Fire sprinklers

Introduction

Major Harrison invented fire Sprinklers in the United Kingdom in 1864. But like so many good things invented in the U.K. it needed to be developed abroad by Henry Parmelee in the USA, who wanted to protect his piano factory.

The components of a fire sprinkler system are;

• A network of fixed water pipes supplied by two water sources with sprinkler heads fitted at recommended distances apart.

• Detector heads are nozzles that direct a jet of water on to a deflector plate, which defuses over a large area. The water is held back by a glass bulb or soldered strut, which holds a plug in place. When heat is applied from a fire below, the glass bulb will burst, due to expansion of the liquid in the bulb, or the solder will melt, which then releases the plug and water flows through the detector head.

• A pelton wheel, which rotates when water starts flowing in the system and in turn it, operates a warning bell.

• Main water shut off valve, which allows the system to be closed down when the fire has been extinguished.

Fire sprinklers have been continuously developed throughout their history and the modern residential fire sprinkler is the latest piece of sprinkler equipment. Its development started as a result of a report prepared in the United States by the Presidential Commission on Fire Prevention & Control, entitled "America Burning". This report, published in 1973, highlighted the scale of the fire problem in the United Stated and in particular drew attention to the fact that over 75% of all fire deaths and injuries occurred in the home, a statistic that is equally true in the UK. They recommended the development of a residential fire sprinkler system and this prompted the NFPA, the American equivalent to the British Standards Institute, to set about developing a modification of its fire sprinkler standard, NFPA 13, to produce a reliable but inexpensive residential system. More details of this can be found under Residential Sprinklers on this web site.

Fire Sprinklers are an excellent solution for fire safety and fire protection in buildings. They are constantly on guard and will attack a fire automatically even if the occupants are infirm, asleep or not even there.

Legislation

Fire sprinklers are not required by any national fire safety legislation but are required by certain local acts. The Merseyside Act for instance requires sprinklers in any storage warehouse in excess of 7000 cubic meters. Indubitable they are an efficient and effective fire control measure but are expensive so the fire safety industry has to persuade owners the advantages of installing them. They provide a very convincing argument but cost is a deterrent.

The case for Fire Sprinklers

Sprinklers are the most efficient and effective fire safety devices, worldwide, they have over a 99% success rate. The record of fire sprinklers is unsurpassed in the fire safety field. For instance in New Zealand, where all fires have had to be reported for over 100 years, records show that sprinklers have been effective in 99.7% of cases.

The advantages of sprinklers are recognized by the insurance industry, which insists on the installation of sprinkler systems in areas of high risk. There has been a long association between insurers and the sprinkler industry, which resulted in fire sprinklers being developed primarily to protect property. It was for this reason that their life saving properties were largely ignored until comparatively recently.

The Fire Service supports the installation of sprinklers in many circumstances, including domestic and residential property. When conducting a fire risk assessment you could consider the provision of a sprinkler system to achieved the desired fire safety standard and make the property much safer. Insurance companies are beginning to look much more closely at industrial fire risks, and insurance premiums are rising. In some cases, clients could find it impossible to obtain insurance cover. Fire sprinklers, along with good fire safety management can help.

Not only do property and life sprinkler systems provide a very high level of protection there are a number of areas in which their cost of installation can be mitigated: -

• A reduction can be achieved of other passive fire safety measures. The requirements for fire retardant materials, the number of escape routes may be reduced with increased travel distances.

• Allowing buildings to be used for purposes other than which they were designed for.

• Allowing buildings to be built or converted to other uses which planning restrictions would otherwise prevent.

• Under building regulations you can double the size of a fire compartment if you sprinkler it.

• The provision for access by fire engines is lessened allowing higher housing densities to be employed.

• Arson accounts for many fires and has increased steadily over the past decade or more. Although fire sprinklers cannot prevent arson as such they will minimize the damage caused.

• Although there is no general policy insurance companies may give discounts for sprinkled properties.

There are other less obvious benefits for fire sprinklers, which are usually only appreciated after a fire,

• Consequential loss and inconvenience in buildings that are in involved in a fire, they are usually uninhabitable afterwards and maybe demolished. On the other hand a room protected by a fire sprinkler can usually be back in use within a few hours and the rest of the building is often unaffected.

• Bankruptcy after a major fire, the statistics show that over 90% of businesses that experience a major fire cease to trade and may go into receivership.

• Loss of income and cost of re-housing can be a direct result of a large fire. Landlords and mortgage companies may experience a reduction in income and the cost of re-housing. Where property is demolished and rebuilt the landlord will be without income for many months at a time of major expenditure.

• Demand on the Fire Service. Where fire sprinklers are fitted Fire Brigades need employ fewer resources in fighting the fire and know that their men will be less likely to suffer injury.

• By reducing injuries to persons involved in the fire the cost to the National Health and Social Services will be considerably reduced. Fire injuries are probably the most difficult to treat and result in the longest time off work, if indeed a return is possible. Although external burns are the most obvious injuries, it is lung damage from hot smoke and fumes which is often the most incapacitating injury and which may well prevent a return to work ever being possible.

The case against Fire Sprinklers

They are very expensive to install, but embarking on a cost analysis exercise it may be worth the extra cost for the benefits gained. Installing in an existing building could cause problems and it is more than likely to be more expensive.

The Myths:

They cause excessive water damage. Sprinklers use only a fraction of water compared with a fire hose. Sprinklers operate very early in the development of a fire, and consequently only require a relatively small quantity of water to extinguish it. In over half of activating, fires are controlled by 4 sprinkler heads or less, and in many instances only 1 head operates.

The pipes burst through frost. Sprinklers can be provided with various forms of frost protection, like installing a dry systems or providing heating elements to protect the sprinkler systems.

They might accidentally go off. Sprinklers are very reliable; the chances of a sprinkler going off without mechanical assistance are 1 in 16 million. Forklift truck drivers soon learn to avoid them!

When they go off, all heads will operate and everything will get wet. This one is largely thanks to Bruce Willis films. When he gets into a tight corner, he shoots a sprinkler head and they all go off, allowing him to make his escape. In actual fact, each head is activated by heat, so only the heads involved in the area of the fire are activated.