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


 Why is an interlock required?

An interlock is required to ensure the safety and comfort of the kitchen staff. If the ventilation system is not operating correctly, gases including carbon monoxide and nitrogen dioxide can build up to dangerous levels. These two gases give most concern to the Health and Safety Executive (HSE).

How does the interlock work? 

A sensor must detect an airflow above a certain threshold and then the system will allow the gas isolation valve to open, thus allowing the gas appliances to be used. If the air is NOT flowing, the gas isolation valve CANNOT open. To comply with Gas Safe regulations, actual airflow “draught” must be measured to determine if the isolation valve should open or not. Any form of electrical, or “fan running” interlock does not comply with the regulations. The important point here is that it is not sufficient just to have a ventilation system, but that it must actually be working correctly for the chef and staff to be safe from poisoning.