1、Designation: F1129/F1129M 09Standard Guide forUsing Aqueous Foams to Control the Vapor Hazard fromImmiscible Volatile Liquids1This standard is issued under the fixed designation F1129/F1129M; the number immediately following the designation indicates the yearof original adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe vapor released by spills of volatile hazardous substances (either flammable or toxic) can pre
3、senta significant hazard to life and property in the spill area and for some measurable distance downwind.Such spills may also cause natural resource damage by penetration into the ground or by movementinto groundwater.Aqueous foam blankets have been shown to be an effective technique to reduce the
4、hazard arisingfrom vapor release of volatile chemicals and to reduce the chance of accidental ignition of flammableliquids. Because they are a common tool of the fire services, they are available early in the spillresponse effort. Foams can be used to control spill vapors to extend evacuation time a
5、nd may offer acontrol for the life of the incident.Effective actions have been demonstrated for a wide variety of chemical classesvolatile organics,some water reactive inorganics, and certain classes of liquefied gases.The water reactive compounds and liquefied gases require special considerations p
6、eculiar to eachchemical grouping.Although foam solutions are not considered to be dispersants, foam treatment mayenhance the penetration of water soluble materials into the ground, or transport into the groundwater,or both. Adequate information is not available to generalize on such questions.1. Sco
7、pe1.1 This guide restricts itself to addressing the application offoam to water immiscible liquid and some water reactivecompounds with boiling points above 15C for vapor controlor fire suppression of land spill or contained spills on water.1.2 The values stated in either SI units or inch-pound unit
8、sare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address
9、all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For hazard state-ments, see Section 10.2. Referenced Documen
10、ts2.1 ASTM Standards:2F716 Test Methods for Sorbent Performance of AbsorbentsF726 Test Method for Sorbent Performance of Adsorbents2.2 NFPA Standards:NFPA 11 Standard for Low-, Medium-, and High-Expansion Foam33. Terminology3.1 alcohol or polar solvent foamThis is one type of foamthat is resistant t
11、o destruction by water miscible polar com-pounds. It is usually termed polar solvent resistant, andcontains a water soluble polymer. When this polymer contactsa water miscible polar fuel, it gels and forms a membranewhich floats on the fuel and serves as a barrier to protect thefoam from destruction
12、 by the fuel. Polar solvent resistantfoams may be either surfactant or AFFF based. They behave1This guide is under the jurisdiction of ASTM Committee F20 on HazardousSubstances and Oil Spill Response and is the direct responsibility of SubcommitteeF20.21 on Initial Response Actions.Current edition a
13、pproved Nov. 1, 2009. Published December 2009. Originallyapproved in 1988. Last previous edition approved in 2001 as F1129 01. DOI:10.1520/F1129_F1129M-09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
14、Standards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/www.nfpa.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
15、n, PA 19428-2959, United States.like a conventional foam on hydrocarbons. They may beapplied by nozzle or by any other low expansion foam-makingequipment on either hydrocarbons or polar fuels. Alcohol orpolar solvent resistant foams produce surface tensions in waterranging from 15 to 50 dyne/cm.3.2
16、aqueous film forming foam (AFFF, pronounced “A tripleF”)AFFF is a mixture of fluorocarbon and hydrocarbonsurfactants. It is usually used at low expansion. The very lowsurface tension of AFFF solution permits the formation of anaqueous film on top of most hydrocarbon fuels and alcohol-compatible mate
17、rial is resistant to destruction by miscible orimmiscible water-reactive or strong polar compounds, or both.Because maintenance of this film requires drainage of solutionfrom the foam, AFFF is fast draining and the foam is notpersistent. The film is easily disrupted and should not be reliedupon for
18、vapor sealing unless a visible foam blanket is present.The surface tension of AFFF solutions in water is 15 to 19dyne/cm.3.3 aqueous foama mixture of water and a foaming agent.3.4 fluoroprotein foamconventional protein foam modi-fied by the addition of fluorocarbon surfactants. Fluoroproteinfoams ar
19、e similar to protein foams except that they producefoam with greater fluidity, dry chemical resistance (for clarifi-cation see NFPA 11) and greater resistance to fuel pick-up.They are used only at low expansion. The surface tension offluoroprotein foam solution (FP) is 27 to 30 dyne/cm. Film-forming
20、 fluoroprotein agents (FFFP) are being marketed withaqueous surface tensions in the 16 to 17 dyne/cm range.3.5 foama mass of bubbles formed by the mechanicalagitation of foam solution with air.3.6 foam expansionthe ratio of air to water in the foam. Ameasure of the volume of foam produced for each v
21、olume offoam solution used.3.7 foaming agentan organic compound or mixture ofcompounds which lowers the surface tension of water andimparts a foaming capability to it. Five major types of foamliquid concentrates are in general use by the fire service.3.8 high expansion foama volumetric ratio of grea
22、ter than200:1. (See foam equipment for practical ranges of expansion.)3.9 low expansion foama volumetric ratio of typically 6:1or 12:1 but less than 20:1.3.10 medium expansion foama volumetric ratio of 20:1 to200:1. (See foam-making equipment.)3.11 protein foama mixture of hydrolyzed animal proteinw
23、ith various stabilizing materials. Protein foam may be usedonly at low expansion. The surface tension of protein foamsolutions in water is 40 to 50 dyne/cm. Protein foams aresubject to bacterial and fungal attack and may have shelf lifelimitations, as well as a biological oxygen demand (BOD) inwater
24、.3.12 surfactant foamalso known as syndet or detergentfoam. These foams are based on high-foaming syntheticsurface active agents. While these foams are normally used athigh expansion, they may also be applied through low expan-sion foam-making devices. Surface tensions in water are in therange 23 to
25、 30 dyne/cm.4. Significance and Use4.1 This guide is intended as a general guide to the correctuse of foams. Specific decisions on when or if foam should beused will depend on the circumstances and conditions of eachspill situation.4.2 Polar solvent resistant AFFF can be applied to somewater reactiv
26、e chemicals with a medium expansion foamnozzle to extinguish a fire and to reduce toxic vapor release tothe environment.5. Film Forming Foam5.1 Film forming foam develops a thin film of aqueoussolution over the surface of a non-aqueous liquid chemical inresponse to a surface tension differential. Si
27、nce water is denserthan many liquid organic compounds, it will normally sinkthrough such compounds. Foam agents reduce the surfacetension of water. If the surface tension of the foaming solutionis less than that of the organic compound, the drainage comingfrom the foam will tend to form a water film
28、 between the foamand the organic compound. The term “film forming” has beenapplied basically to those foaming systems with low surfacetensions, normally below 24 dyne/cm. Film forming mayoccur, however, whenever the ratio of surface tensions isappropriate.5.2 Use of polar solvent foam on some water
29、reactivechemical compounds, such as silanes, will reduce the amountof water that comes in contact with the compound-reducingtoxic vapor release. Water reactive vapors are scrubbed orreacted by the foam to lessen the vapor release to theenvironment.6. Stability6.1 Stability is used in two senses, as
30、a foam collapse rateand as a resistance to chemicals. Foam collapse rates aremeasured only for high expansion foams. They will range from8 to 20 in. 20 to 50 cm per h in laboratory tests, but can behigher in the field due to sun, wind, and precipitation. Stabilityin contact with reactive chemicals i
31、s a property unique to eachfoam type.6.2 Stability of foam in contact with water reactive chemicalcompounds is unique to each foam type. However, the rate thatthe water drains from the foam blanket, represented by thequarter (or 25 %) drain-down time, is thought to be the primaryfactor in this regar
32、d. For example, when foam is applied to achlorosilane compound, water draining from the foam reactswith the chlorosilane chemical forming a layer of hydrolysisproducts on the surface. It is this layer of hydrolysis productsthat, when a sufficient thickness and consistency is established,affects the
33、fire extinguishing capability or vapor suppression,or both, by excluding oxygen and limiting vapor evolution.However, the hydrolysis layer shall be formed relatively slowlyfor extinguishing capability or suppression of vapors to takeplace. If the drainage rate is too fast (that is, quarter drain-dow
34、ntime is short), the hydrolysis reaction takes place too quickly,producing a large amount of heat, which in turn produces morevapors. In addition, the rapid reaction causes turbulence on thewater reactive chemical surface, preventing the formation of astable layer of hydrolysis products. If the drai
35、nage rate is tooF1129/F1129M 092slow (that is, quarter drain-down time is too long), thehydrolysis reaction takes place too slowly, and a stablehydrolysis layer is not established before the foam blanketdissipates.7. Foam Equipment7.1 Low Expansion FoamSeveral types of foam-makingdevices are availab
36、le for generating low expansion foams. Thetraditional foam nozzle consists of a tube through which a jetof foam solution is projected. Holes in the tube just down-stream of the jet permit the aspiration of air. Various types ofobstructions are fixed in the tube to create turbulence and mixthe aspira
37、ted air with the foam solution. There are manyvariations in design of foam nozzles, but all produce expansionratios in the 6:1 to 12:1 range, depending on the type of foamliquid used.7.1.1 Water fog nozzles may be used to generate foam withAFFF or synthetic agents. Such foam rarely exceeds anexpansi
38、on ratio of 4:1. AFFF made this way has a very fastdrainage and short life. Some water fog nozzles are designedfor the attachment of foam-making tubes. When the foam-making tubes are in use, the foam-making ability of the waterfog nozzle is essentially the same as that of a true foam nozzle.7.1.2 Fo
39、am nozzles in smaller sizes (up to 250 g/m) 945L/m may be used on hose lines. Larger capacity foam nozzlesare mounted on monitors or turrets. Foam nozzles are availableas straight stream devices, and combination straight stream andspray. Some designs permit several different patterns.7.1.3 Straight
40、streams give the best range, but may cause thefoam stream to plunge into the spill. Plunging can aggravatevapor release and, in the case of a fire, may reduce control andincrease extinguishment times. If possible, impinge straightstreams against an obstacle or the ground in front of the spilland the
41、 foam allowed to flow onto the spill.7.2 Medium Expansion FoamProper application of me-dium expansion foam requires matching the foam concentratewith an eductor (in line proportioning system), and foamnozzle. The pressure drop across the eductor and the pressuredelivered at the nozzle shall be set c
42、orrectly in order to ensurethe correct dilution of the foam concentrate and make a foamof the right expansion ratio with slow water drainage. Only usefoam generation and delivery systems that are recommendedby the foam manufacturer.7.2.1 Limit the distance between the educator and the nozzleto the m
43、anufacturers recommendation. If possible, roll thefoam gently onto the spilled material. Once the area is covered,stop the foam application and allow the foam to work atforming a barrier membrane. It is best to limit use to the leastamount of foam necessary to cover the spill in order tominimize the
44、 amount of water added to the spill. Reapply foamas necessary to maintain the blanket over the spilled material.7.3 High Expansion FoamHigh expansion foam genera-tors spray the solution onto a screen or net and induce anairflow to blow the foam. Air is supplied either by aspiration inthe case of han
45、dheld hose line units or by a fan in the case oflarger units (see NFPA 11 for design illustrations). Air aspirat-ing units, because of their limited air supply, produce expan-sions of less than 350:1 and have foam capacities of less than1000 ft3/min 28 m3/min. Larger units using water, electric, ord
46、iesel powered fans can produce expansions up to 1000:1 andare available in sizes up to 30 000 ft3/min 85 m3/min of foam.7.3.1 Two types of water power are available, (1) waterreaction motors, and (2) water turbines.7.3.1.1 Water reaction motors divert a small portion of thefoaming solution to form a
47、 jet and drive a paddle wheelattached to the fan. They are less expensive and light in weight,but require higher pressures to operate, are less efficientfoam-making devices and produce lower head pressures thanturbines.7.3.1.2 High expansion foam-making devices have verylittle range. If the spill ca
48、nnot be approached at close range, itis possible to conduct high expansion foam through flexiblefabric ducts to the spill. The higher head pressure availablefrom a turbine driven foam-making device is an importantadvantage in this case.7.4 Medium expansion foam nozzles have more range thanhigh expan
49、sion nozzles but generally less range than lowexpansion foam nozzles. One effective method of applicationof foam is to roll the foam onto the spilled material. This canbe accomplished by placing the foam in front or the spilledmaterial and rolling it on by the application of additionalamounts of foam.7.4.1 Several foam nozzles on the market will produce foamin the desired range. It is important to provide matchingproportioning system where the eductor (foam proportioningequipment) is matched with the nozzle.8. Guidelines for Foam Application to Control Vap
