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Be safe – clean your ductwork

Risk assessments for water systems have been standard practice for many years, largely thanks to the level of publicity surrounding outbreaks of Legionnaires’ disease. Indoor air quality and the associated health and safety risks from poorly maintained ventilation have always been more of a grey area for building owners.

Even where they are aware of the risks posed by dirty ductwork and clogged kitchen grease extract systems, many end clients and facilities managers still struggle to put strategies in place to protect occupants. In a bid to make life easier, the Building and Engineering Services Association (B&ES) has carried out a comprehensive revision of the ventilation hygiene industry’s main source of technical guidance: TR/19 Guide to Good Practice : Internal Cleanliness of Ventilation Systems.

Since it first appeared in 1998, TR/19 has been widely accepted within the building engineering services sector and by the UK insurance industry as the standard to which ventilation systems should be cleaned.

The updated edition was developed to complement British and European Standard BS EN 15780: ‘Ventilation for Buildings – Ductwork – Cleanliness of Ventilation Systems’, which was introduced in 2011 and highlights the role ventilation hygiene plays in maintaining healthy indoor conditions for building occupants.

The revised B&ES guidance also explains best practice for ensuring that kitchen extract ventilation is maintained to minimise the fire risk associated with grease accumulation, which is not covered by BS EN 15780.

If there is a coating of grease inside the ductwork, it will act as a highly efficient transmitter of heat and flames through the rest of the building – all it needs is an ignition source, and kitchens have plenty of those.

A fire will often start inside the ductwork simply because the temperature becomes high enough to ignite the accumulated grease, and 90% of catering fires are exacerbated and intensified by ignition of grease deposits in grease extract ducting.

As a result, many insurance providers will simply not cover commercial kitchens or, where insurance is provided, will include caveats in their policies that can lead to claims being rejected on the grounds that the building operator has failed to maintain the ventilation effectively – or can not prove that they have maintenance strategies in place.

Many insurers advise that unless ventilation systems are cleaned to the standards set in TR/19, compensation claims in the event of commercial kitchen fires may not be successful. The updated TR/19 provides clarity about when and to what standard grease extract systems should be cleaned, and provides a detailed explanation of the frequency of cleaning required based on the type of cooking and the hours of kitchen use.

This will also help building owners meet their obligations under the Regulatory Reform (fire safety) Order 2005 and stay on the right side of fire officers, who have the power to close down a building if they are not satisfied that the extract systems are safe.

In addition to a regular cleaning regime, TR/19 offers guidance on the fitting of efficient filtration systems such as the new generation of high-capacity filters that are capable of removing up to 94.6% of grease deposits.

Richard Norman is chairman of the Ventilation Hygiene group branch at the Building & Engineering Services Association

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