Behind the grease filter

Published:  18 March, 2006

A planned ventilation hygiene strategy carried out by specialists will not only improve indoor air quality and comfort conditions; it should also keep you safe, according to the HVCA’s Richard Norman .

It is a sad fact that we often need a high-profile disaster to force people to face up to health and safety hazards. We are all guilty, to a greater or lesser degree, of treading a fine line while we think we can get away with something, but it is rarely worth gambling with ventilation hygiene — there is too much to lose.

New fire safety regulations, due to come into effect later this year, are also designed to improve risk assessment so that all building operators are aware of potential fire hazards such as uncleaned ventilation ductwork and have taken steps to minimise that risk.

Out-of-sight-out-of-mind is not a good defence and is often the problem with hidden services such as extract systems. The new fire regime — Regulatory Reform (Fire Safety) Order 2005 (RRFSO) — will place a heavy burden on building operators to address potential hazards.

Last summer, there was a well-documented fire at one of London’s best-known restaurants — a spot popular with tourists and Londoners alike. The source was traced back to the grease-extract ductwork and, while thankfully no one was hurt, the fire still caused extensive damage to the restaurant, leading to an expensive repair bill and substantial loss of earnings. It was another clear reminder to facilities and buildings managers of the importance of keeping grease-extract ductwork systems professionally cleaned.

A grease-extract ventilation system draws grease-laden air directly from the areas above cookers, grills and fryers via the cooker hood and out to the atmosphere.

Flammable coating

Whilst the filters usually found above the fryers are designed to trap grease particles, they can never be 100% efficient, and a significant number of these grease particles will pass through into the extract system. This allows a potentially flammable coating to form on the inside of the canopy/extract plenum (void behind the grease filters) in the extract ductwork and on the fan blades. These grease deposits are easily ignited by even a small flash fire on or in the fryer, hob or grill and flames, and heat can then quickly spread through the building, causing substantial damage and endangering lives.

Almost a quarter of the 24 000 accidental fires in non-domestic buildings each year are attributed to cooking appliances. In the last decade fires in grease-extract ducts linked to catering facilities have caused considerable damage at Witney town centre, Heathrow Airport, South Mimms services and, more recently, the Hard Rock Café in London.

The cleaning of the grease-extract system is frequently overlooked, often because it runs behind false ceilings or walls and, therefore, tends to be in areas that no one feels responsible for. It is estimated that over 80% of kitchen extract ducts in the UK are never cleaned and are, therefore, in a hazardous state.

Responsibility

The sweeping changes made to the fire-safety legislation by the new Fire Safety Order will place responsibility for preparing fire-risk assessments and addressing the identified risks to building occupants, squarely on the shoulders of a designated ‘responsible person’.

Every organisation will be required to nominate their ‘responsible person’. This could be an in-house or outsourced manager, or any person deemed to be ‘in control’ of all, or part of, the premises.

The RRFSO approach be will be based on a fire-risk assessment, and the responsible person/s for the premises must decide how to address the risks identified, while meeting certain requirements.

By adopting a fire-risk assessment, the responsible person will need to look at how to prevent fire from occurring in the first place by removing or reducing hazards and risks (ignition sources) and then at the precautions to ensure that people are adequately protected if a fire should still to occur. The main emphasis of the changes will thus be to move towards fire prevention.

The fire-risk assessment must also take into consideration the effect a fire may have on anyone in or around your premises and the neighbouring properties. The building fire-risk assessment will also need to be regularly reviewed.

  The RRFSO will apply to virtually all non-domestic buildings, including voluntary organisations. It will be subject to monitoring and, where appropriate, enforcement by the local-authority fire service.

Insurers

As a result of the escalating costs of compensation for losses arising from major fires, insurers now regularly include specific clauses in their policies requiring particular action to be taken to reduce fire risks in grease-extract ducting by the regular removal of grease deposits.

  To quote one of the UK’s leading insurers: ‘Kitchen extract ductwork needs to be inspected internally to check on the build up of grease deposits and cleaned six monthly as a minimum, although the exact frequency will depend on the level of usage of cooking equipment.’

Increasingly, those who fail to take note of these developments will find property insurance either impossible to obtain, difficult to renew or invalid in the case of fire.

Inspection and cleaning of grease-extract systems requires specialist techniques, training and equipment and should only be carried out by a professional specialist contractor and not left to a general cleaning contractor.

Court cases

In fact as a result of recent court-case judgements, insurance companies are also starting to take an increased interest in who carries out this work. Two recent court cases concerning uncleaned extract systems highlighted that the cleaning companies involved were not specialists.

Insurers are increasingly demanding that deep cleaning should be carried out in accordance with advice given in the HVCA’s Guide to Good Practice TR/19, and only contractors who can comply with this guidance should be retained. TR/19 gives comprehensive information about how often grease-extract systems should be cleaned, depending on the amount and type of cooking that is done.

TR/19 also recommends that a post-clean report should include a sketch or schematic of the system indicating where access panels have been installed and where there are any uncleaned areas, with a written explanation why such area/s could not be accessed or cleaned.

A planned ventilation-hygiene strategy brings improvements in air quality that is quickly noted by all occupants, but happiest of all will be the ‘responsible person’ carrying the heavy burden of reducing the threat of fire.

Richard Norman is vice-chairman of the HVCA’s ventilation hygiene branch.

For your copy of TR/19 write to: HVCA Publications, Old Mansion House, Eamont Bridge, Penrith, Cumbria, CA10 2BX. Tel: 01768 860405.

caption

Grease filters in kitchens can never be totally efficient, and grease particles will inevitably get into the extract system to form a potentially flammable coating on ductwork and equipment behind the filters. That is why effective cleaning of the grease-extract system is so important. (Photo: Ledaire Fabrications)



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