Fire dampers — out of sight but should not be out of mind

Airmec, Fire damper, maintenance, refurbishment

Do not assume that fire damper testing is covered as part of the maintenance your fire-protection systems — it rarely is, warns Andrew Steel of Airmec.

Everyone knows what a fire door, is but fire dampers are not so well known, and their importance can be overlooked. They are generally hidden above ceilings and mounted in a ductwork run; most people don’t know that they exist. Even though they form a key part of the fire protection within a building, fire dampers are often overlooked in the maintenance regime and, at worst, propped or left open.

You wouldn’t leave a fire door open or disable its automatic closer, would you? Yet, all too often, our inspectors report that they have seen dampers clogged with debris so thick they would not be able to close effectively or because they’ve once automatically ‘nuisance closed’, they’ve been jammed open with bit of wood or bricks. The answer to nuisance closures is testing, maintenance and repair; in fact I’d argue that nuisance tripping is a useful way of alerting you that there is a potential problem so you can de-risk it straight away.

The harsh reality of fire dampers can include them being blocked open (middle), corroded (bottom) and damaged (top).

With HSE ACoP L24 stating so clearly that ventilation and air-conditioning systems should be cleaned regularly and British Standard BS EN 15780 providing refreshingly straightforward guidance, it is surprising how many incidents for duct fires there still are. Fire officers tell me that one of most common causes of fires within commercial buildings is still the failure to remove combustible grease deposits from ductwork. Many insurance companies will no longer pay out on claims where it was found that the fire was started or spread by unclean ductwork systems. So, if the worst should happen, you need to minimise the risk of fire spread and damage.

Most importantly, of course, fire dampers in ducts are there to prevent the spread of fire and smoke through ducts which breach fire walls, ceilings and floors, and to prevent it reaching areas where it can compromise escape routes. This is essential, potentially life-saving equipment — not the finishing touches to a system.

While they are described as passive fire protection, fire dampers really do need active management. Under current legislation, the ‘responsible person’ (England, Wales and Ireland), the ‘duty holder’ (Scotland), or the ‘appropriate person’ (Northern Ireland) has to undertake a fire-risk assessment for the premises for which they are responsible — and those hidden fire dampers are a key component of fire protection. As there is no definition of what level of knowledge such a person should have, it is a brave boss who does not seek professional advice on fire risk assessment and prevention.

British Standard 9999 stipulates the following requirements.

• All fire dampers to be tested by a competent person on completion of the installation and at regular intervals not exceeding two years.

• Spring-operated fire dampers should be tested annually, and fire dampers situated in dust-laden and similar atmospheres should be tested much more frequently, at periods suited to the degree of pollution

You can see that there is room for judgement and interpretation, which can often mean room for confusion, but you need to get the balance between the cost of inspection and the need for inspection right. Do remember though that you cannot outsource your legal responsibility; it is still the building owner and operator who would carry the can in court if prevention measures were found to be inadequate. We have also found that facility managers often assume that the fire-damper testing will be covered as part of the maintenance and testing of their fire-protection system, but in reality it rarely is. Choose your specialist partner wisely.

Curiously, there is no lack of awareness of the need to clean and degrease ducts, and the current European Standard (BSEN15780:2011) has actually resulted in a plainer English explanation of what is needed there. It recognises different levels of risk and different levels of investment needed in a cleaning regime, and you can model your inspection regime for the fire dampers along similar lines.

The first step is to categorise the risk levels, and that means building a current asset register of your ventilation systems. Logically, fire dampers should be an integral part of that register — each one identified by its position, its type (curtain, blade etc.), the level of risk it presents and frequency of inspection needed. You might be surprised at how many there are secreted in your ductwork; a recent contract at Heathrow’s Terminal 3 involved us inspecting over 800 (all with a clean bill of health, by the way)!

Typically, of course, it is kitchen extracts that will be found to need the most frequent cleaning, and they rarely have fire dampers because the likely build-up of grease can affect their activation, so these ducts usually vent straight outdoors. That means, of course, that the ducts which do have dampers are likely to be the ones less frequently scheduled for cleaning work, but just make sure they don’t get forgotten.

Whoever inspects ducts should also be able to inspect all of your dampers and test that they work while they are there. Do make sure that firm can actually repair faulty dampers as well — just having a FAIL notice stuck on the ducting and your business grinding to a halt cannot be allowed to be an option.

Remember, just because the risk is low, it doesn’t mean that the consequences of failure and smoke potentially billowing through escape routes will not be disastrous.

Andrew Steel is managing director of Airmec.

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