Burning issue

The Grenfell Tower fire in June 2017, in which 72 people lost their lives, sent shockwaves through the construction industry. The tragedy highlighted the devastation that fires can cause and the significant resources required to quell them when fire suppression systems aren’t in place.

The 24-storey residential tower block in West London did not have a sprinkler system installed at the time of the fire because it was built before such systems were required by law for buildings of that height. While the building had been refurbished, there was no requirement to install sprinklers during the renovation.

“Fires escalate when buildings are not protected by automatic sprinkler systems,” says Tom Roche, secretary of the Business Sprinkler Alliance (BSA), an organisation that aims to enhance protection against fire through the increased acceptance and use of fire sprinklers in business premises.

“The outcomes of sprinkler-protected fires are notably different. Automatic sprinkler systems activate early, containing or extinguishing a fire before it can spread. They are an essential component of a fire protection strategy, reducing the burden on fire crews, minimising property damage and helping businesses recover faster.”

Current legislation

Changes have been made to regulatory guidance in England since Grenfell and sprinklers are now required in residential properties and care homes with a final floor over 11m. This aligns England with Scotland and Wales, which have similar or lower limits. Wales, for example, requires sprinklers in all new-build domestic dwellings.

Sprinklers are also required in retail spaces, such as large supermarkets and DIY stores, with a floor area greater than 2,000m². There is also guidance for sprinklers being required in tall buildings, with a final floor height above 30m.

“Surprisingly, there is no requirement for sprinklers in buildings such as hotels, or sheltered and specialised housing – all of which look very similar to buildings that do have guidance,” points out Iain Cox, chief executive of the BSA. “Similarly, guidance for sprinklers in schools is largely ignored and few hospitals have them installed.”

Industrial buildings also fall outside current sprinkler guidance, unless they exceed 18m in height or 20,000m² in floor area.

“Given the words of the English government to ‘protect the most vulnerable’, we expect to see movement on sprinklers in sheltered/social housing in the coming year,” says Cox. “However, the BSA campaigns for greater focus on schools, hotels, and large industrial and warehouse buildings.

“We feel it makes economic, social and environmental sense to protect such properties. For instance, schools are a key element of our social fabric and need protecting for long-term stability and to lessen the impact from fires on the education of our children. Schools in Scotland and Wales must have sprinklers for this reason.

“Large industrial complexes should not be disposable in the face of fire, yet today they are. In a world where resources are being constrained, we need to think more broadly about the value of automatic sprinkler systems,” Cox adds.

The British Automatic Fire Sprinkler Association (BAFSA) has been calling for uniform fire sprinkler legislation across the UK for many years, believing that sprinklers should be mandated in all buildings – both new and existing. It has campaigned, in particular, for sprinklers to be mandatory in schools.

Minimising impact

Fires escalate rapidly, and one of the most prominent lessons from Grenfell and similar fires is that early suppression is critical, enabling people to evacuate and the emergency services to mount an effective response.

“Automatic fire sprinkler systems stand out as one of the most effective tools we have to prevent loss of life and limit damage,” says Ali Perry, CEO of BAFSA. “Fires in enclosed spaces can grow from a small ignition source to a full-scale blaze in a matter of minutes. Flashover – the point at which nearly all combustible materials in a room ignite simultaneously – can occur in as little as three to five minutes. Once this point is reached, the room temperature may exceed 600°C, making it impossible for occupants to survive or for firefighters to enter safely.

“Even before flashover, smoke and toxic gases pose a deadly threat. The majority of fire-related deaths are not caused by burns but by smoke inhalation. Thick, toxic smoke can render people unconscious in minutes, and particularly affects vulnerable groups such as the elderly, disabled or very young. In high-rise buildings or residential blocks, fire and smoke can quickly spread beyond the flat of origin, threatening multiple households in a very short space of time.”

Suppressing a fire at an early stage dramatically increases the likelihood of safe evacuation and prevents a small fire from becoming a large-scale disaster. Automatic sprinkler systems are designed to activate individually when they detect heat, typically at around 68°C. Water is discharged directly onto the flames, often within seconds of ignition, cooling the area and soaking flammable materials to prevent the fire spreading.

Suppressing a fire at this early stage can limit the spread of smoke and maintain survivable conditions for long enough for the occupants to safely evacuate. In most cases, the fire is either extinguished or brought under control before emergency services arrive. In fact, according to fire service data, in 90-95% of incidents in which sprinklers operate, they control or completely extinguish the fire.

“Automatic sprinklers do more than save lives, they significantly reduce the strain on fire and rescue services,” adds Perry. “A fire that is contained by sprinklers requires fewer personnel and less equipment to manage, freeing up vital resources for other emergencies.

“The fire service is often under immense pressure, especially in urban areas where multiple incidents may occur simultaneously. Sprinklers allow smaller fires to be resolved quickly and safely, reducing overall risk to both firefighters and the public.

“In addition, fires controlled early cause less property damage and are less disruptive to the community. Sprinklers use far less water than traditional firefighting methods, minimising the collateral damage caused by hoses or fire suppression foams. Insurance costs, repair bills and community displacement are all significantly reduced.”

Simple systems

Automatic sprinkler systems vary, with the pressurised water supply coming from pumps and tanks, or mains water, via a network of pipes (steel, plastic and other alloys), with sprinkler heads spaced at regular intervals throughout the premises.

“There are parts of the UK where a connection to the mains would supply enough flow and pressure to sustain sprinklers,” says Cox. “However, this would also be subject to the local water company. Pumps and tanks are matched to the hazard. In a residential setting with smaller rooms, and designs for one or two sprinkler heads operating, these systems are relatively modest. In a larger warehouse with high rack storage, the pumps and water supply would be considerably larger. The point being that it is not one size fits all.”

The sprinkler heads have either a small glass bulb or a solder fusible link, which works like a plug that retains the water in the pipes. The bulb and link are coloured to denote the operating temperature and when the heat reaches the sprinkler head it either expands the liquid in the glass bulb or melts the solder of the fusible link, causing the bulb or link to fall away and the water to discharge. When the water is discharged, it strikes a serrated deflector plate that usually distributes it in a circular pattern. Other patterns of distribution are also available.

“Sprinklers aren’t activated by burnt toast or someone smoking beneath them,” adds Cox. “The thermal element for most settings is around 68°C, so the layer of gas around the element needs to rise to this temperature to operate. We generally only see these temperatures during a fire.”

Water efficient

Thanks to TV and movies, there is a common misconception that water is released from all the sprinklers at the same time. However, this is not the case. Each sprinkler head is triggered thermally, with 85% of incidents controlled by two heads or fewer.

“Water escape claims in the UK amount to around £1 billion annually, according to the Association of British Insurers, but the vast majority of these involve non-sprinkler systems,” explains Cox. “This is typically domestic plumbing, HVAC and central heating systems. Sprinklers account for only a small fraction of claims.

“Sprinklers, like other water-based systems, can be vulnerable to poor installation and deterioration, therefore qualified installers using the right components are needed in the first place. They need ongoing maintenance, coordinated plans for weather and a response when they operate.”

Accidental activations are rare. According to the BSA and various insurance bodies, the rate of accidental discharge is less than one in 16 million sprinkler heads per year.

“Modern sprinkler systems use durable components (e.g. CPVC piping, corrosion-resistant metals) and are pressure-tested to minimise leaks,” says Perry. “Also, dry pipe or pre-action systems can be used in colder areas or data-sensitive environments. These only fill with water when a fire is detected.”

BAFSA stresses the importance of regular maintenance and inspections as outlined under current legislation (BS 9251 or BS EN 12845) to reduce the chance of system failure or leakage.

“Sprinklers are effective at controlling fires, limiting damage and, importantly, reducing casualties,” concludes Cox. “We know many people think sprinklers are only for property protection, however they also save lives.”

Damage reduction

• Studies from the National Fire Chiefs Council show that in 85% of cases fire damage is reduced by between 50-80% if sprinklers with two heads or fewer are operating.
• Insurance figures place the differential for claims values being seven times greater for those without sprinklers.
• The government impact analysis supporting the use of sprinklers for purpose-built flats placed the reduction in fatalities due to sprinklers at 90% and the reduction in casualties at 60%.

British Standards

There are currently two main British Standards for the design and installation of automatic sprinkler systems in the UK.

• BS 9251 is the standard for domestic and residential buildings, including houses, flats and maisonettes, houses of multiple occupancies, blocks of flats, bed and breakfast accommodation, boarding houses, residential care premises, dormitories and hostels. The standard was most recently amended in 2024.
• BS 12845-1 is the standard for commercial and industrial settings. Under current building regulations, commercial buildings of over 20,000m² in England are required to have a sprinkler system fitted.

Legal round-up

• England: High-rise residential buildings (over four storeys or above 11m in height) must include automatic fire sprinkler systems throughout residences – although not necessarily in corridors or stairways. All newly-built care homes in England (irrespective of height) must include sprinkler systems.
• Scotland: Requirements extended to large multiple-occupancy dwellings and care homes.
• Wales: Sprinklers have been mandatory in all new homes since 2011.