Impact of HFC Fire Extinguishing Clean Agents on Climate Change and Its System Design Requirements for Fire Hazards in India—A Brief Study

Abstract

This paper discusses the impact on climate change of hydrofluorocarbons (HFCs) in fire suppression applications. Alternatives and substitutes for HFCs, perfluorocarbons (PFCs), and ozone depleting substances (ODSs) have recently been extensively evaluated. NFPA 2001 defines a clean fire extinguishing agent as an electrically non-conducting, volatile, or gaseous fire suppressant that does not leave a residue upon evaporation. A clean agent must have no known effect on the ozone layer and also, no effect on any human survival within an enclosure protected by a clean agent, and in normally occupied areas must be used in a concentration that is less than “no observed adverse effect level (NOAEL)”. NOAEL is a measure of clean agent toxicity to humans under test conditions. The HFCs that are projected for large volume use have global warming potentials (GWPs) lower than the replacing ODSs. GWPs of HFCs replacing ODSs ranges from 120 to 12,000 as per the year 2000 data of Intergovernmental Panel on Climate Change (IPCC). HFC-23 with a GWP of 12,000 is used as a replacement for ODSs to a very limited extent. However, there are relatively large emissions of HFC-23 from the HCFC-22 manufacturing process. However, the majority of HFCs have GWPs much lower than that of HFC-23. NFPA 2001 standard demonstrates the fact that the GWP value considered by itself does not provide an indication of the impact of fire extinguishing clean agent on climate change. Further, the paper briefly describes the clean agent fire extinguishing system design considerations to extinguish fires either by flame extinguishment or by inerting in accordance with the changing characteristics of fire hazard scenarios in building and industrial occupancies. An important finding of this brief study is that the value of 0.4858 kg/m3 is a total flooding factor for HFC-227ea fire extinguishing agent representing the quantity of halocarbon clean agent required to achieve a selected design fire extinguishing concentration of 6% at a specified ambient temperature of 21 °C. It is further important to understand that the impact of a fire extinguishing clean agent on climate change is a function of both the GWP of the gas and the amount of gas emitted. For example, carbon dioxide has one of the lowest GWP values of all greenhouse gas emissions (GWP = 1), yet emissions of CO2 account for approximately 85% of the impact of all greenhouse gas (GHG) emissions. The characteristics of fire hazard scenarios with respect to anticipated fires have been continuously changing in India due to emerging trends in the up gradation/modern furnishing and interior design considerations/requirements in almost all the urban, semi-urban, and rural occupancies. The data from IPCC and Asia Pacific Fire Magazine, October 25, 2011 showed that if nothing changes, the HFC emissions are likely to be equivalent to between 9 and 19% of global greenhouse gas emissions by 2050, which indicates that the impact of HFC fire extinguishing clean agents on climate change is minuscule. As a result, HFCs are expected to remain viable, sustainable, and environmentally acceptable replacements for Halon 1301, which was phased out due to ozone depletion potential problems under Montreal and other protocols.