In this article we examine the concept of global warming potential (GWP) and its implications on the use of HFC-based clean fire suppression agents.
GWP: What Is It?
No other issue related to the clean fire suppression agents is more misunderstood or misrepresented than their impact on global warming. This results from a misunderstanding of the meaning of global warming potential (GWP) values and what those values mean with regard to the impact of a given agent on global warming.
A GWP value is simply a measure of how much a given mass of a gas can contribute to global warming IF that mass is emitted. GWP values are given relative to carbon dioxide (CO2): for example, if a gas has a GWP value of 100, the impact on global warming of releasing 1 kg of that gas is equivalent to the release of 100 kg of CO2.
GWP Value and Its Relationship to the Impact of a Gas on Global Warming
It is important to note the “P” in GWP, which stands for potential: if the gas is not released, there is no impact on global warming. Hence, the GWP value by itself does not allow for comparison of the impact of two gases on global warming. The impact of the release of a gas depends on two factors – both the GWP value of the gas and the mass of gas released, and is found by simply multiplying the GWP value of the gas by the mass released:
Impact on Global Warming = (GWP of gas) X (mass of gas released)
The resulting impact value has units of kg of CO2 equivalents. For example, the GWP of SF6 is 22,800. The impact on global warming of releasing 50 kg of SF6 is thus 23,900 x 50 = 1,140,000 kg CO2 equivalents.
Comparison of the GWP values – or of the emissions – of two gases DOES NOT provide a comparison of their impact on global warming. Comparison of impacts on global warming requires the comparison of the kg of CO2 equivalents (i.e., Impact = GWP x mass released).
Does a High GWP Value Equate to a High Impact on Global Warming?
A misrepresentation oft-encountered in the marketplace is the false assertion that a high GWP value equates to a high impact on global warming (and a low GWP value equates to low impact on global warming).
What do the facts say?
Carbon dioxide has a very low GWP of 1.0, but based on US EPA data [1], and as seen from Figure 1, the impact of CO2 on global warming is extremely high – accounting for 82% of global warming! Data from the European Environment Agency (EEA) for the EU-28 countries and Iceland is in excellent agreement with the US EPA data, and indicates that CO2 emissions result in the largest impact on global warming of all greenhouse gases (GHGs), accounting for a total of 81% of global warming [2]. Clearly a low GWP value does not equate to a low impact on global warming. In the case of CO2, the GWP value is low, but the emissions of CO2 are enormous, stemming from automobiles, power generation, and the exhalation of living creatures. As a result, the impact (GWP x emissions) of CO2 emissions on global warming is very high – despite it’s having a very low GWP value.
FM-200 (HFC-227ea) has a GWP value of 3220 – does that mean it has a large impact on global warming? The facts provide a clear answer of no, as evidenced by data from the US EPA, the European Environmental Agency, the Halon Technical Options Committee and the HFC Emissions Estimating Program.
Why is the impact of HFCs in fire protection on global warming negligible, despite their having relatively high GWP values? Low emissions (Impact = GWP x Emissions). Since HFC clean agent systems may be required to provide protection for a given facility for decades, extreme measures are taken to ensure that HFC clean agent fire protection systems do not leak, and the systems are only employed in the event of a fire. As a result, the emissions of HFCs in fire protection applications are extremely low, and as seen from US EPA data [1] depicted in Figure 1, these emissions account for a mere 0.02% of global warming.
US EPA data [1] shown in Figure 2, clearly demonstrates that the GWP value by itself does not determine the relative impact of a given gas on global warming. The impact on global warming of CO2, which has a very low GWP of 1, dwarfs that of HFCs in fire protection, due to the huge amounts of CO2 emissions. At the same time, the extremely low amount of emissions of HFCs from fire protection systems results in a negligible contribution to global warming, despite their high GWP values.
Emissions data from the European Environment Agency (EEA) are in excellent agreement with the data from the US EPA, and also indicate that the emissions of HFCs in fire protection accounts for only 0.02% of global warming [2].
The Halon Technical Options Committee (HTOC) is part of the United Nations Environment Programme (UNEP), and provides information to the UNEP Technology and Economic Assessment Panel (TEAP) related to the production and regulation of Halons, and information related to the use and sustainability of Halon replacements, such as HFCs. The TEAP in turn serves as the the technology and economics advisory body to the Montreal Protocol Parties. The HTOC reports [3] that the impact on global warming of HFCs in fire protection is estimated to be 0.015% and 0.05% of the impact of all GHGs in the US and EU, respectively, in excellent agreement with the US EPA, and European Environment Agency evaluations.
In addition to the above studies, data from the HFC Emissions Estimating Program (HEEP) also demonstrates the relatively miniscule contribution of HFCs in fire protection to global warming [4]. As seen in Figure 3, which shows the combined impact on global warming of both hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) in fire protection, the magnitude of this impact has remained steady for over a decade.
Figure 4 summarizes the facts related to FM-200 and global warming.
Science and Regulations
Understanding that the use of HFCs in fire protection has a negligible impact on global warming, regulators have not proposed any bans or limitations on the use of FM-200 in fire protection. For example, the recently ratified Kigali Amendment to the Montreal Protocol does not propose any bans or limitations on the use of FM-200 in fire protection.
Another oft-encountered misrepresentation in the marketplace is that, since there are regulatory proposals to limit the use of certain HFCs in other applications such as refrigeration, this must also apply to HFCs in fire protection. Again, regulators understand the science and recognize the difference between these applications. In contrast to the very low production volumes and low emissions associated with HFCs in fire protection, the production volumes and emissions of HFCs in refrigeration dwarf those of HFCs in fire protection. As a result, the impact on global warming of HFCs in refrigeration dwarfs that of HFCs in fire protection, as seen in Figure 5 [1,2].
Conclusion
The relative impact of any gas on global warming is found by multiplying the GWP value of the gas by its emissions on a mass basis. Due to extremely low emissions, the impact of HFCs such as FM-200 on global warming is negligible. Regulators understand this science and are not proposing any bans or limitations on the use of FM-200 in fire protection. Additional support for the long term environmental acceptability of FM-200 is the FM-200 Falcon Warranty, a 20 year warranty against any future regulations, offering users further long term peace of mind.
For more information, go to FM200.com
References
- US EPA Report 430-R-17-001 (2017).
- Annual EU GHG Inventory 1990-2015 & Inventory Report 2017 (EEA).
- HTOC Technical Assessment Report, Volume 1, 2014.
- HEEP Final Report for 2002-2015, December 2016.
About the Author
Mark L. Robin is Senior Technical Services Consultant, Specialty Fluorochemicals at Chemours.
