CLEAN AGENT SYSTEMS
Clean agent fire extinguishing systems utilize clean agent gaseous chemicals for the protection of certain fire hazards in today’s world. Clean agents are gaseous extinguishing agents that leave no residue behind and do not conduct electricity. Clean agents include both halocarbon and inert gaseous agents.
A typical fire hazard fuel array is generally classified according to a well-recognized classification scheme (Class A, B, C, D, or K), and Class C fires are those that involve energized electrical equipment. Normal protection methods attempt to de-energize the electrical equipment to minimize the fire challenge of Class C fires (also referred to as energized electrical equipment fires or energy augmented combustion). However, it may be necessary to provide protection for scenarios where the power cannot be removed and the performance of clean agents on such fires is not completely understood.
The optimal design of clean agent fire extinguishing systems for energized electrical equipment depends on: (a) defining the hazard to be protected, and (b) establishing the appropriate design parameters. Defining the hazard depends on the type of electrical equipment, the worst case anticipated level of energy, and the nature of the unwanted fire that might require control. Establishing the appropriate design parameters primarily requires determining the clean agent extinguishing concentrations for each type of clean agent, but additionally considers other factors such as minimizing secondary adverse effects (e.g., minimizing the generation of products of decomposition).
Fire Protection Research Foundation report: “Clean Agent Suppression of Energized Electrical Equipment Fires” (PDF, 959 KB)
Author: Gregory T. Linteris, Ph.D., Building & Fire Research Laboratory, NIST
Date of issue: January 2009