1、Designation: F 1129 01Standard Guide forUsing Aqueous Foams to Control the Vapor Hazard fromImmiscible Volatile Liquids1This standard is issued under the fixed designation F 1129; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe vapor released by spills of volatile hazardous substances (either flammable or toxic) can presenta signi
3、ficant 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 hazard aris
4、ingfrom 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 and may offe
5、r 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 peculiar to
6、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. Scope1.1 This
7、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 This standard does not purport to address all of thesafety concern
8、s, 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 Documents2.1 ASTM Standards:2F
9、716 Methods of Testing Sorbent Performance of Absor-bentsF 726 Test Method for Sorbent Performance of AdsorbentsF 1011 Guide for Developing a Hazardous Materials Train-ing Curriculum for Initial Response PersonnelF 1127 Guide for Containment by Emergency ResponsePersonnel of Hazardous Materials Spil
10、lsF 1644 Guide for Health and Safety Training of Oil SpillRespondersF 1656 Guide for Health and Safety Training of Oil SpillResponders in the United States2.2 NFPA Standards:111994, Low Expansion Foam311A1994, Medium- and High-Expansion Foam Systems33. Terminology3.1 alcohol or polar solvent foamThi
11、s is one type of foamthat is resistant to 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 bar
12、rier to protect thefoam from destruction 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 In
13、itial Response Actions.Current edition approved Oct. 10, 2001. Published December 2001. Originallypublished as F 1129 88. Last previous edition F 1129 88 (1995)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from National Fire Protection Association, 1 Batterymarch Park,Quincy, MA 02269.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
15、 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 aqueous film forming foa
16、m (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 material is resistant to des
17、truction 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 vapor sealing unless a v
18、isible 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 are similar to protein foa
19、ms except that they producefoam with greater fluidity, dry chemical resistance (for clarifi-cation see NFPA Standard 11) and greater resistance to fuelpick-up. They are used only at low expansion. The surfacetension of fluoroprotein foam solution (FP) is 27 to 30dyne/cm. Film-forming fluoroprotein a
20、gents (FFFP) are beingmarketed with aqueous surface tensions in the 16 to 17dyne/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 volume offoam solu
21、tion 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 greater than200:1. (S
22、ee 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 proteinwith various stabi
23、lizing 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.3.12 surfactant
24、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 30 dyne/cm.4. Si
25、gnificance 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 reactive chemicals with
26、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. Since water is dens
27、erthan 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 between the foam
28、and 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 reactivechemical
29、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 a foam collapse r
30、ateand 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 is a property un
31、ique 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 regard. For example,
32、 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 fire extinguish
33、ing 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-downtime is short)
34、, 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 drainage rate is to
35、oF1129012slow (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 available for generating low e
36、xpansion 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 aspirated air with the foam s
37、olution. 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 anexpansion ratio of 4:1. AFFF m
38、ade 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 Foam nozzles in smaller s
39、izes (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 streams give the best
40、 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 foam allowed to flow
41、 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 correctly in order to
42、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 manufacturers recommen
43、dation. 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 amount of water adde
44、d 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 handheld hose line units
45、 or by a fan in the case oflarger units (see NFPA 11A for design illustrations). Airaspirating units, because of their limited air supply, produceexpansions of less than 350:1 and have foam capacities of lessthan 1000 ft3/min (28 m3/min). Larger units using water,electric, or diesel powered fans can
46、 produce expansions up to1000:1 and are available in sizes up to 30 000 ft3/min (85m3/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 jet and drive a padd
47、le 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 cannot be approached at
48、 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 expansion nozzles but gene
49、rally 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 Vapor8.1 Foam SelectionGuide
