Proportioning Characteristics of Aqueous Film-Forming Foam Concentrates
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
Aqueous Film-Forming Foam AFFF has now widely replaced protein-type foam in the Navy for fire suppression purposes. Because this changeover has been accompanied by very little change in the mechanical equipment, there has been a need to study the full impact of using AFFF in equipment designed for protein foam. One of the areas studied and covered in the report is concerned with the proportioning equipment used to inject foam concentrate into a fire main to form a 6 solution at fixed flow rates, variable flow rates, or both. The early AFFF concentrates differ from the later ones in one physical property which affects their proportioning characteristics, i.e., viscosity. By operating the equipment with a wide range of concentrate viscosities, it was possible to establish the proper viscosity for optimum operation. Also studied were the use of booster pumps to supercharge the proportioner pump inlet and the use of positive displacement injection pumps for systems with fixed flows, such as the flush- deck nozzles on aircraft carrier flight decks. In the latter equipment, concentrate viscosity was found to be a less critical factor in pump performance.
- Safety Engineering