According to the NFPA standard, in fire extinguishing systems, volatile materials or gases that are indirecting the current of electricity and do not leave any waste after discharge is called a clean agent. These materials are subject to various assessments of potential hazards to personnel and their impact on the environment, and if they meet the conditions, they are listed in NFPA 2001. This list is given in the table below. It should be noted that CO2 gas is classified as a clean agent due to its lack of residue and inefficiency, but due to its toxicity and associated risks, it is not within the scope of NFPA 2001 standard.
The NFPA 2001 standard lists the approved clean agents in Table 1.1.1 (2022). These materials are generally divided into two categories:
- (Halocarbons)
- Inert gases (IG)
Originally, the Clean Agent Fire Suppression Systems were developed in response to Halon 1301’s prohibition of using Halon 1301 as an alternative to the Montreal Protocol.
The most widely used halocarbons are HFC-227ea (FM-200) and FK-5-1-12 (Novec 1230).
IG (inert gases) fire suppression systems consist mainly of nitrogen (N), argon (Ar), or a combination of these gases, which include:
- IG-55 (50% Nitrogen– 50% Argon)
- IG-01 (Argon)
- IG-100 (Nitrogen)
- IG-541 (52% Nitrogen-40%Argon-8%CarbonDioxide)