Just hot air?

Just hot air?

The recent International Ventilation Hygiene Conference raised the subject of the new CIBSE document, Hygienic Maintenance of Office Ventilation Ductwork(TM26). This aims to show building managers the importance of ductwork maintenance and to provide practical guidance on the safe and effective maintenance of such ductwork.

At the conference Dr Colin Hunter from BRE Limited talked about acceptable levels of micro-organisms in ventilation ductwork. TM26 lays out the protocols for sampling and testing air and surfaces for microbes and interpreting what is acceptable and what is not. It also provides guidance on when cleaning is required.

Since 1992, building owners and managers have been under pressure from the ventilation hygiene fraternity to clean their ductwork as a "legal requirement". This is said to result from the Workplace (Health, Safety and Welfare) Regulations, which state that mechanical ventilation systems should be regularly and properly cleaned. However, the frequency of such cleaning is not specified.

It was clear from the conference that the ductwork cleaning industry is frustrated by the low priority given to general ventilation systems in office buildings by both the HSE and environmental health department and the lack of prohibition notices or prosecutions under The Workplace (Health, Safety and Welfare) Regulations 1992 – but, of course, they would be, wouldn't they?

There is need for clearer guidance; in the meantime, organisations should take independent advice from appropriately qualified personnel. The sheer existence of TM26 will mean that organisations will be further pressured into what may be unnecessary cleaning – and poor testing and maintenance practices may even result in an increase in positive reasons to justify the original cleaning schedule.

So, make sure that the advice you read – and pay for – is independent, and not coming from a company with a vested interest in persuading you to clean more often than is necessary.