Energy Efficiency in Biological Safety Cabinets

With our planet’s finite resources and the successive energy, environmental and financial crises, we have been repeatedly reminded of the need to be more careful of how we expend our resources. As a commonly used piece of laboratory equipment, the biological safety cabinet (BSC) is vital in ensuring the safety of the user as well as the sample. However, these cabinets can consume vast amounts of energy. This article looks at how to ensure that the important safety benefits and quality of work offered by Class II BSCs, can be maintained while still consuming resources more efficiently.

A COSTLY EXHAUST
Many life science research protocols require the use of BSCs to provide protection for the operator, product and environment. They achieve this through the use of an inward flow of air at the front aperture, in combination
with the filtration of air circulated into, and exhausted from, the cabinet.

However, filters are only able to capture solid particles, not gases, so if BSCs are used with volatile toxic chemicals or radionuclides, it is recommended that the exhaust be conveyed out of the laboratory through the buildings’ air ducts, which can be costly. In addition, every cubic meter of air conveyed out of the building must be replaced to ensure balance is maintained.

As such, energy is expended moving the air, while the replacement air may need to be treated for temperature and/or cleanliness, increasing the cost of using externally ducted cabinets.

When researching low flow fume hoods in 2003, Mills and Sartor [1] of Livermore National Laboratories in the United States estimated that the average annual cost of exhausted air was US$2.65 per cubic meter per hour (CMH).

It is clear therefore that in order to increase energyefficiency, external exhaust requirements need to be reduced. There are three ways of doing this: