Decontamination

Examining the applications and economies for decontamination of common vivarium equipment and materials.

Lowering energy usage and limiting carbon footprints have become an important theme across the world—in our homes, on our roads, and in our workplaces. Using less energy eases the strain on the environment, which becomes increasingly vital as our population and industries continue to grow. Vivariums have been increasingly committed to joining the green movement with newer, more efficient products being introduced to help cut down on water, power, and time. One of the newest methods of reducing energy consumption in a vivarium or research facility is the use of a decontamination chamber.

Decontamination chambers offer a completely sealed chamber for the decontamination of equipment and materials entering or leaving a barrier facility, or for decontaminating equipment within the facility. While autoclaves use steam and high temperatures to decontaminate the items within, decontamination chambers use chemical sterilants such as chlorine dioxide gas and vapor phase hydrogen peroxide.

Utility and Energy Consumption
Autoclaves use a lot of energy in their daily operation. They require a substantial amount of steam as a means of increasing the temperature within the chamber, and steam is used constantly throughout the day for the steam jacket which keeps the chamber walls warm to minimize condensation of steam injected into the chamber during the cycle. Autoclaves also use a large amount of water. Some water is heated for steam production, and more water is used to cool the waste steam prior to its disposal down the drain. Effluent steam and condensate must be cooled from its 212°F temperature to below 140 °F, as most municipalities require—and autoclaves traditionally cool down the effluent steam by mixing it with cold water. These are costly and energy consuming operational expenses.

Decontamination chambers use no steam during their decontamination cycle, whether using vapor phase hydrogen peroxide or chlorine dioxide gas. Decontamination chambers do need to use some water to raise the humidity level within the chamber. Increased humidity levels are necessary for spore-log reduction as they cause the spore to swell and crack, creating openings for the sterilant to enter. Decontamination chambers utilizing chlorine dioxide gas use approximately one cup of water per cycle. Decontamination chambers utilizing vapor phase hydrogen peroxide introduce humidity during its vaporization of a 35% hydrogen peroxide - 65% water solution, so the water is part of the consumable and not a separate addition. The use of steam by autoclaves also leads to increased wear on animal caging. Steam gets absorbed into the cages and can cause fissures in the plastic over time. An animal facility can replace up to 10% of its caging per year, with weakened caging an underlying cause for most breakages. Eliminating steam usage with bulk autoclaves can help reduce the replacement rate of a facilities caging, thereby offering a rather high savings potential.

In terms of infrastructure, bulk autoclaves necessitate a larger footprint and more system equipment than decontamination chambers. A bulk autoclave with an interior chamber size of around 300 ft³ has a footprint of 120-130 ft². Decontamination chambers of the same 300 ft³ interior have a footprint of around 45 ft². In addition, the price of a decontamination chamber is significantly less, as much as half, than a bulk autoclave.