Since I set up the European Fire Sprinkler Network in 2003 sprinklers have become much more widely recognised in building codes, with buildings of certain types and uses now routinely being protected with sprinklers. I estimate that more than twice as many sprinklers are now sold each year. I also believe the market can grow a lot further, perhaps doubling again. There is no guarantee that this will happen, and there are powerful vested interests who see sprinklers either as a competitor or as an extra cost that will reduce their profits. We are familiar with that, but could there also be a disruptive technology out there that could replace sprinklers?

Disruptive technologies and concepts seem to be changing every industry, so perhaps we should consider what might disrupt the sprinkler industry. Thirty years ago water mist emerged as a more efficient way of using water, challenging sprinkler designs. In marine applications, where weight is a crucial factor, water mist took the market. Yet on land it did not, largely because water mist is usually more expensive than sprinklers and weight is less critical. There are even some applications, such as high bay warehouse protection, where water mist struggles to offer a solution. Against that there are others, such as heritage protection, where the consequences of any accidental water discharge often lead to a preference for water mist because it would release less water. Thirty years later, water mist has become part of the continuum of water-based fire protection systems, with many sprinkler installers and manufacturers also offering a water mist option.

In more recent years the rapid evolution of new risks has challenged sprinklers. This is particularly true for warehouses, which are becoming taller and more compact with less space for sprinklers. While a sprinkler system may control a warehouse fire, in most cases the fire brigade will still need to complete extinguishment. There are warehouses being proposed that are over 100 m tall, without any thought to how firefighters would reach an internal fire at that height to complete extinguishment. Insurers can refuse to cover such risks but clearly if some other technology could adequately protect this scenario sprinklers would lose the market. Some are advocating oxygen reduction for warehouse protection, yet to maintain the correct oxygen concentration the warehouse operator has to limit movements in and out of the building, restricting capacity. Moreover, these systems can be expensive to operate and at greater height static pressure differentials may make it difficult to ensure a uniform concentration. There are also disagreements between laboratories over the appropriate design concentration. Yet oxygen reduction systems are being used, particularly in refrigerated warehouses. Meanwhile in automated warehouses sprinklers are being installed alongside facilities for firefighters to attack the fire from above, while the storage system can be quickly dismantled so that firefighters on the ground can access any remaining burning material. In a building protected by an oxygen reduction system firefighters would still need to enter the building to find and deal with the source of a fire.

Sprinklers have protected car parks for decades but the advent of electric vehicles has raised questions about their effectiveness. We know that sprinklers will probably not extinguish a battery fire inside an electric vehicle, in fact some fire brigades have found the only solution is to drop the car in a pool of water! Yet extinguishment need not be the goal. As long as a sprinkler system can prevent spread from one vehicle to another, the heat release rate will remain moderate and firefighters will be able to approach the vehicle to complete their work in relative safety. Some research has been conducted and more is in progress to understand what performance sprinklers bring. No credible competing technology has emerged.

Could other technologies be faster or do a better job? Systems that are operated by electronic detection could apply water a minute or two before the first sprinkler would normally open, further reducing the risk of injury and death, and the amount of damage. But injuries, deaths and damage are already reduced by over 80% by sprinklers, so this is about diminishing returns. Systems that offer this performance are more complex, comprising separate detection and extinguishing systems, making them more expensive and inherently less reliable. Yet there are some applications where glass bulbs or solder fuses are too slow – the fire spreads so quickly that an even faster response is needed from the suppression system. Deluge systems operated by electronic detection have been used for decades to protect buildings from rapidly spreading fires. While such systems are effective there is a delay to fill the pipes with water. One application where electronic detection has been tested in combination with a wet pipe sprinkler system is the protection of rolled paper. This is not a challenger technology to sprinklers so much as an enhancement of sprinkler technology, only commercially viable where nothing else works.

During the last review of British regulatory guidance, almost 20 years ago, fire tests were run using pig carcasses to represent sleeping people. The researchers concluded that sprinklers would not normally operate fast enough to save someone who was immobile if the fire began in their bed, particularly if the person was frail. Anecdotal incidents of fires in care homes have confirmed this. Some tests run in Germany a few years ago, not on pig carcasses but just on bedding, showed a huge reduction in fire damage when the sprinkler was operated earlier using electronic detection. If this concept could be proven to offer a reasonable chance of survival even to those intimate with an incipient fire it would sometimes be specified, as long as false activations were prevented. Again, this is not a replacement for sprinklers but an enhancement of their performance that will probably not be commercially viable in most applications.

Most fire fatalities are caused by smoke inhalation. This fact is used by some to claim that sprinklers are the wrong technology and that smoke control is the answer if life safety is the objective. They are partly correct. Smoke control is the answer, but sprinklers are one of the most effective smoke control measures. By keeping the fire small or extinguishing it, sprinklers hugely reduce the amount of smoke released compared to a fire that is allowed to spread to involve all the combustible material in a room. Sprinklers also cool smoke and gases, so that they contract and the pressure drops, reducing the tendency of smoke to spread to other rooms. Fire testing conducted in Belgium and The Netherlands has shown how sprinklers contribute to smoke control in residential buildings. While some older national fire safety codes emphasise vents, fans and dampers, which play an important role, research is showing the benefits of sprinklers and that evidence is leading to sprinklers being recognised in building codes for their contribution to smoke control.

Environmental concerns affect every activity today and sprinkler systems are no exception. Twenty years ago materials used in sprinkler system switches came under the spotlight as the European Union and other jurisdictions moved to ban the use of lead and other toxic materials. Manufacturers responded by changing the solders and alloys they use. Sprinklers themselves are mainly made of brass, an alloy of copper and zinc, with up to 2% lead added to improve its machinability. While there is no evidence that sprinklers can introduce lead to drinking water and they are separated from potable water by backflow prevention, California has insisted the brass be lead-free in domestic systems. Manufacturers have produced special lead-free sprinklers for domestic applications, with one manufacturer unexpectedly employing a plastic body. The industry has shown it can adapt.

Since the 1960s AFFF has protected airports from flammable liquid fires but the fluorosurfactants in AFFF are being phased out. Foam concentrate manufacturers and the foam systems industry have risen to the challenge and there are now fluorine-free foam systems to protect flammable liquid hazards. Polytetrafluoroethylene (PTFE), branded Teflon by one manufacturer, is to be phased out in Europe. Many sprinkler manufacturers use PTFE as part of the seal and no doubt they are now working on alternative materials.

Could technology render fire obsolete? Sensors and software could certainly help to identify potential fire risks before they become fires, shutting down equipment, and white goods can now have in-built fire protection. Yet such measures will not come close to eliminating fires, particularly when so many are caused by one-off human error.

Finally, there is reputational risk. What if a sprinkler system fails to operate correctly and people die or there is a polluting fire? Won’t that discredit sprinkler systems? In practice I have found the opposite response. Authorities conclude that the sprinkler system could have saved the day had it been correctly designed and installed. They then tighten inspection regimes. Most recently this happened in France following a serious fire at a site in Rouen, where 9,800 tonnes of liquids burned and local farmers were forced to destroy their crops. Failures in other countries have also led to tightened supervision, something that helps ensure fair competition for installers.

Perhaps I have missed some threats but as far as I can tell, sprinklers are here to stay as the most effective, reliable and economical of fire safety measures. At the same time, to maintain that position they must continue to evolve.

This article was first published in Sprinker Outlook No. 2