The phase-down and restriction of the most common and widely used refrigerants was initiated in the late 1980’s and has spurred innovation, both for the alternative refrigerants that have been introduced as well as in the equipment that uses them. Safety Group A2L refrigerants (lower toxicity and lower flammability) represent the most recent in the focus of deployable reduced GWP/zero ODP refrigerants. Studies conducted by the industry have shown that in order to reach the goals of the Kigali Amendment for global warming impact reduction it is likely that A2L refrigerants will be required.
The fire service requested that data be developed to identify hazards to the fire service personnel when responding to fire events in occupancies with the new refrigerants. Specifically, they have identified the following areas where performance data of A2L refrigerants would assist them in their tactical considerations.
- Comparison and contribution of A1 and A2L refrigerants in a fire relative to heat and gases generated;
- Potential for flash fire, deflagration, or explosion hazards in residential and commercial applications; and
- Influence on fire dynamics from refrigerant leakage during fire service suppression and overhaul activities.
The data from the testing will be used by UL Fire Safety Research Institute (FSRI) to develop training materials for the fire service towards their tactical considerations. This activity is to be performed in a separately funded and contracted project following completion of this statement of work.
The following objectives for this investigation were identified in collaboration with AHRI and the fire service organizations:
- Demonstrate through fire scenario tests the hazards that may be encountered by the fire service when fire involves SafetyGroup A2L refrigerants as compared to existing Safety Group A1 refrigerants; and
- Prepare information for the later development of educational materials for the fire service for their tactical considerations.
The original plan called for testing two safety group A1 refrigerants (R-410A and R-466A) and two safety group A2L refrigerants (R-32 and R-454B). It was found in Scenario 1 that the facility’s smoke abatement system was not able to scrub iodine from the exhaust gases. Use of R-466A was suspended because of this issue. Based upon these objectives fire scenarios were designed as follows:
Scenario 1: Comparison and contribution of A1 and A2L refrigerants relative to heat and gases generated in an open flame.
Scenario 2: Hazards during suppression activity from change in fire dynamics in the hallway where firefighters may be advancing towards the fire room with a forced refrigerant release in ventilation-controlled conditions.
Scenario 3:This scenario was planned as optional pending a review of Scenario 2. The difference between Scenario 2 and Scenario 3 is that the leak would not be forced as in Scenario 2
Scenario 4: Hazards in fire room during overhaul activity if firefighters action results in a refrigerant line break.
Scenario 5: Fire conditions in a below-grade closed room without any air movement, having an excessive amount of refrigerant pooling, well above the allowable limits of refrigerant to demonstrate how refrigerant burns when ignited with a flame.(This scenario was added to the original plan based upon input from UL FSRI and fire service.)The results for each scenario relevant for firefighter tactical considerations are summarized here.
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