In defence of sprinklers

Published:  01 January, 2009

Hollywood certainly hasn’t helped promote the use of sprinklers among many building owners and developers. Images of the “hero” escaping some villainous pursuer by setting off the sprinkler system throughout a building after applying a cigarette lighter to a sprinkler head are not only misleading, but help perpetuate the myths that these systems are unreliable and damaging to business. Pat Cox gets tough on some prevailing misconceptions.

Lack of understanding of the manner in which the systems operate is one of the chief reasons such myths continue to influence architects and designers when they argue against installing them. The classic misrepresentation statement on sprinklers, or in this case the absence of them, has to be the UK Government Minister who stated after the Windsor Castle fire in 1992; “Thank God there were no sprinklers, the damage would have been far worse if there had been.” It is difficult to imagine how he thought this might be so. After all, with sprinklers, at worst, the discharge would have been a few thousands of litres of water. Without them the Royal Berkshire Fire Service had to pump several million litres into the building – a great deal of which is still in the walls and substructures.


The most reliable statistics seem to be those from Australia, which show that the majority of fires are dealt with by less than eight sprinkler heads. In fact, in the vast majority of cases, they successfully control the fire by the operation of one or two heads. These findings directly support the data collected in the US and UK, which confirms that the vast majority of fires in sprinkler protected premises do relatively little damage. Even more impressive is the record reportedly from a Mid-Western State in the US. This city, since the implementation of an ordinance requiring sprinklers in all new-build domestic and commercial premises, has recorded no fire deaths within the last decade.
To some degree it must be said that UK Building Regulations don’t encourage the installation of sprinkler systems. While their installation does permit some trade-offs, such as allowing an increase in compartment size or gaining relaxation of safety features within buildings (such as lobbies, provision of fire doors), these are limited.


This can be traced back to the rather restricted vision that sprinklers are an insurance matter and are about property protection, contributing nothing to life safety.


How wrong this view is can be seen by everyone with the mind to look more carefully at the statistics – a recent briefing note to a UK minister showed that only ten people had died in sprinkler protected buildings in a review period covering several years. And all of these were as a result of matters that the sprinklers could not prevent, such as murder, explosions or accidents which gave ignition.


Another modern myth is the concept of the “sacrificial building”. This promotes the idea that as long as the occupants all escape, the building and its contents can be sacrificed and will be replaced by the insurers. As you may imagine, insurance policy terms and conditions with excess and limits often do not indemnify the full cost of rebuilding a facility and loss of profits. And where it does, these sums do not cover the full cost impact in terms of jobs, lost business and damage to the local economy caused by the loss of jobs or products, etc.


The aspect of protecting the business and its economic contribution to the local and national economy should not be overlooked. Put simply, the “sacrificial building” concept is a reckless and – frankly – cavalier approach to a company’s responsibility to the community it draws its workforce from.

The iceberg effect


Research into this by the insurance industry has shown that a large fire in any commercial or industrial enterprise has a far greater impact than the insurers can possibly cover and the actual loss is comparable to an iceberg.


The visible bit, about 10 – 20 per cent at most, is covered by the insurer – the rest falls upon the shoulders of the community in increased dependence on social security payments, loss of jobs in supporting industries and the concomitant ripples in terms of lost income in other local retail and commercial activities.


So, a sprinkler system will contribute to business continuity, life safety, property protection and limit damage to stock and equipment. It must be stressed that it also contributes to the safety of firefighters that you, as the owner/occupier, are relying upon to come and deal with the fire.


Sprinkler systems have a long and well proven history.


In the UK and Europe the current standard is BS/EN 12845 and in the US and elsewhere these are matched by the NFPA 13 series and other National codes. All existing standards are underpinned by years of sound research into fire behaviour and system design by such organisations as the Loss Prevention Council, funded by the Association of British Insurers, Underwriters Laboratories and laboratories operated by insurers such as FM Global.


Again and again, the research shows that fires in buildings where there is a properly designed and installed sprinkler system in operation, the fire losses are small. Testament to their efficacy is the estimate from FM Global that approximately 80 per cent of fires successfully controlled by sprinklers go unreported. The sprinkler system controls a fire to a size where extinguishment can often be achieved by first-aid firefighting without the need for significant recourse to the fire service or their insurers.


Most people today understand the fact that each sprinkler head is a simple heat activated water delivery device. The heat from a fire sets off a sprinkler head, allowing water to discharge from that head only and on to the floor area it is designed to protect, ranging typically between nine and 12 m2. Any additional sprinklers, recalling the small average number of heads that typically operate in a fire, will only operate in response to a growing fire. Once fire control is achieved, no additional heads open.


In addition, the water flowing the system sets-off an alarm at the main valve and, if it is linked to the normal fire alarm system, can be reported to a remote alarm panel . As each head is located to discharge water over a particular area, obstructions to the spray pattern need to be avoided and you will notice that columns or large downstands in ceilings often have a head on both sides so as to ensure that water is evenly distributed.


Each system is designed to have a maximum number of heads in operation, in the case of most premises this is typically around16 to 18 heads (48 in high hazard premises). The sprinkler water supply is sized that the required pressure giving the necessary flow. In commercial premises, the required discharge, about five litres a second but rising steeply in high hazard systems, is achieved and maintained.


Even so, compared to firefighter hose streams discharging up to five times that amount of water per second, a sprinkler system is far more efficient and does less damage.
So, you have a sprinkler-protected building, does this mean you can safely ignore the fire precautions you would have in place if the building were not sprinklered? While sprinklers are proven as very reliable and robust protection, it most certainly should not.

Good management practice tells you that if the sprinklers are to do their job and provide the protection they are designed to give, it is vitally important that you consider them whenever any change is made to the contents or the usage of the building. It is essential that everyone with responsibility for fire safety understands how the sprinklers operate, how that operation may be impaired and the precautions to be taken when they are, for whatever reason, offline.

Common faults


The most common faults are due to a lack of understanding of what the system does and how it operates.


Typical examples include the change of a layout so that an open plan office is changed into small enclosed offices. Some areas are now over protected but more importantly, others are left with no protection at all as the new partition layout ignores the sprinkler grid on the ceiling. This is particularly vital in high rise structures or structures where there is a fire engineering solution designed to provide for the safety of the people, the business and the structure.


Such solutions incorporate sprinklers, fire detection and alarm systems and smoke control systems into an engineering package which is supplemented by the other half of the equation – the passive fire protection built into walls, floors and structural elements. Changing the use, the layout or type of storage in a warehouse can also impact adversely on the ability of a system to deal with the fire.


There is one change which may affect the sprinkler system, and it is one that is perhaps less obvious than we imagine. Modern packaging uses a large amount of plastic, particularly when packaging electrical goods. The result is that the packaging may be far more combustible and therefore hazardous than the goods wrapped in it, and the fire load may now exceed that for which the sprinkler was designed. Again, if there is any doubt, the designer should be consulted and, if necessary, the system altered or the stock levels reduced to bring the fire load within acceptable boundaries.


Next we must consider the water supply for the sprinklers. This has to be reliable and almost every rule book makes provision for either duplication of the supply or some means to ensure that the water supply cannot be lost in the event of a single supply failure. Where these systems are fed from town mains it is usual to require that the system be supplied from two separate mains, or from a static tank and a separate supply which may be pumped, or an elevated reservoir.


In order to operate effectively, sprinkler systems require that water be available at a minimum pressure specified in the design, typically five bar pressure. Any reduction in pressure or disruption to the supply needs to be flagged up immediately and measures put in place to reduce the risk of fire as far as possible until full protection is restored. In fact, in buildings where the sprinklers are provided for life safety, the building should be shut down entirely until the system can be restored.


Precisely because the sprinklers are vital for the safety of the people, the business and the building, whenever a system is taken offline, measures must be put in place immediately to mitigate against the possibility of a fire starting. A supplementary Technical Bulletin issued by the Loss Prevention Council to the BS/EN on sprinkler design suggests that, should the sprinkler system in a building be taken offline for any reason, the occupier should immediately put in place a number of measures, including increased security patrols, reduction of stock, removal of specific hazards, suspension of all hot-work, cessation of certain hot or hazardous processes. The list in TB 203 (Previously TB 6) is extensive and matches those in other codes on sprinkler design.


Drawing on the data provided by FM Global for this article, it is interesting that they identified 90 major loss fires in sprinkler protected buildings over the last decade – all of them occurring in buildings where the sprinkler systems had been impaired or shut down so that work could be carried out. Importantly, in every case, the above-mentioned additional precautions seem not to have been put in place. Also in their experience, more than 96 per cent of fires that occurred in sprinklered buildings were dealt with effectively by the systems as planned.


In the same period, the average cost of such fires was less than 20 per cent of the average value of fires in premises not protected with sprinklers. As noted earlier, due to the fact that the majority of smaller instances are never reported, this statistical benefit is likely in reality to even be considerably greater.


There can be no doubt that sprinklers do provide effective and cost efficient protection to life and property. The key for owners and occupiers is to take proper notice and care of them when considering any change to the way buildings are used. If your building has sprinklers, take time out to see what they cover and how best to take advantage of the protection they afford. The research by your insurers is conclusive – properly maintained and properly installed they can provide you and your employees with a safe and secure working environment. As an added bonus, a number of the international insurers will adjust your insurance risk rating in reviewing your risk management plan if you take the sprinklers seriously.


And the firefighters certainly won’t mind having to deal with a small fire, which, as Shakespeare said, “Is quickly trodden out – that, being suffered, rivers cannot quench.”

  • Operation Florian

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