04 July 2008
Stewart Kidd

Until the end of the 1980s, sprinklers were seen primarily as a property protection measure, beloved by insurers but largely unappreciated by others. Interest in the potential of sprinklers to reduce the serious toll of fire death and injuries began to grow in the 1990s.

The decline in insurers' influence over new buildings towards the end of the decade was paralleled by increasing enthusiasm in the UK fire service to promote the idea of fixed suppression systems. At the same time, more widespread use of sprinklers in dwellings in the US was paying off - in lives saved and reduced property damage and fire brigade costs.

Sprinklers have a good reliability record and can provide a significant improvement in fire safety. They are particularly successful in containing and extinguishing arson fires, as they demonstrated recently at a shopping centre in central Birmingham, a primary school in Manchester and a DIY superstore in Barnstaple.

But their effectiveness and reliability depends on planned maintenance carried out by competent people to the recognised standards.

Isolated showers

Sprinkler systems use grids of pipes with sprinkler heads fitted into them at regular intervals. Water from a tank - via pumps or from the service main (if it can give enough flow) - fills the pipes.

When it reaches its preset temperature, a sprinkler head will open and spray water on to a fire. The hot gases from a fire are usually enough to operate the thermal device in the head. Only the heads in the area of the fire open, and many fires are controlled or extinguished by the operation of only one or two heads; the others remain closed. This limits damage to areas where there is no fire and reduces the amount of water needed. It's important to note that only heat can operate the heads: they will not be activated by smoke (inlcuding that from burning toast), dust or steam.

Sprinkler heads are generally placed on the ceiling, and spaced to ensure there is always sufficient water flow. The designer will calculate the flow to make sure there is always enough water to control or extinguish a fire, taking into account the size and construction of the building, the goods stored in it and its use.

Heads can be placed in enclosed roof spaces and in floor ducts to protect areas where a fire could start without occupants noticing. In a large warehouse, sprinklers may be placed in the storage racks as well as the roof.

There is a valve at the point the water enters the sprinkler system. This can be used to shut off the system for maintenance. For safety reasons it's kept locked open and only authorised persons should be able to close it. If a sprinkler opens and water flows through the valve, it lets water into another pipe which causes a bell to ring, sounding an alarm, using water rather than electricity.

Condition precedent

Automatic sprinkler systems are now widely accepted as compensating for some of the requirements of the Building Regulations. Many of these trade-offs will be codified in the forthcoming BS 9999: Code of Practice for Fire Safety in the Design, Management and Use of Buildings.

Once a sprinkler system has been handed over to its owners, the responsibility for the equipment rests with them. Whether or not the system will operate as designed when needed will depend on whether you carry out the correct maintenance procedures.

Article 17 of the Fire Safety Order 2005 imposes significant liabilities on the responsible person (read employer or property owner) who fails to maintain fire safety equipment, including sprinkler systems, intended for the protection of life.

Sprinklers in non-residential premises should be designed, installed and maintained in line with BS EN 12845 (2004): Fixed Firefighting Systems: Automatic Sprinkler Systems: Design, Installation and Maintenance (this has been the case since September 2007).

Section 20 of BS EN 12845 details the maintenance requirements for a sprinkler system, and Annex J of the standard describes the precautions you should take in the event of a system shutdown. The standard recommends that testing, servicing and maintenance is carried out by the system installer, or a similarly qualified company, but there's no reason why weekly test procedures cannot be carried out by the owner, provided the person undertaking the work is competent.

Given that a sprinkler system not only protects property but also life, the value of following procedures cannot be overstated. It's particularly important to verify that all valves are left in the correct position and that the system is fully operational on completion of any test procedure. Where these tests are carried out in-house, a second person should be present to check this.

If a sprinkler system has to be taken out of service or rendered inoperable for some other reason (such as a loss of water supply from a public main), you should notify the fire and rescue service and your insurer. This is a "condition precedent" in many insurance policies and failure to comply could result in a subsequent claim being denied.

Testing times

Where an insurer has specified a system or offered a premium discount, sprinkler maintenance should also comply with technical bulletin TB203, part of the LPC Rules for Automatic Sprinkler Installations. This reiterates the importance of trained people carrying out the testing procedures and the need for approved companies to service and inspect sprinklers.

The bulletin also emphasises the need to document testing and servicing, and to have procedures for shutdown of the system, together with the actions to take when the installation triggers an alarm.

Section 20 of BS EN 12845 recommends weekly visual checks of the installation and activation of the water-driven motor alarm (opening a valve to simulate the operation of a sprinkler head will activate the alarm). If the system is fed from a service main, you should record the readings of the pressure gauges before and after the test. 

Where the sprinklers are supplied by pumps, simulating the sprinkler-head activation will activate the duty pump. If the pump is diesel-powered, the engine should be run for 20 minutes and you should check the cooling system, oil pressure, batteries and fuel. In winter, it's essential to check that any anti-frost measures - such as trace heating, pump-house heating and tank immersion heaters - are functioning correctly.

BS EN 12845 recommends quarterly inspections of sprinkler heads, pipework and pipe supports, and suggests a flow test on the water supplies. Section 20.3.2.2 requires a quarterly review to take account of any changes in building structure, occupancy, storage configuration, heating, lighting or other parameters that would change the hazard classification or render the installation in any way inadequate. This is not a procedure that can be carried out by the end user - it requires the services of a specialist, normally the system installer or a specialist maintenance contractor, insurance surveyor or specialist fire engineer.

Any pump should be tested yearly at full load condition, according to BS EN 12845. Water storage facilities need extra checks. You should make a visual check for corrosion of the exterior of the tank every three years and it should be refurbished as necessary. All storage tanks should be cleaned and examined internally by a competent person at least every 10 years.

In certain cases where sprinklers are installed for life safety purposes - as a condition of the Building Regulations or Scottish Building Standards approval, or in compliance with other legislation, such as the Fire Safety Order or Fire (Scotland) Act 2006 - you will need to make sure all sprinkler maintenance is fully documented, undertaken only by a competent person, and fully complies with the appropriate standards.

The British Automatic Fire Sprinkler Association (BAFSA) believes that, apart from the basic inspections and tests outlined above, all maintenance work should be undertaken by a third-party certified installation or maintenance company listed by a United Kingdom Accreditation Service (UKAS) approved accreditation body.

If your follow these simple procedures, it's almost certain that a sprinkler system will operate as intended.

Sprinkler facts

• No one has ever died in a fire in a UK commercial or industrial building protected by a working sprinkler system.
• 80% of fires are controlled by 10 or fewer heads opening.
• Not all sprinkler systems need tanks and pumps if mains pressure and flow are adequate.
• Fire damage in sprinklered buildings costs 80% less than that in non-sprinklered buildings.

Stewart Kidd is secretary general of BAFSA, www.bafsa.org.uk

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Fire, Safety, Article