FO-1
COMMITTEE
PERSONNEL
AND
VOTE
Report of Committee on Foam
D r . R i c h a r d L. Tuve, C h a i r m a n
J o h n s H o p k i n s U n i v e r s i t y , Applied P h y s i c s L a b o r a t o r y ,
8621 G e o r g i a A v e n u e , S i l v e r S p r i n g , MD 20910
Herb E. Wolff, S e c r e t a r y
R e l i a n c e I n s u r a n c e C o m p a n i e s , 4 P e n n C e n t e r P l a z a , Philadelphia, P A 19103
(Rep. A m e r i c a n I n s u r a n c e A s s o c i a t i o n )
T h e r o n A r r a s , I n s u r a n c e S e r v i c e s Office
of Ohio
W a y n e E. A u l t . R o l l J e n s e n & A s s o c i a t e s
Inc.
C. F. Averill, N a t i o n a l A u t o m a t i c S p r i n k l e r & F i r e Control A s s n .
R. R. B u r f o r d , 3M C o m p a n y
L a y a r d Campbell, N a t i o n a l A u t o m a t i c
S p r i n k l e r & F i r e Control A s s n .
J . R. C o r c o r a n , Edison E l e c t r i c I n s t i t u t e
F r e d Deacon, A m e r i c a n M u t u a l I n s u r a n c e
~lllance
Ralph H. Hiltz, Fire Equipment M a n u facturers Services Assn.
P. E. Johnson, Factory Mutual Research
Corporation
Donald J. Kerlin, United States Coast
Guard
W i l l i a m G. L e m k e , F a c t o r y I n s u r a n c e
Assra
C. H. L i n d s a y , E l m i r a . N Y
N o r m a n R. L o c k w o o d , A m e r i c a n P e t r o leum Institute
Horace Mahley, Consultant, Woodbury I NJ
J a c k P. M c L a u g h l i n , U n i o n C a r b i d e Corporation
D. N. M e l d r u m , N a t i o n a l F o a m S y s t e m ,
Inc.
R. F. M u r p h y , A m e r i c a n P e t r o l e u m I n stitute
J a m e s O ' R e g a n , F e e c o n Corp.
REPORT
STATEMENT
John Perry, Underwriters' Laboratories,
Inc.
H. B. Peterson, U . S. N a v a l R e s e a r c h L a b oratory
L. E. R i v k i n d , T h e Mearl Corp.
H. S. Robinson, Oil I n s u r a n c e Assn.
E u g e n e Stauffer, F i r e E q u i p m e n t M a n u facturers Assn.
S t u r g i s L. S t e n t z , Lorcon F o a m , Inc.
Alternates
William G. Boyce, U. S. Coast G u a r d
( A l t e r n a t e to Donald J . K e r l i n )
T h o m a s L. Culbertson, A m e r i c a n P e t r o l e u m I n s t i t u t e ( A l t e r n a t e to R. F.
Murphy)
Arthur
Lagadinos,
Insurance Services
Office ( A l t e r n a t e to T. A r r a s )
F r a n k J . Noyes, F a c t o r y I n s u r a n c e A s s n .
( A l t e r n a t e to W. G. L e m k e )
E. A. S a u n d e r s , A m e r i c a n M u t u a l I n s u r ance
Alliance
(Alternate
to
Fred
Deacon)
R. E. Sherwood, 0il I n s u r a n c e Assn.
( A l t e r n a t e to H. S. R o b i n s o n )
K e n n e t h A . Zuber, F i r e E q u i p m e n t M a n u f a c t u r e r s Assn. (Alter~iate to E u g e n e
Stauffer)
Nonvoting
D e s m o n d Hird, A n g u s F i r e A r m o u r
Thi~ list r e p r e s e n t s the m e m b e r s h i p ~t the time the C o m m i t t e e w a s balloted on the t e x t of
this edition. Sinve t h a t time, changes in t h e m e m b e r s h i p m a y have occurred.
The Report of the Committee on Foam consists of two
parts:
P a r t I presents for official adoption amendments to N F P A
11, S t a n d a r d for Foam E x t i n g u i s h i n g Systems. Chapters 3,
4, 5 & 6 have been editorially reorganized to make the standard easier to use. The substantive changes are indicated by
a vertical line. N F P A 11 is published in the 1975 National
Fire Codes, Volume 1, and in separate pamphlet form.
Part I has been s ubm i t t ed to letter ballot of the committee
which consists of 26 voting m e m ber s o / w h o m 25 have voted
affirmatively and Mr. M u r p h y has not returned his ballot .
OF
COMMITTEE
ON
FOAM
FO-2
Par, II presents for official adoption N F P A 11A, S t a n d a r d
for High Expansion Foam Systems. The s t a n d a r d has been
rewritten according to the N F P A Manual of Style and
equivalent SI units have been added to the customary units.
The substantive changes to the s t a n d a r d are indicated by a
vertical line. N F P A 11A is published in the 1975 National
Fire Codes, Volume 1, and in separate pamphlet form.
Par, II has been su b m itte d to letter ballot of the committee
which consists o / 2 6 voting members, o / w h o m 25 have voted
affirmatively and Mr. Mu~'phy has not returned his ballot .
Part I
Proposed Revisions to the
Standard for Foam
NFPA
Extinguishing Systems
11 -
1974
1. 1735. Delete the 4th sentence o / p a r a g r a p h 1735 and rewrite the 4th th¢'u 7th sentences of the parag¢'aph as follows:
Pipe sizes shall be so selected as to produce the proper
delivery rate and pressure at the discharge outlet. (See Chapter 7 of N F P A No. 13, S ta n d a rd /or the Installation of
S p r i n k l e r Systems, for hydraulic calculation procedures for
water and solution flow.) For friction losses in piping carrying foam concentrate see N F P A No. 16, S t a n d a r d / o r the Installation of F o a m - W a t e r Sprinkler and F o a m - W a t e r S p r a y
Systems, Section 4064. F o r friction losses in piping c a r r y i n g
foam, see A-3561. F o r purpose of computing friction loss in
piping, the following "C" factors shall be used for the Hazen
and Williams formula:
Black Steel or Unlined Cast-Iron Pipe . . . . . . . . . .
100
Galvanized Steel Pipe . . . . . . . . . . . . . . . . . . . . . . .
120
Asbestos-Cement or Cement Lined Cast-Iron Pipe 140
2. 261. In the last sentence delete N F P A No. 16 and add
N F P A No. 13, S t a n d a r d for the Installation of Sprinkler ]
i
Systems.
3.
Revise Chapter 3 to read as follows:
FO-3
REVISIONS TO NFPA I I
CHAPTER 3.
FIXED SYSTEMS FOR EXTERIOR STORAGE TANKS
*300.
General.
301. SCOPE:
This chapter contains requirements
which apply specifically to the foam systems used for the protection of outdoor vertical atmospheric storage tanks containing flammable and combustible liquids by means of fixed foam
discharge outlets. System design shall be based on the maxii m u m solution flow for protecting a single tank and the required supplementary hose streams.
Tanks containing Class III liquids are not, as a rule,
required to be protected by foam. Foam protection for Class III
liquids may be desirable where abnormal situations exist, such as
storage of high value stocks or liquids heated above their flash point.
NOTE:
*302.
DEFINITIONS:
(a)
FIXED FOAM DISCHARGE OUTLET:
A device
p e r m a n e n t l y attached to a tank by means of which foam is
introduced into the tank.
(b)
TYPE I. DISCHARGE OUTLET:
An approved
discharge outlet which will conduct and deliver foam gently
onto the liquid surface without submergence of the foam or
agitation of the surface.
(c) TYPE II. DISCHARGE OUTLET: An approved
discharge outlet which does not deliver foam gently onto the
liquid surface but is designed to lessen submergence of the
foam and agitation of the surface.
(d)
SUBSURFACE FOAM INJECTION:
Discharge of
foam into a storage t a n k from an outlet at the tank bottom or
below the liquid surface.
(e) FIXEDINSTALLATIONS: These are complete installations piped f r o m a central foam house to the tanks, disc h a r g i n g t h r o u g h fixed delivery outlets on the tanks. Any
required pumps are p e r m a n e n t l y installed.
(f)
SEMI-FIXED INSTALLATIONS:
(1) The type in which tanks are equipped with
fixed discharge outlets connected to piping which terminates
at a safe distance f r o m the tanks. The fixed piping installation
m a y or m a y not include a foam maker. Necessary foam-producing materials are t r a n s p o r t e d to the scene a f t e r the fire
starts and are connected to the piping.
REPORT OF COMMITTEE ON FOAM
FO-4
(2) The type in which foam-producing solutions
are piped from a central foam house t h r o u g h the area, the
solution being delivered t h r o u g h hose lines to portable foam
towers which are erected a f t e r the fire starts (Chapter 5) ; or
applied by hose streams (Chapter 4).
310.
Foam Application Rates.
311.
follows:
3110:
RATES: The m i n i m u m delivery rate shall be as
TANKS CONTAINING LIQUID HYDROCARBONS:
(a) F o r air foam systems, the foam solution delivery
rate shall be at least 0.1 gpm/sq, ft. of liquid surface area of
the tank to be protected.
NOTE 1 : Flammable liquids having a boiling point of less than
100°F may require higher rates of application. Suitable rates of
application should be determined by test.
NOTE 2: For high viscosity liquids heated above 200°F, lower
initial rates of application may be desirable to minimize frothing
and expulsion of the stored liquid. Judgment nmst be used in
applying foams to tanks containing hot oils, b u r n i n g asphalts or
burning liquids which are above the boiling point of water. Although the comparatively low water content of foams can beneficially cool such liquids at a slow rate, it can also cause violent
frothing and "slop over" of the contents of the tanks.
"3111. TANKS CONTAINING OTHER FLAMMABLE AND
COMBUSTIBLE LIQUIDS REQUIRING SPECIAL FOAMS:
Water
soluble and certain flammable and combustible liquids and
polar solvents which are destructive to regular foams require
the use of alcohol type foams. Systems using these foams
require special engineering consideration. Conditions other
than routine m a y require t h a t higher application rates be
used. In all cases, the m a n u f a c t u r e r of the foam concentrate
and the foam-making equipment should be consulted as to the
limitations and for recommendations based on listings or
specific fire tests. The following are m i n i m u m recommended
application rates:
TYPE OF LIQUID
Methyl and ethyl alcohol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acrylonitrile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SOLUTION RATE
gpm/sq.ft.
0.1
0.1
Ethyl acetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Methyl ethyl ketone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0.1
Acetone ..........................................................................................................
Butyl alcohol ....................................................................................................
0.15
0.1.5
Isopropyl ether ................................................................................................
0.15
0.1
[,d
¢aa
[,d
FO-5
REVISIONS TO N F P A ] l
REPORT OF COMMITTEE ON FOAM
Products such as isopropyl alcohol, methyl isobutyl
ketone, methyl methacrylate monomer, and mixtures of polar
solvents in general m a y require higher application rates. Protection of products such as amines and anhydrides, which are
particularly foam destructive, require special consideration.
NOTE 1 : T h e solvent a n d fire r e s i s t a n c e of alcohol t y p e a i r f o a m
m a y be a d v e r s e l y affected by such f a c t o r s a s excessive solution
t r a n s i t time, t h e use of f o a m - m a k i n g devices not specifically des i g n e d or a d e q u a t e l y t e s t e d f o r a p a r t i c u l a r alcohol f o a m a p p l i c a tion, o p e r a t i n g p r e s s u r e , f a i l u r e to m a i n t a i n p r o p o r t i o n i n g w i t h i n
t h e r e c o m m e n d e d c o n c e n t r a t i o n limits, t h e m e t h o d of a p p l i c a t i o n
a n d t h e c h a r a c t e r i s t i c s of t h e p a r t i c u l a r solvent to w h i c h t h e f o a m
is to be applied.
S o l u t i o n t r a n s i t time, t h a t is t h e elapsed t i m e between i n j e c t i o n
of t h e f o a m c o n c e n t r a t e into t h e w a t e r a n d t h e i n d u c t i o n of air,
m a y be limited, d e p e n d i n g on t h e c h a r a c t e r i s t i c s of t h e f o a m conc e n t r a t e , t h e w a t e r t e m p e r a t u r e , a n d t h e n a t u r e of t h e h a z a r d
proLected. ,,1._
.
. . . . . ~pecific inl . e m a x m• a u m solutlon
t r a n s i t t i m e a_t. . .~neh
s t a l l a t i o n shall be w i t h i n t h e l i m i t s e s t a b l i s h e d b y the m a n u f a c t u r e r .
NOTE 2: F o r p r o t e c t i o n of c o m b u s t i b l e o r flammable liquids
w h i c h a r e h i g h l y toxic, h i g h a p p l i c a t i o n r a t e s m a y be d e s i r a b l e
to r e d u c e r e s p i r a t o r y h a z a r d to p e r s o n n e l b y p r o v i d i n g f o r m o r e
r a p i d c o v e r a g e of t h e t a n k c o n t e n t s .
• 3112.
S U P P L E M E N T A R Y F O A M H O S E STREAM R E Q U I R E MENTS:
Approved foam hose stream equipment shall be
provided in addition to tank foam installations as supplement a r y protection for small spill fires. The minimum number of
fixed or portable hose streams required shall be as specified
in the following table, and shall be available to provide protection of the area. F o r the purpose of this requirement, the
equipment for producing each foam hose stream shall have a
solution rate of at least 50 gpm, with the minimum n u m b e r of
hose streams shown below:
DIAMETER OF LARGESTTANK
Up to 65 ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over 65 to 120 ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over 120 ft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
320.
Minimum number of
hose streams
required
FO-6
Type of Foam
Discharge Outlet
Type I
Type II
TANKS CONTAINING LIQUID HYDROCARBONS
Lubricating oils; dry viscous residuum (more than 50 seconds
Saybolt-Fural at 122°F); dry fuel oils, etc. with flash point above
200°F ................................................................................................
Kerosene; light furnace oils, diesel fuels, etc. with flash point
from 100 ° to 200°F ..........................................................................
15 rain.
25 rain,
20 min.
30 rain.
Gasoline, naphtha, benzol and similar liquids with flash point
below 100°F ....................................................................................
Crude petroleum ..............................................................................
30 min.
30 rain.
55 min,
55 rain.
TANKS CONTAINING OTHER FLAMMABLE AND COMBUSTIBLE LIQUIDS
REQUIRING SPECIAL FQAMS
Alcohol type foams require gentle application by Type I devices unless listed as
suitable for application by Type II devices. The operation time shall be 30 minutes at
the specified application rate, unless the manufacturer of the foam concentrate has
established by fire test that a shorter time can be permitted.
330.
Foam Producing Materials.
331.
F O A M CONCENTRATE C O N S U M P T I O N R A T E S :
332. REQUIREMENTS FOR TANKS: The quantity of
foam-producing material shall be determined by multiplying
the consumption rate in gpm for each tank by the appropriate
time in 321. The largest resulting value shall determine the
quantity required.
333.
MENTS:
SUPPLEMENTARY
F O A M H O S E STREAM R E Q U I R E -
Additional foam-producing materials shall be provided to permit operation of the hose stream equipment simultaneous with tank foam installations specified for the period
set forth in the following table:
i
2
3
Duration of Discharge.
321. MINIMUM DISCHARGE TIMES: The system shall
be capable of operation at the delivery rate specified in 311,
for the tank to be protected, for the following minimum
periods of time. If the a p p a r a t u s available has a delivery rate
higher than specified in 311, proportionate reduction in the
time figures m a y be made, except that they shall not be less
than 70 percent of the minimum discharge times shown.
The
consumption rate shall be based on the percentage concentrate used in the system design (e.g., 3 or 6 percent or other
if so listed or approved by the authority having jurisdiction.)
DIAMETER OF LARGESTTANK
Up to 35 ft ...............................................................................................................
Over 35 to 95 ft .....................................................................................................
Over 95 ft ...............................................................................................................
.¥Animum
Operating
time*
10 min.
20 mln.
30 min.
*Based on s i m u l t a n e o u s o p e r a t i o n of the m i n i m u m n u m b e r of 50 g p m
hose s t r e a m s r e q u i r e d . A d j u s t m e n t s m a y be m a d e w h e r e s t r e a m s of
g r e a t e r c a p a c i t y a r e provided.
NOTE: I n t h e case of alcohol type f o a m , solution t r a n s i t t i m e
l i m i t a t i o n s m a y r e q u i r e t h e use of s e p a r a t e w a t e r a n d f o a m conc e n t r a t e lines a n d t h a t t h e i n t r o d u c t i o n of t h e f o a m c o n c e n t r a t e
be accomplished close to t h e f o a m nozzle r a t h e r t h a n in t h e c e n t r a l
f o a m house.
FO-7
REVISIONS TO NFPA l l
REPORT OF COMMITTEE ON FOAM
334. REQUIREMENTS TO FILL PIPE LINE: A q u a n t i t y
of foam-producing materials sufficient to produce foam or
foam solutions to fill the feed lines actually installed between
the source and the most remote t a n k shall also be provided.
Where a w a t e r supply source will continue a f t e r the foamproducing material is depleted and displace the solution or
foam f r o m the lines to the tank, no added q u a n t i t y is required
by this paragraph.
335. RESERVE SUPPLY OF FOAM-PRODUCING MATERIALS:
There shall be a readily available reserve supply of foamproducing materials as specified in 1742.
*336. TOTAL SUPPLY REQUIREMENTS: Supplies to be
m a i n t a i n e d shall be the sum of the quantities defined in 332,
333, 334 and 335.
340.
Foam Discharge Outlets.
341.
"3411.
SURFACE APPLICATION:
VERTICAL FIXED ROOF ATMOSPHERIC STORAGE
TANKS: For the protection of a flammable liquid contained
in a vertical fixed roof atmospheric storage tank, discharge
outlets shall be attached to the tank. Where two or more
discharge outlets are required, the outlets shall be equally
spaced around the t a n k periphery and each outlet shall be
sized to deliver foam at approximately the same rate. Fixed
discharge outlets shall be securely attached at the top of the
shell and so located or connected as to preclude the possibility
of the t a n k contents overflowing into the foam lines. They
shall be securely attached so t h a t displacement of the roof is
not likely to subject them to serious damage.
(a) Tanks shall be provided with approved discharge outlets as set f o r t h below:
TANK DIAMETER- FEET
(or equivalent area)
MINIMUM NUMB£R
DISCHARGE OUTLETS
U p t o 8 0 ..................................................................................................
1
Over 80 to 120 ........................................................................................
Over 120 to 140 ......................................................................................
Over 140 to 160 ......................................................................................
Over 160 t o 180 ......................................................................................
Over 180 t o 2 0 0 ......................................................................................
FO-8
with foam application to fires in fixed roof tanks over 140 feet in
diameter, requirements for foam protection on tanks above this size
a r e based on extrapolation of data from successful extinguishments
in smaller tanks. Tests have shown that foam can travel effectively
across at least 100 feet of burning liquid surface. On large tanks,
subsurface injection may be used to reduce foam travel distances.
(b)
Fixed outlets shall be provided with an effective
and durable seal, frangible under low pressure, to prevent
entrance of vapors into foam outlets and pipe lines. Fixed
outlets shall be provided with suitable inspection means to
permit proper maintenance and for inspection and replacement of vapor seals.
"3412.
OPEN TOP FLOATING ROOF STORAGE T A N K S :
Fixed outlets are generally not required on open top floating
roof tanks. These tanks have an excellent fire record. Their
design has been for the purpose of fire prevention as well as
f o r conservation of product. It is usually possible to utilize
trained personnel to extinguish fires in the a n n u l a r ring using
portable equipment. There are locations, however, where
fixed protection m a y be desired because of value of products
stored, remoteness of installation, or lack of fire fighting personnel. Suggested methods for providing fixed foam systems
for open top floating roof tanks will be found in the Appendix.
"3413.
COVERED FLOATING ROOF STORAGE T A N K S :
Fixed outlets are generally not required on covered floating
roof tanks. The possibility of fire is greatly reduced in comparison with other types because of the F a r a d a y Cage type
construction of this type of tank. In the event of fire, these
tanks are diffficult to extinguish using portable equipment.
Fixed protection m a y be desired in certain locations because
of value of products stored, remoteness of installation, or
lack of fire fighting personnel. Suggested methods for providing fixed foam systems for these tanks will be found in the
Appendix.
NOTE:
A " F a r a d a y Cage" is a grounded metallic screen completely surrounding a space or piece of equipment in order to shield
it from external electrostatic influence.
2
3
4
5
6
NOTE: It is suggested that for tanks above 200 feet in diameter,
at least one additional discharge outlet be added for each additional
5000 sq. ft. of liquid surfaces. Since there has been no experience
• 3414. DIKED AREAS: Fixed foam systems are not
generally required for t a n k diked areas. Portable foam monitors or foam streams or both generally provide an acceptable
method of protection. See 402 for the recommended method
of fighting diked area fires. Where fixed system protection is
desirable for diked areas, see Appendix for suggested design
criteria.
taa
FO-9
REVISIONS TO NFPA 11
3415. SUPPLEMENTARY PROTECTION:
It is desirable
t h a t at least one portable tower or portable monitor be provided as supplementary protection in the event t h a t a fixed
discharge outlet is damaged by an explosion within the t a n k
(see Chapters 4 and 5).
REPORT OF COMMITTEE ON FOAM
3425. Tanks shall be provided with discharge outlets
as set forth below:
MINIMUM NUMBER OF DISCHARGE
OUTLETS REQUIRED
TANK DIAMETER
342.
SUBSURFACE APPLICATION TO FIXED ROOF STORAGE
T ANKS CONTAINING LIQUID HYDROCARBONS:
"3421. GENERAL: Subsurface foam injection systems
are suitable for protection of liquid hydrocarbons in vertical
fixed roof atmospheric storage tanks.
NOTE: F o r pertinent information regarding fire fighting operations, see Appendix A-3421.
3422. LIMITATIONS:
Subsurface injection systems
are not suitable for protection of products such as alcohols,
esters, ketones, aldehydes, anhydrides, etc. Liquid hydrocarbons t h a t contain such products which are foam destructive
m a y require higher application rates. The m a n u f a c t u r e r of
the foam system should be consulted for recommendations.
Subsurface or semi-subsurface injection systems are not
recommended for floating roof tanks because of the possibility
of improper distribution of foam to the fuel surface.
*3423.
FOAM-PRODUCING MATERIALS AND EQUIPMENT:
Foam-producing materials and equipment for subsurface injection shall be listed for this purpose. Fluoroprotein foam
concentrates will provide satisfactory subsurface injection
performance.
3424. FOAM DISCHARGE OUTLETS: The discharge outlet into the t a n k m a y be the open end of a foam delivery line
or product line. Outlets shall be sized so t h a t foam generator
discharge pressure and foam velocity limitations are not exceeded. The foam velocity at the point of discharge into the
t a n k contents shall not exceed 10 feet per second for Class IB
liquids or 20 feet per second for other type liquids unless
actual tests prove higher velocities are satisfactory (see
Appendix A-352).
Where two or more outlets are required, they shall be located so t h a t the foam travel on the surface does not exceed
100 feet. Each outlet should be sized to deliver foam at approximately the same rate. For even foam distribution,
outlets m a y be shell connections or m a y be fed through a pipe
manifold within the t a n k from a single shell connection. Shell
connections m a y be made in m a n w a y covers r a t h e r than
installing additional t a n k nozzles.
FO-10
U p.to 80
-
-
FEET
CLASS IB LIQUIDS
CLASSES IC, II & I I I
LIQUIDS
I
I
2
I
O v e r 120 to 140 .................................................
3
2
O v e r 140 to 160 ..................................................
4
2
O v e r 160 to 180 ..................................................
5
2
O v e r 180 to 200 ..................................................
6
3
O v e r 200, add one inlet for each additional
5000 sq. ft.
7500 sq. ft.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O v e r 80 to 120 ....................................................
NOTE 1:
Class IA Liquids require special consideration.
NOTE 2: The above table is based on extrapolation of fire test
data on 25, 93 and 115 foot diameter tanks containing gasoline,
NOTE 3: The most viscous fuel which has been extinguished I
by subsurface injection when stored at ambient temperatures
(60°F.) had a viscosity of 25 S.S.U. at 122°F. and a pour point of
15°F. This is similar to heavy fuel oil. In addition to the control
provided by the smothering effect of the foam and the cooling effect
of the water in the foam which reaches the surface, fire control and
extinguishment may be further enhanced by the rolling of cool
product to the surface. No known tests have been conducted on
product having a higher viscosity than this fuel oil.
I
3426.
FOAM DISCHARGE OUTLET ELEVATION:
Foam
discharge outlets should be located above an established water
bottom, if possible. Otherwise, if it is established t h a t there i s
a water bottom in the t a n k above the foam discharge outlets,
it should be drained to below the point of foam injection prior
to p u t t i n g the foam system into operation. I f this is not
accomplished, efficiency will be reduced as a result of dilution
of the foam, prolonging or preventing extinguishment.
*343. SEMI-SUBSURFACE INJECTION METHOD: I n f o r for the use of this method will be found in the
Appendix.
mation
344. HORIZONTAL ATMOSPHERIC AND PRESSURE T A N K S :
Fixed outlets are not recommended to discharge into horizontal or pressure tanks.
350.
Foam System Piping.
351.
GENERALREQUIREMENTS:
taa
F0-11
REVISIONS TO N F P A [ [
3511. All piping inside of dikes and within 50 feet of
tanks not diked should be buried under at least one foot of
earth but m a y be permitted above ground if properly supported and protected against mechanical injury.
3512. Piping which is normally filled with liquids, such
as the suction pipes, shall be protected from freezing when
necessary.
3513. Piping f r o m the dike or within 50 feet of tanks
not diked to the t a n k foam discharge outlet shall be designed
to absorb the u p w a r d force and shock due to a t a n k roof rupture. Preferably, use steel pipe and all-welded construction.
One of the following designs m a y be used:
(a) When piping is buried, a swing joint or other
suitable means shall be provided at the base of each t a n k
I riser. The swing joint m a y consist of a system of approved
s t a n d a r d weight steel, ductile or malleable iron fittings.
(b) When piping is supported above ground, it shall
have upward and lateral support as needed, but should not
be held down a distance of 50 feet f r o m the t a n k shell to provide flexibility in an u p w a r d direction so t h a t a swing joint is
not needed. If threaded connections occur within this distance
I they shall be back welded for strength.
(c) When t a n k risers are four-inch pipe-size or
greater, they can be welded to the tank by means of steel
brace plates positioned perpendicular to the t a n k and centered on the riser pipe. One brace shall be provided at each
shell course. This design m a y be used in lieu of swing joints
or above ground flexibility as described above.
3514. One flanged or union joint shall be provided in
each riser within five feet of the ground to permit hydrostatic
testing of the piping system up to this joint. With all welded
construction, this m a y be the only joint t h a t can be opened.
I
3515. In systems with semi-fixed equipment on fixed
roof tanks, the foam or solution laterals to each foam chamber
shall t e r m i n a t e in connections which are at a safe distance
f r o m the tanks; outside of dikes and at least 50 feet from
tanks of 50 feet in diameter or less, and one tank diameter
f r o m the shell of larger tanks. The inlets to the piping shall
be fitted with corrosion-resistant metal connections provided
with plugs or caps.
REPORT OF COMMITTEE ON FOAM
FO-12
eta
Os
*352. PIPE LINES CARRYINGFOAM: Pipe lines shall be
of such sizes and lengths as to deliver on the surface protected
the required q u a n t i t y of foam of s t a n d a r d quality. The sizes
and lengths of discharge pipe or lines used beyond the foammaker shall be such t h a t the back pressure is within the range
of pressures under which the device has been tested and listed
by nationally recognized testing laboratories.
353. VALVESIN SYSTEMS: All valves, except h y d r a n t
valves, shall be the O.S. and Y. or post indicator type. The
laterals to each foam chamber on fixed roof tanks shall be
separately valved outside the dike in fixed installations. Control valves to divert the foam or solutions to the proper t a n k
may be in the central foam house or m a y be at points where
laterals to the protected tanks branch from main feed line.
Control valves shall be located outside dikes and not less t h a n
the following distances f r o m the shell of the t a n k which they
serve: 50 feet for tanks less t h a n 50 feet in diameter; one
diameter for tanks 50 feet in diameter or larger, except t h a t
control valves m a y be permitted at less than the above distances where adequately protected or remotely operated,
subject to the approval of the a u t h o r i t y having jurisdiction.
Where two or more air foam proportioners or chemical foam
generators are installed in parallel discharging into the same
outlet header, valves shall be provided between the outlet of
each device and the header. The w a t e r line to each air foam
proportioner or chemical foam generator inlet shall be separately valved.
F o r subsurface applications, each foam delivery line
shall be provided with a valve and check valve unless the
latter is an integral p a r t of the high back pressure foammaker or pressure foam-generator to be connected at time of
use. When product lines are used for foam, product line valving shall be a r r a n g e d to ensure foam enters only the tank to
be protected.
354. FOAM HOSE OUTLETS: Centralized fixed piping
systems shall be provided with hose outlets for foam hose
streams for supplementary use on spill fires, supplying portable towers, etc. In lieu of foam (or solution) outlets, water
h y d r a n t s and portable proportiofiers or other devices acceptable to the a u t h o r i t y having jurisdiction m a y be provided.
The m i n i m u m number of foam outlets or w a t e r h y d r a n t s shall
be located at a distance of 50 to 250 feet from the shells of
tanks protected, as set forth below:
]
I
I
[
FO-13
REPORT OF COMMITTEE ON FOAM
REVISIONS TO N F P A 1__1
Tank Diameter ~
U p to 65 ................................................................................
1
6 5 and over ..........................................................................
2
4.
m a x i m u m flexibility due to the u n c e r t a i n t y of location and
the e x t e n t o f a possible spill in p r o c e s s a r e a s a n d t a n k f a r m s ,
p o r t a b l e o r t r a i l e r - m o u n t e d m o n i t o r s are m o r e p r a c t i c a l t h a n
fixed f o a m systems. T h e p r o c e d u r e f o r fighting diked a r e a
fires is to e x t i n g u i s h or s e c u r e one a r e a and t h e n m o v e on to
e x t i n g u i s h the n e x t section w i t h i n the dike. T h i s t e c h n i q u e
should be c o n t i n u e d until the c o m p l e t e dike a r e a has been
extinguished.
Minimum Number o f
Outlets Required
Feet
Revise Chapter 4 to read as follows:
CHAPTER 4. MONITOR AND HOSE NOZZLES
FOR EXTERIOR PROTECTION
400.
*403.
General.
"401. SCOPE: T h i s c h a p t e r relates to systems in w h i c h
t h e f o a m is a p p l i e d t h r o u g h fixed or p o r t a b l e m o n i t o r or hose
nozzles. T h e y are r e c o m m e n d e d as a u x i l i a r y p r o t e c t i o n in
COIIJUIICUIOIL
Wlbll
IIX~2L[ i ) l l J l l l ~
~ ¢ ~ U t C l I I D tot
I J O I u D , UIt¢ U O W ~ i ~
/:t~
specified in C h a p t e r s 3 and 5. T h e y are suitable w h e n used
alone f o r e x t i n g u i s h m e n t of spill fires, diked a r e a fires, and
fires in v e r t i c a l fixed r o o f a t m o s p h e r i c s t o r a g e tanks. P o r t a b l e
hose nozzles a r e suitable f o r e x t i n g u i s h m e n t s of r i m fires in
I open top floating r o o f tanks.
NOTE 1: F i r e s in t a n k s u p to 130 feet i n d i a m e t e r h a v e been
e x t i n g u i s h e d w h e n t h e e n t i r e liquid s u r f a c e was involved b y use
of l a r g e c a p a c i t y f o a m m o n i t o r s . D e p e n d i n g on the fixed roof t a n k
o u t a g e a n d fire i n t e n s i t y , t h e u p - d r a f t due to chimney effect m a y
p r e v e n t sufficient f o a m f r o m r e a c h i n g the b u r n i n g liquid s u r f a c e
f o r f o r m a t i o n of a b l a n k e t . F o a m m u s t be applied c o n t i n u o u s l y
a n d evenly. P r e f e r a b l y , i t should be directed a g a i n s t the i n n e r t a n k
shell so t h a t it flows g e n t l y onto t h e b u r n i n g liquid s u r f a c e w i t h o u t
u n d u e s u b m e r g e n c e . T h i s c a n be difficult to accomplish as a d v e r s e
winds, d e p e n d i n g on velocity a n d direction, will reduce t h e effectiveness of t h e f o a m s t r e a m . Due to t h e i r limitations, m o n i t o r s should
not be d e p e n d e d u p o n as a p r i m a r y m e a n s o f e x t i n g u i s h m e n t f o r
fixed roof t a n k s over 60 feet in d i a m e t e r . Monitors o p e r a t e d a t
g r a d e u s u a l l y a r e n o t r e c o m m e n d e d f o r floating roof r i m fire exting~dishment because of t h e difficulty of d i r e c t i n g f o a m into t h e
a n n u l a r space. F i x e d f o a m m o n i t o r s m a y he installed f o r p r o t e c t i o n
of d r u m s t o r a g e a r e a s or diked a r e a s . U s e of portable t o w e r s m a y
p r e s e n t a s a f e t y h a z a r d to fire f i g h t e r s inside the diked a r e a if
u s e d to a p p l y f o a m to t a n k s c o n t a i n i n g hot oils, b u r n i n g a s p h a l t s ,
or o t h e r liquids w h i c h a r e above t h e boiling p o i n t of w a t e r .
NOTS 2: F o a m hose s t r e a m s a r e s u i t a b l e as a p r i m a r y m e a n s
of e x t i n g u i s h m e n t of fires in t a n k s not over 30 feet in d i a m e t e r n o r
o v e r 20 f e e t high. F o a m hose s t r e a m s can be used for open top
f l o a t i n g roof r i m fires e x t i n g u i s h m e n t w h e n applied f r o m t h e t a n k
w i n d g i r d e r or roof.
i
FO-14
402. DIKED AREA PROTECTION: Generally, p o r t a b l e
m o n i t o r s , a n d / o r f o a m hose s t r e a m s , h a v e been a d e q u a t e in
f i g h t i n g diked a r e a and o t h e r spill fires. In o r d e r to o b t a i n
DEFINITIONS:
(a)
FOAM HOSE STREAM: A f o a m s t r e a m f r o m a
hose nozzle w h i c h can be held a n d d i r e c t e d b y hand. T h e nozzle
r e a c t i o n usually limits the solution flow to a b o u t 300 gpm.
(b)
F O A M MONITOR S T R E A M : A l a r g e c a p a c i t y f o a m
s t r e a m f r o m a nozzle which is s u p p o r t e d in position and
w h i c h can be d i r e c t e d b y one man. A solution flow of 300 g p m
o r h i g h e r c a n be used.
(c)
FIXED MONITOR ( C A N N O N ) :
A device w h i c h
delivers f o a m m o n i t o r s t r e a m a n d is m o u n t e d on a s t a t i o n a r y
s u p p o r t at g r a d e or elevated. T h e m o n i t o r m a y be f e d solution
by p e r m a n e n t p i p i n g o r hose.
(d)
PORTABLE MONITOR ( C A N N O N ) : A device w h i c h
delivers a f o a m m o n i t o r s t r e a m and is on a m o v a b l e s u p p o r t
o r wheels so it can be t r a n s p o r t e d to t h e fire scene.
410.
Foam Application Rates.
411. RATES: T h e m i n i m u m d e l i v e r y r a t e f o r p r i m a r y
p r o t e c t i o n based on t h e a s s u m p t i o n t h a t all the f o a m r e a c h e s
the a r e a b e i n g p r o t e c t e d shall be as follows:
In d e t e r m i n i n g t o t a l solution flow r e q u i r e m e n t s , considl l' o. ~. e. ~.
J~_ i o m W""-~
l l l ~ CUlU
c~ ~ u n shall be ~-:w. ... . to pouen~la~
" "" ' ~l o a l l -°~
o t h e r f a c t o r s as n o t e d in 401, N o t e 1.
4110.
T A N K S C O N T A I N I N G LIQUID HYDROCARBONS:
(1)
T h e f o a m solution d e l i v e r y r a t e shall be at least
0.16 g p m / s q , ft. of liquid s u r f a c e a r e a of the t a n k to be
protected.
NOTE 1: F l a m m a b l e liquids h a v i n g a boiling p o i n t of less t h a n
100°F. m a y r e q u i r e h i g h e r r a t e s of a p p l i c a t i o n . S u i t a b l e r a t e s of
a p p l i c a t i o n m a y be d e t e r m i n e d by test. F l a m m a b l e liquids w i t h a t
wide r a n g e of boiling p o i n t s c a n develop a h e a t l a y e r a f t e r prolonged b u r n i n g a n d t h e n m a y r e q u i r e a p p l i c a t i o n r a t e s of 0.2 g p m
p e r s q u a r e foot or more.
FO-15
I
REPORT OF COMMITTEE ON FOAM
REVISIONS TO N F P A 11
NOTE 2 : C a r e m u s t be t a k e n in a p p l y i n g p o r t a b l e f o a m s t r e a m s
to h i g h viscosity m a t e r i a l s h e a t e d above 200°F. J u d g m e n t m u s t
be used in a p p l y i n g f o a m to t a n k s c o n t a i n i n g hot oils, b u r n i n g
a s p h a l t s or b u r n i n g liquids which a r e above the boiling p o i n t of
w a t e r . A l t h o u g h the c o m p a r a t i v e l y low w a t e r c o n t e n t of f o a m s can
beneficially cool such fuels a t a slow r a t e , it can also cause violent
f r o t h i n g a n d "slop o v e r " of t h e c o n t e n t s of t h e t a n k .
4111. T A N K S C O N T A I N I N G O T H E R F L A M M A B L E AND
COMBUSTIBLE LIQUIDS R E Q U I R I N G SPECIAL F O A M S :
Water
soluble and certain flammable and combustible liquids and
polar solvents which are destructive to regular foams require
the use of alcohol type foams. In general, alcohol type foams
can be effectively applied through foam monitor or foam hose
streams to spill fires of these liquids when the liquid depth
does not exceed 1 inch. F o r liquids in greater depth, monitor
I and foam hose streams shall be limited for use with special
alcohol type foams listed for Type II discharge. Systems using
these foams require special engineering consideration. In all
cases, the m a n u f a c t u r e r of the foam concentrate and the
I foam-making equipment shall be consulted as to limitations
and for recommendations based on listings or specific fire
tests. The following are minimum recommended application
rates:
TYPE OF LIQUIDS
SOLUTION RATE
gpm/sq, ft.
Methyl and Ethyl Alcohol ................................................................................
Acrylonitrile ......................................................................................................
Ethyl Acetate ....................................................................................................
Methyl Ethyl Ketone ........................................................................................
0.16
0.16
0.16
0.16
Acetone ............................................................................................................
Butyl Alcohol ....................................................................................................
ISOl~r~pyl Ether ................................................................................................
0.24
0.24
0.24
Products such as isopropyl alcohol, methyl isobutyl
ketone, methyl methacrylate monomer, and mixtures of polar
solvents in general m a y require higher application rates. Protection of products such as amines and anhydrides, which are
particularly foam destructive, require special consideration.
NOTE 1 : T h e s o l v e n t a n d fire r e s i s t a n c e of alcohol t y p e a i r f o a m
m a y be a d v e r s e l y affected by such f a c t o r s as excessive solution
t r a n s i t time, t h e use of f o a m - m a k i n g devices n o t specifically des i g n e d or a d e q u a t e l y t e s t e d f o r a p a r t i c u l a r alcohol f o a m a p p l i c a tion, o p e r a t i n g p r e s s u r e s , f a i l u r e to m a i n t a i n p r o p o r t i o n i n g w i t h i n
t h e r e c o m m e n d e d c o n c e n t r a t i o n limits, t h e m e t h o d of a p p l i c a t i o n
and t h e c h a r a c t e r i s t i c s of t h e p a r t i c u l a r solvent to w h i c h t h e f o a m
is to be applied.
Solution t r a n s i t time, t h a t is, the elapsed t i m e b e t w e e n i n j e c t i o n
of t h e f o a m c o n c e n t r a t e into t h e w a t e r a n d t h e i n d u c t i o n of air, m a y
FO-16
be limited, d e p e n d i n g on t h e c h a r a c t e r i s t i c s of t h e foam c o n c e n t r a t e ,
the w a t e r t e m p e r a t u r e , a n d t h e n a t u r e of t h e h a z a r d protected.
The m a x i m u m solution t r a n s i t t i m e of each specific i n s t a l l a t i o n
shall be w i t h i n the limits e s t a b l i s h e d by t h e m a n u f a c t u r e r .
NOTE 2: F o r p r o t e c t i o n of flammable or c o m b u s t i b l e liquids
which a r e h i g h l y toxic, h i g h e r a p p l i c a t i o n r a t e s m a y be d e s i r a b l e
to reduce r e s p i r a t o r y h a z a r d to p e r s o n n e l by p r o v i d i n g for more
r a p i d coverage.
4112.
S U P P L E M E N T A R Y H O S E STREAM R E Q U I R E M E N T S :
Additional foam hose streams and required equipment shall
be provided as supplemental protection for ground fires at
least as specified in 3112.
420.
Duration of Discharge.
421. MINIMUM DISCHARGE TIMES: The equipment
shall be capable of operation to provide p r i m a r y protection at
the delivery rates specified in 411 for the following minimum
periods of time.
TANKS CONTAINING LIQUID HYDROCARBONS
Lubricating Oils; dry viscous residuum (more than 50 seconds SayboltFurol at 122°F.); dry fuel oils, etc. with flash point above 200°F .....................
Kerosene; light furnace oils, diesel fuels, etc. with flash point 100°F.
to 200°F ...............................................................................................................
Gasoline; naphtha, benzol, and similar liquids with flash point below 100°F.
Crude petroleum
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35 min.
50 min.
65 min.
65 mln.
Tanks Containing Other Flammable and Combustible Liquids
Requiring Special Forms
Alcohol type foams require special application procedures as
discussed in 4111. The operation time shall be 65 minutes at
specified application rates, unless the m a n u f a c t u r e r has established by fire test that a shorter time can be permitted.
E X T I N G U I S H M E N T OF S P I L L F I R E S :
Where the p r i m a r y
purpose of the protection is for extinguishment of spill fires,
the minimum discharge time shall be 10 minutes for fixed
equipment. F o r portable equipment, the minimum discharge
time shall be 15 minutes. F o r protection of diked areas designed to contain the contents of a storage tank, see 402.
430.
Foam Producing Materials.
431. FOAM CONCENTRATE CONSUMPTION RATES: The
consumption rate shall be based on the percentage concentrate used in the system design (e.g., 3 or 6 percent or other
if so listed or approved by the a u t h o r i t y having jurisdiction).
t~
O0
FO-17
REVISIONS TO N F P A 1[
432.
R E Q U I R E M E N T S FOR TANKS:
The q u a n t i t y of
foam-producing material shall be determined by multiplying
the consumption rate in gallons per minute for each tank by
the appropriate time in 421. The largest resulting value shall
determine the q u a n t i t y required.
433.
MENTS:
S U P P L E M E N T A R Y F O A M HOSE STREAM REQUIRE-
Additional foam-producing materials shall be provided to permit operation of hose stream equipment simultaneous with t a n k foam installations as specified in 333.
434. R E Q U I R E M E N T S TO F I L L P I P E L I N E S :
These shall
be the same as specified in 334 when piping is part of the
design.
435.
RESERVE S U P P L Y OF FOAM-PRODUCING MATERIALS:
There shall be a reserve supply of foam-producing materials
436. TOTAL SUPPLY REQUIREMENTS: Supplies to be
m a i n t a i n e d shall be the sum of the quantities defined in 432,
433,434 and 435.
437. R E Q U I R E M E N T S FOR SPILL FIRES: Sufficient foamproducing materials shall be available for extinguishment
of spill fires as defined in 421 and in addition, as specified in
434 and 435.
440.
Hose Requirements.
Unlined fabric hose
441.
U N L I N E D FABRIC HOSE:
shall not be used with foam equipment.
Revise Chapter 5 to read as follows:
5.
CHAPTER 5. PORTABLE TOWER SYSTEMS FOR
EXTERIOR STORAGE TANKS
500.
REPORT OF COMMITTEE ON FOAM
FO-18
of the a u t h o r i t y h a v i n g jurisdiction, shall be based upon the number and availability of the men and equipment to extinguish a
possible fire. On tanks over 200 feet in diameter, the use of a portable foam towers m a y not be practical, due to the a m o u n t of equipment and number of men needed to meet requirements.
NOTE 2: T a n k s containing combustible liquids ( a t or above
140°F. flash point) are not, as a rule, required to be protected by
foam. F o a m protection for combustible liquids m a y be desirable
where abnormal situations exist, such as storage of high value
stocks or liquids heated above their flash point. Use of p o r t a b l e
towers m a y p r e s e n t a safety hazard to fire fighters inside the diked
a r e a if used to apply foam to tanks containing hot oils, b u r n i n g
asphalts, or other liquids which a r e above the boiling point of w a t e r .
*502.
DEFINITIONS:
PORTABLE FOAM TOWER: A device which is brought
to the scene of the fire, erected and placed in operation for
delivering foam to the b u r n i n g surface of a t a n k a f t e r the
fire starts. Portable foam towers are equipped with Type
I or Type II discharge outlets shaped to apply foam i n w a r d
toward the tank shell.
NOTE: Within the scope of this standard, monitor nozzles
mounted on aerial ladders or booms a r e not considered portable
foam towers because of the higher application rates required with
such devices. See C h a p t e r 4.
PORTABLE INSTALLATIONS: The type in which the
foam apparatus, foam-producing materials, hose, etc., are
t r a n s p o r t e d to the scene a f t e r the fire starts, the foam being
delivered to the t a n k by portable towers.
510.
Foam Application Rates.
511. RATES: The m i n i m u m delivery rate shall be as
specified in 311.
512.
S U P P L E M E N T A R Y F O A M H O S E STREAM AND H O S E
OUTLET REQUIREMENTS: The m i n i m u m requirements for
hose streams and h y d r a n t s shall be as specified in 3112.
General.
501. SCOPE: This chapter relates to those systems in
which the foam is applied t h r o u g h approved portabl~ towers
which are placed in operating position a f t e r the fire starts.
NOTE 1: Generally, portable towers a r e to be r e g a r d e d as
limited in use. P o r t a b l e tower systems require accessibility to tankage, and an adequate number of men to place and m a i n t a i n the
a p p a r a t u s in operation; and in some cases, special truck units for
the r e a d y t r a n s p o r t a t i o n of the e q u i p m e n t to the location of the fire.
The adequacy of a portable tower system, subject to the a p p r o v a l
520.
Duration of Discharge.
521. MINIMUM DISCHARGETIME: The system shall be
capable of operation at the delivery rate specified in 511 for
the following m i n i m u m periods of time. If the a p p a r a t u s
available has a delivery rate higher t h a n t h a t specified in 511,
proportionate reduction in the time figures m a y be made,
except t h a t they shall not be less than 70 percent of the minim u m discharge times shown.
t~
FO-19
TANKS CONTAINING LIQUID HYDROCARBONS
Lubricating oils, dry viscous residuum (more than 50 seconds
Saybolt-Furol at 122°F.), dry fuel oils, etc., with flash point above
200°F .................................................................................................
Kerosene, light furnace oils, diesel fuels, etc., with flash point
from IO0°F. to 200°F .......................................................................
Gasoline, naphtha, benzol and similar liquids with flash point
below 100°F .....................................................................................
Crude petroleum ..............................................................................
TYPE OF PORTABLE
FOAM TOWER
TYPE I
TYPE II
25 rain.
35 rain.
30 rain.
50 min.
min.
min.
65 min.
65 rain.
55
55
TANKS CONTAINING OTHER FLAMMABLE AND COMBUSTIBLE LIQUIDS
REQUIRING SPECIAL FOAMS
Alcohol type foams require gentle application by Type I outlets unless listed as suitable for application through Type II devices. The operation time shall be 5 5 minutes at
the specified application rate, unless the manufacturer of the foam concentrate has
established by fire test that a shorter time can be permitted.
530.
Foam-Producing Materials.
531. FOAM CONCENTRATE CONSUMPTION RATES: T h e
c o n s u m p t i o n r a t e shall be b a s e d on t h e p e r c e n t a g e concent r a t e u s e d in t h e s y s t e m d e s i g n (e.g., 3 o r 6 p e r c e n t or o t h e r
if so listed or a p p r o v e d b y t h e a u t h o r i t y h a v i n g j u r i s d i c t i o n ) .
532. REQUIREMENTS FOR TANKS:
T h e q u a n t i t y of
f o a m - p r o d u c i n g m a t e r i a l shall be d e t e r m i n e d b y m u l t i p l y i n g
t h e c o n s u m p t i o n r a t e in gallons p e r m i n u t e f o r e a c h t a n k b y
t h e a p p r o p r i a t e t i m e in 521. T h e l a r g e s t r e s u l t i n g v a l u e shall
determine the quantity required.
533. SUPPLEMENTARY HOSE STREAM REQUIREMENTS:
A d d i t i o n a l f o a m - p r o d u c i n g m a t e r i a l s shall be p r o v i d e d to p e r m i t o p e r a t i o n of t h e hose s t r e a m e q u i p m e n t s i m u l t a n e o u s
w i t h t a n k f o a m i n s t a l l a t i o n s as specified in 333.
534. REQUIREMENTS TO FILL PIPE LINES:
T h e s e shall
be t h e s a m e as specified in 334.
535. RESERVE SUPPLY OF FOAM-PRODUCING MATERIALS:
T h e r e shall be a r e s e r v e s u p p l y of f o a m - p r o d u c i n g m a t e r i a l s
t h e s a m e as specified in 1742.
536. TOTAL SUPPLY REQUIREMENTS:
S u p p l i e s to be
m a i n t a i n e d shall be t h e s u m of the q u a n t i t i e s defined in 532,
533, 534 a n d 535.
540.
FO-20
REPORT OF COMMITTEE ON FOAM
REVISIONS TO NFPA 11
Foam Towers.
541. NUMBERS REQUIRED:
T o w e r s shall be a v a i l a b l e
in t h e p r o p e r n u m b e r a n d size as to d e l i v e r f o a m on the b u r n i n g liquid s u r f a c e a t a r a t e to m e e t t h e r e q u i r e m e n t s of 511
a n d as set f o r t h below:
TANK DIAMETER - - FEET
{or equivalent area)
MINIMUM NUMBER
FOAM TOWERS
Up to 80 ..................................................................................................
Over 80 to 120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over 120 to 140 ......................................................................................
Over 140 to 160 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over 160 to 180 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over 180 to 200 ......................................................................................
1
2
3
4
5
6
NOTE 1: When two or more towers are required, they should
be sized to deliver foam at approximately the same rate.
NOTE 2: Since there has been no experience with foam application to fires in fixed roof tanks over 140 feet in diameter, requirements for foam protection on tanks above this size are based on
extrapolation of data from successful extinguishments in smaller
tanks.
550.
C e n t r a l i z e d Fixed Piping Systems.
551. FOAM TOWER HOSE OUTLETS: H o s e o u t l e t s used I
f o r f o a m t o w e r s shall be as specified in 354.
6.
Rewise Chapter 6 to read as follows:
CHAPTER 6. SPRAY FOAM SYSTEMS FOR
EXTERIOR PROTECTION
600.
General.
601. SCOPE:
T h i s c h a p t e r r e l a t e s to s y s t e m s d i s c h a r g i n g a i r f o a m in a s p r a y p a t t e r n t h a t c a n be e f f e c t i v e l y used to
e x t i n g u i s h spill fires u n d e r or a r o u n d p r o c e s s s t r u c t u r e s a n d
equipment, horizontal tanks and small vertical tanks. These
s y s t e m s r e l a t e to s p r a y d i s c h a r g e of a i r f o a m only. S o m e f o a m
s p r a y s y s t e m s a n d devices a r e n o t d e s i g n e d to p r o d u c e effect i v e w a t e r p a t t e r n s f o r cooling p u r p o s e s . F o r s y s t e m d e s i g n
c r i t e r i a f o r d i s c h a r g e of b o t h w a t e r a n d f o a m , r e f e r to N F P A
No. 16, Standard for Installation of Foam-Water Sprinkler
and Foam-Water Spray Systems.
NOTE 1 : Spray foam applied externally to tanks or vessels has
the added advantages of cooling and insulating the tanks or vessels
while the spill fire is being extinguished.
Foam is not considered an effective agent for extinguishment of
three-dimensional running flammable liquid fires. However, in the
event of such a fire, the foam can effectively cover and control the
pool fire beneath the running fire thus facilitating approach and
extinguishment by other means.
NOTE 2: These systems may also be used to protect small open
top tanks having a liquid surface area not exceeding 200 sq. ft.
FO-21
610.
REVISIONS TO N F P A t l
REPORT OF COMMITTEE ON FOAM
Foam Application Rate.
611. RATE: The m i n i m u m rate of foam solution application shall be 0.16 gpm/sq, ft. for the maximum potential
fire area.
620.
Duration of Discharge.
621. MINIMUM DISCHARGE TIME: There shall be a
q u a n t i t y of foam-producing materials sufficient to supply the
system at the design rate for a period of 10 minutes. If the
system discharges at a rate above the minimum specified in
611, then the operating time m a y be reduced proportionately,
but shall not be less t h a n 7 minutes.
630.
Foam-Producing Materials.
631.
FOAM CONCENTRATE CONSUMPTION RATES:
The
consumption rate shall be based on the percentage concentrate used in the system design (e.g., 3 or 6 percent or other
if so listed or approved by the a u t h o r i t y having jurisdiction).
632. RESERVE SUPPLY: There shall be a reserve supply of foam-producing materials in accordance with 1742.
633. TOTAL SUPPLY REQUIREMENTS: Supplies to be
m a i n t a i n e d shall be the sum of the quantities defined in 621
and 632.
640.
Foam Discharge Outlets.
I
641. NUMBERAND LOCATION: There shall be a minim u m of 1 discharge outlet per 100 sq. ft. of protected area
unless listing of discharge devices indicates a larger spacing
I is permitted. These outlets shall be located so as to provide
good distribution t h r o u g h o u t the protected area. However, an
added advantage is gained by locating the outlets so t h a t the
foam discharge envelops the equipment within the protected
area. Therefore, the discharge outlets m a y be concentrated
over closed tanks or equipment rather than being evenly
spaced t h r o u g h o u t the protected area. These outlets are then
located in plan and elevation to provide the most effective
protection of the hazard.
650.
Operation.
651. AUTOMATIC OPERATION: This may be accomplished by use of listed fire detectors installed in accordance
with their accepted spacing rule f o r outdoor applications,
FO-22
and connected to a deluge valve and other equipment to make
a complete system. The requirements of 212 and 270 shall be
complied with where applicable and an auxiliary manual I
I
tripping means shall be provided.
652. MANUAL OPERATION: Controls shall be located
in an accessible place, sufficiently removed f r o m the hazard
so t h a t they m a y be safely operated in an emergency. The
location and purpose of the control shall be plainly indicated.
660.
Foam System Piping.
661. GENERALREQUIREMENTS:
(a) Piping which will be normally be filled with liquid
shall be protected against freezing when necessary.
(b) The requirements of 26 shall be complied with
where applicable.
662. Applicable parts of Chapter 3 of the Standard for
the Installation of Sprinkler Systems ( N F P A No. 13) shall
be consulted for requirements applicable to piping, valves,
pipe fittings, and hangers, including corrosion-protection
coatings (galvanizing or other means). In these open-head
systems, galvanized pipe and fittings shall be used for normal I
occupancies. Corrosive atmospheres m a y require other
coatings.
Since the systems herein covered are required to be
hydraulically designed, the pipe-size tables of the Standard
for Installation of Sprinkler Systems ( N F P A No. 13) are
not applicable.
663. Piping c a r r y i n g foam concentrate shall be black
steel or cast iron.
7.
Revise Appendix to read as follows:
APPENDIX A
8.
A-121(e).
Change 3rd paragraph to read as follows:
The device illustrated in A-121(e) shows a pressure pro- I
portioning t a n k with a single operating head.
I
Delete 4th and 5th paragraphs.
9. A-302 C. Change "C" to lower case with ( ) and "E" to
" ( f ) " to read:
FO-23
REVISIONS
A-302(c)
SEMI-FIXED
10.
TO N F P A
ll
TYPE II DISCHARGE OUTLETS and A-302(f)
INSTALLATIONS.
R e n u m b e r A-324 as A-3112.
11.
A-3311(2). Change to:
(2) When it is desired to provide fixed foam devices
below the p a n t o g r a p h type fabric seal, or the metal weather
shield of a tube seal design, the following m a y be used as a
design guide.
12.
R e n u m b e r A-324 as A-333.
13.
Renumber A-321 as A-336.
14.
Renumber A-331 as A-3411 including Figures (a) and
(b).
15. R e n u m b e r A-3311 as A-3412 including Figures (1), (2)
and (3).
16.
A-3412(2) (b). N e w to read as follows:
(b). A circular dam is not required with the tube
seal design and the m a x i m u m spacing between applicators
should be 130 ft. unless the top of the tube seal is less
t h a n 6 inches below the top of the pontoon deck. Then a circular dam is required and the m a x i m u m spacing between
applicators should be ao more than 60 ft. measured around
the circumference of the tank.
17.
Change the first sentence o / A - 3 4 1 2 ( 2 ) (e) to read:
(e) When a foam dam is not required, the rate of
application and the supply of foam liquid should be calculated
using the area of the a n n u l a r ring between the t a n k shell and
the floating roof edge.
18.
A - 3 4 1 2 ( 2 ) ( f ) . N e w to read as follows:
(f) When a foam dam is required, the rate of application and the supply of foam liquid concentrate should be
calculated using the area of the a n n u l a r ring between the t a n k
shell and the dam. The m i n i m u m rate should be 0.16 gpm/ft.'-'
of area. The supply should be adequate to operate the system
for 20 minutes.
19.
Renumber A-3312 as A-3413 including Fig. A-3312.
20.
A-3414.
A-3414.
N e w t o r e a d a s follows:
Fixed foam protection m a y be desirable for
REPORT OF C O M M I T T E E
ON F O A M
FO-24
common diked areas s u r r o u n d i n g multiple tanks with less than
N F P A No. 30 spacing a n d / o r poor fire fighting access. This
can be accomplished by fixed foam outlets discharging onto
the inner wall of the dike, or by fixed or oscillating monitors,
or by foam spray systems discharging within the diked area.
Suggested design criteria are:
F o r fixed discharge outlets, use a solution application
rate of 0.1 g p m / f t . " of area to be protected with sufficient
supply of foam-producing materials for 20 minutes application to Class II liquids or 30 minutes application for Class I
liquids.
For foam spray systems, see Chapter 6.
F o r fixed or oscillating monitors, use a solution application rate of 0.16 gpm ft. -~ with supplies of foam-producing
materials as for fixed outlets above. It is not necessary to
design to apply foam simultaneously to the total diked area
as long as monitor reach will provide adequate coverage.
F o r protection of diked areas which m a y contain other
flammable and combustible liquids requiring alcohol-type
foams, protection m a y be provided by fixed Type I discharge
outlets applying foam f r o m the dike or by application of
foams approved for the purpose by Type II devices or fixed
or oscillating monitors. For recommended application rates,
see table in Chapter 3 under "Tanks Containing Other Flammable and Combustible Liquids Requiring Special Foams."
Supplies of foam-producing materials should be provided for
30 minutes application.
21.
Renumber A-351 as A-3421.
22.
Renumber A-3511 as A-3423.
23. R e n u m b e r A-333 as A-343 including Figures A-333A
and A-333B.
24. R e n u m b e r A-342 and A-3561 as A-352 including Figures A-3561 A-D.
25.
(2).
Renumber A-601 as A-401 including Figures (1) and
26. R e n u m b e r A-602 as A-403 including Figures ( c ) ( 1 ) (c) (5) and (d) ( 1 ) - ( d ) (3).
27.
Renumber A-402 as A-502 including Figure A-402.
28. Change Figure A-5OIA and A-5OIB to A-6OIA and
A-6OIB.
GENERAL
IIA-5
Part II
Standard
for
High Expansion Foam Systems
(Expansion Ratios from 100:1 to 1000:1)
NFPA 1 1 A - 1 9 7 6
Chapter 1
General
NOTICE: An asterisk (*) prcccding the number or letter designating
a subdivision indicates explanatory material on that subdivision in Appendix A.
1-1 Scope. This standard includes m i n i m u m requirentents
for the installation of high expansion foam systems.
Only those skilled in this field are competent to design and install this equipment. It may be necessary for m a n y of those
charged with the purchasing, inspecting, testing, approving, operating, and maintaining of this e q u i p m e n t to consuh with an experienced and competent fire protection engineer in order to
effectively discharge their respective duties.
1-2 Purpose. This standard is prepared for use and guidance
of those charged with the purchasing, designing, installing, testing, inspecting, approving, listing, operating or m a i n t a i n i n g of
high expansion foam systems, in order that such e q u i p m e n t will
function as intended throughont its life.
1-3 History. High expansion foam is a relatively new agent
for control and extinguishment of Class A and Class B fires and
is particularly suited as a flooding agent for use in confined spaces.
T h e development of the use of high expansion foams for fire
fighting purposes started with the work of the Safety in Mines
Research Estahlishment of Buxton, England, upon the difficult
problem of fires in coal mines. It was found that by expanding
an aqueous surface active agent solution to a semi-stable foam
of ahout 1000 times the volume of the original solution, it was
possible to force the foam down relatively long corridors thus
providing a means for transporting water to a fire inaccessible
to ordinary hose streams.
This work has led to the development of specialized high expansion foam generating e q u i p m e n t for fighting fires in mines,
for application in municipal and industrial fire fighting, and for
the protection of special hazard occupancies.
t~
11A-6
HIGH
EXPANSION
FOAM
GENERAL
SYSTEMS
1-4 Description. High expansion foam is an aggregation of
bubbles mechanically generated by the passage of air or other
gases through a net, screen or other porous m e d i u m which is
wetted by an aqueous solution of surface active foaming agents.
Under proper conditions, fire fighting foams of expansions from
100:1 to 1000:1 can be generated. Such foams provide a unique
agent for transporting water to inaccessible places, for total flooding of confined spaces, and for volumetric displacement of vapor,
heat and smoke. Tests have shown that under certain circumstances high expansion foam when used in conjunction with
water sprinklers will provide more positive control and extinguishment than either extinguishment system by itself. Highpiled storage of rolled p a p e r stock is an example. O p t i m u m
efficiency in any one type of hazard is dependent to some extent
on the rate of application and also the foam expansion and
stability.
High expansion foam is particularly suited for indoor fires in
confined spaces. Its use outdoors may be limited because of the
effects of weather. High expansion foam has several effects on
fires:
(a) W h e n generated in sufficient volume, it can prevent air,
necessary for continued combustion, from reaching the fire.
(b) When forced into the heat of a fire the water in the foam
is converted to steam, reducing the oxygen concentration by dilution of the air. For example, the water in a foam having an
expansion ratio of 1000:1 can provide enough steam to reduce
the oxygen concentration of the resultant air-steam mix to al)out
7.5 percent by volume.
(c) T h e conversion of the water to steam absorbs heat from
tim b u r n i n g fuel. Any hot object exposed to the foam will continne the process of breaking the foam, converting the water to
steam, and of being cooled.
(d) Because of its relatively low surface tension, solution from
the foam, which is not converted to steam, will tend to penetrate
Class A materials.
However, deep-seated fires may require
overhaul.
(e) W h e n accumulated in depth, high expansion foam can
provide an insulating barrier for protection of exposed materials
or structures not involved in a fire and can thus prevent fire
spread.
Class A fires are controlled when the foam completely covers
the fire and burning material. If the foam is sufficiently wet and
is maintained long enough, the fire may be extinguished.
1 ! A-7
Class B fires involving high flash point liquids can be extinguished when the surface is cooled below the flash point. Class
B fires of low flash point liquids can be extinguished when a
foam blanket of sufficient depth is established over the liquid
surface.
This standard is based on test data and design experience so
far developed for use of high expansion foam. T h e intent of
this standard is to indicate general rules applicable to any system.
T h e limited field experience of approved systems makes it difficult to prepare specific recommendations covering the many
potential uses. This standard is issued to outline some of the
factors which shall be given consideration in judging the acceptability of specific installations.
1-5 Definitions. For purposes of clarification, the following
general terms used with special technical meanings in this standard are defined:
l-5.1 Authority H a v i n g Jurisdiction is usually the purchaser
or the competent engineer or organization appointed by him to
interpret and make decisions as set forth in this standard. Where
insurance is involved, the inspection d e p a r t m e n t representing
the insurance carrier generally becomes the authority having
jurisdiction. In some cases, civil or military authorities may
have final iurisdiction.
1-5.2 H i g h Expansion F o a m is an aggregation of 19ulgbles
resulting from the mechanical expansion of a foam solution by
air or other gases with a foam-to-solution volume ratio of 100:1
to approximately 1000:1 (see A-1-9.3).
!-5.3 F o a m Concentrate is a concentrated liquid foaming
agent as received fiom tim manufacturer.
1-5.4 Foam Solution is water into which foam concentrate
has been introduced in the proper proportion.
1-6
General Information and Requirements.
i-6.1 T h e information and requirements in Chapter 1 are
generally common to all high expansion foam systems.
1-6.2 Mechanisms of Extinguishment. High expansion
foam extinguishes fire by reducing the concentration of oxygen
at the seat of the fire, by cooling, by halting convection, and by
excluding additional air from the fire.
1-6.3 Use and Limitations. While high expansion foam is
finding application for a broad range of fire fighting problems,
this standard is presently limited to considering specific types of
hazards.
11 A-8
GENERAL
1-6.3.1 Some important types of hazards that high expansion foam systems may satisfactorily protect include:
1-7.1.1 Personnel working in a hazaM area and with no
responsibility for fire fighting shall be instructed to immediately
vacate the area in the event of fire, if possible. If personnel are
unable to vacate and are trapped so that their lives are endangered by smoke o1 heat, they may enter the foam. Instructions
shall be given to move the hand over the nose and mouth to
minimize discomfort in hreathing within tile foam.
Ca) Ordinary confl~ustibles
(b) Flamumble liquids
(c) Combinations of each
N O T E : U n d e r c e r t a i n c i r c u m s t a n c e s it m a y be possible to utilize h i g h
c x p a n s i o l l foam systems at tires i n v o l v i n g f l a m m a b l e l i q u i d s or gases
iSstlillg t i n d e r presstlre, hilt 11o gellCl'a] r c c o m r l l e n ( l a l i o n s Call ])C 1llallc
in this Sl:lndard d u e to the i n l i n i t e v a r i e t y of p a r t i c u l a r s i l u a t i o n s w h i c h
can be e n c o u n t e r e d in a c t u a l p r a c t i c e .
t
11A-9
J IIGH EXPANSION FOAI~,I SYSTEMS
i-6.3.2 High expansion foam systems shall not be used on
fires in the following hazards unless competent evaluation, which
may include tests, indicates acceptability:
Ca) Chemicals, such as cellulose nitrate, which release suffinxidizing agents~ to sustain conlbustion.
(b) Energized unenclosed electrical equipment (see 1 - 7 . l . 5 ) .
(c) Water-reactive metals such as sodium, potassiunl, NaK.
(d) Hazardous water-reactive materials, such as triethylaluminuna and phosphorous pentoxide.
c. i.o.n.~. . . nxv*,'
. . oen,
. . . .nr
. . . nlher
I-6.4 Types of Systems.
this standard include:
T h e types of systems recognized in
Total Flooding Systems
Local Application Systems
Portable Foam Generating Devices
I-6.5 Systems Protecting One or M o r e H a z a r d s .
Systems
may l)e used to protect one or more hazards or groups of hazards
using the same supply of foam concentrate and water except as
provided in 1-6.5.1.
1-6.5.1 Where, in tim opinion of the authority having
jmisdiction, two or more hazards may be simultaneously involved
in fire by reason o[ their proximity, each hazard slmii be protected with an individual system or the system shall be arranged
to discharge on all potentially invoh,ed hazaMs simultaneously.
I-7
Personnel
Safety.
to P e r s o n n e l .
Tile discharge of large
anlounts of high expansion foam may inundate personnel, blocking vision, making hearing ditficuh, and creating some discomfort
in brc,~thing. This breathing discomfort will increase with a
reduction in expansion ratio of tile foam and also under the
effect of sprinkler discharge.
1-7.1
Hazards
I-7.1.2 Where possible the relative location of foam discharge points to building exits shall he arranged to facilitate
evacuation of personnel.
I-7.1.3 T o re-enter a foam-filled building, a coarse water
spray may be used to cut a path in the foam. Personnel shall
not enter the foam. T h e foam is opaque, and it is impossible
to see when one is submerged. It is dangerous to enter a build•.,~ .......................
a . . . . . . one . . . . . . . . . . . . . .
1-7.1.4 Caution. A canister type gas mask shall not be
worn in the foam. The chemicals of the canister will react widl
the water of the foam and cause suffocation. If emergency reentry is essential, self-contained breathing apparatus shall be used
in coniunction with a life line.
1-7.1.5 Unenclosed electrical apparatus shall be de-energized upon system actuation unless by competent evaluation it
has been deemed unnecessary.
1-7.2 Electrical Clearances. All system components shall
be so located as to maintain m i n i m u m clearances from live parts
as shown in Table 1-7.2.
As used in this standard, "clearance" is the air distance hetween high expansion foam equipment, including piping and
nozzles, and unenclosed or uninsulated live electrical components
at other titan ground potential. Since high expansion foam is
conductive, these clearances do not prevent flashover through
foam. ( S e e 1 - 7 . 1 . 5 . )
T h e clearances given are for altitudes of 3,300 ft (1065m) or
less. At altitudes in excess of 3,300 ft (1065m), tile clearance
shall be increased at the rate of 1 percent for each 330 ft (106.5m)
increase in altitude above 3,300 ft (1065m).
Tile clearances are based upon m i n i m u m general practices
related to des!gn Basic Insulation Level (B1L) values. T o coordinate the required clearance with the electrical design, the
design BIL of the equipment being protected shall be used as
a hasis, although this is not material at nominal line voltages of
161 kv or less.
IlA-IO
tlIGH
EXPANSION
FOAM
TABLE
SYSTEMS
GENERAL
1-7.2
1-8
CLEARANCE FROM HIGH EXPANSION FOAM EQUIPMENT
T O LIVE U N I N S U L A T E D E L E C T R I C A L C O M P O N E N T S
Nominal
Voltage
to Ground (kv)
Design
BI L
(kv)
Minimum
Clearance
(inches)
To 15
23
34.5
46
69
115
138
161
To 9
13
20
27
40
66
80
93
196-230
114-132
110
150
200
250
350
550
650
750
900
1050
6
8
12
15
23
37
,t4
52
63
76
152
203
305
381
584
940
1118
1321
1600
1930
287-380
166-220
500
290
1175
1300
1425
1550
1675
1800
87
98
109
120
131
1,t2
2210
2489
2769
3048
3327
3607
500-700
290-400
1925
2100
2300
153
168
184
3886
4267
d674
f
Specifications, P l a n s a n d A p p r o v a l .
1-8.1 P u r c h a s i n g Specifications. Specifications for high expansion fo:un systems shall be d r a w n up with care u n d e r the
s u p e r v i s i o n of a c o m p e t e n t e n g i n e e r , a n d with the advice of the
atttfiority h a v i n g j u r i s d i c t i o n . T o e n s t n e a satisfactory system,
the following items shall be in the specifications.
Nominal
Line
V o l t a g e (kv)
f
llA-ll
NOTE: Basic Insulation Level (BILl values are expressed as kilovolts
(kv), the number being the crest value of the full wave impulse test that
the electrical equipment is designed to withstand.
U p to e l e c t r i c a l system voltages of 161 kv the design B I I , kv
a n d c o r r e s p o n d i n g m i n i m u m clearances, phase to g r o u n d , have
been e s t a b l i s h e d t h r o u g h l o n g usage.
A t voltages h i g h e r t h a n 161 kv, u n i f o r m i t y in the r e l a t i o n s h i p
b e t w e e n design B I L kv a n d the v a r i o u s electrical system voltages
has n o t b e e n e s t a b l i s h e d in practice a n d is d e p e n d e n t u p o n
several v a r i a b l e s so t h a t the r e q u i r e d clearances to g r o u n d shall
be based u p o n the design B I L used r a t h e r t h a n on the n o m i n a l
line o r gTound voltage.
Possible design v a r i a t i o n s in the c l e a r a n c e r e q u i r e d at h i g h e r
voltages are e v i d e n t in the table, w h e r e a r a n g e of voltages is
i n d i c a t e d o p p o s i t e the v a r i o u s B I L test values in the high v o h a g e
p o r t i o n of the table. H o w e v e r , the c l e a r a n c e b e t w e e n u n i n s u l a t e d e n e r g i z e d parts of the electrical system e q u i p m e n t a n d a n y
p o r t i o n of the h i g h e x p a n s i o n f o a m system shall not be less t h a n
the m i n i m u m c l e a r a n c e p r o v i d e d elsewhere for electrical system
insulations on any individual component.
1-8.1.1 T h e specifications shall designate the a u t h o r i t y
h a v i n g j u r i s d i c t i o n a n d i n d i c a t e w h e t h e r s u b m i t t a l of plans is
required.
1-8.1.2 T h e specifications shall state that the i n s t a l l a t i o n
shall c o n f o r m to this s t a n d a r d a n d m e e t the a p p r o w t l of the
attthority having jurisdiction.
1-8.1.3 T h e specifications shall i n c l u d e the specific tests
t h a t may be r e q u i r e d to meet the a p p r o v a l of the a u t h o r i t y
h a v i n g j u r i s d i c t i o n , a n d i n d i c a t e how cost of testing is to be
borne.
i-8.2 Plans. W h e r e p l a n s are r e q u i r e d , their p r e p a r a t i o n
shall be e n t r u s t e d o n l y to fully e x p e r i e n c e d a n d r e s p o n s i h l e
persons.
1-8.2.1 T h e s e p l a n s shall be d r a w n to an i n d i c a t e d scale
o r bc s u i t a b l y d i m e n s i o n e d , a n d shall be m a d e so that they can
be easily r e p r o d u c e d .
1-8.2.2 T h e s e p l a n s shall c o n t a i n sufficient d e t a i l of Ihe
hazard to enal)le the a u t h o r i t y h a v i n g j u r i s d i c t i o n to e v a l u a t e the
effectiveness of the system. T h e d e t a i l s on the hazard shall inchtde the specific m a t e r i a l s involved, the l o c a t i o n a n d arrangem e n t a n d the i n n n e d i a t e e x p o s u r e to the hazard. T h e d e t a i l on
the system shall i n c l u d e sufficient i n f o r m a t i o n anti c a l c u l a t i o n s
on the r e q u i r e d a m o u n t of foam c o n c e n t r a t e ; w a t e r r e q t t i r e m e n t s ;
h y d r a u l i c c a l c u l a t i o n s on the size, l e n g t h a n d a r r a n g e m e n t of
c o n n e c t e d p i p i n g a n d hose; a n d the size a n d l o c a t i o n of foam
g e n e r a t o r s so that the a d e q u a c y of the q u a n t i t y , flow rate a n d dist r i b u t i o n of the h i g h e x p a n s i o n foam g e n e r a t e d can be determined. (See Chapter 7 o[ NFPA 13, Standard for the hzstallatio~l
o[ Spri~zhler Systems, [or calculation procedures.) D e t a i l e d inf o r m a t i o n shall be s u b m i t t e d p e r t a i n i n g to the location a n d function of d e t e c t i o n devices, o p e r a t i n g devices, a u x i l i a r y e q u i p m e n t
i n c l u t l i n g s t a n d - b y - p o w e r a n d electrical circuitry, if used. Sufficient i n f o r m a t i o n shall be i n d i c a t e d to i d e n t i f y p r o p e r l y the
a p p a r a t u s a n d devices used. A n y special features shall be adequately explained.
I 1A-I 2
l|lGll EXPANSIONFOAIMSYSTE~IS
1-8.3 Approval of Plans. Where plans are required, they
shall be submitted to the authority having jurisdiction for
approval before work starts.
1-8.3.1 Where field conditions necessitate any significant
change from the approved plan, corrected "as installed" plans
shall he supplied for approval to the authority having jurisdiction.
1-8.4 Approval of Installations. T h e completed system
shall be tested by qualified personnel to meet the approval of
the authority having jurisdiction. These tests shall he adequate
to determine that the system has heen properly installed, and
will function as intended. Only listed or approved e q u i p m e n t
and devices shall be used in these systems.
I-8.4.1 Such tests shall include a discharge ot7 foam il
possible. This foam shall be checked visually for desired quality.
If actual discharge is not permitted, the supplier or installer
shall check air flow and liquid flow in a manner satisfactory to
the authority having jurisdiction.
1-8.4.2 All piping up to each toam generator shall be
subiected to a 2-hour hydrostatic test pressure at 200 psi (1379
kPa) or 50 psi (345 kPa) in excess ot the m a x i m u m pressure
;mticipated, whichever is greater. (See NFPA 13, Slan(lard for the
Installation o] Sprinhler S),stems.)
1-8.4.3 Tests shall include a complete check-out of eleclrical control circuits and supervisory systems to ensure proper
operation and supervision in the event of failure.
1-8.4.4 Tests shall establish that all automatic closing
devices for doors, windows ,md conveyor openings, and automatic
e q u i p m e n t interlocks, as well as automatic opening o1 heat and
smoke vents or ventilators, will function upon system operation.
1-8.4.,~ Operating instructions provided by the supplier
and the proper identification of devices shall be checked.
1-9
O p e r a t i o n and Control of Systems.
1-9.1 Methods of Actuation. Systems shall be classified as
manual or automatic in accordance with the method of actuation.
An automatic system is one which is actuated by automatic detection equipnmnt. Such systems also shall ha'Oe':means t or m,mual
actuation.
' g~
I-9.2 Detection of Fires. Fires or conditions likely to produce fire may he detected I)y h u m a n senses or I)y automatic
l l ] e a II_S.
GENERAL
1-9.2.1
1 IA-I 3
Automatic detection shall be used for fixed sys-]
terns.
!
Exception: Automatic detection may be omitted only when
approved by the authority having jurisdiction.
1-9.2.2 Automatic detection shall be by listed or approved
method or devices capable of detecting and indicating heat,
smoke, flame, combustible vapors, or any abnormal condition in
the hazard, such as process trouble, likely to produce fire.
1-9.2.3 An adequate and reliable source of energy shall he
used in detection systems. T h e power supply for electrical]
detection systems shall be independent of the supply for the I
protected area. Otherwise an emergency, battery-powered supply I
with automatic swi~chover shall be provided if the primary]
st ii)ply fails. (See NFPA 72E-1974, Standard on Automatic Detec-]
t ~11 a . ]
"1-9.3 O p e r a t i n g Devices. Operating devices include foam
generators, valves, proportioners, eductors, discharge controls,
and shutdown equipment.
1-9.3.1 Operation shall be controlled by listed or approved mechanical, electrical, hydraulic or pneumatic means.
An adequate and reliable source of energy shall he used. T h e
electrical power supply for an electrically operated high expa!asion foam system shall be as reliable as a fire p u m p circuit m
accordance with NFPA 20-1974, Standard [or the Installation o l
C e n t ri/nga l Fire Pum ps.
1-9.3.2 All operating devices shall be suitable for the
service they will encounter, and shall not be readily rendered
inoperative or susceptible to accidental operation. Provision
shall be made to protect piping normally filled with liquid from
freezing.
1-9.3.3 All devices shall be located, installed, or suitably
protected so that they are not subject to mechanical, chemical,
climatic or other conditions that will render them inoperative.
1-9.3.4 Manual controls for actuation and shutdown shall
be located so as to he conveniently and easily accessible at all
times including the tilne of fire and system operation. Remote
control slations for inanual actuation may be required where the
area is large, egress dilficuh or when required by the authority
having jurisdiction. Manual controls for actuation shall operate
the system to the same extent as the automatic control.
t,4
llA-14
H I G I t E X P A N S I O N F O A M SYSTEMS
1-9.3.5 All automatically operated e q u i p m e n t controlling
the generation and distribution of foam shall be provided wilh
approved independent means for emergency manual operation.
If the means for manual actuation of Ihe system required in 1-9.1
p,ovides approved positive operation independent of the automatic actuation, it may be used as the emergency means. T h e
emergency means, preferably mechanical, shall be easily accessible and located close to the e q u i p m e n t controlled. If possible,
I the system sltall be designed so that complete emergency actuation can be accomplished from one location.
1-9.3.6 All required door and window closers, vent
openers, and electrical e q u i p m e n t shutdown devices shall be
considered integral parts of the system and shall function with
the system operation.
1-9.3.7 All manual operating devices shall be identified ;is
to the hazards they protect.
I
1-9.4
actuation
there will
constantly
Supervision. Supervision of automatic detection and
e q u i p m e n t shall be provided and so arranged that
be an immediate indication of failure, preferably at a
attended location.
1-9.5 Alarms. Audible alarms shall be installed to indicate the operation of the system, alert personnel and indicate
failure of any supervised device or eqt,iplnent. Such devices
shall be of such a type and shall be provided in such numbers and
such locations as are necessary to accomplish satisfactorily their
purpose subject to approwll of the authority having jurisdiction.
I
1-9.5.1 An alarm shall be provided to show that the system has operated, personnel response may be needed, and the
system shall be reserviced.
[
1-9.5.2 Alarms shall be provided to give ample warning
of discharge where hazard to personnel may exist.
1-9.5.3 Alarms indicating failure of supervised devices or
e q u i p m e n t shall give p r o m p t and positive indication of any
failure and shall be distinctive from alarms indicating operation
or hazardous conditions.
1-10
[
Water, F o a m C o n c e n t r a t e and Air Supply.
1-10.1 W a t e r Quantity. Water shall be available in sufficient quantity and pressure to supply the m a x i m u m n u m b e r of
high expansion foam generators likely to operate simultaneously
in addition to the demands of other fire protection equipment.
GENERAL
llA-15
1-10.2 W a t e r Quality. Consideration shall be given to the
suitability of the water for production of high expansion foam.
T h e presence of corrosion inhibitors, antifreeze agents, marine
growths, oil, or other contaminanls may result in reduction
of foam volume or stability. T h e m a n u f a c t u r e r of the t'oam I
concentrate shall be consuhed.
I
1-10.3 W a t e r Storage.
against freezing.
Water supply shall be protected
1-10.4 F o a m Concentrate Quantity. T h e a m o u n t of foam
concentrate in the system shall be at least sufficient for the largest
single hazard protected or a group of hazards which are to be
protected simnltaneously (see 2-3.6 and 3-3.2).
'1-10.5 F o a m Concentrate Quality. T h e foam concentrate
supplied with the system shall be that listed for use with the
e q m p m e n t . T h e performance of the system is dependent upon
the colnposition of the foam concentrate as well as other factors.
T h e quality of the concentrate for proper perforlnancc under
the installation requirements of this standard shall be determined
by suitable tests. One such suitable test, based on fire performance, is described in A-l-10.5.
1-10.6 F o a m C o n c e n t r a t e Reserve Supply. Sufficient foant
concentrate shall be kept or: hand for at least one complete re-I
charge of the systeln based on designated requirements. This
reserve supply shall be stored in separate tanks, compartments,
original shipping containers or by other approved methods. T o
prevent accidental use and depletion of tiffs reserve supply, it
shall be awtilable to the system only by intentional manual
operation.
1-10.7 Foam Concentrate Storage. In-service and reserve
supplies of foam concentrate shall be stored where the tempera-I
ture is maintained between 35°F (2°C) and I I0°F (43°C), or
within such other temperature range for which the concentrate
has been listed. T h e reserve supply containers shall be kept]
tightly closed in a clean dry area to prevent contamination or
deterioration.
1-10.8 F o a m Concentrate Storage T a n k . T h e tank shall
be of corrosion-resisting materials and construction compatible
with the foam concentrate. Consult the loan: e q u i p m e n t nlanufacturer.
1-10.9 Air Supply. Air from outside the hazard area shall
be used for foam generation unless the calculated foam genera-
I1A-16
utah
FXPANSION FOAM SYSTEMS
GENERAL
tion rate using inside air is increased to compensate for foam loss
because of heat, smoke, and chemical effects during a fire. T h e
degree of loss fi'om such effects shall be determined by test.
1-10.9.1 Vents shall be located to avoid recirculation of
c o m b u s t i o n products into the air inlets of the foam geuerators.
I-11 Foam Generating Apparatus Location.
1-11.1 Accessibility for Inspection and Maintenance.
];oanl
g e n e r a t i n g apparatus shall be so located and arranged that inspection, testing, recharging, and other maintenance is facilitated and i n t e r r u p t i o n to protection is held to a m i n i m u m .
*1-11.2 Protection Against Exposure. Foam generating
[ e q u i p m e n t shall be located as near as possible to the hazard or
hazards it protects, but not where it will be u n d u l y exposed to a
fire or explosion, l"oam generators installed inside the hazard
area shall be constructed or protected against fire exposm-e. Such
protection may be by insulation, fire retardant paint, water spray,
or sprinklers, etc. In certain applications additional generators
m a y 1)e substituted for fire exl)osure protection with the approval of the a u t h o r i t y having iurisdiction.
1-12 Distribution Systems.
1-12.1 Pipe and Fittings. T h e piping and fittings in continuous contact with foam concentrate shall be of corrosionresisting materials compatible with the foam concentrate used.
T h e r e m a i n d e r of the piping and fittings should be standard
weight (Schedule 40) black or galvanized steel pipe and standard
weight black or galvanized steel, ductile, or malleable iron fittings.
I Consideration shall be given to possible galvanic effects when
dissimilar metals are joined, especially in piping which carries
foam concentrate.
1-12.2
Arrangement and Installation of Piping and Fittings.
l lA-17
1-12.3 Valves. All valves shall be suitable for the intended
use, particularly in regard to flow capacity and operation. Valves
shall be of a listed type or deemed suitable for such use as a part
of the system.
!-12.3.1 Valves shall not be easily subiect to mechanical,
chemical, or other damage.
i-12.4 Ducts. Foam distribution and air inlet ducts shall
be designed, located, installed and suitably protected so that they
are not subiect to t m d u e mechanical, chemical or other damage.
1-12.4.1 Duct closures such as selector valves, gates, or
doors shall be of the q u i c k - o p e n i n g type, allowing free passage of
the foam. W h e n located where they may be subjected to fire
or heat exposure, either inside or outside the area to be protected,
•'1. . . . . . . . . . . ~ o,,,,. ,,~ taken to ensure p o s m v e operatxon.
1-12.4.2 I)ucts shall I)e designed and installed so that undue turbulence is avoided and the foam discharge rate is in accord with the design requirements.
1-13 Maintenance and Instructions.
1-13.1 Inspection and Tests. At least annually, all high
expansion foam systems shall be t h o r o u g h l y inspected and
checked for proper o p e r a t i o n by a competent engineer or inspector. T h i s shall include d e t e r m i n a t i o n of an}, changes in physical I
properties of the foam concentrate which indicate any deterioration in quality. R e g u l a r service contracts with the m a n u f a c t u r e r
or installing c o m p a n y are r e c o m m e n d e d .
1-13.1.1 T h e goal of this inspection and testing shall be
to ensure that the system is in full o p e r a t i n g condition and to
indicate the p r o b a b l e c o n t i n u a n c e of that condition until the
next inspection.
Piping shall be installed in accordance with practices o u t l i n e d in
N F P A 13, Standard for the Installation of Sprinkler Systems.
1-13.1.2 Suitable discharge tests shall be m a d e when any
inspection indicates their advisability.
1-12.2.1 All piping systems shall be designed using laydraulic calculations to assm'e the desired rate of flow at the foam
generators. Care shall be taken to avoid possible restrictions due
to foreign matter, f a u h y fabrication, a n d improper installation.
1-13.1.3 T h e inspection report, with r e c o m m e n d a t i o n s ,
shall be filed with the owner.
1-12.2.2 A listed strainer shall be provided in the water
line upstream of the water valve suitable for use with the prop o r t i o n e r and foam generator. Supplemental strainers may be
used as r e c o m m e n d e d by the foam e q u i p m e n t m,mufacturer.
"1-13.1.4 Between the regular service contract inspection
or tests, the system shall be inspected by c o m p e t e n t personnel,
following an a p p r o v e d schedule.
1-13.1.5 Strainers shall be inspected and cleaned afterl
each use and test.
llA-I8
HIGII
EXPANSION
FOAM
SYSTEMS
1-13.2 Maintenance. These systems shall be maintained ill
full operating condition at all times. Use, impairment, and
restoration of this protection shall be reported promptly to the
authority having jurisdiction.
1-13.2.1 Any troubles or impairments shall I)e corrected
at once by competent personnel.
1-13.3 Instructions. All persons who may lm expected to
inspect, test, maintain, or operate foam generati,tg apparatus
shall be thoroughly trained and kept thoroughly Irained in the
functions they are expected to perform.
I
1-13.3.1 T r a i n i n g programs approved by the authority
having jurisdiction shall be established.
1-13.3.2
stations.
Operating instructions shall be posted at control
TOTAL
Chapter 2
2-I
FI.OOI)IN(;
SYY, TI:.NIS
IIA-19
Total Fh)oding Systems
General Information.
2-1.1 Description. A total flooding system consists ot: fixed
foam generating apparatus complele with a piped supply ol foam
concentrate and water, arranged to discharge into an enclosed
space or enclosure about the hazard.
2-1.2 Uses. This type of system may be used where there
is a permanent enclosure about the hazard that is adequate to
enable the required a m o m n of fire extinguishing me¢lium to be
built up and to be maintained for the required period of time to
ensure the control or extinguishment of the fire in the specific
combustible material or materials involved.
2-1.2.1 Examples of hazards that may be successfully protected by total flooding systems include rooms, vaults, storage
areas, warehousing facilities and buildings containing Class A
and Class B coml)ustibles either singly or in combination. (See
NFPA 231C-1974, Standard ~or Rach SZorage of MaZcrials.)
Three-dime,lsional fires in tlammable liquids (falling or flowing
under pressure) having flash points below 100°F (38°C) generally
will not be extinguished by total coverage. Although this fire
may continue in the foam, heat radiation will be reduced and
kept under control with continued foam application.
2-!.2.2 Fires which can be controlled or extinguished by
total flooding methods can be divided into two categories: namely,
(1) surface fires involving flammable or combustible liquids and
solids and (2) deep seated fires involving solids subject to smoldering.
2-1.3
General Requirements.
Total flooding systems shall
be designed, installed, tested and maintained in accordance with
the applicable requirements in the previous chapter and with
the additional requirements set forth in this chapter. Only listed
or approved e q u i p m e n t and devices shall be used in these systems.
2-2
Enclosure Specifications.
2-2.1 Leakage and Ventilation. Since the efficiency of the
high expansion foam system depends upon the development and
maintenance of a suitable quantity of foam within the particular
enclosure to be protected, leakage of foam from the enclosure
shall be avoided.
2-2.1.1 Openings below design filling depth, such as doorways, windows, etc., shall be arranged to close automatically
before, or simultaneously with the start of the foam discharge,
11A-20
HIGH EXPANSION FOAM SYSTEMS
TOTAL FLOODING SYSTEMS
w i t h d u e c o n s i d e r a t i o n for e v a c u a t i o n of personnel. T h e y shall
be d e s i g n e d to m a i n t a i n a closure d u r i n g a fire a n d be c a p a b l e
of w i t h s t a n d i n g pressures of f o a m a n d s p r i n k l e r w a t e r discharge.
If a n y u n c l o s a b l e o p e n i n g s exist, the system shall be d e s i g n e d to
I c o i n p e n s a t e for the p r o b a b l e loss of f o a m a n d shall be tested to
assure p r o p e r p e r f o r m a n c e .
2-2.1.2 W h e n o u t s i d e air is used for f o a m g e n e r a t i o n , h i g h
level v e n t i n g shall be p r o v i d e d for air w h i c h is d i s p l a c e d by the
I foam, I f possible, v e n t i n g velocity shall n o t exceed 1000 feet
p e r m i n u t e (305 m / m i n ) in free air. T h e v e n t i n g so r e q u i r e d
shall consist of s u i t a b l e openings, e i t h e r n o r m a l l y o p e n , or norr e a l l y closed a n d a r r a n g e d to o p e n a t t t o m a t i c a l l y w h e n the
systetn operates. W h e n design c r i t e r i a d e m a n d e x h a u s t fans,
they shall be a p p r o v e d for h i g h t e m p e r a t u r e o p e r a t i o n a n d installed w i t h clue c o n s i d e r a t i o n for p r o t e c t i o n of switches, wiring,
a n d o t h e r electrical devices to assure e q u a l r e l i a b i l i t y of e x h a u s t
fan p e r f o r m a n c e as for the foam generators. W h e r e forced air
v e n t i l a t i n g systems i n t e r f e r e w i t h the p r o p e r b u i l d - u p of foam,
they s h a l l be shut d o w n or closed off a t t t o m a t i c a l l y .
2-3
Foam Requirements.
2.3.1 G e n e r a l . F o r a d e q u a t e p r o t e c t i o n , sufficient h i g h exp a n s i o n f o a m shall be d i s c h a r g e d at a r a t e to fill the e n c l o s u r e to
an effective d e p t h a b o v e the h a z a r d b e f o r e an u n a c c e p t a b l e d e g r e e
of d a m a g e occurs.
2-3.2 F o a m D e p t h . T h e m i n i m u m total d e p t h of f o a m
shall be n o t less t h a n 1.1 times the h e i g h t of the h i g h e s t hazard,
b u t in n o case less t h a n 2 feet (0.61 in) over this hazard. F o r flamm a b l e o r conabttstible liquids, the r e q u i r e d d e p t h over the h a z a r d
m a y be c o n s i d e r a b l y g r e a t e r a n d shall be d e t e r m i n e d by tests.
2-3.3 S u b m e r g e n c e V o l u m e .
S u b m e r g e n c e v o h n n e is defined as (1) the d e p t h as specified in 2-3.2 m u l t i p l i e d by the floor
a r e a of the space to b e p r o t e c t e d or (2) in the case of u n s p r i n k l e r e d r o o m s of i n t e r n a l c o m b u s t i b l e c o n s t r u c t i o n or finish, the
e n t i r e v o l u m e i n c h t d i n g c o n c e a l e d spaces. T h e v o h t m e o c c u p i e d
by vessels, m a c h i n e r y or o t h e r p e r m a n e n t l y located e q u i p m e n t
m a y he d e d u c t e d w h e n d e t e r m i n i n g the s u b m e r g e n c e v o h n n e .
T h e v o l u l n e o c c u p i e d by stored m a t e r i a I shall n o t be d e d u c t e d
w h e n d e t e r m i n i n g the s u b m e r g e n c e v o l u m e unless a p p r o v e d by
the a u t h o r i t y h a v i n g j t n i s d i c t i o n .
*2-3.4 S u b m e r g e n c e T i m e . R e c o m m e n d e d times to achieve
s u b m e r g e n c e v o l u m e for v a r i o n s types of hazards a n d b u i l d i n g
c o n s t r u c t i o n are s h o w n in T a b l e 2-3.4. Shorter s u b m e r g e n c e
times m a y be r e q u i r e d d e p e n d i n g on the factors i n c l u d e d in 2-3.5.
llA-21
TABLE 2-3.4
Maximum Submergence Time for
High Expansion Foam Measured
from Start of Foam Discharge* (Minutes)
Hazard
Flammable Liquids
(Flash Points below
140°V [60°C])**
Combustible Liquids
(Flash Points of 140°F
[6O°C] and a!;oVe)**
Low Density Combustibles
i.e., Foam Rubber
Foam Plastics
Rolled Tissue or
Crepe Paper
High I)ensity
Comhustibles
i.e., Rolled Paper
-Kraft or
Coated-Banded
High I)ensity
Combustibles
i.e., Rolled Paper
-Kraft or
Coated-Unbanded
Rubber Tires
Comhustibles, in cartons,
bags, tiber drums
Light or Unprotected
Steel Construction
Heavy or Protected
or Fire-resistive
Construction
Not
Sprinklered Sprinklered
Not
Sprinklered Sprinklered
3
2
5
3
4
4
3
3***
6
6
4
4***
7
5***
8
6***
5
4***
6
5***
7
7
5***
5" * *
8
8
6***
6* * *
This is based on a maximum of 30 see delay between firc detection
and start of foam discharge. Ally delays in excess of 30 sec shall be deducted from the submergence times in Table 2-3.4.
** Polar solvents are not included in this table. Flammable liquids
having boiling points less than 100°F (38°C) may require higher application rates. Where use of high expansion foam is contemplated on these
materials, the foam equipment supplier shall substantiate suitability for
tile intended use.
*** These submergence times may not be directly applicable to highpiled storage above 15 ft (4.6 m) or where fire spread through combustible
contents is very rapid.
11A-22
HIGH
EXPANSION
I:OAI~,I S Y S T E M S
*2-3.5 R a t e of Discharge. T h e rate of foam discharge
necessary for extinguishment or snfficient control to perlnit overhaul depends upon the strength of sprinkler protection, nature
and configuration of the hazard, vulImrability of the strnctnre
and contents to fire, and the loss potential to life, property and
production. T h e rate also depends upon foain properties, such
as expansion ratio, water retention, effect of water contanfinants,
temperature effects on water retention, etc. T h e foam discharge
rate shall be sufficient to satisfy the foam depth requirements
and snbmergence times of T a b l e 2-3.4, making compensation for
normal foam shrinkage, foam leakage, and breakdown effects of
sprinkler discharge.
"2-3.5.1 T h e m i n i m u m rate of discharge or total generator capacity shall be calculated from the following forinula:
0
where:
R = rate of d i s c h a r g e - - ctm
(m~/min)
V = submergence volume I
cubic feet (m a)
T = submergence t i t n e - minntes
1~,~ = rate of foam breakdown
by sprinklers - - cfin
(ma/min)
Cy = compensation for norInal
foam shrinkage
CL = compensation for leakage
*2-3.5.2 T h e factor (R~) for compensation for breakdown
I by sprinkler discharge shall be determined either by test or, in the
absence of specific test data, by the following formula:
R, = S X Q where:
S = Foam breakdown in cfm per g p m of sprinkler discharge.
S shall be 10 c f m / g p m (0.0748 m a . m i n / l . m i n )
Q = Estimated total discharge from maxilnunl n u m b e r of
sprinklers expected to o p e r a t e - - g p m (l/rain).
2-3.5.3 The factor (CN) for compensation for normal foam
shrinkage shall be 1.15. This is an empirical factor based on
average reduction in foam quantity from solution drainage,
fire, wetting of surfaces, absorbency of stock, etc.
TOTAL
FIA)OIJING
SYSTEMS
11 A-23
*2-3.5.4 T h e factor (CL) for compeusation for loss of foaln
due to leakage around doors aud windows and through unclosable openings shall be determined lay the design engineer
after proper evaluation of the structure. Obviously this factor
calmot be less than 1.0 even for a structure completely tight
below the design filling dept]i. This factor could be as high as
1.2 for a bt,ilding with all openings normally closed depending
upon foam expansion ratio, sprinkler operation, and foam depth.
2-3.6 Quantity. Sufficient foaln concentrate and water shall
be provided to perlnit conti,mous operation of the entire systein
for at least 25 ininutes or to generate fonr times the subnmrgence
volume, whichever is less, but in no case less than enough for 15
minutes of full operation (see 1-I0.4).
2-3.6.1
with 1-10.7.
Reserve supplies shall be provided in ,mcordance
*2-4 M a i n t e n a n c e of Submergence Vohime. T o ensure adequate control or extiiaguishnlent, the sublnergence volnme shall
be maintained for at least 60 Ininutes for unsprinkleved locations
and 30 ininutes for sprinklered locations. Where only flalnmable
or combustible liquids :ire involved, this period may be reduced.
2-4.1 Method. T h e subnlergence volulne lnay be inainrained by continuous or intermittent operation of any or all of
the generators provided.
2-4.1.1 Arrangenmnts and procedures shall be provided to
maintain the sublnergence volume without waste of foam concentrate which may be needed in case of re-ignition.
*2-5 Overhaul. As is true with other total flooding extin.guishing systems, control established by the system may be lost lay
nnproper overhaul procedures.
2-6 Distribution. T h e discharge arrangeinents shall be such
that a relatively even bnild-up of high expansion foam will take
place during the discharge period.
tJIt
11A-24
mGH
Chapter 3
3-1
EXPANSION
FOAM
SYSTE.'MS
Local Application Systems
General Information.
3-1.1 Description. A local application system consists of
fixed foam generating apparatus complete with a piped supply
of foam concentrate and water and arranged to discharge foam
directly onto the fire.
3-1.2 Uses. Local application systems may be used for the
extinguishment of fires in flannnable or combustible liquids, and
ordinary Class A combustibles where the hazard is not totally
enclosed. These systems are best adapted to the protection of
essentially fiat surfaces such as confined spills, open tanks, drainboards, curbed areas, pits, trenches, etc. For multiple level or
three dimensional fire hazards where total building flooding is
not practical, the individual hazard shall be provided with st, itable containment facilities acceptable to the authority having
jurisdiction.
3-1.3 General Requirements. Local application systems
shall be designed, installed, tested and maintained in accordance
with the applicable requirements in previous chapters and with
the additional requirements set forth in this chapter. Only listed
or approved equipment and devices shall be used in these systems.
3-2
Hazard Specifications.
3-2.1 Extent of Hazard. T h e hazard shall include all areas
to which or from which fire may spread.
3-2.2 Location of Hazard. T h e hazard may be indoors.
I partly sheltered, or completely out-of-doors. Foam shall be protected from strong winds or air currents.
3-3
Foam Requirements.
3-'3.1 General. Sufficient foam shall be discharged at a rate
to cover the hazard to a depth of at least two feet (0.6 m) within
two minutes (see A-2-3.5).
3-3.2 Quantity. Sufficient foam concentrate and water shall
be provided to permit continuous operation of the entire system
for at least 12 minutes (see 1-10.4).
3-3.2.1
with 1-10.7.
Reserve supplies shall be provided in accordance
LOCAL
APPLICATION
SYSTEMS
11A-25
3-4 Method. Discharge outlets shall be arranged to ensure
that foam is delivered over all areas which constitute the hazard.
Where parts of the hazard are elevated or raised up from the
ground or floor line, the arrangement of the system shall be such
that foam will be delivered to, and retained on, such parts in
sufficient depth to ensure prompt and final extinguishment.
11 A-26
IIlGH
Chapter 4
4-1
EXPANSION
FOAI~,I
PORTABLE
S'~'S'I'E~IS
Portable Foam Generating Devices
General Information.
FOAM
GENERATIN(;
I)EVICES
11A-27
4-4.2 S i m u h a n e o u s Use of Portable Foam Generating Devices. X'Vhcre simttltaneous use of two or more devices is possible, sufficient supplies of fo,tm concentrate and water shall be
available to supply the maximum nuntlmr of devices that are
likely to be used at any one time.
4-5
E q u i p m e n t Specifications.
4-1.1 Description. Portable foam generating devices consist of a high expansion foam generator, manually operable and
transportable, connected by means of hose, or piping and hose,
to a SUpl)ly of wa~er and foam concentrate. T h e proportioniug
equipment may be integral with or separate from the foam e,-enerator. A separate foam concentrate supply may be provided for
each unit, or solution may 1)e piped fiom central proportioning
equipment.
4-5.1 Hose. Hose used Io connecl the generator to the
water or solution supplies shall be listed lined hose. Unlined
fabric hose shall not be used. T h e hose size and length shall be
selected with consideratiola to the hydraulics of the entire system.
Such hose shall be stored in an arrangement that will permit
immediate use and be protected against the weather.
4-1.2 General Requirements. Portable foam generating devices and associated equipment shall be used and maintained in
accordance with the applicable requirements in the preceding
chapters and with the additional requirements set forth in this
chapter. Only listed or approved equipment and devices shall
be used.
4-5.2 Electric Power Supply and Connections. Power supply and connections needed lor operation of the generator shall
be adequate to transmit the required power, and sh:tll be selected
with consideration to the intended use. All power cables shall
be sufficiently rugged to withstand :tbuse in service, be impervious
to water and shall contain a ground wire. Unless eleclric connectors are waterproof, care shall be taken to prevent them from
being innncrscd in water.
4-2
Hazard Specifications.
4-2.1 Portahle foam generating devices may he used to combat fires in all hazards covered under Chapters 2 and 3.
4-3
Location and Spacing.
4-3.1 Location. Portable foam generating devices which
are preconnected to a water or solution supply shall be placed
where they are easily accessible and with enough hose to reach
the most distant hazard which they are expected to protect.
Foam concentrate shall be available for immediate use. These
devices shall he located such that they are not exposed to the
hazard. Those not preconnected to a water or solution supply
and their associated equipment shall be located and arranged for
immediate transport to all designated hazards.
4-4
Foam Requirements.
4-4.1 R a t e and Duration of Discharge. T h e rate and duration of discharge and consequently the quantity of foam concentrate and water shall be determined hy the type and potential
size of hazard. T o the extent that the specific hazards can he
identified, the applicable requirements of Chapters 2 or 3 shall
apply.
4-6
Training.
4-6.1 Successful extinguishment of fire with portahle foam
generating devices is dependent upon the individual al)ility and
techniquc of the operator. All personnel likely to use this equipment shall be properly trained in its operation and in the necessary fire fighting techniques.
It4
1 IA-28
HmU EXPANSION FOAM SYSTEMS
APPENDIX A
Appendix A
T h e f o l l o w i n g notes, b e a r i n g the same n u m b e r as the text of
the Slandard for High Expansion Foam Syst,ems to w h i c h they
a p p l y , c o n t a i n useful e x p l a n a t o r y m a t e r i a l and references to
standards.
11A-29
Foam Generators--Aspirator T y p e . T h e s e m a y be fixed or
p o r t a b l e . Jet streams of foam s o h l t i o n a s p i r a t e sufficient a n m u n t s
of a i r which is then e n t r a i n e d on the screens to p r o d u c e foam.
(See Fig. A-I-9.3(B).) T h e s e n s u a l l y p r o d u c e f o a m w i t h e x p a n sion ratios not over 250: 1.
This Appendix is not part of this NFPA Standard, but is included for information purposes only.
A-1-9.3 O p e r a t i n g Devices. A b l o c k d i a g r a m of typical autom a t i c h i g h e x p a n s i o n foam system is shown in Fig. A-1-9.3(A).
F o a m G e n e r a t o r s . A t the p r e s e n t t i m e foam g e n e r a t o r s for
high e x p a n s i o n foam are of two types d e p e n d i i l g on the m e a n s
for i n t r o d u c i n g air, n a m e l y , by a s p i r a t o r o r blower. I n e i t h e r
case, the p r o p e r l y p r o p o r t i o n e d f o a m s o l u t i o n is m a d e to i m p i n g e
at a p p r o p r i a t e velocity on a screen or p o r o u s or p e r f o r a t e d memb r a n e o r series of screens in a m o v i n g a i r stream. T h e iiquitl
films f o r m e d o n the screen are d i s t e n d e d by tim m o v i n g air
s t r e a m to f o r m a mass of b u b b l e s o r h i g h e x p a n s i o n foam. T h e
foant v o l u m e varies from a b o u t 100 to 1000 times the l i q u i d
v o l u m e d e p e n d i n g on the design of the generator. T h e c a p a c i t y
of f o a m g e n e r a t o r s is g e n e r a l l y d e t e r m i n e d by the t i m e r e q u i r e d
to fill a n enclosure of k n o w n v o h l m e b y t o p a p p l i c a t i o n w i t h i n
1 to 5 m i n u t e s .
"I[]~[~DETECTOR
MANUAL
OVERRID[~
CONTROL j
LIQUID
CONCENTRATE7
J
Fig. A-I-9.3(A). Block Diagram of Automatic High Expansion
Foam System.
oO (~¢
o_ °
8 g%oo(2oO
go
o~
AIR i
--D-!
1
r
~ 0
00
ooOo
OooOooo
oo o o ° o
oO°OOo o
LFOAM SOLUTION
SPRAY
INLET FOAM SOLUTION
Fig. A-I-9.3(B).
Aspirating Type Foam Generator.
Foam Generators iBlower
T y p e . T h e s e m a y be fixed or
portable.
T h e foam s o h l t i o n is d i s c h a r g e d as a s p r a y o n t o
screens t h r o u g h which a n air stream d e v e l o p e d by a fan o r b l o w e r
is passing. T h e b l o w e r m a y he p o w e r e d hy electric motors,
i n t e r n a l c o m b u s t i o n engines, air, gas, or h y d r a t , lic m o t o r s or
w a t e r motors. T h e w a t e r m o t o r s are u s u a l l y p o w e r e d b y foam
solution. (See Fig. A-1-9.3(C).)
A-l-10.5 F i r e Performance Test. T h e p u r p o s e of this test is
to p r o v i d e a r e p r o d u c i b l e fire s i t u a t i o n w h e r e f o a m s h o u l d be req n i r e d to move a s u b s t a n t i a l d i s t a n c e at a slow rate to the fire.
T h e time to move this d i s t a n c e a n d to fill to the t o p of the test
c o m b u s t i b l e s is the F O A M T R A N S I T T I M E . T h e effect of the
t r a n s i t t i m e is to give age to the foam d u r i n g the p e r i o d of its
slow m o v e m e n t froln foam g e n e r a t o r to fire.
T h e test s h o u l d be c o n d u c t e d in an o p e n t o p p e n or h u i l d i n g
of s u i t a b l e c o n s t r u c t i o n a n d s u i t a b l e d i l n e n s i o n s . T o p r e v e n t
the velocity of f o a m m o v e m e n t f i o m b e i n g too high, the w i d t h
of the pen or b u i l d i n g times I00 s h o u h l give a figure n o t s m a l l e r
tllan the c a p a c i t y in cfm ( m a / m i n ) of the foam g e n e r a t o r used
in the test. T h e h e i g h t of the size of the pen o r h u i l d i n g s h o u l d
be a h o u t 10 ft (3in). If the fluidity of the foaln permits, the
h e i g h t m a y be less. However, the foaln s h o u l d n o t flow over the
1,4
11 A-30
APPENDIX A
tI1GH EXPANSION I:OA},{ SYSTEMS
SCREEN-~
BL %
A,R
fLOW
/
---~.-
/
.
/i
//
\~ ~
\~
\
~\
,
S
I
/
°Oo°OoOoo
AoOoo~,o
./
/
b°o'6O~o
I
0 0
I000
/ /
/IOo
/
0
O0
o oo
'UO000
I 0 o000
~1°o%oOo
~.
Io o 020
~ 13oo~o
\
"tgg%°£o
x~,d°° °°
FOAM
SOLUTION
Fig. A-I-9.3(C).
Blower T y p e Foanl G e ne ra t or.
sides of the pen nor COlllilCt the ceiling of the building during the
I test. T h e foam gencralor should be set at one end of the pen or
building, and the fire should be set 10 ft (3m) from tile opposite
end. T h e distance between the foam generator and the fire
should be as required to give the foam transit time desired.
Foam should be produced 1)y a generator in which tile expansion ratio is equal to or greater than that produced by tile generalor proposed for installation.
l Tile test fire should be a stack of eight standards 4 ft x 4 ft
(1.22m x 1.22m) hardwood pallets dried to a moisture content
between 5 and 8 percent, set on suitable noncombustible supports
not over 24 in. (610ram) above tile floor. Beneath the pallets
I should be a 10 sq ft (0.93m") pan containing 1 gal. (3.8/) of
heptane or naphtha floating on water. T h e stuface of tile flamImable liquid shoukl be apl)roximately 19 in. (305ram) below
the bottom boards of the bottom pallet.
I T h e first test of each series should be a timed fill without a
fire to determine the foam transit time. T h e location of the
leading edge of the foam as it progqesses across the floor of the
pen or building should be timed at suitable intervals. Also, the
time should be noted when the foam reaches the edge of the pan.
This data will permit estimating, with reasonable accuracy, the
location of the leading edge of the foam 3 minutes before the
]
11A-31
foam should reach the edge of tile pan. Thereafter, during each
fire test, the heptane should be ignited when tile foam reaches I
that point corresponding to 3 minutes ill adwmce of reaching tile
pan. In this manner the fire is given a reproducible 3-minute
preburn. This fill test can be terminated when the foarn llas
filled to the top of the wood pallets, and the time deterlnined
as the foam transit time.
The minilnt, nl foam transit time should be 12 minutes (150
percent of i n a x i n n . n submergence time, 8 minutes, from Table
2-3.4). T o be considered successful under the foam transit time
condition, the foam shonld give adequate control of tile test fire.
The foam generator sfiould be run for a m,lximum of 30 minutes.
Adeqnate control should be interpreted as the absence of active
burning within the test stack while tile stack is covered with
foanl.
F o a m C o n c e n t r a t e P r o p o r t i o n i n g Systems. Some typical proportioning systems are shown in NFPA 11, Standard for Foam
Extingttishiug S),sZe,n.s.
A - I - I I . 2 Resistance of F o a m Generators to Fire Exposure.
T o determine its ability to withstand fire exposure from the
hazard area a generator, its associated piping and electrical
wiring, protected ill accordance with the manufacturer's recommeudations, should be startecl and operated after a 5-minutcl
exposure 10 ft (3m) above a 50-sq ft (4.65m") gasoline fire using
100 gal. of fuel (379/). T h e test fire should be shielded to ensure
tlame impingenmnt on tile generator.
A-1-13.1.4 Weekly recorded inspections of high expansion
loam systems should be made. Items to be checked include tile
following, ;is applicable:
Foam Control Room., Including Foam ConcengraZe Supply
S)J.sletH :
(a) Foam concentrate pt.nl)S, tanks, and lines checked 1'or
leaks or damage? Concentrate level in tanks normal?
(b) Concentrate pumps operating properly?
(c) All manually operated shutott: wtlves for the systenl pro}>
erly positioned and locked?
(d) Central panel lights operating properly?
(e) All disconnects in tile control panel in ON position?
(f) Water supply pressure normal?
(g) F;atteries fully charged? Liquid level normal?
(h) Fire alarm and trouble alarms tested? Silence switches
in normal position?
(i) All supervised functions checked for proper operation?
It,4
t~
llx
11A-32
I-nGn
EXPANSION
FOAM
SYSTEMS
Electric Foam Generators:
(j) All disconnect switches in the ON position and locked?
sprinf¢ler Water Supply and Alarms:
(k) W a t e r pressure on sprinkler risers normal?
(1) Water flow alarms tested?
(m) All manually operated shutoff valves locked open?
Protected Area:
(n) All closures operating properly?
A-2-3.4 Submergence Time--Vulnerability of Structure. It
is imperative that the integn'ity of primary structnral members
be maintained under fire exposure (which in sprinklered structures normally support the sprinkler system). Light unprotected
bar joist and other similar types of supports are especially vulnerable to damage by fast developing fires as compared to that
of heavy steel construction. So ,~,s,,
~ ~ is heavy ~.T~_protected steel
framing more vulnerable than fire-resistive (concrete) or protected
structural members.
A-2-3.5 Tests with foams of above 400:1 expansion ratio have
shown that extingnishment times for flammable liquid fires increased significantly at rates of foam rise less than 3 feet per
minute. It is expected that at some expansion ratio below 400:1
lower rates of foam rise would be adequate, but insufficient tests
have been conducted to identify this ratio.
A-2-3.5.1
G~w:n:
Sample Calculation of T o t a l Generator Capacity.
Building S i z e - - 100 feet × 200 feet × 30 feet high
Building C o n s t r u c t i o n - - L i g h t bar joist, Class I
steel deck roof, adeqnately
vented.
Masonry walls
with all openings closable.
Sprinkler Protection - - \Vet system, 10 feet × 10
feet spacing. 0.25 g p m / s q
ft density.
O c c u p a n c y - - V e r t i c a l l y stacked u n b a n d e d rolled
Kraft paper 25 feet high.
Assu,x~v.: Fire will open 50 sprinkler heads. Foam leakage
around closed doors, drains, etc., hence, CL = 1.2.
CALCULATION:
Foam Depth
Depth = 25 × 1.1 = 27.5 feet
(This is greater than m i n i m u m cover of 2 feet.)
APPENDIX
A
11A-33
Submergence Volume
V = 100 × 200 × 27.5 =- 550,000 cubic feet
Submergence T i m e
T = 5 minutes (from T a b l e 2-3.4)
Rate of Foam Breakdown by Sprinklers
S --- 10 c f m / g p m (from Section 2-3.5.2)
Q = No. of heads × a r e a / h e a d × density.
= 50 X (10 X 10) × 0.25 = 1250 g p m
R~ -----S X Q = 10 x 1250 = 12,500 cfm
Normal Foam Shrinkage
C N = 1.15 (from Section 2-3.5.3)
Leakage
CL = 1.2 (assumption)
T o t a l Generator Capacity
R=
(V-t-
R~) XC,~ × CL
( 0000
)
5
R = 169,000 cfm
T h e n u m b e r of generators required will depend upon the
capacity of the generators available.
Sample Calculation Using SI Units.
Building Size--30.5meters × 61 meters × 9.1 meters high.
Sprinkler P r o t e c t i o n - - W e t System 3 meter × 3 meter
spacing, 10.2 liters per minute pei"
sq meter density.
Occupancy - - Vertically stacked u n h a n d e d rolled I....
X I a l lr,
paper 7.6 meters high.
Calculation:
Foam Depth
Depth = 7.6 X 1.1 = 8.4 meters
Submergence Volume
V = 30.5 × 61 × 8.4 = 15,565 cubic meters
Submergence T i m e
T = 5 minutes (from T a b l e 2-3.4)
IMb
OII
11A-34
HIGH EXPANSION FOAM SYSTEMS
Rate of Foam Breakdown hy Sprinklers
S = 0.0748 m a . m i n / l . m i n (see 2-3.5.2)
Q = No. of Heads X area/head X density
= 50 X (3 X 3) X 10.2 = 4731 l/rain
R~ = S X Q = 0.0748 x 4731 = 35'hna/min
N o r m a l Foam Shrinkage
C.x = 1.15 (see 2-3.5.3)
Leakage
CI, = 1.2 (assumption)
T o t a l Generator Capacity
R =
~
+ 354
X 1:15 X 1.2
= 4784ma/min
A-2-3.5.2 R a t e of Breakdown by Sprinklers. Where sprinklers are present in an area to be protected by high expansion
foam, simultaneous operation will cause breakdown of the foam.
T h e rate of breakdown will depend upon the n u m b e r of sprinklers operating and the subsequent total rate of water discharge.
T h e n u m b e r of sprinklers expected to operate will depend upon
various factors as outlined in N F P A 13, Standard for Installation
of Sprinkler Systems.
A-2-3.5.4 F o a m Leakage. It is essential that uncontrolled
leakage be reduced to an absolute m i n i m u m through the use of
foam-tight barriers Jt all openings below the effective hazard
control level or depth, contemplating the increased rate of foam
escape as its fluidity is increased by anticipated sprinkler discharge.
Snch leakage through drains, trenches, under doors, around
windows, etc., can be minimized by use of suitable antomatic
closures, sealing agents, or mechanisms. Additional generator
capacity should be added to compensate for the aggregate losses
where foam escapement cannot be effectively controlled.
A-2-4 Maintenance of Submergence Volume. T h e choice of
a total flooding foam system for protection of a hazard does not
necessarily imply that it is expected that the system will completely extinguish the fire, or even so nearly extinguish it as to
APPENDIX A
1 IA-35
render the fire incapable of regaining the offensive. Rather,
tile effect sought might often be speedy control with m i n i m u m
damage to contents not involved in the fire.
When high expansion foam is estahlishing or has established
control of a fire, care must be exercised that control is not lost.
The following points should be kept in mind. Depending upon
the particular fire, some or all might be vital.
(a) All should be aware of the necessity for tight closure. Employees, hrigade members, and the fire departlnent should move
rapidly to close any openings through which foam is being lost.
Improvised closures can be made ot practically any available
material such as screening, plastic, plywood, hardboard.
(b) If the material involved is liable to deep-seated fires, such
as furniture, packaged material, fihers, rolls of paper, etc., particular care must be exercised in opening up the areas and re.
moving the foam. Even where only surface fire is thonght possible as in flammable liquids, smoldering Class A material may
cause reignition.
(e) A "soaking" period should elapse before foam is removed.
This may be as long :is an hour and should be predetelmined
based upon the fuel in the area.
A-2-5 Overhaul. T h e following points should be considered
during overhaul operations:
(a) All foam and sprinkler systems which are shut off should
have inen standing by wdves to turn them back on if this shotfld
become necessary.
(b) Foam supplies should be replenished if depleted.
(c) H a n d hose lines should be charged and manned. Personal
protective e q u i p m e n t should be dolmed. Self-contained breathm g apparatus should be worn in the "ready" position so there
will be no delay in putting it in service.
(d) Foam should be removed first from the fire area and
should be coordinated with overhaul and salvage operations.
T h e total loss will be kept to a m i n i m u m if thoughtless operalions are avoided. T h e fire is under control; undue haste to
extinguish the last ember may greatly increase the loss.
(e) Caution should be taken in entering previously foam-filled
areas, particularly in structures with pits or openings in the
floor.
(f) T h e area should be well ventilated but openings through
which foam might be lost should be kept to a m i n i n m m and
manned for closing if this should become necessary.
(g) Consideration should be given to disposal of the foam to
prevent any undue hazard to adjacent areas.
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