Pillar guide
Gas Safety Sensors & Controls
An interlock is only as reliable as the device proving ventilation. Choosing between a pressure switch, airflow sensor and current monitor is the single biggest factor in nuisance tripping.
- Current monitoring proves the motor, not the airflow
- Differential pressure is the most common proof of extract
- Emergency stops must be on every escape route from the kitchen
System architecture
Sensing device comparison
| Device | Proves | Strengths | Watch out for |
|---|---|---|---|
| Differential air pressure switch | Pressure drop across fan or filter | Cheap, widely used, adjustable | Drifts with filter loading; nuisance trips if set too tight |
| Duct airflow / velocity sensor | Actual air movement in the duct | True airflow proof, good for variable speed | Needs clean straight duct run and grease protection |
| Fan current monitoring sensor | Motor is drawing running current | Simple, unaffected by grease | A spinning fan with a slipping belt still passes |
| Fan speed / VSD status | Drive is running at set speed | Integrates with BMS | Drive status is not proof of air delivery |
Emergency gas shut-off buttons
- Latching mushroom head or key-reset, clearly labelled GAS
- Sited on each exit route, typically 1.2–1.4m above floor
- Wired to de-energise the solenoid valve directly through the panel
- Functionally tested at every annual service
Set-up and calibration
Sensing devices are commissioned with the kitchen at full load and clean filters, then the set point is backed off to a repeatable margin. Record the measured value, the set point and the trip time on the commissioning certificate.
Frequently asked questions
Which sensor causes the fewest nuisance trips?
A correctly commissioned airflow sensor or a current monitor combined with a pressure switch. A single tightly set pressure switch is the most common nuisance-trip cause.
How many emergency stops does a kitchen need?
Enough that a person can isolate gas on any escape route without passing the appliances — usually one per exit.
Related guides
Gas Interlock Systems
Installation, servicing, testing and fault-finding for kitchen ventilation interlocks.
Gas Safety Control Panels
Interlock and proving panels, indicators and diagnostic codes.
Gas Proving Systems
Pressure proving panels, operating sequences and commissioning.
Gas Solenoid Valves
Normally closed automatic shut-off valves and diagnostics.
Commercial Kitchen Gas Safety
Ventilation interlock, airflow proving and CP42 compliance.
Gas Detection Systems
Fixed detection for methane, LPG and combustion areas.
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