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Last edited 22 Feb 2021
Making the case for sprinklers and dispelling myths
In a study¹ carried out by the Business Sprinkler Alliance on attitudes to sprinklers, 33% of those surveyed felt that other fire safety measures guarantee better protection from fire. The reluctance to instal automatic fire safety sprinkler systems in commercial and industrial buildings is based on misconceptions about safety and efficiency, combined with a lack of helpful, accurate information or clear guidance. The Business Sprinkler Alliance dispels and debunks the myths and looks at why we may be missing opportunities that are delivered by the wide ranging benefits of automatic sprinklers in dealing with fire.
When a wrongly disposed of lithium battery caught fire at a London recycling centre, an automatic sprinkler activated and suppressed the blaze, preventing any major damage prior to the arrival of the fire and rescue service. Despite the fire damaging 500kg of recyclable materials, there were no reported injuries, and the fire was contained due to the sprinkler systems activating. With the fire safely extinguished, the Veolia recycling centre was back up-and-running the following morning, less than seven hours later. The London Fire Brigade emphasised the effectiveness of automatic sprinkler systems during the initial stages of a fire, stopping it from spreading and causing more damage.
One of at least 200 sprinkler-saves in large industrial buildings in the last three years, the Veolia fire demonstrates the effectiveness of sprinkler systems. In nearly all cases businesses are up and running again within hours, with little loss of productivity and no loss of jobs.
Despite the fact that well over 40 million sprinkler heads are fitted annually across the globe, there remains a lack of understanding about their effectiveness or that they work in a remarkably broad set of situations. According to statistics, sprinkler systems have a performance effectiveness of 99% across all building types whilst 95% of fires are controlled or even extinguished by the operation of fewer than five sprinklers, debunking the myth that if one sprinkler goes off then all of them will.²
Sprinklers are one of those things that are taken for granted or dismissed. People either understand them and see the true benefits of them, or don’t understand them and too quickly dismiss them without really being able to justify why. From improving life safety to business protection, continuity and sustainability, the introduction of automatic sprinklers offers many positive benefits. Their inclusion can also permit freedom of design which in turn can create savings in the initial capital outlay for construction and in the lifecycle costs of the building.
We are all looking for greater flexibility in the workspaces we are designing today - whether it be extra usable space, greater sight lines or simply more glazing for natural light. Each in turn offers challenges to the buildings we design from a fire safety perspective.
Automatic sprinklers offer an interesting opportunity to meet these challenges whilst minimising the impact of fire on an enterprise. Firstly, an automatic sprinkler system enables the balancing of fire protection measures, which in turn creates a number of significant design opportunities. The automatic sprinklers will operate in a fire to minimise the size and spread of the incident. Therefore an office that has automatic sprinklers allows occupants more time to escape when fire occurs, which for the designer means they can consider longer travel distances and adjust escape doors and stairs, freeing up their space. This provides flexibility in the location of staircases and can avoid the need for escape corridors.
Another design benefit with sprinklers is in the number of firefighting shafts and fire mains which can be reduced if sprinklers are fitted. In a building without sprinklers, a firefighting shaft should be provided such that no part of a floor is more than 45 metres from a fire main outlet in a protected stairway. If a building is fitted with sprinklers, the distance can be increased to 60 metres.
Sprinklers act to limit fire growth so that designers can consider larger compartment sizes, which in turn offers additional design options. In addition to greater freedom in the building layout, sprinklers can work to contain a fire and limit it to the compartment of origin. Indeed we should view sprinklers as a form of compartmentation, using water spray in place of walls.
Building Regulations Approved Document B (ADB) offers guidance that buildings are separated sufficiently, or that a portion of the building’s external wall should be suitably fire resistant to prevent fire spreading between buildings. The area of external wall required to be fire resistant is related to the distance between the external wall and the site boundary. However, because automatic sprinklers inhibit fire size and therefore spread of fire, the non-fire-resistant area of external wall can be doubled, giving designers greater flexibility in external wall design and layout.
A building’s façade, particularly for an office, is a sensitive part of a building design both in terms of capital cost and aesthetics. It is one of the more common areas where automatic sprinklers can be used to gain advantage even though standard guidance does not necessarily recommend them.
The link between façade specification and automatic sprinklers arises as there is a need to ensure the risk of external fire spread between buildings is controlled. This is done either by( or through) a combination of increasing the fire resistance of the external wall of buildings or providing adequate separation. However, cities are becoming denser and space is progressively becoming limited and expensive. To maximise a building’s footprint designers, by fitting sprinklers, can use a glazed façade whilst building close to the site boundary. This removes (or greatly reduces) the need for expensive fire resisting glazing which would otherwise be guided by ADB or BS 9999 in order to prevent fire spread between buildings.
Thus sprinklers could enable sufficient savings on the cost of the façade to fully offset the cost of the automatic sprinkler system, through the difference between the cost of fire rated and non-fire rated glazing. The requirements vary for different distances between buildings and site boundaries, but the presence of a sprinkler system reduces the amount of fire rated glazing that needs to be purchased.
Moving away from façades, there is a misconception that sprinkler heads cannot be concealed and are visually unappealing. The use of concealed heads, however, ensures that they can be discreet when desired, offering uninterrupted, seamless interiors whilst maintaining vital protection from fire.
A BRE Global study published in 2012 considered all the factors relating to the potential for fire including insurance costs, the upfront sprinkler installation cost and maintenance cost over a 45-year lifetime of a warehouse building larger than 2000m2. The study concluded that the whole life costs will, on average, be 3.5 times lower in warehouses that have sprinkler systems installed.
These figures are driven by lower incidents of fire, and therefore less fire damage, and lower insurance premiums over the life of the building. Insurers are so confident of the value of sprinklers that they normally allow fire premium rate discounts for protected properties.
The consideration of automatic sprinklers at the earliest stages of the design will enable all stakeholders to realise and benefit from a wealth of design freedoms. The consideration of automatic sprinklers should be part of a robust design development for any new commercial building project.
Often overlooked, automatic fire sprinkler systems are a cornerstone of physical resilience and business continuity. When a fire starts in a building fitted with a fully functioning sprinkler system, it has a high probability of being contained from the outset, controlling the fire in advance of fire and rescue services’ arrival. In the vast majority of cases, the impacted business is fully functioning within hours. They save lives, reduce the threat to firefighters, reduce the burden on the fire service, save businesses, save jobs and protect the environment.
 Related articles on Designing Buildings Wiki
- Automatic fire sprinkler systems: A good practice guide.
- Building regulations.
- Business Sprinkler Alliance.
- Case study A for offices to show where automatic sprinklers have the greatest impact.
- CIAT articles.
- Costs of water automatic sprinkler systems.
- Design benefits of automatic sprinkler systems granted under approved document B.
- Fire detection and alarm system.
- Fire detector.
- Fire in buildings.
- Fire protection engineering.
- Fire safety design.
- Leading built environment bodies call for sprinklers in all schools.
- Overview of automatic sprinkler system design and operation.
- Sprinkler systems explained: A guide to sprinkler installation standards and rules.
- The cost efficiency of different combinations of fire protection measures.
- The impact of automatic sprinklers on building design.
- Watermist systems for fire protection in domestic and residential buildings DG 534.
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