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WHY SPRINKLERS?

Automatic fire sprinkler systems are the most widely used fire protection system in the world.  Sprinklers are designed to put as little water as possible on the seat of a fire at a very early stage of development in order to control and contain it – and often extinguish it before the fire and rescue service arrive. 

How sprinklers work

An automatic fire sprinkler system consists of a water supply system (pumps and tank or mains water), a network of pipes (steel, plastic and other alloys) and fire sprinkler heads spaced at regular intervals throughout the protected premises. 

Sprinklers have either a small glass bulb or a solder fusible link. The bulb or link works like a plug that retains the water in the pipes. The bulb and link are coloured to denote the operating temperature. 

When enough heat from a fire get to the sprinkler head it either expands the liquid in the glass bulb or melts the solder of the fusible link and the bulb or link falls away allowing water to discharge on the fire. 

When water is discharged, it strikes a serrated deflector plate that usually distributes the water in a circular pattern, other patterns of distribution are also available.

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Types of systems

Wet sprinkler system

These systems are installed in premises where there is no possibility of pipes freezing. The system pipework is charged with water under pressure at all times. When a sprinkler head is activated by the heat from a fire, water flows immediately on to the seat of the fire.

Dry sprinkler system

Dry pipe systems are installed in premises where there is a possibility of water in pipes freezing. Dry systems are charged with compressed air or another inert gas ie nitrogen. When a fire sprinkler head is activated by the heat from a fire, the air pressure drops and the valve opens allowing water to fill the pipes and discharge from the sprinklers on to the seat of the fire.

Pre-action sprinkler system

Pre-action systems are commonly installed in areas where the accidental discharge of water may be problematic ie when a sprinkler head is accidently damaged. They are installed in areas such as data processing facilities, document storage or cold storage warehouses. The system can only be activated by a combination of events ie operation of a smoke/heat detection system AND the operation of a sprinkler in a fire condition. 

The pipes are normally filled with compressed air and water is only allowed to fill the pipes when the smoke/heat detection system is activated. This ensures that accidental discharge will not occur. There are several modes of operation and these can be setup in the sophisticated system control panel to suit the client’s exact requirements.

Water mist systems

A water mist fire suppression is not the same as sprinkler-based fire suppression system, although both use water to help contain and control fires. Like sprinkler systems, with mist systems, a water distribution system is connected to a water supply that discharges water mist where required. The system is fitted with one or more nozzles intended to extinguish, suppress or control the fire. 

Water mist is a performance-based technology, in that it requires specific testing to each possible fire scenario. A set of standardised fire test protocols have been developed for water-mist based fire suppression systems. BAFSA has produced a technical guide for water mist which has further details on water mist and suitable applications and details the differences between mist and sprinkler systems 

 

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Do sprinklers all go off at the same time?

No. Only the sprinkler head closest to the seat of the fire is triggered to discharge water.

Isn't water damage as bad as fire damage?

Sprinklers attack the fire quickly and directly so less water is needed. As they also operate the fire alarm, the flow can be quickly turned off when the fire is out. To give you a comparison - a typical sprinkler discharges 55 litres per minute. A firefighting hose discharges over 600 litres per minute.

Does a smoke detector provides enough protection against fire?

Smoke detectors save lives by providing a warning system but can do nothing to extinguish a growing fire or protect those physically unable to escape on their own.

Don't sprinklers spoil the aesthetics of a building?

Modern sprinklers systems are designed in such a way that they are barely visible and can be incorporated easily into the design scheme of a building. In fact some smaller sprinkler are no bigger than a 50 pence piece. They can also be fitted with ceiling rosettes or painted to match any colour scheme. Sprinklers can also be concealed and fitted flush with the ceiling. 

80%

Sprinklers reduce injuries by at least 80%, reduce property damage by 90% and substantially reduce damage to the environment from fire.

60%

About 60% of fires in commercial premises are controlled when only four sprinklers are operating

10%

Losses from fires in buildings equipped with sprinklers are 1/10th of those in unprotected buildings

68.c

Smoke will not activate a sprinkler head. There must be a fire that generates enough heat to raise the temperature near the sprinkler to above 68⁰C.

Sprinklers in action

A kitchen fire in a primary school in mid-Wales was contained and controlled by the activation of one concealed sprinkler head. The fire was caused by the lit gas-powered cooker hob coming into contact with a plastic container.

The fire was completely extinguished by operational crews on arrival with fire-fighting media. Due to the effective management of fire safety arrangements, the kitchen doors limited smoke percolation to the immediate kitchen area only.

Fire damage was contained to the cooker hob and flooring located directly below the fire. Upon activation of the premises fire alarm, over 200 students and staff were immediately evacuated with no injuries reported.

On this occasion, the impact of this school fire was minimal due to the installation of the sprinkler system which is mandatory for all new build schools in Wales. This is not the case for England.

Compare this to a similar school fire in Yatton, Bristol on the 29 May 2023, where sprinklers were not fitted. The school lost six classrooms and over 100 pupils were displaced to surrounding schools. 

Sprinklers operate on 99% of occasions. Sprinklers save schools and protect our children's education and their lives from fire damage. 

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Sprinkler Standards

One of the most significant differences between automatic fire suppression systems and other building components is the need for strict adherence to published standards, not only in respect of the manufacture of components but also for the design and installation of the systems themselves.

There are currently two main British standards for the design and installation of automatic sprinkler system installed in the UK - BS EN 12845-1 for residential sprinkler systems and BS 9251 for commercial sprinkler systems.

However, there are an additional set of requirements in the UK which may be imposed on the design and installation of such systems by insurers.

All standards below shall be considered at the latest dated version as found on the relevant organisation's website listings.

BS 9251 - Residential

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BS 12845-1 - Commercial

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equipment standards

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standard organisations

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Other standards

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Third party certification

All BAFSA sprinkler installer members are either third party ‘certificated', 'listed' or 'approved'  contractors for the design and installation of sprinkler systems.

The concept of a third party certification scheme is to provide confidence to regulators, specifiers, industry and the public that the manufacturer, contractor has been subject to assessment of their competence against recognised industry or product standards and has satisfied these requirements. 

Third party certification in the UK is a voluntary process and companies that are part of a third party certification scheme are subject to regular audits.

UKAS accreditation

UKAS, the United Kingdom Accreditation Service, is a government body and it is the opinion of all fire safety trade groups, insurers and the UK fire service that only companies, installers or products with certification or approval through UKAS accredited laboratories and testing facilities should be considered third party certificated or approved

Experienced sprinkler contractors

It is of the utmost importance that any selected contractor employed to undertake the work is fully conversant with the design practises of the correct relevant standard and can demonstrate competency within that particular scope of work. You can search for an experienced installer in our member directory.

Certificate of Conformity

On successful completion of a contract, a contractor who is a member of a third party certification scheme is able to issue a Certificate of Conformity verifying compliance with the defined installation standards.

Currently, there are three accredited bodies that operate such certification schemes for sprinkler installations.

The Loss Prevention Certification Board operates the LPS 1048 scheme for commercial automatic sprinkler installations and the LPS 1301 scheme specifically for residential & domestic sprinkler installations.

Warrington Certification Ltd operates separate FIRAS schemes for commercial & industrial sprinkler installations and residential & domestic sprinkler installations. However the FIRAS schemes will end in August 2025. Therefore those companies that have certification under the FIRAS schemes will after that date need to provide alternative third-party certification. 

IFC Certification Ltd (IFCC) operate separate schemes for installers of Commercial & Industrial sprinkler installations (SDI 23) and for installers of Residential & Domestic sprinkler installations (SDI 22).

All are members of UKAS.

 

Maintaining a sprinkler system

To ensure that a sprinkler system operates as designed it must be maintained in accordance with the requirements of the system design rules used. 

In terms of maintenance, BS 9251 provides guidance on regular inspection (at least annually), testing, and maintenance procedures to ensure the ongoing reliability and performance of the sprinkler system. This includes tasks such as checking for leaks, inspecting sprinkler heads, testing alarm systems, and conducting periodic flow tests to verify water flow and pressure. All systems, commissioning and maintenance activity must be documented.

The most important thing is to employ a third party accredited sprinkler installer to carry out any maintenance. You can find one of these in our members directory.

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Maintenance

Current sprinkler legislation


Automatic fire sprinkler legislation is not uniform across the UK - although this is something BAFSA has been calling for for many years. 

Here we detail the legal requirements according to building type where automatic fire sprinklers are mandated in law for England, Wales, Scotland and Northern Ireland.

London
England

Blocks of flats with a top storey more than 11m above ground level, un-compartmented warehouses larger than 20,000m2 and care homes to be sprinkler protected throughout. 

Wales
Scotland
NORTHERN IRELAND