COVID-19 vaccine

Fire and Life Safety Considerations for Very Low Temperature Vaccine Storage

While much of the country is seeing a resurgence in positive COVID-19 cases, hospitalizations and deaths, some positive pandemic news has come in the form of vaccines being approved and mass distribution plans being laid out. This new activity means that many hospitals, long term care facilities, state authorities, and distributors are currently evaluating different variables associated with managing vaccine logistics in an efficient and safe way.

The new coronavirus vaccine needs to be stored in a setting that has very low temperatures.  Some of the ways being discussed to provide the necessary cryogenic storage include compressor-driven units which might use flammable refrigerants such as R290 (propane), and then liquid-nitrogen or dry ice. These solutions and the potential for fire and life safety issues are also being considered by proactive parties responsible for facility management, code enforcement, and emergency response.

While NFPA codes and standards do not reference a significant amount of information directly related to the storage of vaccines, we thought it might be a good time to provide some insight about the three cooling options noted above.

Flammable Refrigerants

The increased use of flammable refrigerants has received a lot of attention in recent years. The Fire Protection Research Foundation, the research affiliate of NFPA, has done several studies on the topic and those findings helped to inform the development of new flammable refrigerant training for the fire service. Both the research and training indicate that the risks associated with flammable refrigerants aren’t significant enough to warrant changes to NFPA codes and standards, but it is important for audiences to remember that flammable refrigerants are recognized as an A3 coolant with lower toxicity and higher flammability.

Chapter 53 of NFPA 1, The Fire Code, includes broad reference to refrigerants where more than 30 lbs. are being stored. That chapter also indicates that where quantities of flammable refrigerants exceed 6.6 lbs., there should be emergency control systems in place. A dditional requirements for flammable refrigerants can be found in listing requirements and in industry standards from ASHRAE

Liquid Nitrogen

Liquid nitrogen is another viable option to provide very low storage temperatures. While nitrogen is not flammable it does present several hazards that should be addressed. For example, NFPA 55, Compressed Gases and Cryogenic Fluids Code, says to separate stationary cryogenic containers in outdoor installations from exposure such as places of assembly or nonambulatory patient areas. Indoor storage also requires appropriate mechanical ventilation as well.

Dry Ice

Dry ice is the third option mentioned for storing vaccines at appropriate temperatures - particularly while supplies are being transported. Dry ice is frozen carbon dioxide, and like nitrogen, isn’t corrosive, flammable, or toxic. Quantities of dry ice aren’t restricted by codes such as NFPA 400 Hazardous Materials Code or NFPA 55 (which does cover liquid carbon dioxide in a tank or other container), but there are potential issues such as asphyxiation (as dry ice melts it turns into gaseous carbon dioxide and if there isn’t enough ventilation it could lower the oxygen levels in the air), burns, and explosions (if kept in a sealed vessel where the gases were not able to escape). In anticipation of potential response challenges involving dry ice, the International Association of Fire Chiefs put out a white paper last month outlining possible hazards that first responders might encounter with dry ice. 

Although NFPA codes and standards do not reference specific requirements that may come in handy as communities prepare for low temperature storage of the COVID-19 vaccine, we are encouraged to learn that code enforcers, the fire service, skilled workers and others responsible for life safety are asking questions about potential hazards that may arise with the most recent pandemic practices. This line of thinking and propensity for connecting the dots on safety is exactly what the NFPA Fire & Life Safety Ecosystem encourages.

NFPA has a wide array of resources available as authorities tackle new pandemic safety considerations or revisit COVID-19-related challenges and solutions that may have been addressed earlier this year.


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Jonathan Hart
Technical Lead, Principal Engineer at NFPA

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