How Do Sprinkler Systems Work?

If you’ve been following our blog, you’ll know that we talk a lot about the benefits of sprinkler systems. The most notable, of course, is that they really can save lives in potentially fatal situations.

However, what we haven’t yet looked at is exactly how they save lives. We’ve already explored how dry & wet risers work. Now, we want to delve deeper into how sprinkler systems work to slow the spread of fire, providing more time for safe evacuation, and helping to minimise the risk of structural damage.

How sprinklers save lives

Firstly, it’s important to know what components make up a sprinkler system. There’s a front end – the hardware you can see – and a back end, which is a concealed series of pipes connected to a water source.

The area we want to focus on is the front end. This is made up of the sprinkler head, a glass tube filled with a heat-expanding liquid, and a plug, held in place by the tube, which prevents the release of water.

Step 1: Heat detection

As a room begins to heat up during a fire, the liquid (usually glycerin-based) inside the glass tube begins to expand. Eventually, this breaks the tube. Here in the UK, this usually happens at about 68 degrees celsius. This is high enough to ensure the tube won’t crack in a summer heatwave, but low enough that it breaks during the earliest stages of a fire. A room can reach up to 600 degrees at eye level during a fire.

The glass won’t break instantly as the room hits this temperature, but it does happen relatively fast. A standard 5mm tube will take around 60-90 seconds to break. 1mm tubes will break a little quicker.

Step 2: Water release

When the glass tube breaks, there’s nothing to hold the plug in place. This drops down and pops off, allowing the water stored in the back end pipe network to be released through the sprinkler head.

The design of the sprinkler head ensures water is scattered throughout the room. The water achieves three things:

  • It cools the environment to slow down burn rate
  • It reduces the amount of smoke in the area
  • It dampens flammable materials so they take longer to ignite, helping to stop the fire from spreading

As the head is connected to a continuous source, water will continue to flow until the valve is shut off.

Can sprinklers stop working?

Unfortunately, yes. A sprinkler system will only work as above if it’s maintained regularly to ensure all the components are clean and operational. For optimal fire protection – and legal compliance – it’s very important to check your sprinkler system regularly. Our guide to sprinkler system maintenance can help.

When sprinkler systems are installed and maintained properly, they form one of the most effective forms of fire protection, and can help to facilitate a safe evacuation in the event of a fire. To find out more about residential and commercial sprinkler systems designed for your building, get in touch with us.