Ductwork cleaning contractors are becoming increasingly alarmed at the state of ventilation and kitchen extract systems says Bob Towse, head of technical and safety at the HVCA.
Specialist ductwork hygiene and maintenance contractors are struggling adequately to clean large numbers of systems because of access problems. This can lead to serious health and safety problems, including, for kitchen systems, dramatically increasing the risk of fire.

On top of that, many insurance companies are now refusing to pay out after fires. This is because the building operator cannot prove that the extract system has been
properly cleaned. Without evidence of a proper maintenance regime, the end user can be seen to be in breach of their insurance policy.

At a seminar during the recent HEVAR Exhibition, Martin Hembling of building services hygiene firm Swiftclean said fewer than 10% of the systems his company surveyed had sufficient access doors to allow the systems to be cleaned properly.

The industry's main guidance on the topic - the HVCA's TR/19 Guide to Good Practice - states access doors should be fitted at least every three metres along a run of ductwork. There is a suggestion that this basic requirement is being ignored, in some cases to save money - or left out at initial design through lack of awareness.

Kitchen extract systems in heavy use - 12-16 hours a day as in commercial kitchens - should be
thoroughly cleaned at least every three months. Medium use
systems - 6-12 hours per day - should be cleaned every six months, and lighter use - 2-6 hours - once a year.

Alan Gregory, from ventilation maintenance firm InDepth Hygiene, said the new fire regulations - Regulatory Reform (fire safety) Order 2005 - placed a heavy responsibility on landlords and managing agents to ensure risk assessments are carried out in their buildings.
During the HEVAR seminar Gregory said: 'They must identify potential ignition sources and take action to minimise the risk. Grease in extract ductwork can be a source of fire, as well as a route for the fire to spread.'

HVCA members report that, even where there are access doors, they are often placed too far apart. They also regularly encounter situations where the ductwork has been installed in solid ceiling voids, so that maintenance staff cannot reach them, and sometimes it is placed too close to combustible materials.

Hygiene contractors regularly find that cooker hoods and other visible parts of the system are
regularly cleaned, but the hidden parts of the system are not. This means fans and flow control dampers inside the system are covered in grease.

Building owners and operators need to protect themselves and their occupants by taking a series of sensible measures. Kitchen extract systems must be inspected at least every six months, and the filters cleaned every week. If you cannot produce evidence that this has been done, then you may be effectively uninsured.

The absence of adequate access arrangements is an obvious sign to any fire inspector that the system is unlikely to have been cleaned properly - if at all.