Mainstream researchers tested a novel tropodegradable fluorinated agent and blends of this agent with with 1-bromopropane for streaming fire suppression applications. We performed large-scale fire suppression tests and determined the toxicity characteristics of the agents, the cardiac sensitization NOAEL of the candidate agents and the atmospheric impact of the agents. We also performed materials compatibility experiments, determined the agent decomposition products, characterized the physical properties of the agents, and assessed the manufacturability of the agents.
This novel agent has the potential to be a substitute for Halon 1211 and HFC-236fa for streaming fire suppression applications. Although to extinguish a fire it requires more agent, higher agent discharge rates, and higher discharge times than Halon 1211, our agent has the same fire suppression performance as HFC-236fa. Also, the fire suppression tests showed that the addition of 1-bromopropane to either octafluoro-2-butene or HFC-236fa had marginal, if any, performance benefits.
Contrary to Halon 1211, which is a known ozone depleter with high GWP, our agent does not have the negative atmospheric impact of either Halon 1211 or HFC-236fa because it has a zero ODP, low atmospheric lifetime and low GWP. Although HFC-236fa has zero ODP, it has a high atmospheric lifetime and high GWP.
The toxicity information developed on this project indicates that more subchronic and long-term toxicity information is required. It does not appear to be as potent of a cardiac sensitizer as other fire suppression agents or refrigerants, but it did appear to cause lethality in dogs after exposure to 9% agent in air. The cause for these lethalities also needs to be evaluated.
Materials compatibility tests indicated that the agent was compatible with all the metals we evaluated and had less of an effect on the elastomers we evaluated than Halon 1211 did. Agent decomposition analysis showed it generated low levels of acid gases (HF), but no other toxic decomposition products were detected.
For this novel agent to be a commercial fire suppression agent, more work on manufacturability needs to be performed. Specifically, the cost of the agent needs to be significantly reduced to the range of $20-$40/lb. Initial estimates of the cost of manufacturing in large quantities in a continuous process show that this cost reduction is feasible with some process development work and the building of a suitable plant.
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