worksheet single vertical

8/13/2019 Worksheet Single Vertical

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Spill Prevention Control and Countermeasure (SPCC) Plan

Single Vertical Cylindrical Tank Inside a Rectangular or Square Dike or Berm

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This worksheet can be used to calculate the secondary containment volume of a rectangular or squaredike or berm for a single vertical cylindrical tank. This worksheet assumes that there are no other objectsor structures within the dike or berm that will displace the volume of the secondary containment.

Steps%1. Determine the volume of the secondary containment, V!

"a. Determine the volume of the tank when the tank shellcapacity is unknown, VTank

"b. Determine the volume of the tank when shell capacity isknown, VTank

#. Determine the percentage of the secondary containmentvolume, V!, to the tank volume, VTank

$. Determine whether the secondary containment cancontain the entire tank shell capacity with additional

capacity to contain rain.

Tank % hell !apacity &gal' (

a

July 2011 - Page 1of 4

Disclaimer% )lease note that these are simplified calculations for qualified facilities that assume* 1' the

secondary containment is designed with a flat floor+ "' the wall height is equal for all four walls+ and #'the corners of the secondary containment system are - degrees. %dditionally, the calculations do not

include displacement for support structures or foundations. or )rofessional /ngineer &)/' certified

)lans, the )/ may need to account for site0specific conditions associated with the secondary

containment structure which may require modifications to these sample calculations to ensure good

engineering practice.

In&ormation needed to use t'isorks'eet%

Tank shell capacity in gallons ortank diameter and height in feet

econdary containment length,width, and height in feet

f rain can collect in secondarycontainment* amount of rain ininches or feet


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* Determine t'e volume o& t'e secondary containment+ VSC

Secondary Containment Area, ASC( 2

3ength&ft'

4idth&ft'

( ft"

,

VSC(ft3)( 2 ( ft#

b&ft"'

5eight&ft'

c

-a* Determine t'e volume o& t'e tank 'en t'e tank s'ell capacity is unknon+ VTank

-,* Determine t'e volume o& t'e tank 'en s'ell capacity is knon+ VTank

ais the tank shellcapacity from page 1.

VTank(ft3) ( 2 -.1##6 ( ft#

a &gal' ft#7gal e

.* Determine t'e percentage o& t'e secondary containment volume+ VSC+ to t'e tank volume+VTank

&to determine whether the volume of the containment is sufficient to contain the tank8s entire shell capacity'.

1teps # and $ in the worksheet determine whether the volume of the secondary containment is sufficient to contain the tank8s

entire shell capacity and rainfall &freeboard for precipitation' as required by the )!! rule. tep # primarily determines whetherthe volume of the secondary containment is sufficient to contain the entire shell capacity of the tank. tep $ is necessary todetermine whether the secondary containment can also contain the e2pected volume of rainfall &both the volume of rain that fallsinto the containment plus the rain from the tank storage site'.


Tank radius (ft)( 9 " ( ft

Diameter&ft'

VTank(ft3)( #.1$ 2 & '" 2 ( ft#

:adius"

&ft'"Tank5eight&ft'

d


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VSCVTank ( 9 (cis the secondary containment !olumecalculated in Step 1.

d / e

is the tank !olume calculatedin Step ".

c&ft#'

d or e&ft#'

&

# ( 2 1-- (

f g

f percentage, g, is 1--; or greater, the capacity of the secondary containment is sufficient to contain the shellcapacity of the tank. f rain can collect in the dike or berm, continue to step $. f percentage, g, is less than 1--;,the capacity of the secondary containment is not sufficient to contain the shell capacity of the tank.

/* Determine 'et'er t'e secondary containment can contain t'e entire tank s'ell capacity it'additional capacity to contain rain*

f rain can collect in a dike or berm, the )!! rule requires that secondary containment for bulk storage containershave additional capacity to contain rainfall or freeboard. The rule does not specify a method to determine theadditional capacity required to contain rain or the si


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:ainfall &ft' ( 9 1"

h &in' in7ft

( ft

i

Volume of :ain to be !ontained, V:ain&ft#' ( 2 ( ft#

bis the area of secondary containmentcalculated in Step 1. i &ft' b &ft

"' 0

Total !ontainment !apacity :equired &ft#' ( B

d/eis the tank !olume calculatedin Step ".

j&ft#'

d or e&ft#'

( ft#

k

f the volume of the secondary containment, c, is equal to or greater than the required containment capacity, k, thesecondary containment is sufficient to contain the shell capacity of the tank with sufficient additional capacity tocontain a typical rainfall amount. f the volume of the secondary containment, c, is less than the requiredcontainment capacity, k, the secondary containment is not sufficient to contain the shell capacity of the tank and atypical rainfall amount*


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