Guide

Commercial kitchen safety: gas, ventilation, and legionella

Gas safety obligations, ventilation and extraction requirements, interlock systems, and legionella risk management for hospitality premises with commercial kitchens and water systems.

Food, Drink & Hospitality UK-wide

Gas safety in commercial kitchens

Commercial kitchens rely heavily on gas-fired equipment including ovens, hobs, fryers, chargrills, and water heaters. Poorly maintained gas equipment poses serious risks: gas leaks can cause explosions, and incomplete combustion produces carbon monoxide, an odourless, colourless gas that kills.

As an employer, you have legal duties under the Gas Safety (Installation and Use) Regulations 1998 and the Health and Safety at Work etc. Act 1974 to ensure all gas appliances and installations are safe.

Ventilation and extraction

Adequate ventilation is essential for both safety and comfort in commercial kitchens. Building Regulations Approved Document F (ventilation) and Approved Document J (combustion appliances) set minimum requirements.

Key ventilation requirements for commercial kitchens:

  • Extraction rates: Commercial kitchen extraction systems must provide sufficient airflow to remove heat, steam, grease, and combustion products. The typical design standard is 20-30 air changes per hour for heavy-use cooking areas
  • Make-up air: Extracted air must be replaced with fresh make-up air. Without adequate replacement air, negative pressure develops, causing doors to slam, back-draughts through flues, and inefficient extraction
  • Grease filters: Extraction canopies must incorporate grease filters that are cleaned or replaced regularly. Grease-laden ductwork is a serious fire risk
  • Ductwork cleaning: Have extraction ductwork professionally cleaned at intervals based on cooking volume. TR19 (the BESA guide to good practice) recommends cleaning at least annually for heavy-use kitchens

Interlock systems

An interlock system automatically shuts off the gas supply to cooking appliances if the extraction system fails or is switched off. This prevents the dangerous build-up of combustion gases, heat, and grease vapour.

While not explicitly required by regulation for all premises, interlock systems are considered best practice and are recommended by the Catering Equipment Suppliers Association (CESA) and referenced in British Standard BS 6173. Insurance companies may require them, and their absence may be noted as a failing in risk assessments.

Carbon monoxide risks

Carbon monoxide (CO) from faulty or poorly ventilated gas appliances is a leading cause of accidental poisoning deaths in the UK. In commercial kitchens, the risk is heightened by the number of gas appliances operating simultaneously in enclosed spaces.

You should:

  • Install CO detectors: Fit audible carbon monoxide alarms in all areas where gas appliances operate. Detectors should comply with BS EN 50291 and be positioned at head height
  • Train staff to recognise symptoms: Headaches, dizziness, nausea, breathlessness, and confusion can indicate CO exposure. Multiple staff experiencing symptoms simultaneously is a strong warning sign
  • Establish emergency procedures: If a CO alarm sounds or CO poisoning is suspected, evacuate the area immediately, ventilate by opening doors and windows, and do not re-enter until a Gas Safe registered engineer has investigated

National Gas Emergency Service: 0800 111 999 (available 24 hours). Call this number immediately if you smell gas or suspect a gas leak.

Legionella risk management

Legionella bacteria can grow in water systems where water is stored or distributed at temperatures between 20 and 45 degrees Celsius. Hospitality premises with complex water systems are at particular risk.

Maintenance schedules

Establishing and following a regular maintenance schedule is essential for kitchen safety and legionella prevention. The following frequencies represent minimum requirements:

Gas safety

  • Annual: Full gas safety inspection and service by a Gas Safe registered engineer. Obtain a gas safety record (CP42 certificate for commercial premises)
  • Monthly: Visual check of all gas appliances for signs of damage, discolouration, or soot marks. Check flame colour (should be blue, not yellow or orange)
  • Daily: Check CO detectors are functioning. Verify extraction system is operating before lighting gas appliances

Ventilation

  • Annual or more frequently: Professional ductwork cleaning to TR19 standards (frequency depends on cooking volume)
  • Weekly: Clean or replace grease filters
  • Daily: Visual check that extraction fans are running and airflow is adequate

Legionella

  • Quarterly or as risk assessment specifies: Legionella monitoring and sampling of water systems
  • Monthly: Check hot water temperatures at sentinel outlets (should be above 50 degrees Celsius within one minute of running)
  • Monthly: Check cold water temperatures at sentinel outlets (should be below 20 degrees Celsius within two minutes of running)
  • Weekly: Flush little-used outlets that have not been run for 7 days or more. Run both hot and cold water for at least 2 minutes

  1. 1. Engage a Gas Safe registered engineer for annual checks

    All gas work on commercial premises must be carried out by an engineer on the Gas Safe Register. Obtain a CP42 gas safety certificate annually. Check engineer credentials at gassaferegister.co.uk.

  2. 2. Install and maintain an interlock system

    Fit a gas-ventilation interlock that automatically shuts off the gas supply when extraction fails. Have the interlock tested and certified annually alongside your gas safety inspection.

  3. 3. Fit carbon monoxide detectors

    Install BS EN 50291 compliant CO alarms in all areas with gas appliances. Test alarms weekly and replace batteries or units according to manufacturer instructions.

  4. 4. Commission a legionella risk assessment

    Appoint a competent person to assess legionella risk in your water systems. The assessment must be reviewed every 2 years or whenever there are changes to the water system.

  5. 5. Establish a temperature monitoring regime

    Record hot and cold water temperatures at sentinel points monthly. Hot water should reach 50 degrees Celsius within one minute. Cold water should be below 20 degrees Celsius within two minutes.

  6. 6. Flush little-used outlets weekly

    Run all taps, showers, and other outlets that have not been used for 7 days. Flush both hot and cold water for at least 2 minutes to prevent stagnation and bacterial growth. Record the flushing in your legionella log.

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