Gas interlock systems have become a key consideration in commercial kitchen refurbishments and safety inspections. If you operate or design a kitchen using gas appliances, knowing how these systems work is essential. They help prevent the risk of gas leaks by ensuring ventilation fans are running before gas can flow. This knowledge lets you make safer, more compliant decisions that protect staff and customers, while keeping your project on schedule and avoiding costly delays.
Gas interlock systems in simple terms
At the most basic level, a gas interlock system acts as a safety gatekeeper for your commercial gas supply. It checks that your ventilation is working properly before allowing gas to flow to appliances.
If the extraction is not running or the system detects a problem, the interlock shuts the gas off. The idea is straightforward: if fumes and combustion products cannot be removed safely, the gas should not be on in the first place.
What a gas interlock system is designed to achieve
Commercial gas appliances produce heat, fumes and combustion gases that must be removed quickly and reliably. A gas interlock links the gas supply to the ventilation so the two cannot operate independently in an unsafe way.
In normal operation, the interlock will only open the gas valve when it has proof that the extract system is working correctly. If the fan fails, someone turns off the extraction, or airflow drops below a set level, the gas interlock system cuts the gas.
This helps to:
Protect staff and customers from a build up of fumes and products of combustion
Reduce fire risk linked to overheating and poor extraction
Support compliance with gas safety and ventilation guidance for commercial kitchens
For operators, this means fewer grey areas. If the interlock is installed and maintained correctly, it becomes a clear safety barrier that supports both daily use and formal inspections.
Typical components in a gas interlock setup
Most commercial gas interlock systems follow a similar pattern, even if the brands and models vary. Understanding the main parts helps you ask the right questions during design, installation and inspection.
Fan-proving devices
The system needs to know that the extract is actually working, not just switched on. Fan proving is usually done with air pressure switches, airflow sensors or current monitoring devices on the fan.
If the proving device detects that the fan is not running properly, it signals the interlock panel to keep the gas valve closed or to shut it if it is already open.
Emergency stop control
An emergency stop button allows staff to shut off the gas supply quickly if there is a problem. It is normally located at a clearly marked, easily accessible point in or near the kitchen.
Pressing the emergency stop will cut power to the gas solenoid valve, closing the gas supply to the appliances and putting the system into a safe state until it is reset.
Gas solenoid valve and control panel
The gas solenoid valve is the physical device that opens and closes the gas line. It is controlled by the interlock panel, which takes signals from the fan proving devices, emergency stop and sometimes additional safety inputs.
The control panel often has indicator lights or a small display, so staff can see at a glance if the system is healthy, in fault, or locked out. A clear panel location and basic staff training go a long way to preventing confusion during busy service.
Typical reasons you are asked to install or upgrade
Gas interlock requirements are often highlighted when something significant changes in the kitchen or during a formal safety check. Many operators first encounter the term during a refurbishment or compliance review.
Common triggers include:
Installation of new or additional gas appliances, especially high-output equipment
Changes to the extraction canopies, ductwork or fans that alter airflow
Kitchen layout alterations that affect where controls and emergency stops are located
Issues raised during a commercial gas safety inspection or landlord certificate visit
In areas such as Gravesend, Medway and Dartford, local authorities and insurers are increasingly expecting modern commercial kitchens to have an effective gas interlock in place as part of their overall risk management.
Common mistakes that lead to safety or compliance problems
Interlock systems are only as good as the way they are installed, labelled and maintained. Several recurring issues show up during inspections and call-outs.
Poor signage and unclear instructions
Staff need to recognise the emergency stop, understand what the panel lights mean and know how to reset the system safely. Without simple signage and basic training, people can bypass controls or waste time during an incident.
Blocked or awkward access to the emergency stop
It is surprisingly common for emergency stop buttons to end up behind stacked boxes, fridges or shelving. In an emergency, this defeats their purpose.
Regular walk-through checks should confirm that the stop is clearly visible, labelled and reachable without climbing or moving heavy items.
Lack of routine checks and maintenance
Like any safety device, a gas interlock system should be tested and checked on a planned basis. Ignoring it until there is a fault can lead to kitchen downtime at the worst possible moment.
Routine checks might include confirming that the fan proving works, the solenoid operates cleanly, and the panel indicators match the actual system status.
Ventilation changes not matched to the interlock
When extraction fans, canopies or ductwork are upgraded or altered, the interlock proving arrangements must be reviewed. A new fan may draw different current or create different airflow, which can confuse older proving devices.
If the interlock is not updated to suit the revised ventilation, you can end up with nuisance trips, a system that never proves correctly, or, in the worst case, an unsafe assumption that extraction is adequate when it is not.
Planning a gas interlock project in your kitchen
Good planning helps you avoid last-minute surprises during a fit-out or compliance upgrade. Bringing the right people together early will keep the design coordinated and practical.
Who should be involved?
Ideally, you want a combination of a commercial kitchen designer or equipment specialist, the ventilation contractor, and a qualified Gas Safe registered engineer familiar with commercial catering.
This team can agree where the gas solenoid goes, how the fan proving will work, where controls and the emergency stop should be located, and how staff will interact with the system day to day.
Information to prepare before you start
Before any detailed design or quotation, it helps to have a clear and up-to-date kitchen layout. This should show the position and type of all gas appliances, existing extract and fresh air systems, and any planned changes.
Providing equipment schedules, canopy sizes, fan specifications and any previous gas safety reports gives your contractors the context they need to design an interlock that is both compliant and workable.
Documentation and handover that matter
At the end of the project, you should expect more than just a working system. Ask for clear as-fitted information, including the wiring diagram, fan proving method, and locations of all key components.
Operating instructions, basic user training and a record of any gas safety tests carried out should also be handed over. Keeping this documentation with your compliance records will make future inspections and repairs much more straightforward.
Next steps if you are unsure about your current setup
If you are planning a refurbishment or have had gas interlock issues raised on a recent inspection, getting qualified advice early can save time and disruption. A commercial gas specialist can assess your current system, explain your options and coordinate any upgrade with your kitchen and ventilation plans.
For help with commercial gas interlocks, installations and safety checks in Gravesend, Medway, Dartford and surrounding areas, you can speak to BCU Plumbing on 08002461041. To learn more about how we can support your kitchen, visit our commercial gas installation services or arrange a commercial gas safety certificate inspection.
