Gas Interlock Systems are designed to shut off the gas supply to a kitchen in the event of an extractor fan failure and are a compulsory requirement for the majority of commercial kitchens, as well as to ensure that the air flow rates of the commercial kitchen extract systems meet the minimum standards as set out by DW/172 (the specification of kitchen ventilation systems).

How does a Gas Interlock System Work?
There are two main ways that this can be done. You can use an electrical current sensor which monitors the electrical current to the fan to achieve the same result. Current monitors are available as a separate element, or in the case of some gas interlock control panels are built in.

Alternatively, a Differential Air Pressure Switch senses the difference in air pressure either side of the fan (either intake or extract) and you can set the pressure switch to different levels of sensitivity to ensure shut off occurs at the required level of air. Both systems require wiring back to the gas interlock control panel, with various panels available to suit different requirements.

Basic level panels can monitor two fans (one intake and one extract) and support at least one remote emergency stop button and one gas solenoid valve. More advanced panels are used to support multiple intake and extract fans simultaneously, with supporting fire alarm and shutter systems and gas proving systems (where gas equipment does not have flame failure).

The gas interlock panel is connected (normally closed) to a gas solenoid valve of suitable size. This guarantees the gas supply to the kitchen is off constantly aside from when the kitchen extract fan system is working accurately.

You can get gas solenoid valves to fit most sizes of pipe, be that as it may it is important to consider the pipe material when choosing your sizes. If the layout of the building has not allowed for the gas interlock control panel to be on the emergency exit point, then an additional emergency stop button must be installed along the emergency exit route.

For further help and assistance please contact us on 01603 498889.