Fire extinguisher gauges: a guide

A fire extinguisher gauge is one of several ways to check the condition of a fire extinguisher – something every responsible person has a duty to ensure. Alongside annual inspections and maintenance of fire safety equipment (in accordance with BS 5306-3: 2017), a regular fire extinguisher gauge check is a quick way to indicate if a unit has adequate pressure to function as it should. And being absolutely certain a fire extinguisher can do its job when needed is a legal requirement. Here, we explain what a fire extinguisher gauge is, how to inspect one, and what a fire extinguisher gauge in red or green means.

What is a fire extinguisher gauge? 

A fire extinguisher gauge displays the pressure of a fire extinguisher’s contents. Put simply, this is to make sure there is enough force to shoot a unit’s contents out in the event of a fire. Alongside other checks, it’s a helpful indicator that a unit hasn’t been used or damaged and is in proper working order. Most fire extinguishers have a gauge on them, apart from CO2 fire extinguishers, which cannot be tested by measuring pressure and must be weighed for CO2 content instead.

How to read a fire extinguisher gauge 

Fire extinguisher gauge displays are divided into three parts: the recharge zone, the overcharged zone, and the green (optimal) zone in the middle. To conduct a fire extinguisher gauge check, take a look at where the fire extinguisher gauge indicator (or needle) is pointing. Each zone indicates the following:

1. Recharge zone:

   Is the fire extinguisher gauge in red and pointing to the left? This is the ‘recharge’ zone. It means the fire extinguisher has either been used or that pressure has leaked from the canister. An undercharged unit lacks the pressure necessary to propel the fire suppressant and must be charged.

2. Green zone:

   In accordance with EN3, a fire extinguisher gauge in green means the fire extinguisher is correctly charged and ready to tackle a fire if needed. The needle should point right in the middle of the gauge.

3. Overcharged zone:

   If the needle is pointing to the red zone on the right, it means that the fire extinguisher contents are under too much pressure. This fire extinguisher gauge meaning cannot be ignored – an overcharged unit can cause a leakage or worse, a cylinder explosion.

Fire extinguisher gauge in red? Here’s what to do: 

As noted above, a fire extinguisher gauge in red indicates that there is too much or not enough pressure in a fire extinguisher, which must be fixed. It is a responsible person’s legal obligation to make sure fire extinguishers in a building or premises can operate efficiently. Firstly, a fire extinguisher gauge in red on a rechargeable unit should be recharged and serviced by a professional. If a fire extinguisher is disposable, however, and the gauge needle is pointing to the red zone, the fire extinguisher should be replaced. In addition to conducting a fire risk assessment, our guide to the different types of fire extinguisher for different classes of fire can help figure out what is needed.

How to perform a fire extinguisher gauge check 

To make sure a fire extinguisher gauge is working correctly (for example, the gauge isn’t blocked or stuck in a certain position) a fire extinguisher gauge tester can be used to apply pressure. This is usually done by a professional when servicing a fire extinguisher. When in use, the fire extinguisher gauge indicator will move opposite to the pressure applied by the container’s contents, then spring back to its original position once the fire extinguisher gauge tester is removed.

As a preventative safety measure, our fire extinguisher storage and stands can protect your fire extinguisher gauge from corrosion, damage, vandalism, harsh weather, and other factors which could cause it to fail British Standards and cause potential risk to life and property in the event of an emergency.

What do fire extinguisher gauge dots mean? 

Fire extinguisher gauge dots are used to clearly indicate when a fire extinguisher was last serviced and the gauge was tested. At CheckFire, we supply gauge dots in packs of 1000. So that they can easily be identified with the change of year, they’re also available in a wide range of colours: white, blue, green, orange, red, yellow, and clear. A regular dot gauge inspection can quickly identify if a fire extinguisher is due a service. This should be done once a year by a certified engineer, who will place a dot gauge date on the unit and record any findings made in the premise or business log book.

To find out more about fire extinguisher expirations and legislations, as well as other useful fire safety news, visit our resource centre or sign up to our newsletter.