Fire damper failings at the Queen Elizabeth Hospital Birmingham were exposed by Channel 4 News in September. Craig Booth explains why it is crucial that fire dampers are regularly tested and maintained.
19 January 2015
Fire and smoke dampers are an important way to stop the spread of fire and smoke through a building's air conditioning and ventilation duct pathways.
Fire dampers are typically spring-loaded shutters held open by a fusible link that releases and allows the damper to shut when the temperature in the duct exceeds 72°C. Smoke damper blades are usually motorised and respond to smoke alarm signals and/or a temperature sensor.
There are many ways to design a fire compartmentation strategy, but whatever route you take it's vital that these life-safety devices operate reliably when called upon to stop the spread of fire and toxic smoke and gases through ductwork. Probably the highest-profile instance of fire compartmentation failure was at Dusseldorf Airport in 1996, where 17 people were killed.
The Regulatory Reform Order (Fire Safety) 2005 calls upon the responsible person, usually the FM, to ensure that protection measures "are subject to a suitable system of maintenance and are maintained in efficient working order and in good repair".
British Standard 9999: 2008 provides a suitable system of maintenance. BS 9999 can be a little confusing as it initially leads you to believe that testing should be carried out every two years, whereas most dampers should be tested once a year. It states that all fire dampers should be tested by competent persons at regular intervals not exceeding two years and must be repaired or replaced immediately if found to be faulty.
But it then goes on to say spring-operated fire dampers should be tested annually and fire dampers in dust-laden and similar atmospheres should be tested much more frequently, at periods suited to the degree of pollution.
Spring into action
Considering that more than 95 of fire dampers are spring-operated and almost every motorised damper has a spring mechanism for fail-safe back-up, then effectively most dampers should be tested annually. The days of the old GLC-style single pivot, unsprung gravity damper, which would simply swing shut when the link broke, are gone.
Healthcare maintenance codes, such as Health Technical Memoranda, recommend annual testing. The Rosepark Inquiry after the fatal care home fire in South Lanarkshire underlined that testing of shutter dampers should normally be carried out annually.
Channel 4 News illustrated a selection of some of the most common problems encountered:
- Damper blades propped open
- Transport ties left in place
- No access panel
- Inaccessible access panel
- Damper skewed
- Spring broken
- Damper fitted wrongly
- Installation fixings block shutter movement
- Access panel too small or too distant
- Dirt and obstructions foul damper channel
- Motor disconnected/loose on shaft
- Runner channel malformed
- Damper remote from fire partition
- Gaps to side of damper
The large number of mis-installations found only serve to underline that much construction is carried out in a race against time for the lowest possible cost. More charitably, one could point to the complexity of multiple trades working in the same area and that the ductwork is usually the 'first in' and so is often obscured by later additions of services, builders' work, finishes and occupant appurtenances.
Testing should be carried out by a competent person. For fire dampers that means a person familiar with ductwork and fire/smoke dampers as found up above the ceiling. The experience and general skill set of the person who can advise on extinguisher types, signage and escape routes is often inadequate for this sort of specialist work.
A critical feature of proper testing is that the damper must be physically dropped or actuated. It is the only way to confirm that it is in good order. The responsible person should insist that a photo be provided of each dropped damper so that a record exists to verify the successful testing. Some property managers have been tempted to accept service that simply confirms the absence or presence of a fire damper as noted on a schedule, but that is unlikely to hold water as 'suitable and sufficient'.
Estates engineers and contractors will prefer to use dedicated fire damper testing specialists with ductwork knowledge because the specialist will also be able to provide practical, workable recommendations for solutions to any problems found. There is usually some maintenance done as part of the testing process, e.g. light oil lubrication of the runner channels or blade spindles. This can often be extended to replace fusible links if faulty.
More complicated remedial works are usually carried out at a later date against a separate instruction. These require ductwork-fitting skills to:
- Install useable access
- Fit removable duct section (especially for smaller ducts)
- Ductwork modifications to provide useable access
- Fit new damper
- Re-fit damper straight
- Re-fit damper in partition/barrier
- Repair damper
Other possibilities include updating drawings, schedules and building management systems; the latter usually in co-operation with controls specialists. The important first step is to have the dampers inspected and tested by a competent person who can ensure that the FM is properly covered, and fire dampers operate reliably when required.
Craig Booth, technical sales manager at System Hygienics Ltd