Temperature management in cold storage facilities is crucial for preserving the quality and viability of biological materials. But It's not just about controlling temperature precisely; consideration also needs to be placed on the effects of moisture on the overall environment.
Maintaining the right balance between temperature and humidity is necessary to create the best storage conditions for sensitive material and avoid excess moisture that can cause issues in a cold room.
In a cold storage environment, the ability of the air to hold water vapor decreases as the temperature decreases. This shows the close link between temperature and moisture content. If the only focus is on controlling temperature and moisture levels are neglected, you may encounter issues that add challenges and complexity to your processes and put both the material you’re storing and the cold room environment itself at risk.
Microbial Growth from Moisture
If the relative humidity in a cold room goes above 65% the conditions become favorable for microbial growth. Moisture can enter a cold room through various sources, increasing the overall relative humidity and complicating moisture control efforts.
Damage or defects, like inadequate or damaged insulation, cracks, gaps, or poorly sealed openings in walls and doors can also facilitate moisture infiltration leading to condensation buildup within the space.
Regular activities, including door openings or standing in the cold room, can also introduce moisture into the space. Additionally, temperature fluctuations caused by doors being opened or improper temperature settings can also contribute to condensation on surfaces in the cold room, adding to the overall relative humidity.
Moisture from damage, defect, or regular access can create microbial growth. This can pose the risk of irreversible damage to the biological materials being stored if they are contaminated and may even pose health risks to the individuals handling and processing the samples.
If left unnoticed or untreated, microbial growth can harm the structure and functionality of the cold room. Microbial growth can spread to the walls, floors, and refrigeration systems, requiring cleaning, repairs, and potentially replacements before the space can be validated and used for storage.
Moisture Impacts Operational Efficiencies
Frost accumulation in a walk-in cold room set to freezing temperatures is a common problem that arises from excess moisture.
This can cause operational inefficiencies. When ice builds up on the evaporator coils, it blocks airflow and makes heat transfer less efficient. As a result, the system must work harder and consume more energy to maintain the desired temperatures. Even a small amount of ice buildup can lead to a significant loss of efficiency.
The resulting excessive strain can lead to premature wear and tear, reducing the lifespan of the system and potentially increasing maintenance costs.
Regular defrosting and maintenance are essential to ensure the optimal performance and longevity of the refrigeration system and this process is not always convenient for the operator or the health of the biological materials.
Excessive Moisture May Impact Temperature Precision
In a cold room, high levels of moisture can create challenges for temperature and sensor controls. When the air is excessively moist, it can lead to unreliable and inaccurate temperature readings. The sensors responsible for temperature control are negatively impacted by moisture resulting in a less precise temperature management. Inaccurate readings resulting from moisture-related issues can disrupt the overall health of the system. This directly affects its efficiency in regulating temperature and indirectly impacts the quality of the materials being stored.
When temperatures are not precise the critical biological materials can become unviable. Vaccines stored in cold rooms that are not precisely temperature regulated can become ineffective resulting in serious implications for patients. Just recently there was a great deal of concern about the viability of the COVID-19 vaccine and its storage temperature requirements. If the vaccine is not stored at a precise temperature, it could become ineffective. Moisture can wreak havoc with the ability of the refrigeration system to function as expected.
There are ways to mitigate the challenges that moisture creates. The obvious solution is to prevent the moisture from entering the chamber so that microbial growth won't occur, frost build-up is limited, and temperature control is precise.
Air-tight doors with seals or weather-stripping help to keep moisture out. Another option is to use zones and anterooms to create buffer zones between the external environment and the cold room environment. Dehumidification systems are a common solution and are effective at reducing air moisture and preventing microbial growth.
The bottom line is that crucial biologics not only need precise temperature control but also need moisture management to protect the integrity of the products being stored.
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