- Author
- Gipe, R. L. | Peterson, H. B.
- Title
- Proportioning Characteristics of Aqueous Film-Forming Foam Concentrates.
- Coporate
- Naval Research Laboratory, Washington, DC
- Sponsor
- Naval Ship Systems Command, Washington, DC
- Report
- NRL Report 7437, July 20, 1972, 30 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NRL-PROBLEM-C05-19-203
- Keywords
- aqueous films | aqueous foams | fire suppression | protein foams | fire pumps | fire extinguishment | viscosity | mechanical equipment
- Identifiers
- proportioning characteristics
- Abstract
- 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 this 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. FC-194 and FC-195 brands of AFFF concentrates are more viscous (ca. 100cS) than the protein form concentrate (20 cS), while the new FC-196, FC-199, and FC-200 brands are less viscous (5 cS). Viscosity temperature relationships are given for all these materials. 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. concentrate viscosity was found, however, to be a factor in setting the pump's internal pressure regulating valve.