Vapor suppression of chemicals using foams



In the handling of chemicals in our plants, there is always concern about the possibility of spillage. The consequences of a spill have to be carefully evaluated. Two of the main hazards are fire and emissions to the environment. Foams have proven to be very effective in blanketing a spill and in giving fire extinguishment by providing a barrier covering. This same barrier covering can also be effectively used to suppress vaporization and emissions. This paper gives the results of measurements of the vapor suppression for various chemicals using foamsm, and gives the test procedures developed. The base conditions simulated a 5.0 mph (8.05 km/hr) wind at 25°C with a 76% relative humidity, using Universal® GOLD foam from Chubb National Foam. Variables studied were chemical, foam type, foam height, relative humidity, and time. Data was obtained for chemical concentration in the vapor and relative percent vapor suppression versus time using acrylonitrile, ethyl acrylate, butyl acrylate, methyl methacrylate, allyl chloride, propylene oxide and vinylidene chloride. Excellent vapor suppression was demonstrated for most systems with 100% vapor suppression for 2 hr for vinylidene chloride, about 95% for 2 hr for the acrylates and allyl chloride, and 90% for 2 hr for acylonitrile. Propylene oxide was suppressed to 95% for 1 hr before marked decrease.