Industrial Fire sprinklers
Fire Sprinklers were invented in the United Kingdom by Major Harrison in 1864. But like so many good things invented in the UK it was left to be developed abroad by Henry Parmelee in the USA, who wanted to protect his piano factory.
Automatic sprinkler systems are used more than any other fixed fire protection system and over 40 million sprinklers are fitted world-wide each year. Sprinkler systems have been proven in use for well over 100 years. Possibly the oldest in Britain was fitted in 1812 at the Theatre Royal Drury Lane and updated form is still in use today.
How Sprinklers Work
A fire sprinkler system are a network of fixed water pipes supplied by two water sources with sprinkler heads fitted at recommended distances apart. Water can be supplied from a tank via pumps or from the town mains, providing the flow is sufficient and fills the pipes.
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 sprinkler head.
The hot gases from a fire will raise the temperature at ceiling level and when the area adjacent to the head reaches a specific temperature that sprinkler head will actuate and spray water on to a fire. Only the sprinklers over the fire will open and the others will remain closed. This limits any damage to areas where there is no fire and reduces the amount of water needed.
Sprinkler heads can be placed in enclosed roof spaces and into floor ducts to protect areas where a fire can start without being noticed. In a large warehouse sprinklers may be placed in the storage racks as well as the roof.
At the point where the water enters the sprinkler system there is a valve. This can be used to shut off the system for maintenance. For safety reasons it is kept locked open and only authorised persons should be able to close it.
A pelton wheel rotates when water starts flowing in the system which in turn operates a warning bell. This way the sprinkler system both controls the fire and gives an alarm using water, not electricity. 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. More details of this can be found under Residential Sprinklers on this web site.
The case for Fire Sprinklers
Losses from fires in buildings protected with sprinklers are estimated to be 1/10 of those in unprotected buildings. In buildings fully protected by sprinklers:
- 99% of fires were controlled by sprinklers alone
- 60% of fires were controlled by the spray from no more than 4 sprinklers
Source: European statistics over 10 year period
Sprinklers are the most efficient and effective fire safety device, 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 recognised by the insurance industry, who 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. 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 reduce 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.
- 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 minimise 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.
- 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 to 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.
Finally a few facts
- No one in the UK has ever died as a result of a fire in a building with a working sprinkler system
- Only the sprinkler heads in the immediate vicinity of the fire actually operate.
- Sprinkler heads can be completely concealed.
- Sprinkler systems do not need pumps or tanks if mains pressure is adequate.
- Sprinklers do not ‘false alarm’ they will only operate if there is an actual fire.
- For a small additional cost an alarm switch can be built-in to the system to call the fire brigade automatically should the sprinklers operate.
- Maintenance costs for sprinklers are very low.
- Sprinklers save lives – and property – and are the only devices which can detect a fire, sound the alarm, call the fire brigade and extinguish or control the fire.
Approved documents accompanying the Building Regulations in England and Wales make specific reference to the use of sprinklers (Regulations for Scotland and Northern Ireland differ slightly).
When sprinklers are installed there may be significant benefits in respect of compliance with Approved Document B of the Building Regulations 1991 (as amended). For example: the installation of sprinklers can allow buildings to be built closer together, half the spacing is required, to adjoining premises. This is a major benefit where site space is limited.
Other requirements in Approved Document B regarding travel distances for escape may also be able to be extended and certain requirements in respect of access for the fire service may be waived. System Design and Installation
While there is nothing mysterious about sprinkler systems the high reliability and effectiveness of these systems has come about over the years by strict adherence to the sprinkler rules and design standards. It would be wise to select a contractor who is not only capable and competent but who also has an established track record and who can offer proof of compliance with an established quality assurance system.
For example, they should be able to provide documentary proof of compliance with international quality assurance standards and also hold an approval (Registration or Certification) from a third party certification service which itself is accredited by a Government-approved body, the United Kingdom Accreditation Service (UKAS).
Standards for Installation
For a Fire Sprinkler system to operate properly and successfully deal with a fire, it must be correctly designed, installed and then maintained. It is therefore essential that the system is designed using a specification that has been tried and tested and proved to provide the level of protection desired and the components used have themselves also be tested and approved for use in those systems.
Sprinklers can be installed using any one of a number of accepted standards. The longest established design and installation standard was BS 5306 Part 2: 1990 (Fire extinguishing installations and equipment on premises : Specification for sprinkler systems). This standard has been superseded by BS EN 12845:2004+A2:2009 – Fixed firefighting systems. Automatic sprinkler systems. Design, installation and maintenance.
The BRE Certification LPS1048.
To make sure your system will work it must be properly designed and fitted. There is an independently accredited organisation which undertakes the certification of sprinkler installers.
The Loss Prevention Certification Board (LPCB) publishes standards for sprinkler systems based on British Standards. This company provides third party verification of the sprinkler installer’s work. It requires their listed companies to issue certificates of conformity to the owners of sprinklered buildings. These certificates are proof to Fire Brigades, Local Authorities and Insurance Companies that the system meets the appropriate standards and has been installed correctly.
The LPCB operates their LPS1048 scheme through BRE Certification. Certification falls into a number of categories dependent on the type of work undertaken and qualifications of staff. The latest version of the LPS1048 scheme (revision 4) is currently replacing version 3.
Further details are available from BRE Certification at BRE Certification Limited, Bucknalls Lane, Garston, Watford WD25 9XX Telephone: 01923 664100 Fax: 01923 664603
The Loss Prevention Certification Board came into being in the late 1980′s following a reorganisation of the insurance trade bodies. The FOC technical documents became Loss Prevention Council (LPC) rules and standards, and the approval schemes became Loss Prevention Standards (LPS). The Loss Prevention Certification Board joined BRE Certification on 31 March 2000. The intention is to provide independent assurance that a sprinkler system has been properly designed and installed in accordance with the relevant British Standard.
The British Automatic Fire Sprinkler Association website totally devoted to Fire Sprinklers.
Fire Sprinkler Association website totally devoted to Fire Sprinklers.
Q: Is there any limitation on the distance between a buried sprinkler tank and associated above ground sprinkler pump room?
A: LPCB Technical bulletin TB 210, section 6.2.3 states that the maximum length for suction pipework (tank to pump) must not exceed 30m including allowance for bends and fittings