=IO

o00

m21kg)

thousand square feet per pound (1000 €t2/ib) (=

204.816

rnz/kg)

square yard

per

ounce (yd2/oz) (= 29.4935 mykg)

square foot per ounce (ftyoz) (= 3.277 O6 mz/kg)

acre per pound (acrelib)

square mile per

UK

ton (milezlton)

173

A

selection of imperial units is:

(= 8921.79 mykg)

(= 2549.08 m2/kg)

For interconversion

factors

for the above see Table

17.

30

,-- -.

Previous

page

is blank


7/17/2019 BS 00350-1꞉1974


r r )

I

s

d

X

io

@-I

a

*

I

o,

i

2

X

d

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t-

t-

2

2

Area

per

unit ma s s

O

O

*

I

s

x

ril

ril

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Q\

Cu

Cu

2

io

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d

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8

m

2

G

2

X

N

CO

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?

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O

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II

i

II

31


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-

.

1 square yard per gallon

1 square foot per gallon

--

Y

d2/gal

ft2/gal

I

=

BSI B S * 3 5 0 : P A R T * 3

'i4

= 3 6 2 4 b b 9

0 3 3 6 3 4 9

2

=

0.183 992

1 .

9

0.020

435

8 0*111

1 1

1

B S 350

Part 1 : 1974

Area per un it capacity

Density

18.

Area per uni t capacity

Ano ther com bination with somewhat similar application is ' area per unit capacity (used for the ' covering

power

'

of paints, etc.). Table 18 gives interconversion factors for square metres per litre, square yards

per U K gallon, and square feet per UK gallon.

Table

18.

Area

per

unit capacity

I l

I

-- I

48*9337

1 square metre per litre

m2/l

19.

Density *

(mass/volume)

19.1

The coherent

SI

unit of density

is

the kilogram per cubic metre (kg/m3), a derived unit.

19.2

Other com mon ly used metric units are:

(= loo0

kg/m3)

(=27 679.9

kg/m3)

(= 16.0185

kg/m3)

gram per cubic centimetre (g/cm3)

or

gram per millilitre (g/ml)t

pound per cubic inch (lb/in3)

pound per cubic foot (lb/ftJ)

UK

on per cubic yard (UK ton/yd3)

(=

1328.94

g/mJ)

pound per UK gallon (lb/UKgal) (=

99.7763

kg/m3)

pound per

US

gallon (Ib/USgal)

(= 119.826

g/m3)

}

19.3

A


For

interconversion factors for the above see Table 19.

See

also section

20,

Concentration,

* It should be noted that ' relative density ' i.e. density/reference density) is a dimensionless quality. T he relative density of

a

substance is defined as the ratio of the mass of a given volume of tha t substance to

the

mass of an equal volume of

a

reference

substance, under conditions which should be specified for both substances.

When t he reference substance is water the term ' specific gravity ' s commonly used for relative density. For conversions of

readings of hydrometers on different density and specific gravity bases see BS 718,

i

gram

per

millilitre

(1901)

=

999.972

kg/mJ.

See

4.3,

litre,

32


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BS

350 Part 1 : 1974

Density

N

I

I C :

I

I

I

x

O

o

t-

Y

-

m

X

E

8

rn

N

c?

d

W

li

in

Do

8

2

8

I

I

I I

II

33


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BSI

B S * 3 5 0 :

P A R T * l 74 L b 2 Y b b î

Q L L b L 5 4

0

m-

B S

350

Part 1

:

1974

Concentration

20. Concentration (mass/volume)

20.1

The coherent SI unit for the expression of concentration* (in the sense of the mass

of

a substance

per unit volume

of

a solution, or the like) is the kilogram per cubic metre ( k g / d ) , a derived unit.

This uni t is equaf to 1 gram per cubic decimetre, and is comm onty expressed as 1 gra m pe r litref'.

1

kg/m3

=

1 g/dm3

=

1 g/1

20.2

Some imperial and

US

units which are in practical use for the statement of coiicentratioii

are:

grain per cubic foot (gr/ft3) (= 0.228 835 x 10-2 kg/in3)

grain per U K gallon (gr/UKgal) (= 0.014 253 8 kg/m3)

grain per US gallon (gr/USgal) (= 0.017 118 1 kg/m3)

ounce per WK allon (oz/UKgal) (= 6.23602 kg/mJ)

ounce per

US

gallon (oz/USgal)

(= 7,489 15

kg/m3)

For

interconversion factors for the above see Table 20. See also section

19,

Density.

*

Concentration is sometimes expressed in otherways,

for

example, mass (of a substance) per unit

mass

of a

solution), or,

in

physical chemistry,

in

terms of moles per unit volume,

t

1

gram

per litre

(1901)

=

0.999

972

kg/m3.

See

43,

litre.

.

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B S I

B S * 3 5 0 : PART*KL 7 4

l b 2 4 b b î O l l b l 5 3 4

m

BS

350

Part I : 1974

Specific

volume

21. Specific

volume (volume/mass)

21.1 The coherent SI unit of specific volume (which is the reciprocal

of

density) is.the cubic

metre per

kilogram (mj/kg), a derived unit.

21.2 Anothcr commonly used metric unit is:

litre*

per

kilogram (l/kg) =

0.01

m3/kg.

21.3

A selection o f imperial units is:

cubic foot per pound (ft3/lb)

cubic inch per pound (in3/lb)

cubic foot per UK ton (ft3lUKton)

U K gallon per pound (UK gal/lb)

(=

0,062

428 O

m3/kg)

(=

3.612 73

x

10-5 m3/kg)

(= 2.786 96 x 10-5 mJ/kg)

(= 0.010 022 4 rnJ/kg)

For

interconversion factors for the above

see

Table

21.

* 1 litre

(1901) per kilogram = 1.ûûû 028 x 10-3 mi/kg. See 4.3, titre.

36


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E

a

o

t

o

al

P

cß

I

Ki

n

iI

al

m

Qo

O0

CJ

W

3

ci

BS 350 P a r t 1 :

1974

I

Specific

volume

7/17/2019 BS 00350-1꞉1974


- _

- .

BsI B S * 3 5 0 :

P A R T * L

74 L b 2 4 b b q O J , L ~ J ~ ~ S

B S 350

Part I

:

1974

M a s s rate of f low

Volume

rate

of

f low

22. M a s s rate of f low (masc/time)

22.1

The coherent

SI

unit of mass rate

of

f low is the kilograin

per

second (kgls),

a

derived unit.

22.2 Ano ther com monly used m etric unit is the kilogram per hou r (kg/h).

1 kg/h = 2.777 78 x

10-4

kg/s

22.3

A

selection of imperial units

is:

pound per second (Ib/s)

pound per hour (lb/h)

UK ton per hour (UKton/h)

(=

0.453

592 kg/s)

(= 1.259 98 x 10-4

kg/s)

(= 0.282 235 kg/s)

For interconversion factors for the above see Table 22.

Table 22.

M a s s rate o f

f low


kilogram

per

second

1 kilogram per second =

1

kg/s

k d h

1

kilogram per hour = 2.777 78x 10-4

1

pound per second

= 0.453 592

lb/s

1

pound per hour

= 1.259 98 x

10

-4

Ib/h

1

U K

ton per hour

=

0.282 235

UKton/h

kilogram per

pound

per

hour second

lb/s

--

k d h

3600

2.204 62

1 6.123 95x 10-4

I l

632.93

0.453 592

2.777 78 x 10-4

1016

.O5

0.622 222

I

pound pr UK ton

per

hour

how

lb/h

UKton/h

7936.64 3.543 14

_ I _

2.204 62

9.842

07

x

IO-4

%O0 I

1'607

l4

1

4.464 29 x 10 4

2240

1

I

23. Volume rate

of

f l o w " (volume/time)

23.1

The coherent

SI

unit of volume rate of

f low

is the cubic metre per second.f.

d/s ) ,

a derived unit.

23.2 Some other comm only used m etric units are:

cubic metre per

hour

(m3/h)

litre# per second (@I

litre# per minute (I/min)

litre# per hour (I/h)

cubic foot per se condg (ft3/s)

cubic foot per hour (ft3/h)

UK gallon per second (UKgal/s)

UK gallon per minute (UKgal/min)

UK gallon per hour (UKgal/h)

(= 2.777 78

x

10-4 m3/s)

(= 0.001

m3/s)

(= 1.666 67

x 10-5

m3/s)

(=

2.777 78 x 10-7 m3/s)

(=

0.028 316 8

1n3/s)

(=

7.865 79 x

10-6 m3/s)

(= 4.546 O9

x 10-3

in3/s)

(=: 7.576 82 x 10-5

m3/s)

(= 1,262

80

x 10-6mJ/s)

23.3 A selection of imperial units is:

For interconversion factors for the above see Table

23.

* For gases, the conversion factors given here are based on the

ussiiniption

that the reference conditions of temperature,

pressure and humidity remain unchanged.

$ The litre (1901) = 1.OOO 028 litre (see

4.3).

5

The cubic foot per second is sometimes known

as

the

'

cusec

'.

The cubic metre per second i s sometimes known as the ' cumec ',

38


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BS 350

Part

1

:

1974

Volume

rate o f f l ow

F

-

pi

Q

f

E

9

O

-

X

E

a

3

r-C

O)

.:

n

E

R

X

IC

m

2

n

E

X

u))

u)

m

f

-

f

-

N

h

8

u)

-

n

E

8

8

X

N

7

r

E

X

i

n

E

g

8

8

X

N

2

r

X

N)

N

-

8 f

N

u)

h

N

m

8

w

-

O

n'

-

u)

N

E

6

o

-

IC

E

2

m

_.

m

pi

H

o

-

n

E

X

m)

m

2

-

f

O

m

Y

m

n w

E b

X X

z Fi

t :

m' u)

IC

8

8

c

t

R

1

-

8

I

-

8

c

8

N

m

u

-

pi

t

u)

O

4

m

9

t

-

E

R

m

2

X

-

8

-

c

l b. Y

o

b

X

(1)

8

m

m

n

E

R

R

2

x

r.

0

m

m

9

IIY

O

R

u)

m

O

m

Lo

. -

r-

N

8

l e

6

c

6

m

f

m m

R

X

m

r-

Q

O

u)

m

)

h

I-

O)

-

c.

c

pi

t

3

z

o,

R

n

X

r.

pi

Q

ã

b

B

d

II

X

8

0

c

X

r.

IC

i

R

a

.

o

i

_.

R

L

a

I-

u)

n'

8

d

Yi

u)

K

R

a

-

s

X

l

II

c

p3

k 5

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.


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E S 1 B S * 3 5 0 : P A R T * L

74

1 6 2 4 b b 9

Ollb157 1

BS 350 Part

I

: 1974

Traffic factors

24. Traffic factors

(in connection with volume of fuel consumed, distance run and load carried)

It should be noted that in European countries fuel consumptions are usually expressed in terms of litres

per kilometre,

or

litres per

100

kilometres, i.e. volume of fuel per distance run (see Table

244.

In the UK

the reciprocal factor (distance/volume) in terms

of

miles per gallon

is

used (see Table

24b).

Figure

1

is a

graph indicating the relationship between litres per

100

kilometres and miles per gallon, over the range

10

miles to 100 miles per gallon.

Table

24a.

Fuel consumption

(voIume/distance)

Exact values are printed in

bold

type.

I

ütritrper

kilometre*

UK

gallon per mile

UKgal/mile USgal/mile

U S gallon per mile

1

litre per kilometre*

= I

1

I

0.354 006

I

0.425 144

l/km

1

UK gallon per mile

= 2.824 81

1

1.200 95

UKgal/mile

1

US gallon per mile

= 2.352 15 0.832

674

1

USgal/mile

* Several European countries use the factor

'

itre per

100

kilometres '.

Table

246.

Fuel consumption

(distance/volume)

Exact va lues are printed in bold type.

kilometre per litre

h l i

1 2.824

81

2.352 15

miie per UK gallon

mile/UKgal mile/USgal

mile per U S gallon

1

kilometre per litre

=

km/l

1

mile per UK gallon 0.354 006

mile/UKgal

0.832 674

=

I

mile per

US

gallon

mile/USgal

1.200 95

Mass carried

x

distance

1

tonne kilometre

1

UKton mile

= 1.635 17

tonne kilometre

Mass carried x distance/volume

1

tonne k ilometre per litre

1

UKton mile per

UK

gallon

= 0.359 687

tonne kilometre per litre

= 0.611

558

UK ton mile

= 2.780 20

UKton mile per

UK

gallon

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U

U

C

3

c

p

8

P

B S I BSr35O: P A R T * : L

7 4 1

b 2 Y b b 9

O L L b L C B

3

=

_ _ ~

~~ -

BS 350

Part

I 1974

Traffi c factors

O

*

e

O

Miles per gal lon

Fig.

1 Fuel consumpt ion

41


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BS*3CO: P A R T * l 74

131

1624bb9

Oll6359 5

BS

350 Part

I : 1974

Moment

of

inertia

Momentum

Angular momentum

25.

Moment of inertia (mass x

length

squared)

25.1 The coherent SI unit of moment

of

inertia is the kilogram metre squared (kg m2),

a

derived unit.

25.2

Som e other metric units which have been used are:

kilogram miliimetre squared (kg mm2)

gram centimetre squared (g cm2)

25.3

A


pound foot squared (íb ft2)

pound inch squared (Ib in2)

ounce (avoir) inch squared (oz in2)

(1

kg mm2

=

10-6

kg

m2)

(1 g cm2

=

10-7 kg m2)

(= 0.042 140 1 kg m2)

(=

2.926 40 x IO 4 kg m2)

(= 1.829 O0 x 10-5 kg m2ì

For interconversion factors for the

above

see Table 25.

Table 25. Moment of inertia


kilogram

metre

pound

foot

pound

inch

ounce

inch

kg m2

squared squared squared

lb ft2

Ib in2

oz

in2

s q d

1

kilogram metre squared =

1

23,7304 3417.17 54

674.8

kg m2

1 pound foot squared = 0.042 140 1

1

144 2304

lb ft2

-

1 pound inch squared = 2.926

40x

10-4 6.944 44 x 10

- 3 1

16

íb in2

--

1

1

ounce

nch squared

-

1.829

O0

x

10

-5

4.340

28

x

IO

4

0.0625

oz in2

NOTE.

1

kg m2

=

106 kg mm2 = 107 g cm2,

26. Momentum (linear) (mass

x

velocity)

The

coherent SI unit of mom entum is the kilogram m etre per second.

Some key conversion factors are:

1 kg m/s = 7.233 O 1 lb ft/s

1 Ib ft/s = 0.138 255 kg m/s

(1

kg m/s =

105

g cm/s)

27.

Angular momentum (mass

x

velocity

x

length)

The coherent SI unit of angular momentum is the kilogram metre squared

per

second.

Some key conversion factors are :

1

kg

1 Ib ftz/s = 0.042 140 1kg m2/s

;= 23.7304 Ib ftz/S

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B S

350 Part

1

:

1974

Force

28.

Force

(mass

x acceleration)

28.1 The coherent SI unit of force is the newton

(N), a

derived unit with a special name. Expressed in terms

of base uiiits of the

SI

the newton is the kilogram metre per second squared (kgm/s2) and is that force

wliicli, when applied to a body having a mass of one kilogram, gives it an acceleration of one metre per

second squared.

28.2 Other m etric units of force of historical or practical importance are :

the dyne (dyn), the force u nit in th e centimetre-gram-second system,

the sthène (sn), the force unit in the m etre-tonne-second system, an d

the kilogram-force (kgf), which is often described

as

the metric technical unit

of

force. I n G ermany and

some other co ntinental countries the kilogram-force is called the kilopo iid (with symbol kp).

1 dyn =

1

g cm/s2

1 sn

=

1 t m/s2

(=

103 N)

(=

10-5 N)

l h e kilogram-force (or kilopond) is that force which, when applied to a body having a mass of one

kilogram, gives it th e standard acceleration* due to gravity (Le. 9.806 65 m/s?).

Thus,

28.3

In the foot-pou nd-second system the cohe rent force unit

is

the poundal (pdi).

1 kgf (or kp)

==9.806

65 kg iii/s2

(=

9.806

65 N)

1

pdl

= 1

lb ft/s2

-- 0.453 592 37

x

0.3048 kg ni/s2

(=

0.138 255 N) (approximately)

The

corresponding technical force unit in general use in the UK and USA

is

the pound -force (lbf). It is

that force which, when applied to a body having a mass of one pound, gives it the standa rd acceleration*

due to gravity.

Thus,

9.806 65

0.3048

lb ft/s2Ibf

=

= 32.1740 pdl (approximately)

(=

4.44822 N)t

Furfher technical force units associated with the pound-force a re th e ounce-force (ozf), the

U

K ton-force

1

ozf

= ~ I b f (= 0.278014N)

1

tonf

= 2240 lbf

(= 9964.02N)

1

US on-force

=

2000 lbf

(= 8896.44

N)

1 kip (USA only) = loo0 bf

(=

4448.22N)

(tonf) sind the

US

ton-force. in the

USA

a

unit

of

loo0

bf named the

‘

kip

’

s

often used.

1

28.4 The kilogram-force (kgf), and the pound-force (Ibf) and its associated units, are both exactly defined

in

terms of t he standard acceleration du e to gravity. Because local acceleration due to gravity usually differs

slightly from standa rd acceleration, it foliows that the forces exerted by gravity on bodies having a mass of

1

kg

o r 1 Ib are rarely exactly equal to 1 kgf o r 1 lbf respectively, and a ccount has t o

be

taken

of

this when

very high precision is required. See

also

section 29,Weight.

Interconyersion

factors

for the above units are

given,

or can be readily

inferred,

from Table 28.

*

See 13.4.

I-

In

exact

ternis,

0.453

592 37

>:

9.806

65

N.

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B S a 3 5 0 :

P A R T * l

74 m 1ib24bb9

O l L b l b L 3 m

BS

350

Par t 1 :

1974

Force

C

f

Pz

-

N

m

v,

w

B

n

2

I

8

g k

o c

l-4


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29. Weight

29.1 Meaning

of '

weight

'.

The term 'weight

'

s commonly used either to denote mass

or

force, i.e. the

mass of a b ody o r the force of gravity acting upon it. It is used in the sense of mass in the

UK

Weights

and Measures Act,

1963

and in comm on parlance; it

is

used in the sense

of

force by

CGPM

and in scientific

and some technical work.

As

weight values may

be

found quoted in either mass o r force units bot h usages are accom mod ated n these

conversion tables, To onvert weight units when using weight in the mass sense use Tables 14a, 146 or 14c:

to convert weight units when using weight as

a

force use Table

28.

29.2 Relatioitship

between force of gravity

and mass.

Th e force

of

gravity (for exam ple, expressed in newtons)

is equal

to

the mass (in kilograms) multiplied by the local gravitational acceleration (in metres per second

squared).

For

most practical purposes variations in local gravitational acceleration

can

be ignored and the

standard value of

9.806 65

m/s2 is assumed (usually rounded to

9.81

m/s2).

It

is the standard value

of 9.806

65

m/s2 that

is

used in defining with precision

the

technical

force

units,

the ki1ogram:force an d the pound-force.

29.3

Accurate weight conversions, Conversions from one system of units to another on a mass to mass

basis, o r on a force to force basis, can be m ade with go od accuracy by using the tables for sections

14

and 28

respectively, However, to obtain the accurate relationship

of

a mass to its associated gravitational force

account has to

be

taken

of

the exact local value of the earth's gravitational field. The downward force on

the mass

is

also affected

by

the bupyancy

of

any displaced atmosphere,

45


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B S s 3 5 0 : P A R T x L

74

W L b Z 4 b b 9

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7 W

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350 Part

I

: 1974

Moment of force (torque)

30. Moment

of force, or

torque

(force i:

ength)

30.1 The coherent

SI

unit of moment (of force) is the iiewtoii metre (N m), u derived uiiit. See the note

below concerning the energy unit, which has a different physical significance.

303 A metric unit often used for moment, or torque,

in

continental countries

i s

the kilogram-force metre

(kgf m).

1

k g f m

=

9.806

65

N

m

This unit is called the kilopond m etre (kp m) in Germany.

poundal foo t (pdl ft) (= 0.042 140 1 N

m)

pound-force foot (Ibf ft) (= 1.355 82N m)

pound-force inch (Ibf in)

(=

0.112

985

N

m)

UKton-force foo t (tonf ft)

ounce-force inch

(ozf

n)

30.3 A selection of imperial units is:

(=

3037.03 N m)

(=

7.061

55 x

10-3 N

ni)

NOTE. The product newton

x

metre (N

m)

lso expresses the SI unit for work done, or energy, a tinit having lhe special

name joule

(J), (see

section

36,

Energy). How ever, torque arid energy

are

diíïerent physical quantities; b oth a re dimensionally

force x

length but

in

the former the directions of the force and length components are perpcndiciilar to each other while

iii

the latter they a re in line with each other.

With imperial units

a

distinction between torque units and energy units is made (by convention) by reversing the order

of

the units; e.g. the fo ot pound-force (ft Ibf) is an energy unit and t he pound-force

fooi

(Ibf ft)

a

torque unit. There is

no

similar

convention used

or

advisable with metric (including

SI)

units; it can

be seen

for

exainple that

rn-N

(the reverse of

N

m) would

easily

be

mistaken for mihe wto n.

Metric moment or torque units should be expressed

89

indicated in 30.1 and 30.2 above.

It may be useful to point out that because both torque and energy are dimensionally the same (force

x

length) there

is

a

numerical correspondence b etween energy conversion tables and torque conv ersion tables.

P

46


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BS 350

Part

1 : 1974

Moment

of force

( torque)

rl

Q

8

/o

-

I+)

I

EI

%

8

X

Y

io

O

ril

8

8

ri

O

Pl

m

I

EI

o,

Y

X

t-

OI

W.

m

1

m

47


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B S * 3 5 0 :

P A R T * L

74

m

3 6 2 4 b b î O L L b L b 5 O m

BS 350 Part I : 1974

Force per unit length

Pressure

31. Force per

unit length * ( fo rcdength)

31.1

The coh erent SI unit is the newton per metre (N/m).

31.2

Another metric unit that may still be encountered is the dyne per centimetre (dyn/cm).

i

dyn/cm

= 10-3 N/m

No interconversion tables are provided for force per unit length, The main reason for mentioning it here

is to show the distinction from torque.

32.

Pressure

(force/area)

32.1

The coherent

SI

unit of pressure is the newton per square metre, N/in2,

for

which the special name

pascal (symbol Pa) was approved by the CGPM in 1971.

One pascal represents a very small pressure, and its multipies kilopascal (kPa) (or kN/m2) a nd megapascal

(MPa)

(or

MN /m2) a re therefore frequently used.

322

Arising from the historical evolution

of

the

SI

from the CGS system, some pressure units have a decimal

relationship with the pascal. T hese are the dyne per square centimetre (dynlcm2) (sometimes called the

barye), the pièze (pz), and the bar (bar)?. Only th e last of these, with its multiples, persists in comm on use.

The dyne per square centimetre is also a very small pressure:

i x

1 0 - 5 ~

(m/1W2

= 0.1

N/m2

= 0.1

Pa.dyn/cm2

=

The pièze is the coherent pressure unit in the rnetre-tonne-second system, being equal to one sthène per

1 pz

= 1

sn/m2

=

1

x

103 N/m2

= 1

kN/m2

= 1

kPa.

Th e bar, 106 dyn/cmZ, is legally recognized in EE C countries and has a m agnitude not far removed from

1

bar

=

106 dyn/cm2

=

106

x

0.1

N/m2 =

o5 N/m2

=

105 Pa .

One of its submultiples, the millibar,

is

widely used in the expression of barometric pressures.

square metre

:

that of u sual atm ospheric pressure at sea level.

32.3

Also

in com mon use on the Co ntinent are the technical pressure units, the kilogram-force per square

metre, and, in particular, the kilogram-force per square centimetre

:

1 kgf/m2

=

9.806 6 5 N/m 2 (exactly)

1 kgf/cm2 = 0.980 665 x 105 N/m 2 (exactly) = 0.098 066 5 MPa

In Germany a nd some other C ontinental countries the kilopond (kp) is used in place

of

the kilogram-force

These technical units have a simple relationship with conventional columns of water expressed in metric

=

9.806 65 Pa

(kgf), e.g. 1 kp/cm2 = 1 kgf/cmz.

terms (see

32.5).

32.4

Some imperial units in use, and that are expressed directly in terms of force per unit are a, are:

poundal per square

foot

(pdl/ft2), the coheren t unit in the foot-pound -second system

pound -force per squ are inch (lbf/in2)

pound-force per square foo t (lbf/ftz)

UKton-force per square foot (tonf/ft2)

UKtoii-force per square inch (tonf/in2)

technical units

approx,

.453 592

37 x

(0.3048)

N

(0.3048

m)2

0.453 592 37 x 9,806 65

N

(0.3048

m)2

1

pdl/ft2 =

=

1.488 16 Pa (or N/m2)

-

lbf/ft2

=

47,8803 Pa (or N/m2)

approx.

* For example, surface tension.

t The internationallyrecognized unit symbol for th e bar is the same as the unit name. In meteorology, however, the commonly

used

symbol

for

the m illibar

is

simply mb.

48


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1 Ibf/inz = 144 bf/ft2

= 6894.76

Pa (or N/m2) approx.

1 UKtonf/ftz

=

2240 bf/ft2

==

1.072

52

x

105

Pa (or N/m2) approx.

1

UKtonf/in2 =

2240

bf/in2 =

1.54443 x

lo7 Pa (orN/m 2) approx.

The pound-force per square inch (lbf/in2) is often known and shown by the abbreviation p.s.i., but,

alth oug h widely used in the UK and

USA,

this abb reviation is inconsistent with the internationally recognized

symbology for units. In the

USA,

the expression

'

ksi.' is often used to signify kips

per

square inch (Le.

loo0 lbf/in2).

32.5 Liquid columns. Pressu res are often measu red in term s of the height of co lumn of liqu id, e.g. ofmercury

or of w ater. The pressure associated with a given height is depend ent upon th e density of th e liquid and the

local acceleration due t o gravity. The following pressure units, based upon conventional density and gravity

conditions, are internationally recognized:

the conven tional miliimetre of mercury (symbol mmHg)

;

the

conventional inch of mercury (symbol inHg);

the conventional millimetre of water (symbol mm H2 0);

the con ventional inch of wa ter (symbol inH2O).

The m etre of water (mH2O) an d foot of water (ftH 20) ar e also used.

1 mmHaO = 0.001 m

x

lo00 kglm3 x

9.806 65

m/s2 =

9.80665

N/m2 = 9.806 65 Pa

(This is the pressure due to an ideal column of water of length

1

mm and of uniform density

1

g/cmJ,

1 mmHg

=_

13.5951 m m H 2 0

=

13.5951 x 9.806 65 Pa

=

133.322Pa (approx.)* '

i i n H 2 0

= 25.4

m m H 2 0 =

9.806 65 x 25.4

Pa

= 249.089Pa (approx.)

1 inHg

=

25.4 mmHg

= 9.806

65

x 13.5951

x

25.4

Pa

=

3386.39

Pa (approx,)

I ftH2O = =

304.8

mmH2O

= 304.8

x 9.806 65 Pa

= 2989.07 Pa (approx.)

Another pressure unit in comm on use known as the torr is equal, within one part in

7

million, to the

conventional rniliinietre of mercury (mmHg). It is, however, precisely defined in terms of the pascal as

follows

:

when under the standard condition

g,

= 9.806 65 m/s2)

101

325.0

760

Patorr

=

-- 133.322Pa (approx.)

Because of its size, the pascal is well-suited to vacuum technology. However, in addition to the millibar

and tor r and the ir submultiples, the term ' micron

'

meaning mic rome tre of mercury (pmHg), is still common

in this field. The symbol pmH g

is

sometimes (incorrectly) contracted t o p.

Following from its definition, the conventional millimetre of water is exactly equal to the kilogram-force

per square metre:

1 mmH2O

=

1 kgf/m2 ( or kp/m2)

Similarly,

10

m H 2 0

= 1

kgf/cm2 (or kp/cm2).

32.6 Atmospheres. Attention is called to the significance of th e following terms an d symbols:

Standard atmosphere

(atm). This is an internationally esfablished reference fo r pressure of

101

325 Pa,

being equal to

760

mmH g within one part in

7

million. It should not be regarded o r used as a u nit, but it

is

of great im portan ce and in widespread use as a reference.

The technical

atmosphere

(at). This unit, which is used on the Continent, is equal to the kilogram-force

per square centimetre, or kilopond per square centimetre:

1 a t = 1 kgf/cm2 (or kp/cm2) =

98

066.5 Pa

32.7

'

Absolute ' and

'

auge '.

All the pressure units men tioned in

32.1

to

32.6

may be used to state the

mag nitude of a n absolute pressure or of a pressure difference, an d misunderstandings in interpretation an d

conversion may a rise if th e quantity concerned is not clearly expressed.

It

has been internationally recommended t ha t pressure units themselves should not be modified to indicate

whether the pressure value is

'

bsolute ' i.e. with zero pressure as the d atum ) or ' gauge

'

i.e. with atm os-

pheric pressure as the datum).

*

For

detailed

information

on

barometer conventions

see

BS

2520.

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~

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BS*350:

P A RT*L

74 Lb24bbq OLLb1 ib7

4

B S 350 Part 1 :

1974

Pressure

Both in the U K and USA it was commoii practice to use the abbreviation p.s.i. to indicate Ibf/in2, and

Lo

differentiate between gauge and absolute pressures by adding the further letters

'

g ' and ' ' o make

'

p.s,i.g.' and

'

p.s.i.a.' respectively. A similar situation existed in German practice, where the symbol for

the technical atmosphere (at) was modified to atü or a ta to indicate the expression of ' gauge ' (über) or

'

absolute

'

pressure respectively*. Of these, only ' t

'

was an internationally recognized unit symbol;

furthermore the modiñcations did not change the units of measurement, but were in fact an indication

of

the qu antity being expressed.

From the recommendation in the second paragraph it follows that, if the context leaves any doubt as

to which quantity is meant, the word

'

pressure' should

be

qualified appropriately:

e.g. ' at a gauge pressure of 12.5 bar '

or '

t a gauge pressure of 1.25 MPa

'

or

'

at an absolute pressure

of 2.34

bar '

or ' at a n absolute pressure of 234 kPa '.

Absolute pressures are always positive, but gauge pressures are shown as negative when indicating a

It is

comm on practice in the power and process industries to refer

to '

vacuum

'

alues,

e.g. ' mmHg vacuum ' represents a gauge pressure of -1 mmHg, and

pressure less than the d atum pressure.

' one per cent

of

vacuum ' epresents a gauge pressure of minus one p er cent of the datum atmosphere

in use.

*

With the atü, the

datum is an absolute pressure

of

1 at.

Interconversion factor s for the above

units

are given, or can be deduced from, Tables 320, 32b and

32c.

See

also section 33, Stress.

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BS

350

Part I :

1974

Pressure

W

I

X

5:

3

8

c?

ut

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Stress

Viscosity (dynamic)

33. Stress

( f o r d a r e a )

Though it is a differ ent physical quantity, stress is iiaturally trea ted

with

pressure, since

it is also

force

divided by area. Many, but not ali, of the iiiiits mentioned in connection

with

pressure are used

for

stress,

so the conversion factors in Tables 320,

326

and

32c

will be found useful.

The cohe rent SI unit of stress is again the pascal (Pa), Le. the newton p er square metre (N /rna).

Technical units that have been widely used for stresses in metals and some other m aterials are the kilog ram-

force per square millimetre (kgf/mm2), pound-force per square inch (Ibf/in2) and

U

Kton-force per square

inch (UKtonf/in2)*. In the change to SI, a practical unit

of

similar size to the kgf/mm? was sought, the

first proposa l being the he ctobar (hbar), which

came

nto some use. How ever, the hbar is being abandoned

in favour of the N/mm2, which can be otherwise stated as MN/m2

or

MPa:

1 N/mmz = 1 MN/m? = 1 MPa

1 kgf/mm2

=

9.80665 N/mm2

=

9.80665 MPa

1 hbar = 100 bar

=

102

x

105 N/ni?

-= 10 NIPa

NOTE. ntercoii\ersion factors for these and other units used

for strcsscs are

givcn

o r ciiii be

dcditccd

ïroiii Tables 31u, 3 3

and

32c.

See also section

32,

Pressure.

34.

Vipcosity,

dynamic (stress/velocity gradient)

34.1

The coherent

SI

unit

of

dynamic viscosity

is

the pascal second (Pa

s) ,

which iilay

also

be expressed

a s

the newton second per square metre

(N

s/m2),

or

as

the kilogram

per

metre second

(kg/(rn

s)).

This unit has also been called the poiseuille (Pi) iii France. (It should be noted that this is iiot the same

as

the poise

(P),

described in

34.2).

34.2

The poise

(P)

is the8orrespondiiig CGS unit.

1 P = 1

dyn s/cm2

=

10-1 N

s/m2 = 10-1 Pa s.

The commonIy used submultiple is the centipoise (cP).

1

CP = 10-2 P

=

10-3 Pa

s.

34.3

Other metric and imperial units that have been used for dynamic viscosity are:

kilogram-force second per square metre

poundal second per square foot

pound-force second per square foot

pound force hour per square foot

pound-force second per square inch?

pound per foot hour

(kgf slni?)

=

pound per foot second, Ib/(ft

s>

(pdl s/ftz)

=

slug per foot second, slug/(ft

s)

(lbf s/ft2)

= slug hour per foot second squared, slug

ii/(ft sz)

(lbf h/ft2)

(lbf s/in2)

(lb/ft li)

1 kgf

s/m2 = 9.806

65 Pa

s

1

pdl s/ft2

= 1.488 16

Pa

s

1

Ibf s/ft2

= 47.8803

Pa

s

i

Ibf h/ft2

=

1.723

69

x

iOS Pa

s

TI

lbf s/in2

=

6894.76Pa s

1

Ib/ft h =

4.133 79

x

10-4

g/(m

s)

=

4.133

79

x

10-4 Pa

s

NOTE.

For reference to frequently used

but

empirical uiiits

of

viscc>s¡ty, such

i l s

the Redwood sccoiid. sw scctioii

33,

Viscosity, kinematic.

Interconversion factors for most of these units are given

in

Table 34.

*

Ii i

tlie

U S A ,

tlie expressioii ' k.s.i.' is ofteii

uscd

to S¡gii¡fY kips pet square inch (¡.c.

1000 Ibf/iii:ì.

t

Sonietinies called the

'

reyn

'.

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Viscosity (kinematic)

35.

Viscosi ty , kinematic (length squared/time)

35.1

The coherent

SI

unit of kinematic viscosity (which is dy nam ic viscosity divided by density) is the

metre squared per second (m2/s).

35.2

The corresponding

CGS

nit is the stokes (St).

1

St

= 1

cm2/s

=

10-4 m2/s

Th e com mo n subm ultiple is the centistokes (cSt).

1

cSt

= 10-2 St = 10-6

m2/s

(=

1 rnmys)

35.3

Ano ther m etric unit sometimes used is the me tre squared per ho ur (m2/h).

1 m2/h

= 2.777 78 x

10-4 m2/s

35.4

A selection of imperial units is:

inch squared

per

second in2/s

foot squared per second ft2/s

inch squared

per

hour in2/h

foot squared per hou r ft2/h

1 in2/s

= 6.4516 x

10-4 m2/s

1

ft2/s

= 9.29030

X

10-2

d / s

1

in2/h =

1.792

11

x

10-7 m2/s

1 ftZ/h

=

2.580 64

x

10-5 m2/s

35.5

The units referred

to

in

35.1 to 35.4

are absolute units with physical dimensions, as distinct from

values on frequently used but empirical scales such as Redwood

No.

1,

Saybolt Universal, and

Engler

degrees. For tables from which viscosity values in these empirical scales may

be

converted to centistokes

see ESDU* Item

No.

68036, sponsored by the Institution

of

Mechanical Engineers.

Interconversion factors for the

uni ts

in

35.1

to

35.4

ar e given in

Table

35.

No te th at this table may be used

for

the conversion of values of therm al diffusivity,which also has the dimensions of length squared/tim e.

* ESDU Item No. 68036

'

Introductory m,emorandum on the viscosity

of

liquids and the classification

of

lubricating oils

'

obtainable from :

Engineering Sciences Data Unit,

251-259

Regent Street, London

W1R

7AD.

56

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Energy

36. Energy (work, heat, etc.)

36.1

The coherent

SI

unit for the expression of all.for./risof energy is the joule (symbol J).

in different ways, e.g.:

Just a s energy arises in many ways, the connection between the joule and other

SI

unils may

be

iiidicated

I

J = 1

N m (force x distance, newton metre)

=

I

W

s

(electrical energy, wa tt second)

= 1

Pa m 3 (pressure x volume, pascal cubic metre)

(This unit was, prior to the

Si,

known a s the absolute joule, but

i t

is

now

simply the joule

(J).

The

'

nternational

'

oule, which became obsolete in

1948,

was approximately equal to

1OOO 19

J.)

36.2

Arising from the historical development of the

SI

from the

CGS

system, the unit of energy

in

the

CGS system (the erg) is decimally related to the joule.

1

erg

=

1

dyn cm

= 1 x lO-sN x 0.01 m

= 10-7 N

m

= 10-7 J

36.3

A

unit

in

extensive use for the expression of electrical energy is the kilowatt hour (kW

li).

I

kW

h = 1

x

IO00 x W

x 36009

=

3.6

X

106

W = 3.6 MJ

36.4 Two

other metric units used for the expression of energy are the kilogram-force

iiietrc*

( k f g

ni)

and

the litre atmosphere.

1

kgf m

=

9.806 65

N m = 9.806 65

J

1

litre atm osphere

=

1 dm3 x

101 325

Pa

7 - 101.325

Pa

in3

= 101.325

J

(The litre used he re is equal to

i

decimefre cubed (see

4.3),

and the atmosphere used

is

the standard atinos-

phere (see

32.Q.)

36.5 Some corresponding imperial units used for the statement of energy are the foot poundal (ft pdl), the

foot pound-force (ft Ibf) and the horsepower hour (lip

li).

1 ft pdl = I x

0.3048

m

x 0.453

592

37

x

0.3048

N see 31.3)

=

0.042 140 1 J (approx.)

I

ft

Ibf L- 1 x

0.3048

m x

0.453 592 37

:

9.806 65

N see 31.3)

= 1.355 82 J

(approx.)

1

lip h

=

550

ft lbf/s

x

3600

s

(see

37.3)

= 2.68452 x 106 J

(approx.)

= 1.98 x 106

ft lbf

36.6

Heat units.

Heat is one of the forms of energy and, a s stated abovc, tlic Si unit for all forms is the

joule. The following heat units originally arose from the concept of the heat required to warm unit mass of

water throu gh u nit tem perature, but so me of these are now precisely defined

in

terms of the joule:

the various calories (originally relating t o the gram

of

water

aiid

the deg ree Celsius);

the various British

thermal units

(originally relatiiig to the pou nd of water and degree Fahrenheit)

;

and

the various

Centigrade

heat units (based on the po und of water and the degree Celsius).

Th e specific heat capacity of water changes with temp erature and a num ber of different calories, British

thermal units, and Centigrade heat units came into use according to their

memis

of definiiioii.

Three of tlie calories are still in some practical use and

in

precise work need to be separately identified.

These are the In terna tiona l Table calorie (cailT), the therm ochemical calorie (cal,,,)

and

tlie

15

C

calorie

(cal

5)

described below

:

I

calIT

= 4.1868 J

(as

defined at the F ifth International C onference

on

Properties

of

Steain, London

1956).

I cal,,, = 4.1840 J (a '

defined

'

calorie).

I

cal

15 = 4.1855

(approx.) (This is defined

as

the amount of heat required to

\varni

I g of air-freewa ter

îrom

14.5

"C to 15.5 C at a constant pressure of

1

atm. The joule equivalent shown above wíis

adopted by the

CIPM i n 1950

as being the most accurate value which could then be deduced

from experinien

.)

Associated with the cal15 are the thermie (tli), also sometinies describcd as

the '

tonne-calorie

'

and the

1

thermie

= 106

cal15

= 4.1855 MJ

(approx.)

1

frigorie

= - O 3

call5

= -4.1855 kJ

(approx.)

frigorie, used in connection with tlie extraction of heat.

*

Known as the kilopond metre (kp m) n Germany.

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e

BS 350 Part i

1974

Energy

The

'

calorie

'

commonly referred to

in

nutritional science is

in

fact

a

kilocalorie, which

is

sometimes

called a

'

kilogramcaloric

'

or

'

arge caloric

'.

n this standard, if the symbol

cal

is used with out qualification,

i t

refers

to

the International Table calorie

(callT).

The dietitians calorie is based

on

the

call5.)

The most important British thermal unit (Btu), aiid the one used throughout this standard,

is

the

one

corresponding to the International Table calorie and is defined

by

the equation:

I

Btu/lb

=

2.326

J/g

thus

1

Btu

=

2.326

x

453.592 37

J

=

1055.06

I

approx.)

Among other British thermal units formerly in

use

but now obsolescent are:

the

'60 F

British thermal unit

'

(heat required to warm

1

lb of w ater from

60

F

to

61

O F ) .

1 BtU60/61 = 1054.5

J (apprOX.)

the

'

mean British thermal unit

' ( i / i 8 0 of tlie

heat required to warm i Ib of liquid water from

32 F

I

Btu,,,"

-= 1055.8 3

(approx.)

The British thermal unit used for

most

purposes by the British Gas industry relates to the 15 C aloric

to 212 O F ) .

and

is

equal to:

-

1054.73

(approx.)

.1855

4.1868

.326 X 453.592 37 J x

Associated with the Btu is the therm, used as an energy

unit

by the G as Industry.

1 therm = 100

o00

Blu = 105.5

M J

(approx.)

The ' Centigrade heat unit (C.H.U.), based on the Ib

of

water and tlie

OC,

s still sometinies used.

I C.H.U.

1.8

Btu (but

to

each British thermal unit there corresponds

a

Centigrade heat

m i t )

1

C.H.U.,,,,, = 1.8

Btu,,,ciin=-1900.4

J

(approx.)

For

interconversion

factors for most of

the above units see

Tables36a

and

36U.

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BS 350

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Power

37. Power

(energy/time)

37.1

The coherent SI unit for all forms of power, including heat flow rate, is the watt (symbol

W),

which

is

equal to the joule per second.

1 W = I

J/s

The kilowatt

(kW)s

a commonly-used m ultiple of th e watt.

37.2

Tw o metric technical units of power are the kilogram-force metre per second (kgf

m/s)

and the metric

horsepower*.

A P a m n d e à

1 kgf m/s = 9.806

65 31s = 9.806 65 w

1 metric horsepower =

75

kgf m/s =

735.499

W

uly 198.3

37.3

Similar technical units

in

the imperial system are the

foot

pound-force

per

second

(ft Ibf/s)

and the

horsepow er (hp).

1 ft lbf/s

= 1.355 82 J/s

(see 36.5)

= 1.355

82

W

1 hp =

550

ft lbf/S =

745.700

W

37.4

The

following

is a selection of heat flow units shown in terms of the watt:

calorie

per

second

1 cal/s = 4.1868

W

British thermal unit per hour

'

on of refrigeration

'

=

12

o00

Btu/h

=

3.516

85

kW

kilrocalorie per

hour 1 kcal/h

= 1.163 W

}see

36.6

1

Btu/h = 0.293

071 W

For interconversion factors for most

of

the above units see Table 37.

The metric

horsepower

goes

under

the

name

'

cheval

vapeur

*

in

Francs

and

sometimes

the

Symbols

ch

or

CV

arc

used.

In

Germany

t

is called

the

'

ïerdeatgrke*

(symbol

PS).

62

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63


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BS

350 Part I : 1974

Temperatu e

38.

Temperature, including temperature dif ference or interval

38.1 The SI unit of temperature

is

the kelvin

(K).

It is one of the base units of the SI aiid is defined as a

specified fraction (&-J of the thermo dynam ic tempe rature of the trip le po int* of water. The kelvin is

used fo r the expression of thermody namic temperature, for which the datum is absolute zero:

i t

can also be

used for the expression of any temperature difference or temperature interval.

38.2

The temperature unit in most practical use in metric countries, and recognized for use in conjunction

with the

SI,

s the degree Celsius ( O C , The now incorrect terni

‘

Centigrade ’ is still in widespread use for

Celsius. The zero datum for Celsius temperature (O ‘C) is now exactly defined by the thermodynamic

temperature 273.15 K ; formerly it was defined by the melting point of ice at 1 atm, The units o f temperature

1983

difference, one degree Celsius and one kelvin, are exactly equal, by definition. In this sense

and any temperature difference therefore has the same numerical value when expressed

i n

OC as it has

when expressed in K.

For formulae showing the interrelationships between Celsius temperatures and thermodynamic tempera-

tures expressed in kelvins, and some other temperatures mentioned below, see Table 38.

38.3 Traditional in practical use in the UK and USA s Fahrenheit temperature, now being rapidly displaced

by Celsius. The Fahrenheit scale is not formally defined, but i t is generally recognized that:

i ° C =

1 K

32 O F s the ice point

212 O F is the boiling point of water a t 1 atm

and that the un it of temperature difference one degree Fahrenheit I O F ) is equal to five ninths of the unit

of

temperature difference the degree Celsius (1 OC). In this sense

1 ° F = (:OC) = (:IC)

Fo r form ulae giving the interrelationship between Fahrenheit, C elsius, and other temperatures see Table 38.

38.4 For thermodynamic temperatures, the degree Rankine (OR) is still occasionally used. The un it

interval of the degree Rankine is equal to

1

O F , a thermody namic temperature of

O O R

being absolute zero.

See Table

38.

38.5 In the last edition of this standard, for temperature interval the letters ‘ deg ’ were recommended,

instead of the degree sign

( O )

which was reserved for temperature. In 1967-68, the 13th CG PM considered

the arguments for and against this practice and decided to recommend that the use

of

‘

deg

’

should be

discontinued.

38.6 For the purpose of practical measurements the CIPM adopted i n 1968 the ‘ nternational Practical

Temperature Scale of 1968

’,

IPTS - 68, based o n reproducible fixed points an d interpolation instruments

and procedures. The IPTS - 68 has been designed so that the International Practical Kelvin and Celsius

temperatures closely approximate the Kelvin and Celsius temperatures described in 38.1 and 38.2. The

IPTS - 68 is defined only from a thermodyna mic temperature of 13.81 K upwards.

*

The temperature at the triple point of water, (where water, ice, and water vnpour are in equilibrium) is very

slightly

removed

from the temperature of the melting point of ice at atmospheric pressure (the ice point).

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Temperature

Specific energy

Table

38.

Equivalent values on fo ur temperature scales

For the

bdme

temperature,

if [T]

K ,

[0] OC,

[t] O F and [r] O R represent that temperature o n the Kelvin,

Celsius, Fahrenheit and Rank ine scales respectively, then the formu lae relating the pure num bers [TI

O],

[t] and [r] are as shown below.

(kelvins)

UI>lL~l l l l l

i

5 5

Jeli

I W

/ T /

=

/ e /

+ 273.15 = -

( I t /

+ 459.67) =

9

Ir]

9

(degreesCelsius)

í r ]

-

491.67)

- 5

9

/ e / = / T I - 273.15 =

( i t ]

- 3 2 ) - -

9 9

= Ir] -

459.67

degrees Fahrenheit)

/ I /

= / T / - 59.67 =

I,

/ e / + 32

- -

[ e /

+ 491.67

= / t /

+ 459.67

- 5

(degrees Rankine)

NOTE.

emperafure difference.

For

the same temperature difference:

5

9

temperature difference

in

C

or

K)

=

-

(temperature difference

in

OF

or

OR).

39. Specific energy

[(energyor heat)/massl

39.1

There a re several different terms for energy per u nit mass which a re used in different contexts, e.g.

specific enthalpy

specific laten t heat

calorific value, m ass basis

The SI unit for all such quantities is the joule per kilogram (J/kg).

kilocalorie per kilogra m (kc al/kg) (see

36.6)

kilogram-force metre per kilogram (kgf m/kg)

1

kcal,,/kg = 4186.8 J/kg

1 kcalth/kg = 4184 J/kg

1 kcalis/kg =

4185.5

J/kg (approx.)

I kgf m/kg =

9.806

65 J/kg

39.3

Corresponding imperial units are:

British thermal unit per pound

foot pound-force per pound

1 Btu/lb =

2326

J/kg

1

f t

lbf/lb =

2.989

07 J/kg (approx.)

For interconversion factors s ee Table 39.

39.2

Othe r units sometimes used in metric countries are:

(Btu/lb)

(ft lbf/lb)

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Specific

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BS 350 Part 1 :

1974

Heat content, volume basis

40. Heat content, volume basis (heat/volume)

40.1 The

SI

unit for this quantity, which is mainly used in

connection

with the combustion of gaseous or

liquid fuels, is the joule per cubic met re (J/m3). For

most

practical purpose s either the kJ/m3 or MJ/m3 are

suitable multiples.

40.2

Units that have been in common

use

in metric countries are:

e.g. calor if ic value, vo lume basis

kilocalorie per cubic metre (kcallm j) (see

36.6

for th e various calories)

thermie per litre (th/Utre)

1 kcal,,[mJ = 4186.8

J/niJ

1 kcal,,/m3 = 4184 J/m3

1 kcal&3 = 4185.5 J/m3

1 thermie/litre

=

4185.5

x 106

J/m3 (see

4.3

for litre)

40.3 Correspo nding imperial units are:

British thermal unit pe r cub ic foot (Btu/ft3)

therm per UK galloii (therni/UKgal)

I

Btu/ft3

1 therm/UKgal = 2,320 80 x 1010 J/m3

= 37

258.9 J/m3

40.4

In

the above and in Table

4ûu

i t

is

assumed that, where

guses

are

concerned,

he volumes involved in

the conversion have the same reference conditions of temperature, pressure and

humidity.

For some

con-

versions

of

calorific value (volum e basis), when the reference conditions ar e different,

see

Tables

406

and

4oc.

67


7/17/2019 BS 00350-1꞉1974


BS 350 Part I : 1974

Heat con tent,

volume basis

I

n

3\

2

4

?

Fl

m

II


7/17/2019 BS 00350-1꞉1974


BS

350

Part I : 1974

Heat content,

volume basis

(u

O

c

O

e

*

9

69

O

in

2

ò

It

c

U

n

a

8

B

E

(u

O

-

II


7/17/2019 BS 00350-1꞉1974


ES1 B S * 3 5 0 : P A R T * 3

74

624669

0336387

T

~

orie)

Sat

BS 350

Part

1 :

i974

Hg (i5 calorie)

Dry

I

Sat

Heat

content, volume basis

Specific heat capacity

40c.

Conversion factors

used

by the

UK

Gas Indust ry

The following information and conversion factors are extracted from the booklet 'SI Units and conversion

factors for use in the B ritish Ga s Industry ' ssued by the G as C ouncil and Society of British Ga s Industries,

May

1972

edition.

Dry Sat

1 0.9832

I

.O1 7 1

0.037

3 1

0.036 69

0.037 97 0,037 34

0.037 30 0.036 67

0.037

96

0.037 32

~~ ~~~~

~

The conversion factor for converting from British thermal units per cubic foot (m easured at

60

OF,

30

inches Hg (@ 60

OF

53

ON

nd satu rated with water) to megajoules per stand ard cub ic metre (measured

at 15

C 013.25

mbar and dry) is:

1 Btu/ftJ =

0.037 96

MJ/m3

Other conversion factors for various conditions are given in the table

below.

Whereas two bases for the British thermal unit are included, for practical purposes there is

no

sigiiífi-

cant difference between them.

In

the gas industry the British thermal unit is based on the

15 O

calorie.

1

MJ/mJ

= 26.34

Btu/ftJ

Dry

26.80

27.26

1

1.018

0.9997

1.017

MJ/m-'

15

OC

1013.25

mbar

26.33

26.78

Bt

u/

t3

M)O F 30

inches

Hg (Internationa l calo rie basis)

26.81 26.34

27.27 26.79

Btu/ft3

60"F30

inches

Hg 115 O

calorie basis)

0.9826

1

0.9823

0.9997

-

Dry

Sat

1.ûOû 0.9829

I

1.018

Dry

Sat

-

Dry

Sat

-

MJ/mJ

15OC

I Btu/R3

60

OF, 30 inches

This tiote is for users of BS 350 and is not part of the G C/SB GI booklet.)

Attention is called t o the foilowing differences in th e reference bases

of

Tables

4Oh

and

4Oc.

(1)

In Table 4ûb the only British thermal unit used is the one corresponding to the International Table calorie (sec

36.6).

n Table

4oc

his Btu

is

indicated by th e parentheses (International calorie basis)

or (IT

calorie), and factors relating to a

Btu

d on the 15

C

alorie are stated in the preamble above the table and included in th e table.

(2)

The pressure ' 30 inches

Hg

' s shown and under th e conditions stated in Table 4Oc is given as being eqiial

to

1013.7405

30

inHg

shown in Table 406 (and as defined at 32.5) is, approximately, 1015.9166 mbar.

Specific heat capacity"

[heat/(mass

x

temperature interval)]

Th e SI unit of specific heat capacity is the jou le per kilogram kelvin

(J/(kg K)).

Th e degree Celsius is often used in the expression of the abov e unit:

I

J/(kg OC)

= I

J/(kg

K)

a

similar rema rk ap plies wherever kelvin or K is m entioned in the re main der of section

41.

Other m etric units are:

kilocalorie per k ilogram kelvin (kcal/(kg

K))

(See

38.6

for the various calories.)

kilogram-force me tre per kilogram kelvin (kgf m/(kg

K)

)

1 kcal,,/(kg K)

= 4186.8

J/(kg K)

1

kcal,,/(kg K)

= 4184

J/(kg

K)

I kcallS/(kg K)

=

4185.5 J/(kg K)

1 kgf

m/(kg K)

= 9.806 65

J/(kg K)

Corresponding imperial units are:


per

pound degree Fahrenheit (Btu/(lb

O F ) )

foot pound-force per pound degree Fahrenheit (ft Ibf/(lb

OF

I

Btii/(lb

OF

1

ft lbf/(lb OF)

= 5.380 32

J/(kg K)

=

4186.8

J/(kg K)

inteaconversion factors

for

the above units see

l'able

41.

The older and simpler t e m

'

pecific heat

'

eferred

to

heat capacities, usually

on

a

mass

basis but sometimes

on

a

volume

Jt i s now preferred

to

reserve for

'

pecific' lie meaning

'

per

unit

mass

'.

70

O

0

a

l


7/17/2019 BS 00350-1꞉1974


BS 350 Part i

1974

Specific heat capacity

F

2

o

Q\

-

'o

W

G

7

U

m

W

n

v>

0:

W

N

t

I-

2

a

lo

u5

I-

-

H

c>

2

X

I-

O

'o

U

N

-

m

2

s

X

v>

U

N

-

o

0,

f l

X

o\

CU

m

O

P

-

m

E?

X

W

O

O

Q\

O

N

-

O

O

9

-

I-

W

Q

m

E:

2

X

W

CU

O

N

-

rl

rl


7/17/2019 BS 00350-1꞉1974


BS 350 Part I

:

1974

Specific

entropy

Heat capacity,

volume basis

42.

Specific entropy [heat/(mass

x

thermodynamic temperature)]

Table

41

may also be used for the conversion

of

values

of

specific entropy, expressed

in

jouies per kilogram,

kelvin, J/(kg K), in kilocalories per kilogram kelvin, kcal/(kg K), or in British thermal units per pound

degree Ran kine,

Btu/(lb OR).

43. Heat capacity, volume

b a s k *

[heat/(volume x temperature interval)

43.1 The

SI

unit

of

heat capacity, volume basis, is the joule per cubic metre kelvin (J/(mJ K)).

43.2 The degree Celsius is often used in the expression

of

the above unit:

I

J/(m3

O C = 1

J/(m3

K)

and a similar remark applies wherever kelvin or

K

is mentioned in section 43.

43.3

Other metric units are:

kilocalorie per cubic m etre kelvin (kcall(m3

K))

(see

36.6

for the v arious calories).

4

kcalIT/(m3K) = 4186.8 J/(m3 K)

1

kcal,,/(m3

K)

= 4184 J/(m3

K)

1

kcalls/(m3

K) =

4185.5 J/(m3

K)

43.4 The corresponding imperial unit

is:

British thermal

unit

per cub ic foot degree Fahrenheit (Btul(ft3

OF))

1 Btu/(ft3 O F

=

67 066.1 J/(m3

K)

For interconversion factors for the above units see Table 43. In Table 43 and in the abo ve conversion factors

it is assumed that, for gases, the volumes involved in the conversions are measured under the same con-

ditions of temperature, pressure and humidity.

*

This is sometimes

known

as

'

pecific heat, vo lume ba sis

'

but

see

footnote fo

section

41.

Table 43. Heat capacity, volume basis

Exact values

are

printed i n bold type.

I

I

I

I

1

oule per cubic metre

-

elvin? -

joule per cubic

metre kelvin?

JKm3 K)

1

kilocalorie$

per

cubic metre

kelvin

kC&~/(ni~

)

0.238 846 x 10-3

thermochemical

kilocalorie per

cubic metre

kelvin

k d d ( m 3

K)

0.239 006 x

10

-3

15

Ckilocalorie

per

cubic metre

kelvin

kwhd(m3 K)

0.238 920

X l O - J

4186.8 I

1

1

kilocalorie$ per cubic

metre kelvin

kcallT/(rn3

K)

1.ooO 67

l.OO0 31

1 thermochemical kilocalorie

per cubic metre kelvin =

kcal,,,/(mJ

K)

1

15 C kilocalorie per

-

ubic metre kelvin -

k C a l d m 3K)

1

British thermal unit per

cubic foot degree

Fahrenheit -

Btu/(fts OF)

-

1

0.999

642

184

0.999

331

4185.5 0.999 690 1.O00 36 1

67

066.1

16.0185 16.0292 16.0234

British thermal

unit

per

cubic

foot

degree

Fahrenheit

Bhi/(ftj "F)

14.910 7 x 10

-6

0.062 428

O

-

0.062

386

2

-

0.062

408 6

1

t Wherever the kelvin occurs in this table it may bereplaced by th e degree Celsius (

C),e.g.

J/(m3

K)

s often show as

J/(rn3

OC).

$ This is th e International Tab le kilocaforie. For a description

of

the th ree calories mentioned see36.6.

NOTE. n

his table it is

assumed

that, for gases, the volumes involved in the conversions are measured under th e

same

conditions

of

temperature, pressure a nd humidity.

.

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BS 350 Part I

:

1974

Heat

flux density

4 4 Heat flux density (heat/(area

x

t ime))

44.1 The SI unit for this quantity, which is sometimes known as intensity of heat f low rate and commonly

appears,

for

example, in calculations

of

heat losses from surfaces, is the watt per square m etre (W/m2).

44.2 Other metric units are:

calorie per square centime tre second (cal/(cm2 s))

(see 36.6

for the various

calories)

kilocalorie per

square

metre hour (kcal/(m2 h))

1 calIT/(cm2

s)

= 41

868

W/m2

1kcaliT/(mz h)

= 1.163

W/m2

British thermal un it per square foot h our (Btul(ft2 h))

wa tt per square inch (Wlin2)

1 Btul(ft2 h) = 3.154 59 W/m2

1 WIin2 = 1550.00 W/m2

44.3 Correspond ing units in the imperial system are:

For conversion factors

for the

above see TabIe

44.

Table 44. Heat flux density, intensity of heat flow rate (ag . heat loss from

surfaces)

Exact figures are printed in

bold

type.

W/m2

1watt per square metre = 1

W/m*

1

wa tt per square inch

= 1550.00

W/in2

1calorie* per square

centime tre second

=

41868

W1iT/(cm2s)

1kilocalorie* per square

metre

hour = 1.163

kCa1,T/(m2 h)

-

1British thermal unit

per square foot hour

=

3.154 59

Btu/(ft2 h)

*This refers

to

the International Table calor ie.

0.238 846x 10-4

3.702 12x 10-2

I l

7.0116

ir

other caloriessee

36.6.

0.859 845 I 0.316 998

1332.76 491.348

%o00

13 272.

i

1 0.368 669

2.71246 1

73


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BS

350 Part I :

1974

Thermal

conductance

45. Thermal conductance (heat transfer coeff ici ent)

[heat/(area x time x temperature difference)] or [power/(area x temperature difference)]*

45.1 The SI unit is the watt per square metre kelvin [W/(m2 K)]

45.2 The degree Celsius

( O C )

is often used in the expression of the above unit:

and

a

similar remark applies wherever kelvin or K is mentioned

in

sectioii 4 5

45.3 Other m etric units are :

1

W/(m2

OC) =

1

W/(m2

K)

calorie per square centimetre second kelvin [cal/(cm 2 s

K)]

kilocalorie per square metre

hour

kelvin

[kcal/(rna

li

K)]

1 caI/(crn2 s IS) = 41 868

W/(m2

K)

1

kcal/(m2 h K )

=

1.163 W/(nG K)

45.4 The imperial unit in com mon use is:


per

square foot hour degree Fahrenheit [Btu/(ft2 h “F)]

I dtu/(ft2 li

O F )

= 5.678 26 W/(m2 K)

(The conversion factors given below refer to the Iiiternational T able calo rie, sce

38.6

for other calories.)

For interconversion factors

for

the

above

units see Table

45.

Table 45. Thermal conductance

Exact

values

are printed in bold type.

\V/(mZ K)P

cal$/(cmz s K) kcai$/(mz h

K)

-

1

watt

per

square

metre kelvin? = 1 0.238 846 x IO -4 0.859 845

W/(m2 K)

1 calorie$ per square

centimetre secoiid kelvin

=

41

868

1 36

O00

cal/(c&

s K)

i

kilocalorie$

per

square

metre hour kelvin = 1.163 2.777 78 x

10-5

1

kcal/(mz h K)

1 British thermal unit per

square foot hou r

degree Fahrenheit

=

5.678 26 1.356 23 x IO -4 4.882 43

Btul(ft2 h

O F

0.176 110

7373.38

0.204

816

1

O

e

*

Also

corresponds to (heat flux density/temperature difference).

I_ Wherever the kclvin occurs in this table it may be replaced by tho

degree Celsius:

e.p.

W / ( d

K)

is ofteii

sliowii

as W/(nii-OC)

3 This

refers

to

the International Table calorie. For other calories sce

36.6.

74


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BS

350 Part 1 : 1974

Thermal conductivity

0.577 789

46.

Thermal conductivit y

[heat

x

length/(area x time x temperature difference)]

46.1

The

SI

unit is the watt per metre kelvin [W/(m K)]

46.2 The

degree Celsius

( O C )

is often used in the expression

of

the abov e unit:

1

W/(m

O C )

==

1

W/(m

K)

and

a

similar

remark applies wherever kelvin or

K

is mentioned

in

section 46.


calorie per centimetre second kelvin

kilocalorie per metre

hour

kelvin

I

cal/(cm s

K)

= 418.68 W/(m

K)

1

kcal/(m h

K) =

1.163 W/(m

K)

[cai/(cni s

K)]

[kcaI/(m

h K)]

(Theconversion factors given below refer

to

the Internationai Table calorie. See

36.6

for other caiurics),

46.4

Two imperial units in com mon use are:

British thermal unit per foot hour degree Fahrenheit

[Btu/(ft

11

F)]

British tliernial unit inch per sq uare foot

hour

degree Fahrenheit

1 Btu/(ft h O F )

I

R t i i

in/(ftz

li

'F)

--

0.144 228

W/(m

K )

[Btu in/(ftz h O F ) ]

= 1.730 73 W/(in K)

6.933 47

For interconversion factors for

the

above units see l'able 46.

1.488 16

0.124 014

~

Table 46. Thermal conducti vity

1

caloriet per centimetre

second kelvin

=

cal/(cm

s K)

Exact figures ar e printed in b old type.

kcal/(m h K)

' 418.68 1

l I -I

1 kilocalorie* per metre

hour kelvin

=

kcal/(m h

K)

I

0.238 846x

10-2

=I

watt per metre kelvin*

W/(m K)

1.163

1

British thermal unit per

foot

hour degree Fahrenh eit=

Btu/(ft

h°F)

1.730 73 4.133 7 9 x

10-3

2.777 78

x

10

-3

1

British thermal unit inch per

square foot hour degree

=

Fahrenheit

Btu

in/(ft2 h O F )

0.859 845

0.144 228

3.444

8 2 x

10-4

360

1

Bíu/(ft h

'F)

Btu in/(ft2

h

J

2902.9141.909

-

1

I 1 2

0.083

333

3

1

Wherever the kelvin occurs in this table it ma yb e replaced by the degree Celsius

Oc)

e.g. W/(m K)

s

often shown a s W/(m

O C ) .

P

This

refers

to

the International Table caloric. F or other calories see 36.6.

75


7/17/2019 BS 00350-1꞉1974


BSI B S * 3 5 0 : P A R T * &

74

b24bbï

O l i l b L 9 3

5

~~

BS 350 Part

i

1974

Therma

I resist

vi

y

47. Thermal resistivit y

[area

x

t ime x temperature dif feren ce/(heat

x

length)]

The

SI

unit of therm al resistivity (the inverse

of

thermal conductivity) is the metre kelvin per watt m

K/W).

Interconversion factors between tue

above and

some other units are given

in

Table

47.

Similar remarks con-

cerning the use

of

the degree Celsius and the other calories apply as in section

46

and T able

46.

Table

47.

Thermal resistivit y

Exact

figures

ar e printed in bold

type.

I m K/ W I cmsK/caì*

1 m K / W

= 1

418.68

1

cm

s

K/cal*

= 0.238 846 X 10-2 1

360

241.909

1

ft2 h OF/(Btu

in) = 6.933 47

2902.91

I

I

It2 h 'F/(Btu in)

i.144 228

m

h

K/kcal* it h 'F/Bîu

1.163

1.730 73

~~~~~~ ~~

2.777

78

x

10 -3 I 4.133 79

x 10 -3

1 3.444 82 x

10-4

1 1.488 16 0.124 014

0.671 969 1 0.083 333 3

8,063 63 12 1

-

*

This refers

to

the International Table calorie.

For

othe r calories

see 36.6.

NOTE. For thermal conductivity, s e e Table 46, the

notes to

which also apply here.

76


7/17/2019 BS 00350-1꞉1974


8

1 wa tt per cubic metre

1 calorie* per cubic

W/m3

centimetre second =

cal/(cm3 s)

1

kilocalorie* per

cubic metre ho ur

=

kcal/(m3 h)

1 British thermal u nit

per cubic foot hour =

Btul(ft3

h)

*

watt

per cubic

metre

W/m3

= 1

4.1868~106

1.163

10.3497

BSI

~

BS*350:

~~~

P A R T * l

~ 7 4

_________

œ 3 6 2 4 6 6 9 O l L b L S Y 7 œ

_

-~ -

BS

35Ö:Part

I 1974

Heat release rate

Thermal diffusivit.y

48.

Heat release rate (ems .

s

used

in

connection

with

furnaces)

[heat/(volume x time)], or (power/volume)

48.1 The SI unit for this quantity

is

the watt per cubic metre (W/m3).


calorie per cu bic centimetre second

kilocalorie per cubic metre hou r

The conve rsion factors given below refer to the International Table calorie. (See

36.6

for other calories).

1 cal/(cm3 s) = 4.1868 x 106W/m3

1 kcal/(mj

h)

= 1.163 W/m3

British thermal unit per cubic

foot

hour

1 Btu/( ftJ h) = 10.3497

W/m3

[caI/(cm3

s)]

[kcaI/(m3

h)l

48.3

A similar imperial unit is:

[Btu/(ft3 h)]

For

interconversion factors for

the

above units see Table

48.

Table

48.

Heat release rat e


1

I I

caiorie*[cubic

centirnetre

second

cal/(cm3 s)

0.238 846x 10 -6

1

2.777 78

x

10-7

2.471 99

x 10

-6

kuocalorie*/cubic

metre hour

kcai/(m3 h)

0.859 845

3.6 x 106

1

8.899 1 5

I I I

* This refers to

the

International Table calorie. For other calor ies see 36.6,

1 W/cmJ = 106 W/m3 = 1 MW/m3.

49.

Thermal di ff usivity

(area/time)

British thermal

unit/cubic foot hour

BhJ(ft3

h)

9.662

l x

10

2

4.045 3 3 ~05

0.112 370

i

O

The S I unit of therm al diffusivity (which is thermal conductivity divided by heat capacity per unit

volume)

is the metre squared per second (mys).

Since kinematic viscosity has the same dimensions

as

therma l diffusivity, for un its and conversion factors

reference can b e m ade to Section

35

and Table

35.

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B S I B S * 3 5 0 : PART*L 74 L b 2 4 b b î

O L l b L 9 5

9

=

BS 350 Par t I

:

1974

Commentary

Appendix A

Commentary on imperial and metri c

systems of

measurement and un its

A.l Development of units. In the past, units have evolved in a haphazard manner to meet the basic iiieasure-

ment requirements of early and often unconnected societies. With improvement in communications and

extension of trade it became necessary to standardize the units in use and also to establish the relationship

between existing units used to measure the same physical quantities. Often, as this latter process developed,

the numerical factors relating one such unit to another w ere cumbersom e and difficult to use in calculations

(for example, the mile is 1760 yards and the U K ton is 2240 pounds). Moreover, while one physical quan tity

might be a simple derivative of anothe r, there was often no co rrespon dingly simple relationship between

their respective units, (for example, area an d volume are simp le derivatives of leng th, but

1

acre is484ûsquare

yards and 1

U K

gallon is 0.160

544

cubic feet).

As science and technology developed, many new aiid coinplex units were required. Inevitably these were

derived froin tlie available units

in

comm on usage and the result was a muddled co nglomeration of technical

units involving many awkwíird factors which were difficult to renieinber and inconvenient to use. The lea riiing

of these factors has long becii a necessary part of scieiitific aiid eiigiiieeriiig education.

A.2 Unit systenis and coherence. The va rious physical quan tities used in science and technology are related

to one another by certain mathematical or physical laws. For example, area equals length multiplied by

length, velocity equals length divided by time, force equals mass niultiplied by acceleration, momentum

equals mass m ultiplied by velocity.

In

a

coherent system of units, the units used to measure the various physical quantities are consistent

with these physical laws.

A

minimum num ber of independ ent physical quaniities are a rbitrarily selected

and base units a re defined for these. Units for all other physical quantities can then be derived in accordan ce

with the physical laws, preserving a unity relationship in terms of the base units. Thus, if unit area results

when un it length

is

multiplied by unit leng th, the units are cohe rent with the pa rticular physical law expressing

tlie relationship between length and area, and no factors are involved in calculations concerned with this

relationship.

With further developme nt of science and technology, certain ' systems ' of units c ame into use, (for example

the foot-pound-second system and the centinietre-gram-second system). While the base units concerned

were clearly defined, the total extent of each of these systems and also units for some physical quantities

were in certain respects vague. The units com prising these systems were coherent with respect to some of

the physical laws, but not

to

others.

A.3 Imperial systems

(in

technology). In British technology the most widely used system has been one in

which the base units for length, mass and time are the foot, pound and second respectively. But, in this

widely-used sy stem there is a non-coherent relationship between the units used for mass, force and accelera-

tion i.e. there is not ' dynamic coherence '. Th e unit of force used is the pound-force (sometimes described

as

a '

echnical unit of force '), aiid, because this force acting on

a

mass of one poun d produces an acceleration

of '

g ' (=32.2 feet/second2 approximately), the factor 32.2 is introduced in an awkward manner into m any

engineering calculations.

There are two other systems based on imperial units used in som e sections of industry which are dynam ically

Coherent. The first is a variant of the foot-pound-second system which has the pou ndal as its force unit.

The poundal acting on a mass of one pound produces a n acceleration of unity (1 foot/second2). The o ther

is the foot-slug-second system in which the mass unit is the slug (=32.2 lb approximately) and the force

unit the pound-force. Again, the acceleration produced by the pound -force on the slug is unity.

In the above, only dynam ic coherence

has

been m entioned. While this is of vital importanc e in mechanics,

there are many o ther im portant physical quantities aiid laws; further base units had to be introduced and

the corresponding units that came about in con junction with these imperial systems were frequently non-

coherent. Furthermore, in dealing with the foot-pound-second, and foot-slug-second systems, there are

the

practical complications in calculations caused by the awkward relationships between the foot, inch and yard,

and the pou nd and ton. In the measurement sense these units all form pa rt of th e imperial system.

A.4

Comparison

of Uniteù

Kingdom (UK or imperial) and United Sta tes systems

of

measurement. The yard

lias the same value in b oth the

UK

and US systems and is defined in terms

of

the SI base unit of length,

the metre. Similarly, the pound lias the sam e value in the UK and US systems and is defined in terms of

the

SI

base unit of mass, the kilogram.

78

8

a

a


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BSI

BS*350:

P A R T * &

~ 7 4~~ =

L b 2 4 b b ï O L L b l S b O m

_ ~

_ _

~ -

BS 350

Part

1

: 1974

Commentary

T h e

U K

Weights and Measures Act,

1963,

makes these deíìnitions valid for all purposes in the

UK. Jn

the

USA

the same definitions are valid for all purposes except for coast and geodetic surveys within the

USA, for which the foot previously adopted there will continue temporarily to be used under the name

'

US

survey foot

'.

Most

of the subsidiary units of length are identical in both the UK and

US

ystems.

There are marked differences between some subsidiary units of mass used in the

UK

and

US

systems,

notably in the

'

ong

'

and

'

short

' ons

and hundredweights. These differences arise from different whole

num ber relationship s between units.

The re are also m arked differences between the sub sidiary units of capac ity used in the UK and

US

systems,

These differences arise both from some different whole number relationships between units and also from

different definifions of capac ity in the two systems.

I n

order to avoid confusion where those differences occur, the units to be distinguished are denoted by

the use

of

prefixes, for example:

U K

gallon, symbolized by

UKgal

US gallon, syiiibolized by USgal

This notation is similar to one ado pted by the International Organiza tion for Standardization

(ISO).

In

certain contexts the qualification ' mperial ' or ' mp ' s also used to make it clear that the unit qualified

by

U K

does in fact belong to the imperial system of units.

A.5

The metric system of measurement.

I n

Britain, units of length, weight (mass) and

so

on have

been

standardized fo r

a

long time, but prior to the adoption

of

the m etric system this was not the case in France

and

in

other con tinental countries. When the metric system was introduced

it

met two main requirements.

Th e first was the standardization and definition of the impo rtant units of measurement, the metre for length

and the gram for mass, from w hich other units then required for general use an d for trade were derived.

The second was the provision

of

a

conven ient and system atic relationship between different-sized units for

the same quantity. These were related by pow ers of ten and

a

system of prefixes developed to ind icate these

powers. This gave

a

flexible means of expression for

a

wide range of m agnitudes, avoiding theneed for very

iarge or very small numerica l values, an d enabled the different-sized units to be mem orized and con verted

with ease.

A.6 Metric

systems

(in science

and

technology).

In

technology, as a t present and taking all countries into

accoun t, probably the most widely used m etric system is one in which the base units for leng th, mass and time

are the metre, kilogram and second respectively, but in which there is

a

non-coherent relationship between

the units for mass, force and acceleration. Th e unit

of

force used is the k ilogram-force (sometimes described

as

a '

et ric technical

unit of

force

'),

and because this force acting

on a

mass of

1

kilogram produces an

acceleration of ' g ' (9.81 m/s2 approximately) the factor 9.81 is introduced in an awkward manner into

many engineering calculations. The system

is

being steadily superseded by the In ternational System (SI),

mentioned below.

The re are othe r metric systems still in use in so me sectors of industry a nd science which are dynamically

coherent, and from the first two of which the d evelopment of the

SI can

directly be traced. Som e are:

Description

and abbreviation msss unit force unit

centimetre-gram-second

(CGS)

gram dyne

metre-kilogram-second

(MKS)

kilogram newton

metre-tonne-secottd (MT S) tonne sthène

Scientists were quick to recognize the convenience

of

the m etric approach in the

CGS

and this system

was developed by them to m eet their imm ediate needs, according to their knowledge a t the time, and among

other things it served in the development of electrostatics and electromagnetism. Although it gained con:

siderable usage

in

industrial technology, many of the associated units were inconveniently sized for this

purpose. I t was also clear that inore than the three base units provided in the

CGS

were required in the

framework of the metric system to deal adequately with the physical quantities required in science and

technology, and tha t some of th e subsidiary w it s th at had come into use in conjunction with

the CGS

were not coherent.

These factors led in d ue course to th e evolution of the MKS ystem, thence to the MKSA , incorporating

the independent quantity electric current and the base

unit

ampere. This system embodied the joule as

the derived and coherent unit of energy in ail its forms, and the w att as the u nit of power.

A.7 Th e Inte ruatio uai System

of units (SI).

This, som etimes described as the 'modern metric system ', is the

most recent extension of the metric system, expanding

on

the

MKS

o include

a

total of

seven

base units

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B S I

B S X 3 5 0 : P A R T * &

7 4

m

L b 2 4 b b 9 O L l b L 9 7

2 m 1

BS 350 Part I

:

1974

Commentary

and two suppleincntary units which, in conjunction with derived units,

will

meet ali known needs for

a

coherent system of units both in science and technology,

Th e base and supplementary quantities, and their units (defined in BS 3763) are:

Quantity Name o f unit Symbol

Length metre (Base) m

Mass

kilogram

1,

kg

Time

second

3,

S

Electric current

ampere $9

A

Thermodynamic temperature

kelvin

Y >

K

Amount of substance

mole Y,

mol

Lum inous intensity

candela

9 ,

cd

Plane angle radian (Supplementary) rad

Solid angle

steradian 39 sr

There are, for practical applications or fo r everyday life, certain other un its, some metric and some non-

metric, which at present are authorized for use in conjunction with the International System. Such units

are listed in ca tegories in BS 3763 : 1970 and their use introduces an elem ent of non-coherence.

The m etric prefixes, which now form part of the International System, are

shown

in detail in 1.1. As

is

evident from the foregoing description of a coherent system, the use of multiples in the form of a prefix

also introduces non-coherence, but in the SI the prefìxed units still retain a simple decimal relationship

one with the other. T his is an imp ortant feature, which is not sacrificed by the fact that the base unit for

mass is the kilogram.

80


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B S I BSS350: PART*I(’L

7Y m

~~~

1624669 OLlb198

---- 4

m

-

~~

BS

350

Part

1

:

1974

References

Appendix B

References

B . l

Detailed conversion tables.

Detailed conversion tables for the units marked with an asterisk can be found

in

Asament/e<

PD 6203.

Length

inches to minimetres

millimetres to inches

fractions

of

an inch, in sixty-fourths, to decimals

of

an inch and to inillimetes (Range:

O

to

1

inch)

inches and fractions of an inch to millimetres

(Range: O to 12 inches)

inches to centimetres (Range: O to

109

inehes at

intervals of one inch)

feet to metres

metres to feet

feet and inches to metres

yards to metres

metres to yards

miles to kilometres

kilometres to miles

Area

square inches to square centimetres

square centimetres to square inches

square feet to square m etres

square metres to square feet

square yards to square m etres

square metres to square yards

acres to hectares

hectares to acres

square miles to square kilometres

square kilometres to square miles

Volume

Cubic inches to cubic centimetres

Cubic centimetres to cubic inches

Cub ic feet to cubic metres

Cubic metres to cubic feet

Cubic yards to cubic metres

Cubic metres to cubic yards

Cubic feet

to UK

gallons

TJ

K gallons to cubic feet

Cub ic feet

to

litres (1901)

Litres (1901) to cubic feet

U K gallons to litres (1901)

Litres (1901) to

UK

gallons

U K fluid ounces to millilitres (1901)

Millilitres (1901) to

UK

fluid ounces

*U K gallons to litres

*Litres to U K gallons

*U K fluid ounces to m illilitres

*Millilitres to

UK

fluid

ounces

M a s s per un it length

pounds per foot

to

kilograms per metre

kilograms per m etre to pounds per foot

*pounds per inch to kilograms per m etre

*kilograms per metre to pounds per inch

Mass

per un it area

*ounces (avoir) per square yard to kilograms per

*kilograms per square metre

to

ounces (avoir) per

square metre

square yard

Density

pounds per cubic foot to kilograms per cubic metre

kilograms per cubic metre to pounds per cubic foot

pounds per

UK

gallon to grams per m illilitre (1901)

grams per millilitre (1901

1

to pounds per U K gallon

81

July IYX.3


inches4 to centimetresd

centimetres4 to inches4

Angle

degrees, minutes and seconds to rad ians

radiacs to degrees, minutes and seconds

Velocity

feet per second to m iles per hour

miles per ho ur t o feet per second

feet per second to kilometres per hour

kilometres per hour to feet per second

miles per hour to metres per second

metres per second to miles per hour

miles per hour to

U K

knots

U K knots to miles per hour

Mass

grains to grams

grams to grains

ounces (avoir) to gram s

grams t o ounces (avoir)

pounds t o kilograms

kilograms to pounds

U K tons to tonnes

tonnes

to U K

tons

pounds to

UK

tons

UK

tons to pounds


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B S 350 Par t

I

: 1974

References

Force

pounds-force

to

megadynes

megadynes to pounds-force

*kilograms-force to newtons

"newtons to kilograms-force

*pounds-force to newtons

"newtons to poun ds-force

*UK

tons-force to kilonewtons

*kilonewtons to

UK

tons-force

Pressure, stress

pounds-force per square inch to kilograms-force

kilo4rams-force per square centimetre to pounds-

pounds-force per square foot to kilograms-force

kilograms-force per square metre to pounds-force

UK tons-force per square inch to kilograms-farce

kilograms-force per square milliinetre to

UK

tons-

U K

tons-force per square foot to tonnes-force per

tonnes-force per sq uare m etre to U K tons-force per

pounds-force per square inch to millimetres of

millimetres of m ercury to p ounds-force per square

millimetres of mercury to millibars

miliibars to inilliinetres of mercury

feet of water t o pound s-force per square inch

pound s-force per squ are inch to feet of water

*UK

tons-force per square inch to meganewtons

*meganewtons per square m etre to UK tons-force

*pounds-force per square inch to kilonewtons per

*kilonewtons per squa re metre to pounds-force per

*pounds-force per square foot to newtons per

"newtons per square metre to pounds-force per

"inches of mercury t o kilonewtons per square metre

*kilonewtons per square m etre to inches of mercury

*feet of water t o kilon ewton s per square m etre

*kilonewtons per square m etre to feet of water

*inches of water to kilonewtons per square metre

*kilonewtons per square metre to inches of water

per square centimetre

force per square inch

per square metre

per square foot

per squa re millimetre

force per square inch

square metre

square foot

mercury

inch

per square metre

per square inch

square metre

square inch

square metre

square foot

BSI

B W 3 5 0 :

P A R T * L 74

m

L b 2 4 b b 9

O L L b L 9 9

b m

82

Work, energy

foot pounds-force t o joules

joules to foot pounds-force

foot pounds-force to kilogram-force metres

kilogram-force metres t o foot pouiids-force

*kilowatt hours to megajoules

"megajoules to kilowatt hours

Power

horsepower

to

kilowatts

kilowatts to horsepower

Temperature

Conversion of temperatures from degrees Fahren-

heit to degrees Celsius, a nd vice versa

Quantity

of

heat

British therm al units to kilojoules

kilojoules to British thermal units

calories to joules

joules to calories

British thermal units to kilocalories

kilocalories to B ritish thermal units

Calorificvalue mass basis)

Btujlb to kcal/kg

kcal/kg

to

Btu/lb

*Btu lb to kJ/k g

*kJ kg to Btu/lb

Calorific

value

(vo lume

basis)

Btu/ft3 to kcal/m3

kcal/m3 to Btu/ft3

*Btu/ft3 to kJ/m3

*kJ/rn3 to B tu/ft3

now called heat capacity (volume basis) in this

standard. See also the note o n page

83

which applies

to

many of the following units.

Specific heat (volume basis)

Btu/ftJ degF to kcal/m3 degC

kcalIm3 degC to Btu/ft3 degF

*Btu/ft3 deg

F

to kJ/m3 degC

.

*kJ/m3 deg C to B tu/ft3 degF

Intensityof heat fl ow rate

Btu/ft2

h

to W/m2

Wjm2 to Btu/ft2 h

kcal/m* h to W /m2

W/m2 to kcal/m2 h

Btu/ft2 h to kcal/m2 h

kcalfmz h to Btu/ft2 h


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BSI B S * 3 5 0 :

P A R T * L 7i.1 L b 2 q b b 9 OLL6200 9

- - ~

-_ -~

~ _ _ -

~ ~~

BS

350 Part

I

: 1974

References

General information

Thermal conductance Thermal conductivit y

Btu/ft2 li degF

to

kcal/m2 h degC

kcal/m2 h degC to Btu/ft2 h degF

*Btu/ft2 h degF to W/m2 degC

*W/m2 degC to B tu/ft2

h

degF

Btu/ft h degF to W/m degC

W/m de gC to Btu/ft h degF

kcal/m h degC to W/m degC

Wlm degC to kcal/m h degC

Btu/ft

h

degF to kcal/m

h

degC

kcal/m h degC to Btu/ft h degF

Btu/in/ft2 h degF to kcal/m h degC

kcal/m h degC to B tu in/ft2 h degF

NOTE. In

this

stand ard degC has been replaced by K and de@ by OF.(See ection 38 and,

in

particular, 38.5).

B2.

General info rmation

Useful general information isconta ined in the following publications. A i urnciiûcd

Je11 I W

BS

1957

BS

3763

BS 5 5 5 5

BS

5775

Presentation

of

numerica l va lues (f ineness ofexpression; roun ding ofnu mb ers )

Th e In t e rna ti ona l Sys t em ofun i t s (SI)

Speci fica tion forSI uni ts a nd recomm endat ions for t he use o f t he i r m ul t i p Ie sand of cer ta in other uni ts

Speci fica tion for quant i t ies , uni t s an d sym bols

Pa r t

O.

Genera l pr inc iples

Pa r t

1-

S p a c e a n d t i m e

Part 2. Periodi c an d re l a ted phenom ena

P a r t 3. Mechan ic s

Par t 4 . Heat

Pa rt 5. Electricity an d magnetism

Part 6 . Light and re la ted e lec t romagnet ic radia t ions

Part

7.

Acoustics

Par t 8 . Physicat chemist ry and molecular physics

Par t 9 . Atom ica nd nuclear physics

Par t

IO.

Nuclear reac tions and ioniz ing radia t ions

Part 1 I Mathemat ica l s igns and sym bols for use id the physica l sc iences and technology

Part 12. Dimensionless parameters

Part

13.

Solid state physics

PD 686 The useo fSI un i ts

SI - Th e Interna t ional System of Uni ts . HMSO (4th edit ion 1982)

Chang ing to the m etr ic system. C onversion fac tors, symbols an d def ini tions. HMSO (5th edition 1979)

63.

Some other British Standards containing conversion nformation

British

Standard Title

BS 718 Density hydrometers an d spec& gravity hydrom eters

BS 860 Tables for com parison of hardness scales

BS 874 Method s of determining thermal properties, w ith definitions of thermal insulating terms

BS 947 Universal system for designating linear density of textiles (Tex system)

BS 1797 Tables for use

in

the calibration of volum etric glassware

BS 2520 Barometer conventions and tables

BS

2856

Precise conversion

of

inch and metric sizes

on

engineering drawings

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BSI B S * 3 5 0 : P A R T * L

74

b 2 4 b b 9 OLL6201

O

BS 350 Part 1 :

1974

General

information

Alphabetical l i s t

of

symbolsfo r unit s and prefixes

Symbols and abbreviations for units, and symbols for prefixes, to which any reference has beeii made i i i

this standard, are listed below together with their textual references. Most but not ail

of

these are inter-

nationally recognized.

Greek letters and som e special signs are shown a t the end.

This list is not extended to include com binations

of

units, or conibinatioiis

of

prefixes and units, except

for a few examples, Many further examples of such combin ations are to be found throug hout the text and

in the general index, pages 88 to 100.

Symbol or abbreviation

A

A

a

a

a

at

ata

atm

atü

AU

bar

bbl

bbl (dry)

Btu

Btumean

bu

BtU60/ 61

C

C

C

Cal

CabT

a l i

d l 5

cd

ch

C.H.U

cl

cm

CP

cSt

ctl

' cumec )

' cusec

'

cv

cwt

d

d

da

deg

dm

dr

dry q t

dyn

erg

Name of unit or prefix, where appropriate

ampere

angström

are

atto (preiìx)

year

technical atmosphere

technical atmosph ere (absolute, German)

standard atmosp here

technical atmosphere (gauge, German)

astronomical unit

bar

barrel

(US,

for petroleum)

dry barrel

US)


mean British thermal u nit

60 "F British thermal unit

bushel (US)

centi (prefix)

cycle

degree Celsius

calorie

International Table calorie

thermochemical calorie

15

C

calorie

candela

cheval vapeur (metric horsepower) (Frenc h)

Centigrade heat unit

centilitre

centimetre

centipoise

centistokes

cental

cubic metre per second

cubic foot per second

cheval vapeur (metric horsepower, French)

hundredweight

day

deci (prefìx)

deca (prefix)

(to indicate temperature interval)

decimetre

dram (avoirdupois)

dry quart (US)

dyne

erg

84

Textual reference

A.7

2.3

3.3

1.1

9, note 2

32.6

32.7

32.6

32.7

2.3

32.2

4.6.3

4.6.4

36.6

36.6

36.6

4.6.2, 4.6.4

1 . 1

12.1

38.2

36.6

36.6

36.6

36.6

A.7

37, footnote

36.6

4.3

2.2

34.2

35.2

14.5

23, footnote

23, footnote

37, footnote

14.5

9.3

1.1

1.1

38.5

2.2

14.5

4.6.4

28.2

36.2

O

e

e


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BS 350

Part 1

:

1974

General

information

Spibol or abbreviation

Name

of

unit or weiìx, w b m a m t e

Textual reference

F

f

fi

d r

f l d r

fl

o z

Fm

ft

ftH2O

G

g

L

6"

Gal

E

gal

gi

gon

gr

h

h

ha

hbar

hl

hP

hP

h

Hz

in

inHg

i n H2 0

J

K

k

kg

kgf

kip

km

kn

kP

' k.s.i '

kW

kW

h

1

Ib

Ibf

liq

d r

liq

oz

liq Pt

q t

1.y.

M

m

m

m b

mil'

'mi l '

'

mil

'

degree Fahrenheit

femto (prefix)

fluid drachm

fluid dram

(US)

fluid ounce

Festmeter (German)

foot

conventional foot of water

g i s (p refix )

gram

acceleration due to gravity

standard acceleration due

to

gravity

grade

galileo (or gal)

gallon

gill

(US)

gon (or grade)

grain

hecto (prefix)

hour

hectare

hectobar

hectolitre

horsepower

horsepower hou r

hertz

.

inch

conventional inch of mercury

conventional inch of w ater

jou ie

kelvin

kilo (preñx)

kilogram

kilogram-force

loo0pounds-force (US)

kilometre

kno t (international)

kilopond (kilogram-force, German)

kips per square inch

(US)

kilowatt

kilowatt hour

litre

pound

pound-force

liquid dram (US)

liquid

ounce (US)

liquid pint

(US)

liquid qua rt

(US)

light

year

mega (prefix)

metre

milli

(prefix)

müübar

(ofarea)

(of angle)

(of length)

38.3

1.1

4.6.1

4.6.3

4.6.1

4.4

2.5

32.5

1.1

14.2

13.4

13.4

7.3

13.2

4.6.1

4.6.3

7.3

14.5

1.1

9.3

3.3

33

4.3

37.3

36.5

12.1

2.5

32.5

32.5

36.1

38.1

1.1

14.1

28.2

28.3

2.2

10.5

28.2

32.4

37.1

36.3

4.3

14.4

28.3

4.6.3,

footnote

4.6.3,

footnote

4.6.3

4.6.3

2.3

1.1

2.1

1.1

32.2,

ootnote

3.5,

and note

2

7,

note

2

2.6,

and note

8

85


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BS 350 Part

I : 1974

General information

Symbol r abbreviation

' m i l ,

Mg

mg

mGal

d 2 0

min

min

ml

mm

-Hg

mmH20

mol

ms

N

n

n mile

ns

oz

ap

oz

apoth

OZf

oz t

oz tr

P

P

P

Pa

P C

oz

Pdl

Pk

P1

PS

'

.s.i

'

'p.s.i.a

' p.s.i.g '

Pt

PZ

4

qr

qt

"R

r

rad

rev

'

eyn

Rm

sh cwt

sn

st

St

st

T

t

th

S

Name of unit or prefix, where appropriate

(of volume)

megagram

milligram

milligal

convention al metre of water

minute

(of

time)

minim

millilitre

millimetre

conventiona l millime tre of m ercury

convention al millimetre of water

mole

millisecond

newton

nano (prefix)

international nautical mile

nanosecond

ounce

apothecaries' ounce (US)

apothecaries' ounce (UK)

ounce-force

ounce troy

(US)

ounce troy

(UK)

pond (gram-force, German)

poise

pico (prefix)

pascal

parsec

poundal

peck

(US)

poiseuille (French)

Pferdestärke (metric horsepower, German)

pounds-forc e per squ are inch

pounds-force per square inch (absolute)

pounds -force per square inch (gauge)

pint

pièze (French)

quintal

quarter

quart

degree Rankin e

revolution

radian

revolution

(viscosity unit)

Raummeter (German)

second (of time)

short hundredweight US)

sthène (French)

steradian

stokes

stère (French)

tera (preñx)

tonne

thermie (French)

86

Textual reference

4.4

14.2

14.2

13.2

32.5

9.3

4.6

4.3

2.2

32.5

32.5

A. 7

9, note 1

28.1

1.1

2.3

9, note

I

14.5

14.5

14.5

28.3

14.5

14.5

see 28.2

34.2

1.1

32.1

2.3

28.3

4.6.3

34.1

37, footnote

32.4

32.7

32.7

4.6.1

32.2

14.3

14.5

4.6.1

38.4

11.2

7.1

11.2

34.3, footno te

4.4

9.1

14.5

28.2

8.1

35.2

4.4

1.1

14.2

36.6


Services


7/17/2019 BS 00350-1꞉1974


Symbolor abbreviation

tonf

UKgal

UKpt

UKqt

USgal

w

Yd

U

I

I I

Y

P

' 1

'

' P '

Pig

pin

111

Cim

11s

L

BS 350 Part I :1974

General information

Name of unit orprefix, where appropriate

Textual reference

ton-force

atomic mass unit

gallon (UK)

pint (UK)

quar t (UK)

gaiion (US)

watt

yard

degree

(of

angle)

minute (of angle)

second (of angie)

degree (temperature)

' gamma

'

(microgram)

micro (prefix)

(micron of mercury)

micron

microgram

micro-inch

microlit e

rnicrometre (or micron)

microsecond

(right angle)

28.3

14.3

4.6.1

4.6.1

4.6.1

4.6.3

37.1

2.4

7.2

7.2

7.2

38.2

to

38.5

14, note

i

1.1

32.5

2.2

14.2

2.6

4.3

2.2

9,

note 1

7.1

87


7/17/2019 BS 00350-1꞉1974


B S I B S * 3 5 0 : P A R T # l 74 B I l b 2 4 b b 9 O l l b 2 0 5 B

BS

350 Part I : 1974

General index

General index

The names of the quantities, subjects, units and preíìxes to which reference has been made in this standard

are listed below with their references. Against units or prefixes the corresponding symbol is also indicated.

Symbol Textual reference Table reference

Term

and

mportant notes

absolute (pressure)

acceleration

acceleration, standard

acre

acre per po und

ampere

angle, plane

angle, right

angle, solid

åHgström

angular momentum

angu lar velocity

apothecaries' units

are

area

area, first moment o f

area, second mom ent of

area per unit capacity

area per unit mass

assay ton (UK)

assay ton (US)

astronomical unit

atmosphere, standard

atmosphere, technical

atmosphere, technical (absolute, Ge rman )

atmosphere, technical (gauge, Germa n)

atomic mass unit

atto

avoirdupois units

g"

acre/lb

A

L

A

a

AU

atm

a t

a ta

ati'

a

U

bar

barn

barrel (beer,

UK)

barrel (cranberry,

US)

barrel (wine, UK)

barrel (petroleum,

US)

barrel, dry (US)

barye

billion


British thermal unit, International T able

British thermal unit, mean

British thermal unit, 60 F

British thermal unit (used by G as Industry)

British thermal unit inch

per

square

foot hou r degree Fahrenheit

British thermal unit per cubic foot



hour

degree Fahrenheit

bar

bbl

bbl (dry)

(dynlcm2)

Btu in/(ft2 h OF)

Btu/ft3

Btu/(ft3 OF)

Btu/(ftJ h)

32.7

13

13.4

3.4

17.3

A.7

7

7.1

8

2.3

27

11

14.5

3.3

3

5

6

18

17

14.6 and note 3

14.6 and note 4

2.3

32.6

32.6

32.7

32,7

14.3

1.1

14.5

32.2

3.3

4.6, note 1

4.6, note 2

4.6, note 1

4.6.3

4.6.4

32.2

1.2

36.6

36.6

36.6

36.6

36.6

46.4

40.3

43.4

48.3

-

13

13

3a

17

7

7

-

---

-

11

-

-

-

4a,4c

6

18

17

-

-

-

326

32a, 326

46, 14c

4Oa,

40b, 40c

43

48

88


7/17/2019 BS 00350-1꞉1974


ES1 B S * 3 5 8 :

P A R T * L

74

W 1624667

81Lb206 T

_ _ ~

~~~

-

~

~~

BS 350 Part 1 : 1974

General index

Term

Symbol Textual

reference

Table referem

and important notes

British thermal unit per foot hour degree

British thermal unit per ho ur

British thermal unit per pou nd

British thermal unit per pound degree

British thermal unit per squ are foot

hour

British thermal unit per square foot h our

bushel

(UK)

bushel (US)

bushel, international corn

Fahrenheit

FahrenhCit

degree Fahrenheit

cable-length

calendar year

calorie

calorie, dietitians

calorie, International Table

calorie, kilogram-

calorie, thermochemical

calorie, tonne-

calorie,

15 '

calorie per c entimetre second kelvin

calorie per cubic centimetre second

calorie per second

calorie per square cen timetre second

calorie per square centimetre second kelvin

calorific value, gases, with differing

reference conditions

calorific value, mass basis

calorific value, vo lume basis

candela

capaciíy

carat, metric

Celsius, degree

cental

centi

Centigrade

Centigrade heat unit

centilitre

centimetre

centinietre cubed

centimetre per second squared

centim etre second kelvin

per

calorie

centimetre to the fourth

centipoise

centistokes

chain

chain, engineers'

chain, Gunter's

cheval vapeur (metric horsepower, French)

coefficient, heat transfer

concentration .

conductance, thermal

conductivity, thermal

o

.

Btu/(ft h OF)

Btu/h

Btu/ib

Btu/(lb

"F)

Btul(ft2 h)

Btul(ft2 h

OF)

bu

a

Cal

call,

calth

d l 5

cal/(cm sK)

cal/(cm3 s)

cal/s

cal/(cm2

s)

cal/(cm2 s K)

cd

CM

(see 14, note 2)

C

ctl

C

C.H.U

cl

cm

cm3

cm/s2

cm s K/cal

cm4

CP

cs t

CV,

ch

46.4

37.4

39.3

41.4

44.3

45.4

4.6.1 and note 3

4.6.2,

4.6.4

14.6 and note 6

2.6 and note 16

9.4, footnote

36.6

see

36.6

36.6

see 36.6

36.6

see

36.6

36.6

46.3

48.2

37.4

44.2

45.3

40.4

39

40

A.7

4

14.3

38.2

14.5

1.1

see 38.2

36.6

4.3

2.2

5.2

13.2

47, note

6

34.2

35.2

2.5

2.6

2.5, note

5

37, footnote

45

20

45

.

46

46

37

39

41

44

45

4d

k,

4d

-

-

-

36b

use 366

36b

use 366

36b

use

366

366

46

48

37

44

45

4ûb,

40c

39

&, 4ûb, 4 0 c

4q 4b, c,

4d

14b

38

l a

-

-

-

-

use 4a,4b,4c

use 2

use

4a,

4c

13

47

6

34

35

2

2

37

45

20

45

46

-

89


7/17/2019 BS 00350-1꞉1974


BSI

B S * 3 5 0 : P A R T * l 94

e b 2 4 b b î íJlLb207

E

W

B S

350 Par t 1 : 1974

General index

Term

Symbol

Textual

reference Table reference

and important

notes

cord

corn bushel, international

cran

cubic centimetre

cubic decimetre

cubic foot

cubic foot per ho ur

cubic foot per pound

cubic foot p er second

cubic foot per UK ton

cubic inch

cubic inch per po und

cubic metre

cubic metre per hour

cubic metre per kilogram

cubic metre per seEond

cubic millimetre

cubic yard

' cumec

'

cusec

cycle

cycle per second

day

deca

deci

decimetre

dei3

degree Celsius

degree Fahrenheit

degree (of angle)

degree per m inute

degree per second

degree Rankine

denier

density

density, linear

density, relative

diffusivity, thermal

drachm (apothecaries', UK)

drachm, fluid (UK )

dram (apothecaries',

US)

dram (avoirdupois)

dram , fluid (US)

dram, liquid (US)

dynamic viscosity

dyne

dyne per centimetre

dyne per square centimetre

cm3

dm3

ft3

ft3/h

ft3/lb

ft3/s

f t i /UK ton

in3

in3/lb

m3

m3/h

m3/kg

m3/s

mm3

Yd3

C

CIS

d

da

d

dm

deg

C

"F

"/min

"R

O

Is

UK

f l

dr

d r

fl dr

liq dr

dYn

dynlcm

dyn/cm2

em

energy

energy, specific

Engler degree

enthalpy, specific

4.6, note 4

14.6 and note 6

4.6, note 5

4.2

4.2

4.5

23.3

21.3

23.3

21.3

4.5

21.3

4.1

23.2

21.1

23.1

4.2

4.5

23.1, footnote

23.3, footnote

see 12.1

12.1

9.3

1.1

1.1

2.2

38.5

38.2

38.3

7.2

11.2

11.2

38.4

15.2

19

15

19, footnote

49

14.5

4.6.1

14.5

14.5

4.6,3

4.6, footnote

34

28.2

31.2

32.2

2.6 and note 13

36

39

35.5

39.1

-

-

-

use 4a,

4c

4a,

6

4a, 46

23

21

23

21

4a, 46, 4c

21

4a, 6

23

21

23

4c

4a

23

23

-

-

l a

l a

use

2

38

38

7

11

11

38

19

15

see 35

14b

4c, 41

14b

4d

4d

34

28

-

-

-

-

-

-

36a, 36b

39

39

-

90


7/17/2019 BS 00350-1꞉1974


Term

Symbol

Textual reference

Tabkdemœ

and mportant notes

entropy, specific

ephemeris second

erg .

Fahrenheit, degree

fathom

.

femto

Festmeter (German)

flow rate, mass

flow rate, volume

flux density, hea t

foot

foot, board

foot,

US

survey

foot cubed

foot hour degree Fahrenheit per British

thermal unit

foot of water

foot per minute

foot per second

foot per second squared

foot poundal

foot pound-force

foot pound-force per pound

foot pound-force per pound degree

foot poun d-force per second

foot squared per hour

foot squared per second

foot to the fourth

force

force per unit length

frequency

frigorie

furlong

Fahrenheit

gal

galileo

gallon

(UK)

gallon (UK ) per hour

gallon (U K) per m ile

gallon (UK ) per minute

gallon (UK ) per pound

gallon (UK) per second

gallon (US)

gallon (US) per mile

gamma

gauge (pressure)

giga

gill (VK )

gill

(US)

gon

I

grade I

grain

grain per cubic foot

erg

F

f

Fm

ft

ft3

ft

h

"F/Btu

ftH2O

ft/min

ft/s

ft/s2

f t pdl

ft lbf

ft lbf/lb

ft Ibf/(lb

O F )

ft Ibfls

ft2/h

ft2/s

f t 4

Gal

Gal

UKgal

UKgal/h

UKgal/mile

UKgal/min

UKgal/lb

UKgal/s

USgal

USgal/mile

Y

G

gi

gon l .

I

g r m 3

gr

91

42

9.2

36.2

38.3

2.6

1.1

4.4

22

23

44

2.5

4.6, note 4

2.6

5.3

-

32.5

10.4

10.4

13.3

36.5

36.5

39.3

41.4

37.3

35.4

35.4

6

28

31

12

36.6

2.5

13.2

13.2

4.6.1

23.3

24

23.3

21.3

23.3

4.6.2, 4.6.3

24

14.2,

note

I

32.7

1.1

4.6.1

4.6.3

7.3

14.5

20.2

see 41

38

2

la

use4,46

22

23

44

2

-

-

4a

47

32c

10

10

13

36a

3óa, 36b

39

41

37

35

35

6

28

-

-

use 366

2

13

13

4th

4d

23

24a

23

21

23

4b, 4á

24a

-

-

la

4d

4d

7

14b

20


7/17/2019 BS 00350-1꞉1974


BSI B S 8 3 5 0 : PARTaL

74

L b 2 4 b b 7 OlLb209 5 I

t

BS 350 Par t 1 : 1974

General index

Tenn

Symbol

Textual reference Table reference

and important

notes

grain per U K gallon

grain per US gallon

gram

gram centimetre squared

gram per cubic centimetre

gram per cubic decimetre

gram per litre

gram per millilitre

gram per square m etre

gravity, specific

gravity, standard

hand

heat

heat capacity (volum e basis)

heat content (volume basis)

heat flow rate, intensity of

heat flux density

heat release rate

heat transfer coefficient

hectare

hectare per kilogram

hecto

hectobar

hectolitre

hertz

horsepower

horsepower, me tric

horsepower hour

hour

hundredweight

hundredweight, long US)

hundredweight, shor t (US)

imperial system, commentary on

inch

inch cubed

inch of mercury, conventional

inch of water, conventional

inch per second

inch squared per hour

inch squared

per

second

inch to the fo urth

inertia, geometrical moment of

inertia, mom ent of

intensity of heat flow rate

inverse second

iron

IPTS - 68

joule

joule, absolute

joule,

in erna tional

joule per cubic metre

joule per cubic me tre degree Celsius

ha

ha/kg

h

hbar

hl

Hz

hP

see 37.2, footnote

hP h

h

cwt

sh cwt

in

in3

inHg

i nHz 0

in/s

in2lh

in*/s

in4

S 1

J

J

J/m3

J/(mJ

OC)

92

20.2

'

20.2

14.2

25.2

19.2

20.1

20.1

19.2

16.2

19,

footnote

13.4

2.6 and note 14

36, 36.6

43

40

44

44

48

45

3.3

17.2

1.1

33

4.3

12. I

37.3

37.2

36.5

9.3

14.5

14.5

14.5

Appendix

A

2.5

5.3

32.5

32.5

10.4

35.4

35.4

6

6

25

44

12.1, 12.2

38.6

2.6, note 10

36.1

36.1

36.1

40.1

43.2

20

20

146

25

19

20

20

19

16

13

-

--

366

43

40n,

406, 40c

44

44

45

3a

17

l a

32a

see 4a, 4b

37

37

36a, 366

14c

14c

48

-

-

-

-

2

4a, c

326, 32c

32c

10

35

35

6

6

25

44

-

-

-

36a, 366

36a, 366

OU, 40b, 40c

43

-


7/17/2019 BS 00350-1꞉1974


Term

BS 350

Part

I

:

1974

General

index

Table reference

ymbol Textual

reference

and important

notes

joule per cubic m etre kelvin

joule per kilogram

joule per kilogram degree Celsius

joule per kilogram kelvin

kelvin

kilo

kilocalorie

per

cubic m etre

kilocalorie per cub ic metre ho ur

kilocalorie per cubic metre kelvin

kilocalorie per hour

kilocalorie

per

kilogram

kilocalorie per kilogram kelvin

kilocalorie

per

metre ho ur kelvin

kilocalorie per square metre hour

kilocalorie per square m etre hour kelvin

kilogram

kilogram-force

kilogram-force metre (energy)

kilogram-force metre (torque)

kilogram-force metre

per

kilogram

e


per

kilogram kelvin


per

second

kilogram-force per square centimetre

kilogram-force per square m etre

kilogram-force per square milíimetre

kilogram-force second per s qu are metre

kilogram metre squared

kilogram millimetre squared

kilogram per cu bic metre (density)

kilogram per cubic metre (concentration)

kilogram

per

hectare

kilogram

per

hour

kilogram per m etre

kilogram per metre second

kilogram

per

second

kilogram per square metre

kilometre

kilometre

per

hour

kilometre per litre

kilopascal

kilopond

kilopond met re (energy)

kilopond metre (torque)

kilopond per square centimetrc

kilopond per square metre

kilowatt

kilowatt hour

kinematic viscosity

knot (international)

knot

(UK)

a

kip

(US)

43.1

39.1

41.2

41.1

38.1

1.1

40.2

48.2

43.3

37.4

39.2

41.3

46.3

44.2

45.3

14.1

28.2

36.4

30.2

39.2

41.3

37.2

32.3

32.3

33

34.3

25.1

25.2

19.1

20.1

16.2

22.2

15.1

34.1

22.1

16.1

2.2

10.3

24

32.1

28.2

36.4,

ootnote

30.2

32.3

see 32.3

37.1

36.3

35

28.3

10.5

10.5

43

39

use

41

41

38

la

40a,

40b,

0c

48

43

37

39

41

46

44

45

14a

28

36u

30

39

41

37

3241,326

32c

32a,

ootnote

34

25

25

€9

20

16

22

15

see

34

22

16

see2

10

24b

see

32a, 32b, 32c

28

36u

30

324 32b

32c

use 37

36a, 36b

35

28

10

10


7/17/2019 BS 00350-1꞉1974


BS

350

Part 1 : 1974

General

index

Textual

reference Table referemie

and important

notes

rem

Symbol

39.1 39

2 2

2.3

2.6 and note 12

-

2.6andnotes 11,12

-

15

10

atent heat, specific

length

light year

ligne

line

linear density

linear velocity

link

litre

litre (1901)

litre atmosphere

litre per ho ur

litre per hundred kilometres

litre per kilogram

litre pei kilometre

litre per m inute

litre per second

mass

mass per unit area

mass per unit length

mass rate of

flow

mass unit atom ic

mega

megagram

megapascal

metre

metre cubed

metre hour kelvin per kilocalorie

metre kelvin per w att

metre of water

metre per second

metre per second squared

metre squared per hou r

metre squared per second

metre to the fourth

metric carat

metric horsepower

metric system, commentary on

micro

microgram

micro-inch

microlitre

micrometre

micron

micron (pressure unit)

microsecond

' mil ', circular

(of

area)

' mi1

'

of angle)

'

mil ' (of length)

'

mil '

(of

volume)

mile

1.y.

I

U

M

Mg

MPa

m

m3

m h

K/kcal

m K/W

mH 2 0

m/s

m/s2

m2/h

m2/s

m4

(see 14.3, note 2)

(see 37.2, footnote)

mil

mil

mile

15

10

2.6

4.3

4.3

36.4

23.2

24

21.2

24

23.2

23.2

14

16

15

22

14.3

1.1

14.2

32.1

2,

I

5.1

47

32.5

10.1

13.1

35.3

35,49

6.1

14.3

37.2

Appendix A

1.1

14.2

2.6

4.3

2.2

2.2

32.5

9, note I

3.5 and note 2

7, note 2

2.6 and note

8

4.4

2.5

-

-

4a,4b, 4c

4a,4b, 4c

36a

23

Fig.

I

21

24a

23

23

I , 146, 14r

16

15

22

ln

14c

32a

2

4a

47

47

see 32a

10

13

35

35

6

14b

37

ia

use 14h

use 2

use 4c

use

2

use 2

use 32c

36

2

4c

2

-

-

-

-


7/17/2019 BS 00350-1꞉1974


Tern i

Textnal reference Table reference

and important nofes

Symbol

mile, international nautical

mile, statute

mile, telegraph nautical

mile,

UK

nautical

mile per gallon

(UK)

mile per gallon (US)

mire per hour

milli

millibar

milligal

milligram

milligram per square centimetre

milligram per square miliimetre

millilitre

millimetre

millimetre cubed

millimetre of mercury, conventional

millimetre

of

water, conventional

millimetre to the fourth

million

mi

11

seco

n

d

minim (UK )

minim

(US)

minute (of angle)

minute (of time)

modu lus of section

mole

moment, first, of area

moment, geometrical, of inertia

mom ent of force

moment of inertia

momentum, angular

momentum (linear)

month

nano

nanosecond

nautical mile (international)

newton

newton metre

newton per metre

newton per square metre

newton per square millimetre

newton second per square m etre

number

ounce (apothecaries' UK )

ounce (apothecaries' US)

ounce (avoirdupois)

ounce, fluid (UK )

ounce, fluid (US)

ounce, liquid (US)

ounce-force

ounce-force inch

ounce inch

squared

mGal

mg

mg/cm2

mg/mm2

ml

mm3

m H g

inmH2O

mm4

ms

UKmin

mm

min

mol

n

ns

n mile

N

N m

N/m2

N/mm2

N s/m2

N/m

oz apoth

oz ap

um oz

u s f i

oz

liq oz

OZ€

ozf

in

oz

in2

OZ

95

13.2

14.2

16.2

16.2

4.3

2.2

5.2

32.5

32.5

6

1.2

9, note 1

4.6.1

4.6.3

7.2

9.3

5

A.7

5

6

30

25

27

26

9.4

1.1

.

9, note 1

2.3

28.1

30.1, 36.1

31.1

32.1

33

34.1

1

14.5

14.5

14.5

4.6.1

4.6.3

4.6.3, footnote

28.3

30.3

25.3

n mile 2.3

mile 2.5 an d note 6

2.6

2.6 and note 16

mile/UKgal 24

mile/USgal 24

milelh 10.4

m 1.1

mbar (mb) 32.2 and footnote

2

2

2

24b and

Fig.

1

246 and Fig. 1

10

la

32b, 32c

13

use 146

16

16

4c

use 2

use 4a

32c

32c, footnote

6

lb

4c, 4d

-

-

4d

7

4a

4a

6

30

25

-

-

-

-

l

2

28

30

3241,

3 2 4

32c

32a

Use 34

la,

l b

14b

14b

14b

4c, 4d

4c, 4d

4c,

4d

28

30

25

-

-


7/17/2019 BS 00350-1꞉1974


BSI B S 8 3 5 0 : PART>i(L 7 4 W 3b24bbî

O L L b 2 L 3 - 7 e_-

BS

350 Part

1 : 1974

General

index

Term

Symbol


and

important notea

ounce per squ are foot

ounce per square yard

ounce per UK gallon

ounce per U S gallon

ounce troy (UK )

ounce troy (US)

parsec

pascal

pascal second

peck (US)

perch

Petrograd standard

Pferdéstärke (metric horsepower, German)

pico

pièze

pint

(UK)

pint, dry

(US)

pint, liquid (US)

plane angle

point

poise

poiseuille (French )

pole

pond (gram-force, Germ an)

pound

pound foot squared

pound-force

pound-force foo t

pound-force hour per square foot

pound-force inch

pound-force per square foo t

pound-force per square inch

peck (UK)

pound-force second per square inch

gound-force second per square foot

pound inch squared

pound per acre

pound per cubic foot

pound per cu bic inch

pound per foot

pound per foot hour

pound per foot second

pound per (UK ) galion

pound per (US) ‘gallon

pound per hour

pound

per

inch

pound p er mile

pound per second

pound per thousand square feet

pound per yard

pound troy (US)

poundal

poundal foot

oz/ft2

oz/yd2

oz/UKgal

oz/USgal

oz tr

oz t

PC

Pa

Pa s

Pk

PS

P

P=

UKpt

liq pt

P

P1

P

Ib

Ib ft2

Ibf

Ibf ft

lbf h/ft2

lbf in

lbf/ft2

Ibf/in2 (p.s.i.)

Ibf s/in2

lbf s/ft2

Ib in2

Ib/acre

Ib/ftJ

lblin3

Ib/ft

lb/(ft h)

lb/(ft s)

lb/UKgal

IbJUSgal

lb/h

lb/in

Ib/mile

Ibis

lb/loOO

ft2

WYd

Pdl

pdl ft

16.3

16.3

20.2

20.2

14.5

14.5

2.3

32.1,33

34.1

4.6.1

4.6.4

2.6 and note 15

4.6,note 4

37, ootnote

1.1

32.2

4.6.1

4.6.4

4.6.3

7

2.6

and note

9

34.2

3 4 . 1

2.6 and note 15

see 28.2

14.4

25.3

28.3

30.3

34.3

30.3

32.4

32.4

33

34.3

34.3

25.3

16.3

19.3

19.3

15.3

34.3

34.3

19.3

19.3

22.3

15.3

15.3

22.3

16.3

15.3

14.5

28.3

30.3

16

16

20

20

146

146

-

32a,

2b.

32c

34

4d

4d

-

-

37

la

-

4b,

4d

%

4d

4b,4d

7

-

l k , 14c

25

28

30

34

30

32c

324

32b

32a, 326

34

25

16

19

19

15

see

34

34

19

19

22

15

15

22

16

15

28

30

-

96


7/17/2019 BS 00350-1꞉1974


Symbol

B S

350 Part 1

:1974

General

index

Texlual referem Table reference

and

mportant

notes

poundal per square foot

poùnd al second per square foot

pounds-force per square inch (absolute)

pounds-force per square inch (gauge)

power

pressure

quadrillion

quart (UK)

quart, dry

(US)

quart, liquid

(US)

quarter

quintal

radian

radian per minute

radian per second

Rankine, degree

Raummeter (German)

Redwood number

refrigeration,

ton of

relative density

release rate, h eat

resistivity, thermal

revolution per m inute

(angular velocity)

revolution per minute

(rotational frequency2


(angular velocity)


(rotational frequency)

' eyn

'

right angle

rod

rood

rotation, speed

of

rotational speed

rotatio nal velocity

Saybo lt scale

Scale, International Practical

scruple (apothecaries')

second (of angle)

second (of time)

second, ephemeris

second, inverse

section, modulus

of

short hundredweight

short ton

slug

slug hou r per foot second squared

Temperature,

of

1968

pdllft2

pdl s/ft2

p.s.i.a

p.s.i.g

UKqt

Iiq qt

qr

9

dry qt

rad

radtmin

rad/s

"R

Rm

rev/inin

r/min

rev/min

rlmin

rev/s

rls

revls

rls

L

IPTS

- 68

I I

S

S

1

sh cwt

sh ton

slug h/(ft

52)

97

32.4

34.3

32.7

32.7

37

32

1.2

4.6.1

4.6.4

4.63

14.5

14.3

7.1

11.2

11.1

38.4

4.4

35.5

37.4

19, footnote

48

47

11.2

12.3

11.2

12.2

34.3, footnote

7.1

2.6, note 15

3.4, note

1

11,

footnote

i l , footnote

li,

footnote

35.5

38.6

14.5

7.2

9.1

9.2

12.1,

12.2

5

14.5

14.5

14.6 and note

5

see

34.3

32u

34

-

-

37

32a, 326,32c

l b

4d

4d

4d

-

-

7

11

11

38c

use

4a,4b

-

.-

_-

48

47

11

-

11

-

-

7

3a

-

-

-

-

-

- _

-_

7

-

-

4a

14c

14c

14a

Use

34


7/17/2019 BS 00350-1꞉1974


B S I

B S * 3 5 0 : P A R T * l

74 b 2 4 b b î OJiLb2L5 O

~

BS

350 Par t

I : 1974

General

index

Term

Symbol

Texhial

reference Table reference

and important notes

slug per foot second

solid angle

specific energy

specific entropy

specific grav ity

speciñc heat

speciñc heat, volume basis

specific heat capacity

specific latent heat

specific surface

specific volum e

speed

speed, rotational

square centimetre

square centimetre per milligram

square decimetre

square foot

square foot hour degree Fahrenheit

square foot per gallon

square foot per ounce

square foot (thousand) per poun d

square inch

square kilometre

square metre

square metre per gram

square metre per kilogram

square metre per litre

square mile

square mile per ton

square millimetre

square millimetre per milligram

square yard

square yard per gallon

square yard per ounce

standard, (Petrograd)

standard atmosphere

standard gravity

steradian

stère (French)

sthène (French)

stokes

stone

stress

surface, specific

per B ritish thermal unit inch

technical atm osphere

technical atmosphere, absolute, Germ an

temperature

temperature, thermodynam ic

temperature difference

temperature interval

tera

tex

slug/(ft

s)

C I l l Z

cm2/mg

dm2

ft2

ft2 h 'F/(Btu in)

ft2/gal

ft2/oz

1000 ft2/lb

in2

km2

m2

m2/g

m 2 / k

m2/l

mile2

mileZ/ton

mm2

mm2/mg

Yd2

yd2/ga1

yd2/oz

atm

gn

sr

st

sn

St

a t

ata

T

34.3

8

39

42

19, footnote

41, footnote

43 and footnotes

41

39.1

17

21

10

11, footnote

3.2

17.2

3.2

3.4

to 41

-

18

17.3

17.3

3.4

3.2

3.1

17.2

17.1

18

3.4

17.3

3.2

17.2

3.4

18

17.3

4.6, note 4

32.6

13.4

8

4.4

28.2

35.2

14.5

33

17

32.6

32.7

38

see 38

38

38

1.1

15.2

34

39

see 41

-

-

43

41

39

17

21

10

use 30

use 17

use 3a

3a

47

18

17

17

3a, 3b

use 3a

3a

use 17

17

18

3a

17

36,3a

'1 7

3a

18

17

326

13

use 4a,46

use 28

use 35

32a,

32b, 32c

17

32a, 326

38

-

-

-

-

-

-

-

-

l a

-

98


7/17/2019 BS 00350-1꞉1974


B S I B S * 3 5 0 : P A R T x L 74

D

L b 2 4 6 6 9 O L L b 2 L b

2

~~~~

__

~~

~

BS 350 Part 1 :1974

General index

Term

ssmbol


and important notes

therm

therm per gallon .

thermal conductance

thermal conductivity

thermal diffusivity

thermal resistivity

thermie

thermie per litre

thermodynam ic temperature

' hou '

time

ton

ton, assay

(U#)

ton, assay (US)

ton, gross

(US)

ton, long (US)

ton, short (US)

ton-force

ton-force

US)

ton-force foot

ton-force per square fûoi

ton-force per squ are inch

therm/UKgal

th

th/litre

thou

ton

ah

ton

tonf

u s t o n f

tonf ft

tonf/in*

tonf/ft2

ton mile

ton mile

per

gallon

ton of refrigeration

ton per cubic yard

ton per hour

ton per mile

ton per square mile

ton per thousand yards

toniie

tonne-calorie

tonne kilometre

tonne kilometre per litre

torque

torr

traffic actors

trillion

tropical year

troy units

unit, atomic mass

'

acuum ' values

velocity, angular

velocity, linear

velocity, rotation al

viscosity, dynamic

viscosity, kinematic

volume, and capacity

volume, specific

volume rate

of

flow

Vollwinkel (German)

UKton d e

UK ton milejUKga1

tonlyd3

ton/h

tonlmile

ton/mile*

ton/lûûû yd

L

t km

t km/l

36.6

40.3

45

46

49

47

36.6

40.2

see 38

2.5, note

7

9

14.5

14.6 and

note

3

14.6 and note 4

14.5

14.5

14.5

25.3

28.3

30.3

32.4

32.4

33

24

24

37.4

19.3

22.3

15.3

16.3

15.3

14.2

see

36.6

24

24

30

32.5

24

1.2

9.4,

footnote

14.5

-

40a

45

46

see

35

47

use 36b

4oa

use

2

14c

-

-

-

-

-

14c

28

use 28

30

32a

3%

32a

under 246

under 246

19

22

15

16

15

1412

use 36b

under 24b

under 246

30

32b

244

246

and Fig.

1

Ib

-

-

14.3

32.7

11

10

11, footno te

34

35

4

21

23

7,

note

3

-

11

10

34

35

4a,

4b, 4c, 4d

21

23

-

-

99


7/17/2019 BS 00350-1꞉1974


BS

350

Part

1

: 1974

General index

watt

watt per cubic metre

watt per metre degree Celsius

watt

per

metre kelvin

watt per square inch

watt per square metre

watt per square metre degree Celsius

watt

per

square metre

kelvin

week

weight

work

Term

Symbol

Tertiralreferm ce Table reference

andimportantnotea

W 37.1 37

W/m3 48.1 48

46.2 46

46

Wl(m "Cl

W/(m K) 46.1

W/in2

44.3 44

W/m2

44.1 44

W/(m2 OC 45.2

45

W l W K)

45.1

45

9.4

29

14a, 146, 14c

36 36a, 366

-

28

yard

year

year, calendar

year, light

year, tropical

Yd

a

a

ley.

a

2.4

9.4

9.4, footnote

2.3

9.4, footnote

1

O0


7/17/2019 BS 00350-1꞉1974


BSI publications referred t o in this standard

This standard makes reference to the following British standards:

BS 718 Density hydrometers and specific gravity hydrometers

RS 860

Tables for comparison

of

hardness scales

RS 874 Methods of determining thermal properties, with definitions of thermal insulating terms

RS 947

Universal system for designating linear density of textiles (Tex System)

BS

1797

Tables for lise in the calibration

o f

volumetric glassware

ß S

1957 Presentation

of

numerical values (fineness of expression; rounding

of

numbers)

BS

7570 Barometer conventions and tables

BS 2856 Precise conversion of inch and metric sizes on engineering drawings

RS 3763

The International System

of

iinits

(SI)

PI) 5686 The use of SI iinits

O


7/17/2019 BS 00350-1꞉1974


bs 00350-1꞉1974

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