Kitchen & Bath Lighting

A good lighting design should:

Look good – both people and design space Provide the proper amount of light in every

room Be built and constructed within budget,

code, and other constraints in mind Be environmentally responsible Respond to the architecture and interior

design Produce good color Achieve the desired mood of each space Allow lighting control

The layered approach to lighting design

Begin by thinking in layers

task

decorativefocal

ambient

Decorative

Ambient

decorative

ambient

Task

Focal

Lighting Concepts

General Lighting Task Lighting Workplane Distance Footcandle Lumen Candlepower (Candelas) Watts Lamp Data Tables

Lighting Concepts general lighting

Every room must have enough illumination to navigate through it.

The amount of light will vary depending on the activities performed in the room.

General lighting is measured at the workplane level. If there is no workplane like in the livingroom it is calculated at 30” above the floor.

General lighting is measured in “footcandles”

Lighting Concepts general lighting

Even light distribution is the key to great general lighting. Fixture placement and spacing must be accurately placed based on the lamps cone of light.

LIGHT SCALLOPS

TASK LIGHTING

EDGE OF BEAM SHOULDNOT INTERSECT CABINETFRONT

General Lighting General

Lighting

Lighting Concepts task lighting

Working at the sink Working at a desk Working at a prep area Reading

Lighting Concepts workplane

Workplane – The actual or implied surface on which work happens

Distance = Lamp Ht. –workplane height

Distance = 96”-36” = 60”6'-7 3/4"

11'-9 1/4"60"

36"

18'-5"96"

Lighting Concepts footcandles

How do we measure the light on a work surface?

Footcandle – a unit of measurement that describes the amount of light on a surface, workplane, art, etc.

Lux – The European Footcandle

Lux = FC x 10.76FC = Lux x .0929

Lighting Concepts footcandles

Sphere w/ 1 foot radius 1 SF of sphere surface 1 Footcandle is the

amount of lighting falling on that surface

There are 12.57 of these one radius square curved planes in any sphere.

They are known as Steradians

Lighting Concepts lumen

Let’s talk about another form of measurement in lighting

Lumen – a unit of measurement defining the quantity of light a lamp produces.

In order to achieve the proper amount of footcandles necessary to illuminate a work surface we must know the strength of the light source.

Only then can we determine how many are needed and how far apart they are spaced.

Lighting Concepts candlepower

Candlepower – the measurement of a lamps intensity, but only if it is directional

SUNsuns intensitymeasured in lumens

mostfootcandles

more footcandles least footcandles

10°28°53°

1110lumens

1110lumens

1110lumens

1,250candlepower

3,600candlepower

16,000candlepower

5’

50 footcandles

640 footcandles

144 footcandles

Lighting Concepts beam angle

A directional lamp focuses or redirects its light energy into a cone emanating from a lamp’s lens where it is measured in candlepower.

The center of the cone has the most intense light

The edges have the least

SPILL

LIG

HT SPILL LIG

HT

2000

cand

lepow

erN

ADI

R

1000

1000

The beam angle is defined where candlepower drops off to 50%

From 50% to 10% is called spill light

200200

Lighting Concepts watts

Wattage tells us how much power or energy is burned by a lamp

Wattage tells us nothing about the amount of light a lamp can produce

A 60 watt PAR38 lamp will have ~ three times the candlepower when compared to a 75 watt R40 lamp.

Color and Reflectance

Color and Reflectance

Color Temperature

Color Rendition Index (CRI)

Reflectance

Color Temperature

Color Temperature

Color temperature is measured in Kelvin 10,000K appears blue 1000K appears red 3000K to 3600K is

considered neutral

Color Temperature

Lower color temperature means warmer color

Higher color temperature means a cooler color

Cool colors

Warm colors

Color Rendition Index

Color Rendition Index

Color Rendition Index is a scale from 1 to 100 which describes the effectiveness of a light source in reproducing accurately, an objects color. 100 being the best.

The sun has a CRI of 100 The best lamps to use are ones with a

CRI over 80 Incandescent lamps have a CRI of over

98 Fluorescents are the ones we want to be

careful with

Color and Reflectance cri

Typical 4 foot fluorescent tube cool white or warm white bulbs have a CRI of around 50 and 60 respectively

Color corrected fluorescent lamps are now available in 70 and 80 CRI and those with rare earth phosphorus reach 90

COLOR TEMP. VS CRI

Color Temperature describes how the lamp itself appears when illuminated.

CRI describes the effectiveness of a light source in reproducing accurately, an objects color.

All together now!

Lumens - define the quantity of light

Candlepower defines the intensity of light

Footcandles defines the amount of light

on a surface

All together now!

Color temperature describes how the lamp

itself appears CRI

describes the effectiveness of a light source in reproducing accurately, an objects color.

Reflectance

Reflectance – is the amount of light which reflects off an object

This quantity of light is measured in “Foot-lamberts”

The amount of light that reflects off of objects in a room adds to the overall illumination

So, reflectance must be taken into consideration when determining the Footcandle requirements for a room.

4%reflected

100%From Lamp

100%From Lamp

80%reflected

REFLECTANCE TABLECOLORS %

White 70-80Light cream 70-80Light yellow 55-65

Light green 45-50Pink 45-50Sky-blue 40-45Light gray 40-45

Beige 25-35Yellow ocher 25-35Light brown 25-35Olive green 25-35Orange 20-25Vermillion red 20-25Meduium gray 20-25

Dark green 10-15Dark blue 10-15Dark red 10-15Dark gray 10-15

MATERIALS %

Mirror 95Plaster 80White enamel 65-75Glazed white tiles 60-65

Maple (nat.) 60Birch (nat.) 60Light oak 40Dark oak 15-20Dark walnut 15-20

Concrete 15-40Red brick 5-25

Carbon-black 2-10

Clear glass 6-8

Ideal Ceiling 60-90Ideal walls 35-60Ideal countertops 30-50

Reflectance

Example – 10’ x 10’ kitchen Ceiling reflectance -The ceiling color is white

80% Wall reflectance

Determine the total wall area10’ x 8’ = 80 x 4 = 320 SFDivide the room into three

predominate materials. 50% is cabinetry (~160 SF)20% is windows and openings (~64 SF)30% is wallpaper (~96 SF)

Reflectance

Next assign each material a reflectance Natural maple cabinets = 60% Windows & doors = 4 % Dark green wallpaper = 15%

Next multiply each reflectance times its percentage of the total square feet .60 x .50 = .30 .04 x .20 = .008 .15 x .30 = .045Total = .353 The average wall

reflectance is 35%

Reflectance

Floor reflectance – 100SF of warm gray slate – use medium gray (25%)

Average the totals:Ceiling – 80%Walls - 35%Floor - 25%Average = 47%

Lighting Spacing Principles

Spacing Directional Lamps -

40" 40" 40"

WORKPLANE

60"

X X X

120"

40" 40" 40"

WORKPLANE

60"

X X X

120"

BRIGHTSPOT

30" 60" 30"

WORKPLANE

60"

X 2X X

120"

WORKPLANE

60"

X X

WORKPLANE

120"

20" 40" 40" 20"2X 2X

135"

55°55°

6”

Lighting Spacing Principles

Calculating Beam SpreadCalculate H the distance from luminaire to 6”

above work surfaceWith a typical 96” ceiling height and a work

surface at 36 “ the distance would be 54”

B = 55°H = 54”2 (tan27.5° * 54) = ~56” = distance between

luminaries

)*2/1(2 HBTAN

135"

56"

55°55°

63"8"

spillspill

56"

39 1/2"• 55 beam spread• 54” distance• 60 to work plane

Let’s work an example

1 3 6 "

13

6"

WOR K SUR FA C E = 3 6 " A FF

c EIL ING hEIGHT = 9 6 "

B EA M SP R EA D = 3 5 °

1 3 6 "

13

6"

WOR K SUR FA CE = 3 6 " A FF

c EIL ING hEIGHT = 9 6 "

B EA M SP R EA D = 3 5 °

1 7 " 3 4 " 3 4 " 3 4 " 1 7 "

17

"3

4"

34

"3

4"

17

"

Let’s work an example

This one exists only in a perfect world!96” Ceiling Height55º Beam Spread

191"

135"

56"

55°55°

63"8"

spillspill

56"

39 1/2"

39 1/2" 56" 56" 39 1/2"

39 1/2"

56"

191"

Another Example

This time from the real world96” Ceiling Height55 Beam Spread

178"

178"

37"

37"

37"

37"

52" 52"

52" 52"5656

72"

30"

12" 24" 24" 12"

15"

15"

30"

What beam angle is required?

NOTE: BETWEEN24" AND 27"

58° Beam Angle

27"

6"

21"

30”

15”15/27 = .5556

ATAN.5556 = 29º

29°x 2 = 58º

58/2 = 29

TAN29 = .5543

.5543 x 21 = 11.6411.64X2= ~24

72"

30"

12" 24" 24" 12"

15"

15"

30"

Lighting the sink

Page 109 in Lighting Kitchens & Baths Made Easy

12”/54” = .2222

ATAN .2 = 12.53º

12.53 x 2 = ~25º Beam Spread

Lighting Measurements

Footcandles LevelsInverse Square Law

Lighting Measurements

Recommended base Footcandle Levels – Page 48

Adjustment Factors – Page 49

Lighting Measurements

Inverse Square Law The greater the distance the

lamp is from the object or workplane, the more powerful it will need to be

The I.S. Law allows you to establish the appropriate lamp candlepower for any distance.

Lighting Measurements

Three factors:Candlepower (Cp)Footcandle (Fc)Distance (D)

If you know two factors you can calculate the third.

Inverse Square Law

Candlepower =

Footcandle =

Distance = Cp Fc

2Cp D

2D Fc

Inverse Square Law

D2

FC

CP

Inverse Square Law

Distance = 5’

Footcandles = 40

Candlepower = ?1000

Inverse Square Law

Distance =

Footcandles = 40

Candlepower = 1000

?5’

Bathroom Vanity Lighting

Side lighting recommended 30” apart