22 Apr A core fire safety measure
Fire safety is achieved by a combination of complementary management, active and passive fire safety measures that together make a building safe from fire and resilient to its threat. In recent years sprinklers have become a more commonly applied measure yet they are still not routinely installed an all new buildings in the same way as is done with fire detection. They should be, writes Alan Brinson Executive Director of the European Fire Sprinkler Network… Too often it seems as though sprinklers are employed as a last resort rather than from the start as a core fire safety measure.
Sprinklers operate in response to heat and spray water over the fire below. Among the measures commonly required in fire safety building codes only sprinkler systems afford some protection to those who are unable to leave the room where the fire starts. All other measures are designed to get people out of that room then prevent fire spreading from it to the rest of the building. Of course it is far better to evacuate if you can and sprinklers help with that too by knocking down the fire so that it produces less heat and smoke, or in many cases is extinguished. At the same time sprinklers reduce the temperature of fire gases so that they contract and their pressure drops. They then spread less readily. These benefits have been proven not just by CFD modelling but also by full-scale experiments, such as those recently conducted in The Netherlands1 and Belgium2. The Dutch researchers concluded that a stay-put fire strategy, where residents of an apartment building or care home are not all immediately evacuated when there is a fire, is only workable if the building is protected with a fire suppression system. The Belgian research was focussed on care homes and proposed various combinations of measures but those with sprinklers were the simplest and therefore probably the most reliable.
Record sprinkler shipments in 2021
As knowledge about sprinklers and understanding of the fire safety benefits they offer becomes more widespread we are seeing them more often included as part of the package of fire safety measures required in new buildings. The International Fire Suppression Alliance3 collects data on the numbers of sprinklers shipped and although the absolute figures are confidential, I can disclose that the European market has more than doubled since the European Fire Sprinkler Network was set up 19 years ago and that 2021 broke all records. Today in most European countries new shopping centres, high-rise buildings and large warehouses are sprinklered, and in many countries so are new care homes and hospitals. For the Middle East 2021 was a good year but IFSA sprinkler shipments to the region did not hit the record of 2016, possibly partly because an increasing part of the market is taken by companies that are not IFSA members and whose shipments are not in the IFSA data. While we do not have the same detailed overview for how code requirements have developed in the Middle East, we do know that codes have had more sprinkler requirements for longer than in some European countries.
Despite this code progress, detailed requirements can vary considerably from one country to another. There are also some uses of buildings which only a few countries protect with sprinklers, such as schools, heritage buildings, houses and apartments. Fire has destroyed many schools across Europe but fortunately not led to deaths, so regulators have not acted even though the disruption to education and impact on the mental health of teachers and children can be significant. Fire has also destroyed famous heritage buildings, the most shocking being Notre Dame de Paris. Public reaction made clear this was unacceptable and we understand that the rebuilt wooden roof of Notre Dame will be protected with fire suppression, as will the roofs of other cathedrals, beginning with Beauvais. This marks a major change of approach in France, where fire tests with sprinklers and water mist will take place as part of a three-year research project to develop a guide for the fire protection of cultural heritage buildings.
Sprinklers were originally developed to protect property from fire. While fire safety building codes focus on life safety, often only delivering property protection as an accidental by-product, more fire safety experts are questioning whether we should accept large fires, given that with sprinklers we have the means to prevent them. Disproportionate damage, such as where a fire destroys many apartments instead of just one, is increasingly seen as unacceptable. Likewise, when a fire causes a large employer to fail or produces extensive disruption and pollution politicians demand a response. In 2019 pollution from a chemical site in Rouen, France forced local farmers to destroy their harvests. This incident has since led to a tightening of regulatory supervision in France of sites classified under the Seveso III Directive4 and in many cases to upgrades of sprinkler systems.
To reduce the carbon footprint of a building increasing use is being made of wood, which is regarded as a sustainable material that captures atmospheric carbon. Yet wood also burns and if it is used in modular construction there will be combustible voids between the modules. These voids are a route for fire to spread throughout the structure. While in theory voids can be sealed to stop fire spread, this is difficult if not impractical to check. Too often fires have proven that fire-stopping was inadequate and what should have been a limited fire has destroyed an entire building. In the UK there have been many high-profile examples:
- Wharfside block, 50 apartments, Wigan, June 2015
- Weybridge Community Hospital, July 2017
- Holiday Inn Hotel, Willenhall, August 2019
- Beechmere Care Home, 150 accommodation units, Crewe, August 2019
- The Cube, 221 student accommodation units, Bolton, November 20195
None of these buildings were protected with sprinklers. Nobody was killed in these fires but all the residents lost their homes and possessions. While sprinklers cannot stop the spread of fire in combustible voids they can suppress a room fire so that it does not enter the void, complementing the fire-stopping. Building resilience comes from employing complementary measures that have separate failure modes. It is worth noting that countries that already use wood widely, such as Canada, Finland, Norway, Sweden and the USA, usually protect wooden buildings with sprinklers. Although these buildings would often be protected with sprinklers whether they were built with wood or not, in Finland there are code requirements to fit sprinklers in 3-8 storey buildings if they are constructed of wood and in Ireland houses of timber-frame construction must have sprinklers if they are three storeys or higher. In the UK, Scotland and Wales require sprinklers in all new apartment buildings and therefore protect wooden apartment buildings as well.
November 2020 England requires sprinklers if there is a residential floor higher than 11 m. While this is an improvement post-Grenfell it still means a new English four-storey wooden apartment building would not necessarily be protected with sprinklers. Debates are ongoing in several European countries as the wood industry successfully campaigns for its product to be more widely used in construction. In France a guide was drafted on behalf of the wood industry but never published. Meanwhile the local government in Paris has published its own guide6 which requires fire suppression or passive fire protection in wooden residential buildings higher than 8 m, and fire suppression in all wooden residential buildings higher than 28 m. Structural wood has been proposed in the Middle East and while it is relatively rare today that can change, as it has in Europe.
Car park fires rarely lead to fatalities but they can lead to large fires and major damage to what is usually a concrete structure. Recent examples include:
- King’s Dock, Liverpool, UK, December 2017 – over 1,000 vehicles destroyed on New Year’s Eve and parts of the structure collapsed. The car park has been rebuilt with sprinklers.
- Douglas Village Shopping Centre, Cork, Ireland, September 2019 – 60 vehicles and car park destroyed with damage of €30 million.
- Stavanger Airport, Norway, January 2020 – 300 cars destroyed and part of the car park collapsed. The car park is being rebuilt with sprinklers.
- ul. Górczewska 181, Warsaw, October 2020 – car park was beneath an apartment building which was then declared unsafe, with 150 residents losing their homes.
The first three of the above incidents were in open-sided car parks, where there has traditionally been thought to be little risk to car park users or firefighters. These incidents show that it may be very unwise for firefighters to enter a car park once a major fire has developed, as there is a risk of concrete spalling and structural collapse. Several European countries already require sprinklers in underground car parks, with Belgium7 and The Netherlands8 in the process of joining them. These requirements are there to protect firefighters, car park users and those who may be sleeping in buildings above the car parks. They also protect important infrastructure, without which fewer people visit city centres and cities lose car parking revenue. Fortunately, car parks are usually protected in the Middle East.
Codification of design freedoms
Stay-put fire strategies for residential buildings, protection of cultural heritage, prevention of disproportionate damage, prevention of pollution, protection of wooden structures and of non-combustible car parks are leading to new requirements in fire safety regulations and guidance for sprinklers to be installed in buildings. In addition, the use of sprinklers to compensate for other fire safety measures is being formally recognised in regulations and guidance, allowing fire resistance to be reduced in some cases, travel distances to escape stairs or the outside to be extended, fire compartments to be larger, restrictions on internal layouts to be relaxed and buildings to be erected where fire brigade access is restricted or hydrants are further away. By deciding to fit sprinklers as a core fire safety measure, architects and fire engineers can use these flexibilities to create buildings that are safer, more attractive and cost less to build.
2021 was a record year for the European sprinkler market and a good year for the Middle East but there is still considerable scope for growth. In particular, I have not discussed what effect sprinklers could have in the home, where most fire fatalities occur.