Biosafety cabinets use large amounts of electricity to power blowers and fans that move air through filters. Some cabinet designs need filtered exhaust air to be expelled via a building’s ventilation system. Making these containments energy efficient is a challenge.
1. Energy intensive lab equipment
Fume hoods and laminar air flow cabinets have long been considered to be the most energy intensive pieces of equipment in any laboratory. These cabinets are containment equipment that provide various grades of protection for laboratory personnel, experimental materials and the environment through a directed air flow. The air can flow in through the front aperture or the top of the cabinet and is exhausted via filters through its sides. In those cabinets used for low risk work the filtered air is exhausted back to the laboratory. In cabinets used for more specialised work in ultra sterile environments, or work with radionucleides and pathogens, the air is double filtered and the clean exhaust is conveyed through a building’s ventilation system to the outdoors. All of this requires a massive energy use especially as some equipment has to be operative 24 hours a day.
2. Deceptive energy use
A laminar air flow cabinet can be deceptive in its energy use. A fume hood can be just as energy intensive as a biological safety cabinet. Fume hoods use about one twentieth of the energy that a Class II biological safety cabinet uses to run. But when the costs of the expulsion of exhaust air are added to overall operating expenditures a fume hood costs the same as an externally ducted Class II B1 biosafety cabinet, the second best contained biohazard cabinet. In fact, when these cabinets are left on and running, but not in use, they consume about 80 percent of the electricity that they use during operations.
3. Biggest costs
The biggest cost in the running of a laminar air flow cabinet is the nature of the motor that runs the air flow. Direct current (DC) motors use far less power than alternating current (AC) motors. DC motors can cost 80 percent less in energy use than AC motors. Further costs are added if the front panel aperture is too large. The narrower the aperture, the lower the energy use. Fluorescent lights inside the cabinet that may be left on indefinitely add even more costs. If additional cooling mechanisms are used inside the cabinet – temperatures are liable to rise inside the cabinet because the motor mechanisms generate heat -, these can add a further 70 percent to costs so far.
To minimise electricity use and make a biological safety laminar air flow cabinet more energy efficient a number of procedures should be followed. Laboratories should minimise the number of biosafety cabinets that require an outdoor exhaust. It’s also best to select a cabinet that uses DC motors to minimise energy consumption and cooling costs. Other energy saving procedures should be followed such as closing the front aperture as much as possible, turning off fluorescent lighting and using timed ultra violet lighting only for disinfection.