Suppressing Foam Blankets

Other dust-suppressing applications of foam blankets include the following  

Other applications of foam blankets are discussed in Sections 9.7 and 13.9. 

and Argali, G.O. (eds) (1973) Tailing Disposal Today, Miller Freeman, San Francisco, CA. 

Cowper, N.T. (1991) in Slurry Handling Design of Solid-Liquid Systems (eds N.P. Brown and N.I. FFeywood), Elsevier, London, pp. 625-652. 

Shelley, J.A. (1991) Proceeding of the 16th International Conference Coal and Slurry Technologies, Coal Slurry Technology Association, Washington, DC, pp. 19-30. 

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Other Fire extinguishing foams Explosion suppressing foam blankets Fumigant, insecticide, and herbicide blankets... 

The use of aqueous foams to control fume or vapour release from reactive chemicals is discussed. An acid-resistant foam NF2 controlled fume emission from 35% and 65% oleum, and from titanium tetrachloride, but was not effective for sulfur trioxide and chlorosulfuric acid. An alcohol-resistant foam NF1 suppressed ammonia vapour emission by 80%, and Universal fire foam reduced evaporation of ethylene oxide, vinyl chloride and methanethiol, and reduced vapour emission of 1,3-butadiene by 60%. Safety aspects of foam blanketing are discussed [1]. Equipment and application techniques are covered in some detail [2],... 

A somewhat different application of foam is in blast and fire suppression during attempts to deactivate, or intentionally destroy, suspected terrorist bombs. When such a device, or even a small explosive device used to destroy the suspected item, explodes, severe damage can be caused by the compression wave emanating from the blast or from the fireball that may follow the blast. In Section 9.6 it was mentioned that foam blankets have been developed for blast noise and pressure wave... 

When using foam as a vapor suppressant, the vapor pressure of the spilled material is important. That is to say, the higher the vapor pressure, the thicker the foam blanket should be. 

SPILL CLEAN-UP ventilate area of spill or leak stop flow of gas if possible if leak cannot be stopped, allow to empty in open air in a safe place use vapor-suppressing foam to blanket release remove all sources of ignition. 

High-expansion foam can be used as an effective vapor suppressant on LNG spills. It adds heat from the water in the foam to the vapors as they pass through the blanket. This procedure induces buoyancy which can reduce downwind concentrations at ground level. Expansion ratios of 750 1 to 1000 1 have been found to be particularly effective (NFPA 11 A, 1988). At the same time, a low-expansion foam in the 20 1 range would be effective for a hydrocarbon spill. As this shows, selection of the actual foam to be used must be based on the intended application and on the foam supplier s test data and recommendations. 

Suppression of the increasing fire can be carried out by various methods. The very first method is to cut the supply of fuel to the fire. Fire suppression can also be achieved by blanketing a fire or by covering it with inert solid, foam, thickened water, or covering it with a nonflammable gas such as CO2. The other available method is the dilution of the fuel, if it is a liquid fuel, by adding noncombustible liquid into it and if it is a gas, by adding nonflammable gas. 

Foams are also used as fire suppressants. They suppress fire by cooling, blanketing, and sealing the burning fuel from the surrounding atmosphere. They are not suitable for gaseous fuel and fuel that reacts with water. 

SPILL CLEAN-UP use water spray to cool and disperse vapors dilute spills to form nonflammable mixtures use appropriate foam to blanket release and suppress vapors clay absorbents are not recommended in cleanup remove all ignition sources. 

SPILL CLEAN-UP Ventilate area of spill or leak use appropriate foam to blanket release and suppress vapors absorb small quantities of liquid on paper towels and evaporate in fume hood allow solid form to melt and cover in noncombustible material for proper disposal atomize large amounts in a suitable combustion chamber equipped with an effluent gas cleaning device remove all sources of ignition. 

SPILL CLEAN-UP evacuate danger area ventilate area of leak or spill stop or control the leak, if possible use appropriate foam to blanket release and suppress vapors absorb liquid in noncombustible materials (e.g., dry earth, sand, vermiculite) for proper disposal remove all sources of ignition. 

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