Report of Commlttee on Foam

Norman R Lockwood Chalrman Washington Crossing PA

Herb Wolff Secretary Reliance Insurance Cos

Rep American Insurance Assn

Lewis E Allen Jr Houston TX Wayne E Ault Rolf Jensen & Assec Inc Charles F Averill Grlnnell Fire Protectlon Systems Co

Rep NAS & FCA Francls X Bender Warner Lambert Co

Rep NFPA Industrlal Fire Protectlon W1lllam G 8oyce U S Goast Guard R R Burford 3M Co Wilham M Carey Underwriters Laboratorles Inc F L Deacon Kemper Insurance Cos

Rep Alliance of Amerlcan Insurers Victor G Gellsler Industrlal Risk Insurers John A Krembs M & M Protectlon Consultants A N Lagad~nos Insurance Serwces Offlce Jack P McLaughl]n Unlon Carbide Corp D N Meldrum Natlonal Foam System Inc

Inc

Robert C Merrltt Factory Mutual Research Corp Richard F Murphy Esso Englneerlng Europe Ltd

Rep Amerlcan Petroleum Instltute Patrick J 0 Brlen Lorcon Foam Inc H B Peterson U S Naval Research Laboratory L E R1vklnd Mearl Corp Orwlle M Slye Jr Mobll Research & Development Center

Rep Natlonal Petroleum Reflners Instltute Eugene Stauffer Ansul Co

Rep Fire Equlpment Manufacturers Assn Sturgls L Stentz Costa Mesa CA Richard L Tuve S11ver Sprlngs MD H Ray Vhet Edlson Fire Department NJ

Rep NFPA Fire Servlce Sectlon Laurence D Watrous Aspen Englneer}ng Inc

Layard E Campbell Reliable Automatlc Sprlnkler Co (Alternate to C F Avert11)

D 0 Crabtree Lorcon Inc (Alternate to S L Stentz)

George R Herzog Natlonal Foam System Inc (Alternate to D N Meldrum)

Edward J 0 Donoghue Industrlal Risk Insurers (Alternate to V G Gelhsler)

John A P1gnato Jr 3M Co (Alternate to R R Burford)

Alternates

Inc Duane L Rehmeyer Unlon Ca~blde Corp (Alternate to J P McLaugh]in)

C E Saunders Kemper Insurance Cos (Alternate to F L Deacon)

M11es R Suchomel Underwrlters Laboratorles Inc (Alternate to W M Carey)

G A Toyek Insurance Servlces Offlce (Alternate to A Lagadlnos)

Klaus Wahle U S Coast Guard (Alternate to W G Boyce)

Nonvotlng

Desmond H1rd Angus Fire Armour Ltd

Thls l l s t represents the membership at the tlme the Commlttee was balloted on the text of thls ed]t}on S~nce that tlme changes in the membership may have occurred

The Commlttee on Foam proposes for adoption ~ts Report on a complete revlslon to NFPA 11A 1975 Standard for High Expanslon Foam Systems NFPA 11A 1975 is publlshed in Volume 1 of the 1980 Natlonal Fire Codes and in separate pamphlet form

This Report has been submitted to letter ballot of the Technlcal Commlttee on Foam whlch conslsts of 26 votlng members of whom 23 voted afflrmatlvely 2 have been recorded as not votlng (Messrs Stentz and Vllet) and 1 ballot not returned (Mr Murphy)

/

"~ 261

11A i (1 1) Accept SUBMITTER Technical Committee on Foam

ATION In the second line of the f i r s t paragraph after "installation" add design operation testing and maintenance SUBSTANTIATION The scope needs expanding to cover all areas where the standard is applicable COMMITTEE ACTION Accept

11A 2 (1 4) Accept SUBMITTER Technical Committee on Foam ~ A T I O N Add a new Section 1 4(f) to read as follows

"( f) For liquefied natural gas (LNG) fires h~gh expansion foam Jwill not normally extlngu~sh a f~re but i t reduces the f l re ] intensity by blocking radiation feedback to the fuel SUBSTANTIATION More guidance on the use of high expansion foam for LNG f i re is needed COMMITTEE ACTION Accept

11A 3 (1 6 3) Accept SUBMITTER Technical Con~n~ttee on Foam ~ A T I O N Add new subsection 1 6 3 2 and 1 6 3 3 to read as fol lows 1 6 3 2 A b l h t y to control or ext inguish a f~re in a given hazard may depend upon such factors as expansion drainage and f l u i d i t y These factors w i l l vary with the concentrate equipment water supply and a i r supply 1 6 3 3 Suscept~blhty of the protected hazard to water damage shal l be evaluated

Renumber 1 6 3 2 as 1 6 3 4 SUBSTANTIATION More guidance on the l imi ta t ions of high expansion foam ~s needed COMMITTEE ACTION Accept

11A 4 (3 4) Accept SUBMITTER Technical Committee on Foam ~ A T I O N Add a new sectlon and subsectlons to read as fol lows

3 4 Foam Apphcatlons fo r Liquefied Natural Gas (LNG) 3 4 1 General High expansion foam has been shown to be e f fec t i ve in cont ro l l ing LNG test f i res and in reducing downwind vapor concentration from unlgnlted test LNG sp i l l s See NFPA 59A for addit ional ~nformatlon on f i r e protect ion requirements fo r other than use of high expansion foam fo r LNG fac l l ~ t l es A 3 4 Special Provisions fo r Liquefied Natural Gas (LNG) Fire & Vapor Control

(a) General Information 1 Apphcat~on Concepts fo r Fire Control Tests sponsored by

the American Gas Association have shown that the amount of radiat ion from a burning LNG sp i l l can be reduced by as much as 95 percent w~th some high expansion foams This is due in part to the foam barr ier which reduces vaporizat ion by blocking heat feedback from the flames to the LNG Foams having a low expansion ratio contain a great deal of water at amblent temperature that tends to increase the vaporization rate when ~t drains into the LNG Control was established with expansion ratios greater than 250 to 1 although an expansion ratio of about 500 to 1 proved most effective in the AGA tests Different brands of foam show considerable varlat~on In their ab~hty to control LNG f~res A rapldly dralnlng foam wil l increase the LNG vaporlzatlon rate and exaggerate the f i re ~ntenslty The dryer foam rema~nlng is less resistant to thermal effects and breaks down more read~ly Other factors such as bubble size f lu id i t y and linear burn rate may affect f i re control Therefore test results on LNG fires should be rewewed before selecting a foam for LNG f~re control

2 Downwind Vapor Hazard Control When f i r s t evolved from a spil l unlgnlted LNG vapors are heavier than a~r As these vapors are heated by sunlight and by contact with the a~r they eventually become buoyant and d~sperse upward Before th~s happens however high vapor concentrations may form downwlnd of an un~gnlted sp~ll at or near ground level H~gh expansion foam can be used to reduce th~s vapor concentration by adding heat from the water in the foam to the LNG vapors as they pass through the foam blanket Because of the induced buoyancy the apphcatlon of hlgh expansion foam can reduce downwind gas concentrations at ground level Expansions of up to 1 000 to I have been found to )rovlde effective dispersion control but may be ~mpractlcal because of wind However as with f~re control ab i l i ty to control vapor dispersion varies among d~fferent foams and should be demonstrated by tests

(b) Design Requirements I Apphcatlon Rate Test data should be presented to the

authority having jurlsdlctlon to show that the apphcatlon rate will reduce radlatlon from a test f i re wlthln 2 minutes Where burning LNG presents limited f i re exposure to surrounding areas the rate should be approximately 3 cfm/ft2 ((0 9m3/mln)/m2) For those areas w~th moderate to high exposure risk to surrounding areas or areas where time to apply high expansion foam must be kept to a minimum the rate should be approxlmately 6 cfm/ft2 (( i 8m3/mln)/m2)

2 Quantity The quantity of foam concentrate should be provided on the basis of continuous apphcatlon at the design appllcatlon rate for at least 15 minutes In addltlon sufficient foam should be provlded as demonstrated by tests acceptable to the authority having 3urisdlctlon to malntaln control for the calculated f~re and/or spil l duratlon For vapor dispersion control the quantity of foam concentrate to maintain cover durlng boll off w111 generally exceed the quantity required for f i re control

3 Arrangement Foam outlets should be arranged to ensure that foam is dehvered to all areas which constitute the hazard The foam outlets should be spaced and generators slzed to ensure that the minimum foam depth at any polnt in the hazard after two minutes of apphcatlon varies from i 5 feet (0 5m) for systems discharging 3 cfm/ft2 ((0 9m3/mln)/m2) to 3 feet (10m) for systems d]scharglng 6 or more cfm/ft2 ((1 8 or more m3/mln)/m2) Two minute foam spread data should be prowded to the authorlty having Ourlsdlctlon to verify that the required coverage can be obtained

(c) LNG F~re and Vapor Control Reference Publlcatlons 1 Amerlcan Gas AsSoclatlon Project IS 3 1 LNG Sp111s on

Land Nov 15 1973 2 American Gas Association Project IS 100 1 An Experimental

Study on the Mltlgatlon of FIem~nable Vapor Dispersion and Fire Hazards Immediately Followlng LNG Sp111s on Land Feb 1974

3 LNG Vapor Concentratlon Reduction and Fire Control wlth MSAR High Expansion Foam undated

4 Welker J R et al Fire Safety Aboard LNG Vessels January 1976

5 Wesson H R J R Welker and L E Brown Control LNG Sp111s Fires Hydrocarbon Processing Dec 1972

6 Liquefied Natural Gas/Characterlstlcs and Burning Behavior Conch Methane Servlces LTO 1962

7 Humbert Basset R and A Montet Flanvnable Mixture Penetration in the Atmosphere from Spillage of LNG Third Internatlonal Conference on LNG Washington D C Sept 1972

8 Gremeles A E and E M Drake Grawty Spreadlng and Atmospheric Disperslon of LNG Vapor Clouds Fourth International Symposlum on Transport of Hazardous Cargoes by Sea and Inland Waterways Jacksonwlle Florlda Oct 1975

9 Schneider Alan L Llquefled Natural Gas Safety Research Overview Natlonal Technical Information Service Sprlngfleld VA Dec 1978

NOTE This paper conta]ns 105 addltlonai references on many aspects of LNG Safety research lncludlng use of high expansion foam on LNG

SUBSTANTIATION There is a need to glve guidance on the use of high expansion foam for the controlhng and extlngulshment of f lres lnvolvlng liquefied natural gas (LNG) COMMITTEE ACTION Accept

In addition the Committee has made the following edltorlal changes

1 3 In the f i r s t llne before agent delete a relatlvely new and add an i 4 In the third hne of the second paragraph add and lack of conflnement after weather 1 4(a) In the f i r s t hne add free movement of after prevent and in the second llne delete from reachlng the f i re 1 4(b) Delete the second sentence 1 5 1 i Delete this section and renumber 1 5 1 2 1 5 1 3 and 15 14 as 15 11 15 12 and 15 13 1 5 1 2 Revise as follows 1 5 1 2 Foam Concentrate is a concentrated llquld foaming agent

as received from the manufacturer and approved for use ~n hlgh expansion foam equipment 1 5 1 3 Revise to read as follows 1 5 1 3 Foam Solution is a homogeneous mixture of water and foam

concentrate in the proper proportion i ~ 2 In the second sentence delete Two unlts ( l l t re and bar) and add One unit ( l l t re) 1 5 2 2 Add a new section to read as follows 1 5 2 2 The conversion procedure for the SI units has been to

multiply the quantity by the conversion factor and then round the result to the appropriate number of slgn~flcant dlglts Table 1 5 2 Revlse to read as follows

Table 1 5 2

Name of Unit Unit S~mbol

h t re L l l t re per m~nute per square meter (L/mln)/m2

cubic decimeter dm3 pascal Pa

Conversion Factor

i gal 3 785L

1 gpm/ft2 (40 746L/mln)/mZ

I gal 3 785 dm3 i psl 6894 757 Pa

For addltlonal converslons and information see ASTM E380 Standard for Metrlc Practice

1 6 2 In the thlrd llne after convection add and radlatlon 1 6 3 Revise to read as follows

262

1 6 3 Use and Limltatlons Whlle high expansion foam is finding appllcatlon for a broad range of f i re fighting problems each type of hazard shall be speclfically evaluated to verify the appllcabil lty of hlgh expansion foam as a f i re control agent 1 6 3 l(b) Revise to read as follows

(b) Flammable and combustible liquids 1 6 3 1(c) Rewse to read as follows

(c) Combinations of {a) and (b) 1 6 3 1(d) Add a new secton to read as follows

(d) L1quefled natural gas (LNG) 1 6 3 1 In the second line of the NOTE delete at after systems and add for control of

1 6 3 2 Renumber 1 6 3 2 as 1 6 3 4 1 6 3 4(e) Add a new section to read as follows

(e) Liquefied flammable gas other than llquefied natural gas (LNG) 1 7 1 At the end of the f i r s t sentence add the following and causing spatial disorientation

1 7 1 2 Add a new sentence to read as follows Addltlonal exits and other measures may be necessary to insure

safe evacuation of personnel 1 7 2 In the third paragraph In the f i r s t second and fourth lines change 1065 to 1000 and in the third line change 106 5 to 100

Table 1 7 2 Change the f i r s t 5 Items in the fourth and f i f t h columns to read as follows

7 178 10 254 13 330 17 432 25 635

Add an asterisk after clearance in the fourth column and at the bottom of the Table add the following

*For voltages up to 69 kv the clearances are taken from NFPA 70 National Electrical Code 1 8 2 2 In the twelfth llne delete 1975 1 8 4 1 In the second line delete visually 1 8 4 2 In the second line delete (13 8 bars) and add (1379 kPa) in the third llne delete (3 5 bars) and add (345 kPa) and in the fourth line delete 1975 1 9 2 2 In the f i f t h llne delete 1974 i 9 2 3 In the sixth line delete 1974 1 9 3 1 In the sixth llne delete 1976 1 9 5 1 Delete everything after operated i 10 2 In the second sentence after The add the folloWlng use of salt water or hard water or the

1 10 5 In the second line delete supplied wlth and add used in and in the thlrd llne after equlpment add the following or a foam concentrate of equivalent quality acceptable to the

authority havlng 3urlsdlction In the nlnth line after performance add the followlng

on a Class A f i re wlth a flammable llquld accelerant 1 10 6 In the thlrd line change deslgnated to design 1 10 7 In the third 1~ne change 110°F to IO0°F and (43oc) to (38oc)

1 10 8 Add an asterisk and a new second sentence to read as follows

Conslderation shall be g~ven to design of the storage tank to minimize evaporation of concentrate 1 10 9 In the third llne delete inslde and after a~r add the following from wlth~n the protected area

1 12 1 Add a new second sentence to read as follows Galvanizing may not be compatible with foam concentrate

1 12 2 In the third llne delete 1975 1 12 4 2 Revise to read as follows 1 12 4 2 Ducts shall be designed and installed so that undue

turbulence is avoided and the actual foam discharge shall be determined by test or other method acceptable to the authority having jurlsdlctlon 2 1 2 1 In the f i f t h line delete 1975 Table 2 3 4 Under Hazard revise the f i r s t entry to read as follows

Flammable Liquids (Flash Points below lO0OF (38OC))** and the second entry to read as follows

Combustible Liquids (Flash Points of lO0OF (38Oc) and above)** Also put footnote in table for rubber tires not sprinklered 2 3 S 1 Revise S to read as follows S Foam breakdown ~n cfm pe T gpm of sprinkler discharge S

shall be 10 cfm/gpm (0 0748 ma/mn)/(L/m~n) / 2 5 Revise to read as follows 2 5 Overhaul Overhaul procedures shall be carefully

preplanned to avoid loss of control establlshed by the system Z 6 Rewse to read as follows 2 6 D~str~butlon The high expansion foam generators shall be

located such that a relatively even build up of h~gh expanslon foam wil l take place throughout the protected area during the dlscharge period 3 1 1 In the fourth line after f~re add or sp~ll 3 1 2 In the second 1~ne after extinguishment add or control 3 1 3 In the f i f t h l~ne delete and and substitute a comma and after dewce add and agents

3 2 2 Revise to read as follows 3 2 2* Location of Hazard Local appllcatlon high expansion

foam systems may be used to protect hazards located indoors partly sheltered or completely out of doors Provls~ons shall be made to compensate for winds and other effects of weather 3 3 Change the t i t l e to read as follows 3 3 Foam Requlrements for Flammable and Combustible Liquids and

Solids 3 3 3 Redesignate 3 4 Methods as 3 3 3 Arrangement 4 5 2 Delete the last sentence and replace wlth the following

E1ectrlcal connectors shall be waterproof A I I0 5 Change the t i t l e to Fire Performance Test for Class A Materlals and add Class A after reproduclble Renumber this section A 1 10 5(a) In the next to the last llne delete 197b Add a new Section A i 10 5(b) Quallty Control Tes t Section on Foam Concentrate Proportlonlng Systems should be A 1 10 b(c) A 1 10 8 Add a new section to read as follows A 1 10 8 Exposure of the foam concentrate to the atmosphere may

cause evaporation of some or all components of the concentrate and in some cases may cause crusting of the agent This ~s exaggerated when a tank w~th an open vent is located in an area where the temperature fluctuates For example sunlight strklng a tank during the day wil l cause the concentrate to expand and some concentrate vapors to escape When the tank cools at nlght fresh air will be drawn in to replace the lost vapors Over a period of time the amount and the composition of the concentrate may change This loss can be minimized by designing the concentrate tank to include the following

(a) An expanslon dome which reduces the free surface of the concentrate to an area much smaller than the tank

(b) A pressure vacuum valve whlch reduces the amount of escaping vapors and also reduces the amount of fresh air enterlng the tank A 1 13 1 4(f) Revise to read as follows

(f) Water supply pressure and flow rate normal A 2 3 S 2 In the seventh line delete 1975 A 2 3 S 4 In the thlrd line of the second paragraph delete seallng agents and add seals

A 2 4 In the sixth llne add f i re after minimum A 2 4(a) In the f i f t h llne add fine mesh before screening A 3 2 2 Add a new section to read as follows A 3 2 2 Fences constructed of ordinary metal window screen mesh

have been shown to provlde an effectlve barrier which allows confinement of high expansion foam to a protected area B 1 1 Add the followlng to the l i s t of NFPA Standards

NFPA 70 1980 National Electrical Code B 1 2 Revlse to read as follows B 1 2 ASTM Standard This publlcatlon makes reference to the

followlng ASTM standard and the year date indicates the latest edltlon available I t ~s available from Amerlcan Soclety for Testing and Materlals 1916 Race Street Phlladelphla PA 19103

ASTM E380 76 Standard for Metrlc Practice

11A5 (Entire Standard) Accept 0 SUBMITTER Technical Committee on Foam ~ A T I O N Revise the entlre 1976 edltlon of NFPA 11A as shown in the reprinted draft of the standard SUBSTANTIATION Thls total revlslon is necessary to incorporate provlsions for the use of high expansion foam on liquefied natural gas to edltor ial ly update the standard to bring the standard into compliance with the NFPA Style Manual and to include technological advances in the use and testing of hlgh expansion foam COMMITTEE ACTON Accept

! Standard for

High Expanslon Foam Systems (Expanslon Ratios from 100 I to 1000 1)

NFPA 11A 1981

NOTICE

An asterlsk (*) followlng the number or letter deslgnatlng a subdivlslon indlcates explanatory material on that subdlvlslon in Appendix A

Information on referenced publications can be found in Appendix B

Chapter 1 General

1 1 Scope This standard includes mlnlmum requirements for the ]nstallatlon deslgn operation testlng and maintenance of hlgh expansion foam systems

Only those skilled in thls f ield are competent to design and install this equipment I t may be necessary for many of those charg d with the purchasing inspectlng testing approving operatlng and malntalnlng of thls equlpment to consult wlth an experienced and competent f i re protection englneer in order to effectively discharge thelr respectlve dutles

263

1 2 Purpose Thls standard is prepared for use and 9uldance of those charged wlth the purchasing designing installing testing inspecting approving l lsting operating or maintaining of hlgh expansion foam systems in order that such equlpment will function as intended throughout its l l fe

1 3 History High expansion foam is an agent for control and extinguishment of Class A and Class B fires and Is part]cularly suited as a flooding agent for use in confined spaces The development of the use of hlgh expansion foams for f l re fighting purposes started wlth the work of the Safety in Mines Research Establishment of Buxton England upon the d i f f i cu l t problem of fires in coal mines I t was fobnd that by expanding an aqueous surface active agent solution to a seml stable foam of about 1 000 times the volume of the original solution i t was possible to force the foam down relatlvelv lonq corridors thus providing a means for transportlng water to a f l re inaccessible to ordinary hose streams

This work has led to the development of specialized hlgh expansion foam generatlng equipment for flghtlng fires in mines for application in municipal industrlal f i re fighting and for the protection of special hazard occupancies

1 4 Description High expansion foam is an aggregation of bubbles mechanically generated by the passage of alr or other gases through a net screen or other porous medium whlch Is wetted by an aqueous solution of surface active foaming agents Under proper conditions f l re flghtlng 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 floodlng of confined spaces and for volumetric displacement of vapor heat and smoke Tests have shown that under certain circumstances hlgh expansion foam when used in con3unctlon wlth water sprlnklers wil l provide more posltlve control and extinguishment than either extinguishment system by i tse l f High piled storage of rolled paper stock is an example Optlmum efflclency in any one type of hazard is dependent to some extent on the rate of application and also the foam expansion and stabi l i ty

High expansion foam is partlcularly suited for indoor flres in conflned spaces Its use outdoors may be llm~ted because of the effects of weather and llack of confinement High expansion foam has several effects on flres /

(a) When generated in sufficient volume i t can prevent free movement of alr necessary for continued combustion

(b) When forced into the heat of a f l re the water In the foam is converted to steam reducing the oxygen concentratlon by dilution of the alr

(c) The conversion of the water to steam absorbs heat from the burning fuel Any hot object exposed to the foam wil l continue the process of breaking the foam converting the water to steam and of being cooled

(d) Because of its relatively low surface tenslon solution from the foam which is not converted to steam w111 tend to penetrate Class A materials However deep seated fires may require overhaul

(e) When accumulated in depth hlgh expansion foam can provide an insulating barrler for protection of exposed materials or structures not involved in a f l re and can thus prevent f l re spread

( f ) \ For liquefied natural gas (LNG) fires hlgh expansion foam w111 not normally extlngulsh a f l re but i t reduces the f i re intensity by blocking radlaton feedback to the fuel

Class A fires are controlled when the foam completely covers the f l re and burnlng material I f the foam is suff iciently wet and is ma1ntained long enough the f l re may be extlngulshed

Class B flres Involving high flash point liquids can be extinguished when the surface is cooled below the flash point Class B fires of low flash polnt liquids can be extinguished when a foam blanket of sufflclent depth is established over the 11quld surface

Thls standard is based on test data and design experience so far developed for use of hlgh expansion foam The intent qf thls standard is to indicate general rules appllcable to any system The limited f ield experience of approved systems makes i t d i f f i cu l t to prepare specific recommendations covering the many potential uses Thls standard is issued to outline some of the factors which shall be given consideration ~n 3udglng the acceptability of specific installations

1 5 Definitions and Units

1 5 1 Definltlons For purposes of clarlf lcatlon the following general terms used wlth speclal technical meanings In th~s standard are defined

Foam Concentrate A concentrated liquid foaming agent as recelved from the manufacturer and approved for use in hlgh expansion foam equipment

Foam Solutlon A homogeneous mlxture of water and foam concentrate in the proper proportion

High Expansion Foam An aggregation of bubbles resultlng from the mechanical expansion of a foam solution by alr or other gases wlth a foam to solution volume ratio of 100 1 to approximately 1000 1 (see A i 9 3)

1 5 2 Units Metric units of measurement in thls standard are in accordance wlth the modernized metric system known as the Internatlonal System of Units (SI) One unit ( l l t re) outside of but recognized by SI 1s commonly used in international f i re protection These units are listed in Table 1 5 2 wlth conversion factors

1 5 2 1 I f a value for measurement as given in thls standard is followed by an equlvalent value in other units the f l r s t stated is to be regarded as the requirement A gwen equivalent value may be approximate

1 5 2 2 The conversion procedure for the SI units has been to multlply the quantity by the conversion factor and then round the result to the approprlate number of slgnlflcant dlglts

Table 1 5 2

Name of Unit Unit Symbol Conversion Factor

l i te r L 1 gal 3 785L \

l i te r per minute per square meter (L/mln)/m2 1 gpm/ft2

(4g 746 L/mln)/m2

cubic decimeter dm3 1 gal 3 785 dm3

pascal Pa 1 psi 6894 757 Pa

For addltlonal converslons and informatlon see ASTM E380 Standard for Metrlc Practlce

1 6 General Informatlon and Requlrements

1 6 1 The mformatlon and requlrements in Chapter 1 are generally common to all hlgh expanslon foam systems

1 6 2 Mechanlsms of Extlngulshment High expanslon foam extlngulshes f l re by reduclng the concentration of oxygen at the seat of the f l re by coollng by haltlng convectlon and radlatlon and by excludlng addltlonal alr from the f l re

1 6 3 Use and L1mltatlons While hlgh expanslon foam is flndlng appllcatlon for a broad range of f i re flghtlng problems each type of hazard shall be speclflcally evaluated to verify the appllcab111ty of hlgh expanslon foam as a f l re control agent

1 6 3 1 Some important types of hazards that hlgh expanslon foam systems may satl factorI ly protect Include

(a} Ordlnary combustlbles

(b) Flammable and combustlble hqulds

(c) Comblnatlons of (a) and (b)

(d) L1quefled natural gas (LNG)

NOTE Under certain circumstances I t may be possible to ut i l ize hlgh expanslon foam systems for control of f ires Involving flammable IIqulds or gases issuing under pressure but no general recommendations can be made In thls standard due to the inf ln l te variety of particular situations which can be encountered in actual practlce

1 6 3 2 Abi l i ty to control or extinguish a f l re in a given hazard may depend upon such factors as expansion dralnage and f l u ld l t y These factors w111 vary wlth the concentrate equlpment water supply and alr supply

i 6 3 3 Susceptibility of the protected hazard to water damage shall be evaluated

1 6 3 4 High expansion foam systems shall not be used on fires in the followlng hazards unless competent evaluation includlng tests indlcates acceptability

(a) Liquefied flammable gas other than llquefled natural gas (LNG)

(b) Chemlcals such as cellulose nitrate whlch release sufflclent oxygen or other ox~dlzlng agents to sustain combustlon

P

(c) Energlzed unenclosed electrical equipment (see I 7 I 5)

264

(d) Water reactive metals such as sodium potasslum NaK

(e) Hazardous water reactive materlals such as tr lethyl aluminum and phosphorous pentoxlde

1 6 4 Types of Systems The types of systems recognized in this standard include

Total Flooding Systems

Local Appllcatlon Systems

Portable Foam Generating Dewces

i 6 S Systems Protecting One or More Hazards Systems may be 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 the opinion of the authority having Jurlsdlctlon two or more hazards may be slmultaneously involved in f i re by reason of their proxlmlty each hazard shall be protected wlth an individual system or the system shall be arranged to discharge on all potentially involved hazards simultaneously

1 7 Personnel Safety

1 7 1 Hazards to Personnel The dlscharge of large amounts of high expansion foam may Inundate personnel blocklng wslon making hearing d l f f l cu l t and creating some discomfort in breathing and causing spatial disorientation This breathing discomfort w111 increase with a reduction in expansion ratio of the foam and also under the effect of sprinkler discharge

1 7 1 1 Personnel working in a hazard area and with no responslbillty for f i re flghtlng shall be instructed to immediately vacate the area in the event of f i re I f possible I f personnel are unable to vacate and are trapped so that their llves are endangered by smoke or heat they may enter the foam Instructions shall be given to move the hand over the nose and mouth to mlnlmlze discomfort In breathing within the foam

1 7 1 2 Where possible the relative location of foam discharge points to building exlts shall be arranged to fac i l l ta te evacuation of personnel Addlt~onal exits and other measures may be necessary to insure safe evacuation of personnel

i 7 1 3 To re enter a foam f111ed bullding a coarse water spray may be used to cut a path in the foam Personnel shall not enter the foam The foam is opaque and I t ~s imposslble to see when one is submerged I t ~s dangerous to enter a bulld~ng ~n which there was a f~re ~f one cannot see

1 7 1 4 Caution A canister type gas mask shall not be worn in the foam The chemicals of the canister wil l react w~th the water of the foam and cause suffocation I f emergency reentry ~s essentlal self contained breathing apparatus shall be used in conjunctlonMlth a l l fe l~ne

1 7 1 5 Unenclosed electrical apparatus shall be de energized upon system actuation unless by competent evaluation i t has been deemed unnecessary

1 7 2 Electrical Clearances All system components shall be so located as to malntain m}nlmum clearances from llve parts as shown in Table 1 7 2

As used in th~s standard clearance is the air d~stance between high expansion foam equipment includ~ng p~plng and nozzles and unenclosed or unlnsulated l~ve electrical components at other than ground potential \ Since high expansion foam is conductive these clearances do not prevent flashover through foam (See 1 7 1 5 )

The clearances given are for altitudes of 3 300 f t (1000 m) or less iAt altitudes in excess of 3 300 f t (1000 m) the clearance shall be increased at the rate of 1 percent for each 330 f t (100 m) ~ncrease in altitude above 3 300 f t (1000 m)

The clearances are based upon minimum general practices related to design Basic Insulation Level (BIL) values To coordinate the required clearance with the electrical design the deslgn BIL of the equipment being protected shall be used as a basls although this is not mater~al at nomnal llne votages of 161 kv or less

Up to electrical system voltages of 161 kv the design BIL kv and correspondlng ml~lmum clearances phase to ground have been established through long usage 1

At voltages higher than 161 kv uniformity in the relationship between design BIL kv and the various electrical system voltages has not been established ~n practice and is dependent upon several variables so that the required clearances to ground shall be based upon the design BIL used rather than on the nominal hne or ground voltage

Possible design variations in the clearance required at higher voltages are evident in the table where a range of voltages is indicated opposite the various BIL test values in the hlgh voltage portlon of the table However the clearance between unlnsulated energized parts of the electrical system equlpment and any portlon of the high expansion foam system shall not be less than the minimum clearance provided elsewhere for electrical system insulations on any individual component

TABLE 1 7 2

Clearance from High Expansion Foam Equipment to Live Unlnsulated Electrical Components

Nominal Nominal Design M~nlmum Line Voltage BIL Clearance*

Voltage (kv) To 15

23 34 5 46 69

115 138 161

196 230

287 380

500

500 700

to Ground (kv) I ~ ( i n ) mm To 9 7 I/8

13 1501 10 254 20 200 13 330 27 250 17 43Z 40 350 25 b35 66 550 37 940 80 650 44 1118 93 750 b2 L32L

114 132 900 63 1600 1050 76 1930

1175 87 Z210 1300 98 2489

166 220 [ 1425 109 2769 I 1550 120 3048

290 1675 131 3327 [ 1800 142 3607

1925 153 3886 290 400 ~ 2100 168 4~b7

2300 184 4674

NOTE Baslc Insulatlon Level (BIL) values are expressed as k11ovolts (kv) the number belng the crest value of the fu l l wave impulse test that the electrical equipment is designed to withstand

For voltages up to 69 kv the clearances are taken from NFPA 70 NATIONAL ELECTRICAL CODE

1 8 Specifications Plans and Approval #

1 8 1 Purchasing Speclflcatlons Specifications for high expansion foam systems shall be drawn up with care under the supervlslon of a competent engineer and with the advlce of the authority having jurlsdlctlon To ensure a satisfactory system the following items shall be In the specifications

1 8 1 1 The speclflcatlons shall deslgnate the authorlty havlng jurlsdlctlon and indlcate whether submittal of plans Is required

1 8 1 2 The speciflcatlons shall state that the installation shall conform to thls standard and meet the approval of the authority havlng 3urlsdlctlon

1 8 1 3 The speclflcatlons shall include the speclflc tests that may be required to meet the approval of the authority hawng jurlsdlctlon and indlcate how cost of testing is to be borne

1 8 2 Plans Where plans are required tnelr preparation shall be entrusted only to fu l l y experienced and responsible persons

1 8 2 i These plans shall be drawn to an indicated scale or be suitably dimensioned and shall be made so that they can be easily reproduced

I 1 8 2 2 These plans shall contaln sufflclent detail on the hazard to enable the authority hawngburlsdlctlon to evaluate the effectiveness of the system The details on the hazard shall include the speclflc materlals involved the location and arrangement and the imedlate exposure to the hazard The deta11 on the system shall include sufficient information and calculations on the required amount of foam concentrate water requirements hydraullc calculatlons on the size length and arrangement of connected plplng and hose and the size and location of foam generators so that the adequacy of the quantlty flow rate and distribution of the high expansion foam generated can be determined (See Chapter 7 of NFPA 13 Standard for the Installatlon of Sprlnkler Systems for calculation procedures ) Detailed information shall be submltted pertaining to the location and function of detection devices operatlng devlces auxiliary equlpment lnclud~ng stand by power and electrical circuitry i f used Sufflclent lnformatlon shall be indlcated to identlfy properly the apparatus and devices used Any special features shall be adequately explained

265

1 8 3 Approval of Plans Where plans are required they shall be submitted to the authority having jurlsdlct~on for approval before work starts

I 8 3 1 Where f ie ld condltlons necessitate any significant change from the approved plan corrected as installed plans shall be suppl~ed for approval to the authority hawng jurlsdlctlon

1 8 4 Approval of Installat~ons The completed system shall be tested by qualified personnel to meet the approval of the authority having jurisdiction These tests shall be adequate to determne that the system has been properly Installed and wil l function as intended Only listed or approved equipment and devices shall be used in these systems

1 8 4 1 Such tests shall include a d~scharge of foam i f possible This foam shall be checked for desired quality I f actual discharge is not permitted the supplier or Installer shall check air flow and liquid flow ~n a manner satisfactory to the authority having Jurisdlctlon

1 8 4 2 All piping up to each foam generator shall be subjected to a 2 hour hydrostatic test pressure at 200 ps~ (1379 k Pa) or 50 psi (345 k Pa) in excess of the maximum pressure anticipated whichever }s greater (See NFPA 13 Standard for the Installation of Sprinkler Systems )

1 8 4 3 Tests shall include a complete check out of electrical control c~rcuits and supervisory systems to ensure proper operation and supervision in the event oT failure

1 8 4 4 Tests shall estabhsh that all automatic closing devices for doors windows and conveyor openings and automatic equipment interlocks as well as automatic opening of heat and smoke vents or ventilators w~ll functlon upon system operatlon

I 8 4 5 Operating instructions provided by the supplier and the proper ~ndentification of devices shall be checked

1 9 Operation and Control of Systems

1 9 1 Methods of Actuation Systems shall be classlf~ed as manual or automatic in accordance with the method of actuation An automatic system is one which is actuated by automatic detection equipment Such systems also shall have means for manual actuation

1 g 2 Detection of Fires Fires or condlt~ons l ikely to produce f i re may be detected by human senses or by automatic means

1 9 2 1 Automatic detection shall be used for f~xed systems

Exception Automatic detection may be omitted only when approved by the authority having Jur~sdlction

1 9 2 2 Automatic detection shall be by listed or approved method or dewces capable of detecting and indlcatlng heat smoke flame combustible vapors or any abnormal condltlon ~n the hazard such as process trouble l ikely to produce f i re (See NFPA 72E Standard on Autematlc Fire Detectors )

1 g 2 3 An adequate and reliable source of energy shall be used ~n detection systems The power supply for electrlcal detectlon systems shall be independent of the supply for the protected area Otherwise an emergency battery powered supply w~th automatic swltchover shall be provided ~f the primary supply fal ls (See NFPA 72E Standard on Automatic Fire Detectors )

1 9 3 Operating Devices* ~Operatlng devices ~nclude foam generators valves proport]oners eductors discharge controls and shutdown equipment

I g 3 1 Operation shall be controlled by llsted or approved mechanical electrical hydraulic or pneumatic means An adequate and reliable source of energy' shall be used The electrical power supply for an electrically operated high expanslon foam system shall be as reliable as a f i re pump circuit ~n accordance w~th NFPA 20 Standard for the Installation of Centrifugal Fire Pumps

I 9 3 2 All operating devices shall be suitable for the servlce they wil l encounter and shall not be readily rendered ~noperatlve or susceptible to accidental operation Provlslon shall be made to protect p~plng normally f i l led with llqu~d from freezing

1 9 3 3 All devices shall be located installed or sultaoly protected so that they are not subject to mechanical chemical climatic or other cond]tlons that wil l render them inoperative

1 g 3 4 Manual controls for actuation and shutdown shall be located so as to be conveniently and easlly accessible at all times including the t~me of f i re and system operation Remote control stations for manual actuation may be required where the area ~s large egress d i f f icu l t or when required by the authority having jur]sdlctlon Manual controls for actuation shall operate the system to the same extent as the automatic control

I g 3 5 All automatically operated equipment controlling the generatlon and dlstrlbutlon of foam shall be provided wlth approved independent means for emergency manual operatlon If the means for manual actuation of the system required in i g I provides approved posltwe operatlon independent of the automatlc actuation it may be used as the emergency means The emergency means preferable mechanlcal shall be easily accessible and located close to the equipment controlled If posslble the system shall be designed so that complete emergency actuation can be accomplished from one locatlon

i 9 3 6 All required door and window closers vent openers and electrical equlpment shutdown dewces shall be considered integral parts of the system and shall function with the system operation

i 9 3 7 All manual operatlng devices shall be ~dentlfied as to the hazards they protect

i g 4 Supervision Superv~slon of automatlc detection and actuation equipment shall be prowded and so arranged that there will be an Immedlate ind~catlon of failure preferably at a constantly attended location

i 9 5 Alarms Audlble alarms shall be installed to indicate the operation of the system alert personnel and ~ndlcate fallure of any supervised device or equipment Such devices shall be of such a type and shall be provided in such numbers and such locations as are necessary to accompllsh satisfactorily their purpose subject to approval of the authority having jurlsdlctlon

I 9 5 1 An alarm shall be provided to show that the system has operated

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 indlcatlng fai lure of supervlsed devices or equipment shall give prompt and positive ind~catlon of any failure and shall be distlnctlve from alarms indicating operation or hazardous conditions

1 10 Water Foam Concentrate and Air Supply

1 10 1 Water Quantity Water shall be available in sufflclent quantity and pressure to supply the maximum number of high expanslon foam generators l ikely to operate simultaneously ~n addltlon to the demands of other f i re protection equlpment

1 10 2 Water Quality Conslderatlon shall be glven to the sultab111ty of the water for production of high expansion foam The use of salt water or hard water or the presence of corrosion Inhlbltors antifreeze agents marine growths oII or other contaminants may result in reduction of foam volume or s tabi l i ty The manufacturer of the foam concentrate shall be consulted

1 10 3 Water Storage Water supply shall be protected against freezing

1 10 4 Foam Concentrate Quantity The amount of foam concentrate In the system shall be at least sufficient for the largest single hazard protected or a group of hazards whlch are to be protected simultaneously (see 2 3 6 and 3 3 2)

1 10 5* Foam Concentrate Quality The foam concentrate used in the system shall be that l~sted for use wlth the equipment or a foam concentrate of equlvalent quality acceptable to the authority hawng Jurisdiction The performance of the system is dependent upon the composltlon of the foam concentrate as well as other factors The quality of the concentrate for proper performance under the installatlon requirements of thls standard shall be determned by suitable tests One such suitable test oased on f l re performance on a Class A f i re with a flammable llquld accelerant Is described ~n A 1 10 5

1 10 6 Foam Concentrate Reserve Supply Sufflclent foam concentrate shall be kept on hand for at least one complete recharge of the system based on deslgn requirements This reserve supply shall be stored In separate tanks compartments original shipping containers or by other approved methods To prevent accidental use and depletion of this reserve supply i t shall be available to the system only by intentional manual operatlon

i 10 7 Foam Concentrate Storage In service and reserve supplies of foam concentrate shall be stored where the temperature is malntalned between 35OF (2oC) and lO0OF (38oC) or wlthln such other temperature range for whlch the concentrate has been listed The reserve supply containers shall be kept t lght ly closed In a clean dry area to preveht contam~natlon or deterlorat~on

1 10 8* Foam Concentrate Storage Tank The tank shall be of corroslon reslstlng materlals and construction compatible w~th the foam Concentrate Conslderatlon shall be given to design of the storage tank to minimize evaporation of concentrate Consult the foam equlpment manufacturer

266

1 10 9 Air Supply Air from outside the hazard area shall be used for foam generation unless the calculated foam generation rate using air from within the protected area is increased to compensate for foam loss because of heat smoke and chemical effects during a f i re The degree of loss from such effects shall be determined by test

1 10 9 1 Vents shall be located to avoid rec~rculat~on of combustlon products into the a~r ~nlets of the foam generators

1 11 Foam Generating Apparatus Location

1 11 1 Accessibility for Inspection and Maintenance Foam generating apparatus shall be so located and arranged that inspect~on testing recharging and other maintenance is facil i tated and interruption to protection is held to a minimum

1 11 2* Protection Against Exposure Foam generating equipment shall be located as near as possible to the hazard or hazards i t protects but not where i t w~ll be unduly exposed to a f i re or explosion Foam generators installed inside the hazard area shall be constructed or protected against f i re exposure Such protection may be by insulation f i re retardant paint water spray or sprinklers etc In certain applications addlt~onal generators may be substituted for f l re exposure protection with the approval of the authority hawng jurlsd~ct~on

1 12 D~stribut~on Systems

1 12 1 Piping and Fittings The piping and f i t t ings in continuous contact w~th foam concentrate shall be of corrosion resisting materials compatible with the foam concentrate used Galvan~zlng may not be compat~ble\wlth foam concentrate The remainder of the plp~ng and f~ttlngs shall be standard weight (Schedule 40) black or galvanized steel p~pe and standard weight black or galvanized steel ductile or malleable iron f i t t ings Consideration shall be given to possible galvanic effects when d~ss~mllar metals are joined especially in p~plng which carries foam concentrate

1 12 2 Arrangement and Installation of Piping and Fittings Piping shall be installed ~n accordance with practices outlined in NFPA 13 Standard for the Installation of Sprinkler Systems

1 12 2 1 All piping systems shall be designed using hydraulic calculations to assure the desired rate of flow at the foam generators Care shall be taken to avoid possible restrlct~ons due to foreign matter faulty fabrlcat~on and improper installation

1 12 2 2 A l~sted strainer shall be provided in the water l~ne upstream of the water valve suitable for use w~th the proportloner and foam generator Supplemental strainers may be used as recommended by the foam equipment manufacturer

I 12 3 Valves All valves shall be suitable for the intended use partlcularly in regard to flow capacity and operation Valves shall be of a l~sted type or deemed suitable for such use as a part of the system

I 12 3 i Valves shall not be easily subject to mechanical chemical or other damage ~,

1 12 4 Ducts Foam dlstr]butlon and air inlet ducts shall be designed located installed and suitably protected So that they are not subject to undue mechanical chemical or other damage

1 12 4 1 Duct closures such as selector valves gates or doors shall be of the qu~ck opening type allowing free passage of the foam When located where they may be subjected to f~re or heat exposure e~ther inside or outside the area to be protected special care shall be taken to ensure pos~tlve operation

1 12 4 2 Ducts shall be designed and installed so that undue turbulence ~s avolded and the actual foam d~scharge rate shall be determined by test or other method acceptable to the authority hawng Jurlsdictlon /

1 13 Maintenance and Instructions

i 13 1 Inspection and Tests At least annually all hlgh expansion foam systems shall be thoroughly inspected and checked for proper operation by a competent engineer or inspector Thls shall include determ~natlon of any changes in physical properties of the foam concentrate which indicate any deterlorat~on ~n quality Regular service contracts w~th the manufacturer or Installlng company are recommended

1 13 I i The goal of th~s inspection and testing shall be to ensure that the system ~s in full operating cond~tlon and to indicate the probable continuance of that cond~tlon until the next inspection

i 13 1 2 Suitable discharge tests shall be made when any inspection ~ndlcates their advlsab~l~ty

1 13 1 3 The inspectlon report wlth recommendations shall be f i led wlth the owner

I 13 1 4 Between the regular servlce contract inspection or tests the system shall be inspected by competent personnel following an approved schedule

1 13 1 5 Strainers shall be inspected and cleaned after each use and test

1 13 2 Maintenance These systems shall be maintained in ful l operating condition at all times Use impairment and restoration of this protectlon shall be reported promptly to the authority having jurlsdlct~on

1 13 2 1 Any troubles or impalrments shall be corrected at once by competent personnel

1 13 3 Instructlons All persons who may be expected to inspect test malntaln or operate foam generating apparatus shall be thoroughly trained and kept thoroughly tralned ]n the functions they are expected to perform

1 13 3 1 Training programs approved by the authorlty havlng jurlsdictlon shall be established

i 13 3 2 Operatlng instructlons shall be posted at control stations

Chapter 2 Total Flooding Systems

2 i General Information i

2 1 1 Descrlptlon A total flooding system consists of fixed foam generating apparatus complete wlth a plped supply of foam concentrate and water arrranged to d~scharge ~nto an enclosed space or enclosure around the hazard

2 1 2 Uses This type of system may be used where there is a permanent enclosure around the hazard that Is adequate to enable the required amount of f i re extinguishing medium to be bullt up and to be malntalned for the required period of time to ensure the contffol or extlngulshment of the f l re in the specific combustible material or materlals involved

2 1 2 I Examples of hazards that may be successfully protected by total flooding systems include rooms vaults storage areas warehousing faclht les and buildings containing Class A and Class B combustibles either singly or in comb~natlon (See NFPA 231C Standard for Rack Storage of Materials ) Three dimensional flres in flammable liquids (falling or flowlng under pressure) having flash polnts below lO0oF (38oc) generally will not be extinguished by total coverage Although this f l re may continue in the foam heat radlatlon wll] be reduced and kept under control with continued foam appl~catlon

2 1 2 2 Fires which can be controlled or ext]ngulshed by total flooding methods can be divided into two categorles namely (i) surface flres involwng flammable or combustlble liquids and solids and (2) deep seated flres ]nvolvlng solids subject to smoldering

2 i 3 General Requirements Total floodlng systems shall be deslgned installed tested and maintained in accordance with the applicable requlrements in the previous chapter and wlth the addltional requlraments set forth in this chapter Only llsted or approved equipment and devices shall be used ~n these systems

2 2 Enclosure Speclflcatlons

2 2 1 Leakage and Ventilation ~ Since the efflclency of the high expansion foam system depends upon the development and maintenance of a sultable quantity of foam within the partlcular enclosure to be protected leakage of foam from the enclosure shall be avolded

2 2 1 1 Openlngs below deslgn f l l l l ng depth such as doorways wlndows etc shall be arranged to close automatically before or simultaneously with the start of the foam discharge wlth due consideration for evacuation of personnel They shall be designed to malntaln a closure durlng a f i re and be capable of wlthstandlng pressures of foam and sprinkler water discharge I f any unclosable openings exist the system shall be designed to compensate for the probable loss of foam and shall be tested to assure proper performance

2 2 1 2 When outside air is used for foam generation hlgh level venting shall be prowded for alr which is dlsplaced by the foam I f possible venting velocity shall not exceed 1000 f t per mln (305 m/min) in free a~r The venting so required shall consist of suitable openings e~ther normally open or normally closed and arranged to open automatically when the system operates When design criteria demand exhaust fans they shall be approved for high temperature operation and ~nstalled with due consideration for protection of switches w]rlng and other electrical devices

267

to assure equal re l iab i l i ty of exhaust fan performance as for the foam generators Where forced a~r ventllat~ng systems interfere with the proper buildup of foam they shall be shut down or closed off automatically

2 3 Foam Requirements

2 3 1 General For adequate protection sufflc~ent high expansion foam shall be d~scharged at a rate to f l l l the enclosure to an effective depth above the hazard before an unacceptable degree of damage occurs

2 3 ~ Foam Depth The mlnlmum total depth of foam shall be not less than I 1 t~mes the helght of the hlghest hazard but ~n no case less than 2 f t (0 B m) over th~s hazard For flammable or co~ustible liquids the required depth over the hazard may be conslderably greater and shall be determlned by tests

Z 3 3 Submergence Volume Submergence volume ~s defined as (1) the depth as specified in 2 3 2 multlplled by the floor area of the space to be protected or (2) in the case of unsprlnklered rooms of ~nternal combustlble construction or f~nlsh the entire volume including concealed spaces The volume occupied by vessels machinery or other permanently located equipment may be deducted when determining the submergence volume The volume occupied by stored mater~al shall not be deducted when determining the submergence volume unless approved by the authority hawng Jurlsdlctlon

2 3 4 Submergence Time Recommended times to achieve submergence volume for various types of hazards and bu~Idlng construction are shown in Table 2 3 4 Shorter submergence times may be required depending on the factors included ~n 2 3 5

Table 2 3 4 Maximum Submergence T~me for High Expansion Foam Measured

from Start of Foam Discharge* (Minutes)

Heavy or Protected L~ght or Unprotected or Fire resistive Hazard Steel Construct ion Construction

/ Not

Spr~nklered Sprlnklered Sprlnklered Sprinklered

Not

Flammable Liquids 3 2 5 (Flash Polnts below 100OF (37 8oc) having a vapor pressure not exceeding 40 psia (276 kPa) *

Combustible Liquids 4 3 5 (Flash Points of 100OF (37 8oc) and above)**

Low Density 4 3* * 6 Combustibles

e Foam Rubber Foam P1astlcs Rolled Tissue or Crepe Paper

High Density 7 5*** 8 Combustibles i e Rolled Paper

Kraft or Coated Banded

High Density 5 4 * 6 Combustibles

e Rolled Paper Kraft or

Coated Unbanded

Rubber Tires 7 S **t 8 6***t

Combustibles in 7 5 * 8 cartons bags f~ber drums

4 *

6* *

5 *

6 * *

Notes for Table 2 3 4

*Th~s is based on a maxlmum of 30 sec delay between f~re detection and start of foam discharge Any delays in excess of 30 sec shall be deducted from the submergence t~mes in Table 2 3 4

thigh expanslon foam protectlon without sprinkler protectlon Is not recognized wlthln the scope of NFPA 231D Storage of Rubber Tires NFPA 231D apphes only to locatlons hawng more than 10 000 equivalent passenger tlres \

*Polar solvents are not included in th~s table Flammable llqulds havlng bo~l~ng polnts less than 100OF (37 8oc) may require higher appllcation rates See NFPA 321 Standard on Basic Class}flcatlon of Flammable and Combustlble L1qulds Where use of high expanslon foam is contemplated on these materials the foam equlpment supplier shall substantiate su~tabillty for the intended use

* *These submergence tlmes may not be d~rectly appllcable to high piled storage above 15 f t (4 6 m) or where f~re spread through combustible contents is very rap~d

2 3 5 Rate of Discharge The rate of foam discharge necessary for extlngulshment or sufflclent control to permit overhaul depends upon the strength of sprlnkler protection nature and conflguratlon of the hazard vulnerabillty of the structure and contents to f i re and the loss potential to l l fe property and production The rate also depends upon foam propertles such as expansion ratio water retention effect of water contamlnants temperature effects on water retention etc The foam discharge rate shall be sufficient to satisfy the foam depth requlrements and submergence times of Table 2 3 4 maklng compensatlon for normal foam shrlnkage foam leakage and breakdown effects of sprlnKler discharge

2 3 5 I* The m~nlmum rate of discharge or total generator capacity shall be calculated from the followlng formula

R V.~_+ R S x CN x CL 1 T

where

R rate of discharge cfm (m3/mln)

V submergence volume cublc feet (m3)

T submergence t~me minutes

R S rate of foam breakdown by sprlnklers cfm (m3/mln)

C N compensation for normal foam shrlnkage

C L compensation for leakage

2 3 5 2 The factor (Rs) for compensation for oreakdown by sprlnkler dlschar~e shall be determined elther by test or In the absence of specific test data by the followlng formula

RS S X Q where

S Foam breakdown in cfm per gpm of sprlnkler discharge S shall be 10 cfm/gpm (0 0748 m3/mln)/(L/mln)

Q Estimated total discharge from maximum number of sprinklers expected to operate gpm (/mln)

2 3 5 3 The factor (CN) for compensatlon for normal foam shrinkage shall be 1 15 This is an amplrlcal factor based on average reduction In foam quantlty from solutlon drainage f i re wetting of surfaces absorbency of stock etc

2 3 5 4 The factor (CL) for compensatlon for loss of foam due to leakage around doors and windows and through unclosable openings shall be determlned by the design engineer after proper evaluation of the structure Obvlously thls factor cannot be less than I 0 even for a structure completely tlght below the design f i l l l ng depth This factor could be as h~gh as 1 2 for a bulldlng with all openings normally closed depending upon foam expansion ratio sprinkler operation and foam depth

2 3 6 Quantlty Sufflclent foam concentrate~and water shall be provided to permit continuous operation of the entire system for at least 25 minutes or to generate four t~mes the submergence volume whichever is less but in no case less than enough for 15 minutes of ful l operatlon (see 1 10 4)

2 3 6 1 Reserve supplles shall be provided In accordance wlth I 10 7

2 4* Malntenance of Submergence Volume To ensure adequate control or extlngulshment the submergence volume shall be malntalned for at least 60 minutes for unspr~nklered locations and 30 minutes for sprlnklered locations Where only flammable or combustlble llqulds are involved this period may be reduced

2 4 I Method The submergence volume may be malntalned by continuous or Intermlttent operation of any or all of the generators provlded

268

2 4 1 1 Arrangements and procedures shall be provided to maintain the submergence volume without waste of foam concentrate which may be needed in case of reignition

2 5* Overhaul Overhaul procedures shall be carefully preplanned to avoid loss of control establlshed by the system

1 i 2 6 Distribution The high expansion foam generators shall be located such that a relat ively even bulldup of high expansion foem will take place throughout the protected area durlng the discharge period )

Chapter 3 Local Appllcatlon Systems

3 1 General Information

3 I I Description A local appllcatlon 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 f i re or spil l

3 1 2 Uses Local appllcatlon systems may be used for the extingulshment or control of flres in flemmable or combustible liquids liquefied natural gas (LNG) and ordinary Class A combustibles where the hazard is not to ta l ly enclosed These systems are best adapted to the protection of essentially f la t surfaces such as confined spills open tanks dralnboards curbed areas pits trenches etc For multiple level or three dlmensional f i re hazards where total bullding floodlng is not practical the indlvidual hazard shall be prowded with sultable containment fac i l i t ies acceptable to the authority having 3urisdiction

3 1 3 General Requirements Local appllcatlon systems shall be designed installed tested and malntalned ~n accordance with the appllcable requirements in previous chapters and with the additional requirements set forth in this chapter Only listed or approved equipment devices and agents shall be used in these systems

3 2 Hazard Specifications

3 2 1 Extent of Hazard The hazard shall lnCTude a11 areas to which or from which f i re may spread

3 2 2 Location of Hazard Local appllcatlon hlgh~expansion foam systems may be used to protect hazards located indoors partly sheltered or completely out of doors Provisions shall be made to compensate ~or winds and other effects of weather

3 3 Foam Requirements for Flammable and Combustlble Liquids and Sollds f

3 3 1 General Sufficient foam shall be dlscharged at a rate to cover the hazard to a depth of at least two f t (0 6 m) within two minutes (see A 2 3 5)

3 3 2 Quantlty Sufflclent 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 i Reserve supplies shall be provided in accordance wlth 1 10 7

3 3 3 Arrangement Discharge outlets shall be arranged to ensure that foam ~s 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 wil l be dellvered to and retained on such parts in sufficient depth to ensure prompt and flnal extinguishment

3 4* Foam Applications for Liquefied Natural Gas (LNG)

3 4 1 General High expanslon foam has been shown to be effective in controlllng LHG test f lres and in reducing downwind vapor concentration frem unlgnlted test LNG spil ls See NFPA 59A for addltional information on f l re protectlon requirements for other than use of high expansion foam for LNG fac111tles

Chapter 4 Portable Foem Generating Devices

4 1 General Informatlon

4 1 1 Description Portable foam generating devlces consist of a high expansion foam generator manually operable and transportable connected by means of hose or piping and hose to a supply of water and foam concentrate The proportlonlng equipment may be integral with or separate from the foam generator A separate foam concentrate supply may be provided for each unit or solution may be piped from central proportlonlng equlpment

J

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 2 Hazard Specifications 1

4 Z 1 Portable foam generating devices may be used to combat fires in all hazards covered under Chapters 2 and 3

4 3 Location and Spacing

4 3 I Location Portable foam generating devlces whlch are preconnected to a water or solutlon 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 be located such that they are not exposed to the hazard Those not preconnected to a water or solution supply and their associated equlpment shall be located and arranged for immedlate transport to all designated hazards

4 4 Foam Requirements

4 4 1 Rate and Duration of DiScharge The rate and duration of discharge and consequently the quantlty of foam concentrate and water shall be determined by the type and potential size of hazard To the extent that the speclf~c hazards can be identlfled the appllcable requirements of Chapters 2 or 3 shall apply

4 4 2 Simultaneous Use of Portable Foam Generating Devices Where simultaneous use of two or more devices is possible sufflclent supplies of foam concentrate and water shall be avallable to supply the maximum number of devices that are l lkely to be used at any one time

4 5 Equipment Specifications

4 S i Hose Hose used to connect the generator to the water or solution supplies shall be listed llned hose Unlined fabric hose shall not be used The hose size and length shall be selected with consideration to the hydraulics of the entlre system Such hose shall be stored in an arrangement that wlll permlt immediate use and be protected against the weather

4 5 2 Electric Power Supply and Connections Power supply and connectlons needed for operation of the generator shall be adequate to transmlt the requlred power and shall be selected with conslderatlon to the intended use All power cables shall be suff lclently rugged to withstand abuse in serwce be impervious to water and shall contain a ground wire Electrical connectors shall be waterproof

4 6 Training

4 6 1 Successful extinguishment of f i re with portable foam generatlng devices is dependent upon the individual abi l i ty and technique of the operator All personnel l ikely to use thls equipment shall be properly trained in its operation and in the necessary f i re fighting techniques

Appendix A

This Appendix is not part of the requirements (recommendations) of this NFPA Standard but is included for information purposes only

A 1 g 3 Operating Devices A block diagram of typical automatic high expansion foam system is shown in Figure A 1 g 3(a)

(a) Foam Generators At the present time foam generators for high expansion foam are of two types depending on the means for introduclng air namely by aspirator or blower In either case the properly proportioned foam solution is made to impinge at appropriate velocity on a screen or porous or perforated membrane or series of screens in a moving air stream The llquld films formed on the screen are distended by the moving air stream to form a mass of bubbles or high expansion foam The foam volume varies from about 100 to 1 OOO times the liquid volume dependlng on the design of the generator The capacity of foam generators is generally determined by the tlme required to f i l l an enclosure of known volume by top application wlthln 1 to 5 minutes

269

r-- -- ~ ~ D E T E C T O R MANUAL I

OV f" R R I D [ ~ j ~ _ L _

C O N TI~--JR O L - / ~ - ~ J l "c okcl QE NU VDR A T E I

Figure A 1 9 3(a) Block Diagram of Automatic H~gh Expansion

Foam System

(b) Foam Generators Aspirator Type These may be fixed or portable Jet streams of foam solution aspirate suff~clent amounts of air which ~s then entrained on the screens to produce foam (See Figure A i 9 3(b) ) These usually produce foam with expansion ratios not over 250 1

FOAM SCRE~ FOAM

~ o o o

I '-FOA~,I%U,,O. NLeT FOAM SOLUTION

Figure A 1 g 3(b) Asplratlng Type Foam Generator

(c) Foam Generators Blower Type These may be fixed or portable The foam solution ]s d~scharged as a spray onto screens through which an a~r stream developed by a fan or blower }s passing The blower may be powered by electric motors ~nternal combustion engines alr gas or hydrauhc motors or water motors The water motors are usually powered by foam solution (See F~gure A 1 9 3(c) )

S C R E E N ~

L_ / O;Oob o BLOWER A / ~Io o o ~_°,,

F A N ~ / ~ AIR FLOW / /1:)OOoOOo O00Oo

1 PRIME ~ ~ / ~ Io o o o o IMOVER ~ f ~ - - ~ r ~ L - - - - ~ l O 0o90 ° l, I / \ I I , o oOOoo

' ' I I \ \ ~1 °o~oOo [ ) I I iod'ovo ~ -_ \ i°oOoEO

I,I \ "Lo,,°o°- I ~ l - - u ~ 0 O0 / I I I \ I o o o °

a a . : _ o

FOAM SOLUTI ON

F~gure A 1 9 3(c) Blower Type Foam Generator

A 1 10 5(a) Fire Performance Test for Class A Materlals The purpose of thls test Is to provlde a reproducible Class A f l re sltuatlon where foam should be required to move a substantlal dlstance at a slow rate to the f l re The tlme to move thls dlstance and to f i l l to the top of the test combustlbles is the FOAM TRANSIT TIME The effect of the translt tlme is to give age to the foam duMng the perlod of Its slow movement from foam generator to f i re

The test should be conducted in an open top pen or bulldlng of suitable constructlon and sultable dlmensions To prevent the veloclty of foam movement from belng too hlgh the wldth of the pen or bulldlng tlmes 100 should glve a flgure not smaller than the capaclty in cfm of the foam generator used in the test The height of the s~ze of the pen or bulldlng shall be about 10 f t (3 m) I f the f lu ld l ty of the foam permlts the helght may be less However the foam should not flow over the sldes of the pen nor contact the ce111ng of the bulldlng durlng the test The foam generator should be set at one end of the pen or bulldlng and the f~re should be set 10 f t (3 m) from the opposlte end The dlstance between the foam generator and the f~re should be as requlred to glve the foam translt time desired See Figure A 1 10 5(a)

Foam should be produced by a generator in which the expansion ratlo IS equal to or greater than that produced by the generator proposed for installaton

The test f l re should be a stack of eight standards 4 f t X 4 f t (1 22 m X 1 22 m) hardwood pallets drled to a molsture content between 5 and G percent set on suitable noncombustible supports not over 24 in (610 mm) above the floor Beneath the pallets should be a 10 sq f t (0 93 m2) pan containing 1 gal (3 8 L) of heptane or naphtha floating on water The surface of the flammable llquld should be approxlmately 12 in (305 mm) below the bottom boards of the bottom pallet

The f i r s t test of each serles should be a timed f1] l wlthout a f l re to determlne the foam translt tlme The location of the leading edge of the foam as i t progresses across the floor of the pen or bulldlng should be tlmed at suitable ~ntervals Also the tlme shall be noted when the foam reaches the edge of the pan Th~s data wil l permit est]matlng wlth reasonable accuracy the location of the leadlng edge of the foam 3 mnutes before the foam should reach the edge of the pan Thereafter during each f l re test the heptane should be ignited when the foam reaches that point corresponding to 3 minutes In advance of reaching the pan In thls manner the f l re is given a reproducible 3 minute preburn Thls f111 test can be termlnated when the foam has f11led to the top of the wood pallets and the t~me determlned as the foam transit tlme

The mlnlmum foam translt tlme should be 12 mlnutes (150 percent of maximum submergence tlme 8 minutes from Table 2 3 4) To be considered successful under the foam translt tlme condition the foam should glve adequate control of the test f l re The foam generator should be run for a maxlmum of 30 minutes Adequate control should be ~nterpreted as the absence of active burning within the test stack whlle the stack is covered wlth foam

(b) Quality Control Test The laboratory scale expanslon and dralnage test descrlbed below has been found suitable for quality control purposes The alr and solution temperatures are to be malntalned between 60 and 65OF (15 6 and 18 3oc)

i Mix foam solutlon

2 F~ll foam solution can w~th solutlon

3 Welgh foam can and thread onto apparatus

4 Apply 25 psl (172 kPa) alr pressure to hquid

5 Start blower and adjust damper to approxlmately I/3 opening (May have to readjust later )

6 Open solenold Adjust hquld pressure to 15 psl (103 kPa) using llquld meterlng valve (May have to readjust later )

7 As foam forms at screen catch f i r s t droplets in beaker Keep l~quld in beaker to add to resldue ~n foam can

8 Allow drainage drum to f i l l wlth expanded foam Start t~mer and shut off solenoid when drum ~s ful l

9 Add l~qu~d from step 7 to foam solution can and weigh again Record total ml used (1 gm is approximately 1 ml )

10 Record liquid drainage In ml at Imlnute intervals for 5 minutes then at 10 mnute ~ntervals

11 Plot tlme vs percent dralned and record expansion ratio

Percent drained Total ml drained to ~iven t~me Total ml used

Expansion ratio 206 275m1 Total ml used

2 7 0

See Figures A 1 10 5(b)(1) and A 1 10 5(b)(2)

,L PT PO

PI.AR VIEW

ICY l SECTION A l ~--

w Figure A I I0 5(a)

Fire Performance Test

i - -

i __~A W lgO~; CAP r~

Spray Nozzle

Sc een

( # ~ ~ ; ~ , ~ Blower

I

T ansparent Air Cylinder

Blower Switch

J Llquld P:eter, g Valve ~,enold'~ ~ ~-~ | ~ , r / Valve Solenoid

Switch

,.u,a,or ! L ! _ . Air

Supply

Figure A 1 10 5(b)(1) High Expanslon Foam Quality Test Generator

F~w~rn Sol tion Can

- - - - (

_J

- 22 9

Capacity L 1 206 275 M L

Figure A i i0 5(b)(2) Dralnage Drum for High Expanslon Foam Expanslon and Dralnage Test

(c) Foam Concentrate Proportloning Systems Some typlcal proportlonlng systems are shown In NFPA 11 Standard for Foam Extlngulshlng Systems

A 1 10 8 Exposure of the foam concentrate to the atmosphere may cause evaporatlon of some or all c(xnponents of the concentrate and In some cases may cause crustlng of the agent Thls is exaggerated when a tank wlth a open vent ]s located in an area where the temperature fluctuates For example sunllght strlklng a tank during the day w111 cause the concentrate to expand and some concentrate vapors to escape When the tank cools at nlght fresh air w11l be drawn in to replace the lost vapors Over a perlod of t}me the amount and the composlt~on of the concentrate may change Th~s loss can be m]nlmized by deslgnlng the concentrate tank to include the followlng

(a) An expanslon dome whlch reduces the free surface of the concentrate to an area much smaller than the tank

(b) A pressure vacuum valve whlch reduces the amount of escaping vapors and also reduces the amount of fresh alr enterlng the tank

A i 11 2 Resistance of Foam Generators to Fire Exposure To determlne its ab i l l ty to wlthstand f i re exposure fram the hazard area a generator its associated plplng and electrical wlr~ng protected in accordance wlth tthe manufacturer s recommendatlons should be started and operated after a 5 mlnute exposure 10 f t (3 m) above a 50 sq f t (4 65 m2) gasoline f l re uslng 100 gal of fuel (379 L) The test f l re should be shielded to ensure f]ame implngement on the generator

A i 13 1 4 Weekly recorded inspectlons of hlgh expanslon foam systems should be made Items to be checked Include the following as appllcable

271

Foam Control Room Including Foam Concentrate Supply System

(a) Foam concentrate pumps tanks and lines checked for leaks or damage? Concentrate level in tanks normal?

(b) Concentrate pumps operating properly?

(c) All manually operated shutoff valves for the system properly posltloned and locked?

(d) Central panel lights operating properly?

(e) All disconnects in the control panel in ON position?

(f) Water supply pressure and flow rate normal?

(g) Batteries fu l ly charged? Liquid level normal)

(h) Fire alarm and trouble alarms tested? S11ence swltches in normal posltlon?

(i) All superwsed functions checked for proper operation?

Electric Foam Generators

(j) All disconnect switches in the ON posltion and locked?

Sprinkler Water Supply and Alarms

(k) Water pressure on sprinkler rlsers normal?

( l ) Water f low alarms tested?

(m) All manually operated shutoff valves locked open?

Protected Area

(n) A11 closures operatlng properly?

A 2 3 4 Submergence Time Vulnerabllity of Structure I t is imperative that the integrity of primary structural members be maintained under f i re exposure (which in sprlnklered structures normally support the sprinkler system) Light unprotected bar jo ist and other slmlar types of supports are especlally vulnerable to damage by fast developlng fires as compared to that of heavy steel constructlon So also is heavy unprotected steel framing more vulnerable than f l re reslstlve (concrete) or protected structural members

A 2 3 5 Tests with foams of above 400 1 expansion ratio have shown that extinguishment times for flammable liquid flres increased s~gn]f~cantly at rates of foam r~se less than 3 f t per minute (0 9 m/mln) I t is expected that at some expansion ratio below 400 1 lower rates of foam rise would be adequate but insufflclent tests have been conducted to Identlfy this ratio

A 2 3 5 1 Sample Calculation of Total Generator Capacity

GIVEN Building Size 100 f t X 200 f t X 30 f t high Building Constructlon Llght bar jo ist Class I steel

deck roof adequately vented Masonry walls with all openlngs closable

Sprinkler Protection Wet system 10 f t X 10 f t spacing 0 25 gpm/sq f t density

Occupancy Vert~cally stacked unbanded rolled Kraft paper 25 f t high

ASSUME F~re w~ll open 50 sprinkler heads Foam leakage around closed doors drains etc hence C L 1 2

CALCULATION

Foam Depth Depth 25 X 1 1 27 5 f t (This is greater than minimum cover of 2 f t )

Submergence Volume V 100 X 200 X 27 5 550 000 cu f t

Submergence Time T 5 minutes (from Table 2 3 4)

Rate of Foam Breakdown by Splnklers S 10 cfm/gpm (from section 2 3 5 2) Q No of heads X area/head X density

50 X (10 X 10) X 0 25 1250 gpm RS S X Q 10 X 1250 12 500 cfm

Normal Foam Shrinkage CN 1 15 (from section 2 3 5 3)

Leakage CL 1 2 (assumption)

Total Generator Capaclty

V R + R S X CN X CL

T

550000 R + 12 500 X 1 15 X 1 2

5

R 169 000 cfm

The number of generators required w11] depend upon the capaclty of the generators avallable

Sample Calculat]on Uslng SI Units Bu~ldlng Size Sprlnkler Protection

30 5 m X 61 m X 9 lm high Wet System 3 m X 3 m spacing 10 2 L per mnute per sq m denslty

Occupancy Vertically stacked unbanded rolled Kraft paper 7 6 m hlgh

Calculation

Foam Depth Depth 7 6 X 1 1 8 5 m

Submergence Volume V 30 5 X 61 X 8 4 15565 cu m

Submergence Time I T 5 minutes (from Table 2 3 4)

Rate of Foam Breakdown by Splnklers S 0 0748 m3 mln/L mln (see 2 3 5 2) Q No of Heads X area/head X denslty

50 X (3 X 3) X 10 2 4731L/mn RS S X Q 0 0748 X 4731 354 m3/mn

Normal Foam Shrinkage CN 1 15 (see 2 3 5 3)

Leakage CL 1 2 (assumptlon)

Total Generator Capaclty

V + RS X CN X CL

T

15565 R + 354 X 1 15 X 1 2

5

4784 m3/mln

A 2 3 5 2 Rate of Breakdown by Sprlnklers Where sprlnklers are present in an area to be protected by hlgh expanslon foam simultaneous operatlon w111 cause breakdown of the foam The rate of breakdown wil l depend upon the number of sprlnklers operating and the subsequent total rate of water dlscharge The number of sprinklers expected to operate will depend upon various factors as outllned in NFPA 13 Standard for Installation of Sppnkler Systems

A 2 3 5 4 Foam Leakage I t is essential that uncontrolled leakage be reduced to an absolute mlnlmum through the use of foam tight barrlers at all openings below the effective hazard control level or depth contemplating the increased rate of foam escape as .its f lu id i ty is increased by antlclpated sprinkler discharge

Such leakage through drains trenches under doors around wlndows etc can be mnlmlzed by use of sultable automatic closures seals or mechanisms Additional generator capaclty shall be added to compensate for the aggregate losses where foam escapement cannot be effectlvely controlled

A 2 4 Maintenance of Submergence Volume The choice of a total flooding foam system for protection of a hazard does not necessarily imply that i t is expected that the system w111 completely extlngu~sh the f l re or even so nearly extlngulsh i t as to render the f~re incapable of regalnlng the offensive Rather the effect sought might often be speedy control wlth minimum f~re damage to contents not ~nvolved in the f i re

Whenlhlgh expansion foam is estab1~shlng or has established control of a f l re care must be exercised that control is not lost The following points should be kept ]n mlnd Depending upon the particular f l re some or all mlght be wtal

272

(a) All should be aware of the necess ty for tught closure Employees brlgade members and the f i re department should move rapldly to close any openings through whuch foam is being lost Improvised closures can be made of practically any available material such as fine mesh screenung plastuc plywood hardboard

(b) I f the material Involved is llable to deep seated fures such as furnuture packaged material fibers rolls of paper etc particular care must be exercised un openung up the areas and removlng the foam Even where only surface f l re is thought posslble as un flammable llqulds smoldering Class Amaterual may cause relgnution

(c) A soaking perlod should elapse before foam is removed Thls may be as long as an hour and should be predetermned based upon the fuel un the area

A 2 5 Overhaul The followung polnts should be consudered durlng overhaul operatlons

(a) All foam and sprinkler systems which are shut off should have men standing by valves to turn them back on I f thls should become necessary

(b) Foam supplues should be replenlshed uf depleted

(c) Hand hose llnes should be charged and manned Personal protective equupment should be donned Self contained breathing apparatus shall be worn in the ready posutlon so there wil l be no delay in putting I t in servuce

(d) Foam should be removed f i r s t from the FIRE area and shall be coordlnated with overhaul and salvage operatuons The total loss will be kept to a mlnumum i f thoughtless operatlons are avoided The fure is under control undue haste to extlnguush the last ember may greatly uncrease the loss

(e) Cautuon should be taken in entering prewously foam f i l led areas particularly in structures with pits or openings in the floor

(f) The area should be well ventilated but openings through which foam might be lost should be kept to a mlnlmum and manned for closing i f this should become necessary

(g) Conslderation should be glven to dlsposal of the foam to prevent any undue hazard to adjacent areas

A 3 2 2 Fences constructed of ordlnary metal wundow screen mesh have been shown to provude an effectuve barrler whuch allows confinement of hlgh expansion foam to a protected area

A 3 4 Special Provusuons for L1quefled Natural Gas (LNG) Fire & Vapor Control

(a) General Information

I Applicatlon Concepts for Fire Control Tests sponsored by the American Gas Assocuatuon have shown that the amount of radlatlon from a burnlng LNG spull can be reduced by as much as 95 percent with some high expansion foams This us due in part to the foam barruer which reduces vaporuzatlon by blocking heat feedback from the flames to the LNG Foams having a low expansion ratio contain a great deal of water at ambient temperature that tends to increase the vaporlzat~on rate when i t drains into the LNG Control was established with expansion ratios greater than 250 to 1 although an expansion ratio of about 500 to 1 proved most effectuve in the AGA tests Different brands of foam show considerable variation in their ablluty to control LNG fures A rapidly dralnlng foam wull ~ncrease the LNG vaporlzat~on rate and exaggerate the f i re lntenslty The dryer foam remalnung us less resustant to thermal effects and breaks down more readily Other factors such as bubble suze f l u id l t y and lunear burn rate may affect f l re control Therefore test results on LNG fures should be reviewed before selecting a foam for LNG f l re control

2 Downwind Vapor Hazard Control When f i r s t evolved from a spil l unignlted LNG vapors are heavier than alr As these vapors are heated by sunlight and by contact with the air they eventually become buoyant and dusperse upward Before this happens however high vapor concentrations may form downwind of an unlgnlted spil l at or near ground level High expansion foam can be used to reduce this vapor concentration by adding heat from the water un the foam to the LNG vapors as they pass through the foam blanket Because of the induced buoyancy the appl~catlon of high expansion foam can reduce downwind gas concentratlons at ground level Expansions of up to 1 000 to 1 have been found to provude effective dlsperslon control but may be lmpractlcal because of wund However as with f i re control ab i l i ty to control vapor dispersion varles among dufferent foams and should be demonstrated by tests

(b) Desugn Requlrements

273

J

1 Appllcatlon Rate Test data should be presented to the) authority havlng jurlsdlctlon to show that the appllcatlon rate will reduce radlatlon from a test f i re wlthln 2 mlnutes Where burning LNG presents llmlted f l re exposure to surrounding areas the rate should be approximately 3 cfm/ft2 ((0 9 m3/mln)/m2) For those areas wlth moderate to high exposure risk to surroundlng areas or areas where tume to apply hugh expansuon foam must be kept to a mlnumum the rate ~hould be approxumately 6 cfm/ft2 ((1 8 m3/mun)/m2)

2 Quantity The quantlt~ of foam concentrate should be provided on the basis of continuous application at the desugn appllcatlon rate for at least 15 munutes In addltuon sufflcuent foam should be provuded as demonstrated by tests acceptable to the authority having jurlsdlctuon to maintain control for the calculated f l re and/or spil l duratuon For vapor dlsperslon control the quantity of foam concentrate to malntaln cover durlng boll off wull generally exceed the quantity required for f i re control

3 Arrangement Foam outlets should be arranged to ensure that foam is dellvered to all areas which constutute the hazard The foam outlets should be spaced and generators suzed to ensure that the minimum foam depth at any polnt un the hazard after two munutes of application varles from 1 6 feet (0 5m) for systems discharging 3 cfm/ft2 ((0 9 m3/mln)/m2) to 3 feet ( i Om) for systems duscharglng 6 or more cfm/ft2 ((1 8 or more m3/mln)/m2) Two munute foam spread data should be provided to the authority having JurlsdIctlon to verlfy that the required coverage can be obtauned I

l (c) LNG Fure and Vapor Control Reference Publucatuons

1 Amerlcan Gas Assoclatuon Project IS 3 1 LNG Spulls on Land Nov 15 1973

2 American Gas Association Project IS 100 1 An Experumental Study on the Mutlgatlon of Flan~nable Vapor Dusperslon and Flre Hazards Immedlately Following LNG Spills on Land Feb 1974

3 LNG Vapor ConcentratiOn Reductuon and Fure Control with MSAR Hugh Expansion Foam undated

4 Welker J R et al Fire Safety Aboard LNG Vessels January 1976

5 Wesson H R J R Welker and L E Brown Control LNG Spills Fires Hydrocarbon Processing Dec 1972

6 Llquefled Natural Gas/Characteristics and Burning Behavuor Conch Methane Servuces LTD 1962

+

7 Humbert Basset R and A Montet Filanmlable{Mixture Penetration un the Atmosphere from Spillage of LNG Third International Conference on LNG Washington D C Sept 1972

I

8 Gremeles A E and E M Drake Gravity Spreading and Atmospheric Dispersion of LNG Vapor Clouds Fourth International Symposium on Transport of Hazardous Cargoes by Sea and Inland Waterways Jacksonvllle Florida Oct zg75

9 Schneider Alan L Liquefied Natural Gas Safety Research Overview National Technucal Information Service Sprlngfleld VA Dec 1978 Thls paper contains 105 addltlonal references on many aspects of LNG Safety research uncludung use of high expansion foam on LNG I

Appendux B Referenced Publications

B 1 Thus portlon of the Appendix lusts publlcatlons referenced wlthln thls NFPA document and thus is considered part of the requirements of the doucment

i 8 1 1 NFPA Standards Thls publucatlon makes reference to the following NFPA Codes and Standards and the year dates shown indlcate the latest edutuon available They are avaulable from the National Fire Protecton Association 470 Atlantic Avenue Boston Massachusetts 02210 F

NFPA 11 1978 Standard for Foam Extinguishing Systems

NFPA 13 1980 Standard for the Installatuon of Sprinkler Systems

NFPA 20 1980 Standard for the Installatlon of Centrufugal Flre Pumps

NFPA 59A 1975 Standard for~the Production Storage and Handling of L1quefled Natural Gas (LNG)

NFPA 70 1978 NATIONAL ELECTRICAL CODE

NFPA 72E 1978 Standard on Automatic Fure Detectors

NFPA 231C 1975 Standard for Rack Storage of Materlals

NFPA 321 1976 Standard on Baslc Classlficatlon of Flammable and Combustible Liquids

B 1 2 This publicatlon makes reference to the following ASTM standard and the year date indlcates the latest edltlon avallable I t is avallable from the American Society for Testlng and Materlals 1916 Race Street Philadelphla Pennsylvanla 19103

ASTM E380 76 Standard for Metrlc Practlce

!

274