Ultra-low temperature storage considerations for COVID-19 vaccines
There are many challenges companies need to consider when it comes to ultra-low temperature storage considerations when it comes to safely storing vaccines.
Daily updates on COVID-19 vaccine progress are now the norm. Some of the current forerunners specify cold storage requirements, which influence how manufacturers are able to distribute the vaccine to the mass public. Luckily, a handful of our clients (including those in healthcare and retail, among others) are already discussing their ultra-low temperature (ULT) storage options and how to upgrade their current systems to meet this need. After talking to industry professionals in various practices to gain insights from those with a history of ULT storage, including our friends at George King Bio-Medical, here are a few necessary considerations when assessing your storage options.
A dedicated circuit per freezer is recommended along with a dedicated ground to the freezers. Electrical power can typically be found near the desired location; however, if there are additional electrical needs nearby, then consider feeding all ULTs from a single panel. The voltage required for a ULT is typically higher than what is required for standard freezers, which requires a new circuit be added even if a dedicated circuit is currently provided.
Back-up power is dependent on each facilities’ generator or battery oriented short-term resources but is recommended. It would also be an option to utilize dry ice as an emergency cooling method; however, this can be a chore and will be touched on later in this article.
Keeping compressors cool
Removing heat from the freezer compressor is essential to efficient and stable operation as they produce very high heat loads. The required stand-off from walls should be maintained or even exceeded where possible. Locating building return or exhaust vents directly over the freezers will help to remove the hot air from the condensers and pull room air toward the freezer intake. Cooling in the area should be evaluated to determine if existing systems can compensate for the freezer heat output. The warmer the ambient temperature of the space, the harder the compressors need to work which can diminish the lifespan of the equipment.
Ultra-low temperature freezers produce much more noise than standard temperature freezers with a typical 50-60 DBA sound pressure level. Sound levels differ by manufacturers but the proximity to work areas should be considered. One benefit with having the ULTs within an occupied space, though, is that someone may hear when a compressor/system isn’t functioning properly before it alarms due to temperature, allowing proactive assessment or storage shift.
Personal protective equipment (PPE) is imperative when working with ultra-low temperature cold storage to avoid cold burns. Typically, PPE used in this setting is latex gloves with a rather straightforward set of thick gloves on top of that. The thicker gloves can be anything that offers the necessary articulation with some thickness to prevent burning. These can be as simple as gardening style gloves, as an example, but it’s important to be cognizant of prolonged use/exposure as the gloves don’t protect indefinitely. Also, it’s important to watch out for any exposed skin that might contact the inside of the freezers or shelves meaning users should wear long sleeves to avoid burns from incidental contact.
Monitoring the freezer is essential to detect any mechanical failures and alarms. Every manufacturer offers several different monitoring options, for example in-person monitoring of the building automation system or integrated monitoring through the freezers output which is normally Ethernet. Make sure to coordinate the monitoring requirements and available systems before installing a freezer. Ensure that alarms will be sent to the people who can organize emergency storage provisions as well as people who can get the equipment fixed.
Dry ice considerations
Dry ice is often used as a backup to low and ultra-low temperature freezers or for transporting items to alternative locations. This can be a bigger deal than many might think. Because of how dry ice is used, the person handling it needs to be certified. Storing the dry ice also comes with some regulations. Since dry ice is compressed CO2, building codes require ventilation or alarms in areas where bulk CO2 is stored to protect occupants from a leak which could displace oxygen in the space.
While most entities rely on a local dry ice provider, some choose to produce it in-house. To do this, liquid CO2 is transformed into dry ice snow when discharged through an expansion valve. This “snow” is then compressed into pellets or blocks. The pelletizer utilizes hydraulics and a large motor to generate the pressure required to compress the dry ice into its final form. This machine produces heat and noise which need to be evaluated to accommodate nearby occupant needs.