Safety Regs

Commercial Kitchen Regulations

Education Building

Boiler / Plant Rooms

BS 6173:2020

BS6173 was originally introduced in 2001 revised in 2009 and revised again in 2020, this document makes reference to gas installations within commercial kitchens. It states gas should not be available within the commercial kitchen if the ventilation is not in operation, and this should be controlled by a gas interlock system.

The Gas Interlock System must be CE marked.

A gas interlock system is required to be fitted within every new commercial kitchen which has been built since 2001 or has had any major refurbishment since the release of BS6173:2001.

There are a couple of different ways which a gas interlock system can check that the ventilation is in operation. Firstly, air pressure differential switches can be fitted in the ducting and will physical check for airflow before allowing the gas solenoid valve to open. Alternatively, a more modern method is to use current monitors which will check for a power supply going to the fan and control the gas solenoid valve accordingly. If either at start-up, or during the course of the operation, the fans fail or are turned off the gas solenoid valve will automatically close.

Another aspect of BS6173:2009 is gas pressure proving. The standard states if any of the catering equipment does not have a flame failure device a gas pressure proving system should be installed. A gas pressure proving system will check for any leaks on the pipework or on the appliances at start-up, in the event where a gas leak is detected then this will not allow the gas solenoid valve to open.

The majority of appliances which have been built within the last 10 years should have flame failure devices fitted, however in a kitchen where every appliances does have flame failure devices fitted then gas proving is often still recommended to carry out a gas check on the line and ensure the safety of kitchen staff in the area.


IGEM UP/19  is a recommendation which was introduced in November 2014 and it is written to supersede TB140 (Edition 2) which was previously released in June 2014 and also back up a number of statements within BS6173:2009.

It states gas should not be available within the commercial kitchen if the ventilation is not in operation, and this should be controlled by a gas interlock system. IGEM/UP19 once again states that the gas interlock system can check the ventilation using either air pressure differential switch or current monitors.

IGEM/UP19 does clarify a number of things which are listed in BS6173:2009 however it makes a lot more references to carbon dioxide monitoring within a commercial kitchen. CO2 Monitors should be considered within a commercial kitchen, which hasn’t had any major refurbishment, and there is no gas interlock system is fitted as a means of indicating to staff when the carbon dioxide is increasing and to notify them that they should increase the ventilation within the area.

Also, IGEM/UP19 states that a carbon dioxide monitor should be fitted when there is a variable speed controller to control the ventilation. Where variable speed controllers are fitted the end user has the ability to have all the gas appliances in operation but just trickle the ventilation at a low speed and therefore the CO2 is likely to increase. The CO2 Monitor should alarm at first and second stage, the first stage warning staff at 2800ppm to let them know that they should increase ventilation. In the event where the CO2 continues to rise and the ventilation is not increased, once the CO2 Monitor reaches 5000ppm then (where applicable) the gas solenoid valve shut be closed.

Positioning of the CO2 Monitors within the commercial kitchen is included within DW172 – Edition 2.


DW/172 is the BESA specification for Kitchen Ventilation Systems and since its release in 2005 has become widely acknowledged as the authoritative specification for kitchen ventilation design throughout the UK and many parts of the world.

DW/172 was revised in January 2018 in order to reflect current legislations and the latest cooking techniques and design of catering equipment, by all sections of the catering industry.

The sections that have been modified and amended are –

  • The appliance coefficient schedule has been significantly expanded and modified
  • Modification to Grease Separation
  • The lighting section has been modernised
  • New section for Solid Fuel Equipment
  • New section for Demand Controlled Kitchen Ventilation Systems
  • Gas Interlocking
  • Modifications to Pollution Control
  • New Section for Recirculation Systems
  • Modifications to Cleaning and Maintenance
  • Control Panels


IGEM UP/11 discusses gas safety in educational establishments such as schools, colleges and university explaining in details requirements in standard science laboratories and home economics rooms.

IGEM/UP/11 shows that it is mandatory in science laboratories to have the ability to isolate the gas supply, whether this be by means of a manual valve (ECV) such as a quarter-turn fitted by the entrance to the room, or an automatic isolation valve (gas solenoid valve) linked with an emergency stop button. However, in section 6.2.4 it does state where a gas solenoid valve is installed then a “downstream integrity check) must be included otherwise known as a gas proving test.

A gas pressure proving system will check for any leaks on the pipework or on the benches at start-up, in the event where a gas leak is detected then this will not allow the gas solenoid valve to open. There must be a means of isolation fitted in a “readily accessible position” which most often is by each main exit(s) to the room, so there is a way of shutting off the gas supply in the event of an emergency.

IGEM/UP/11 goes on to discuss the requirements for CO2 and ventilation in a home economics room to ensure the safety of the children and to ensure air quality is at a safe level. For a new installation, where ventilation is installed to extract combustible gases then this should be interlocked by means of air pressure differential switch or current monitor. Where mechanical ventilation is fitted purely for climate control within the room then the need to interlock the ventilation with the gas supply should be analysed by means of a risk assessment.

In the event where the ventilation requirements cannot be met then a carbon dioxide monitor should be installed at seating height (roughly 1.5 metres from floor level). The CO2 monitor should alarm at 2800ppm to notify the teachers or occupants to increase ventilation, where the CO2 levels in the room continue to rise and exceed 5000ppm then the gas supply should be automatically isolated.

Although it is not mentioned within IGEM/UP11, it is very popular in science laboratories to also control the electric and water supply to the benches through the gas proving system.


Building Bulletin 101 is a document produced to give guidance on the ventilation requirements within school buildings.

Building Bulletin 101 discusses both mechanical and natural ventilation within the schools building in great depth, but also makes a number of references to carbon dioxide monitoring. This is based on the need to control carbon dioxide produced by respiration of occupants. In teaching and learning spaces, in the absence of any major pollutants, carbon dioxide is taken to be the key indicator of ventilation performance for the control of indoor air quality.

Carbon dioxide should be measured at seating height and the average concentration should not exceed 1500ppm between the start and end of the day. Building Bulletin 101 states that there should be a carbon dioxide monitor fitted in every learning or teaching space in the school. The CO2 Monitor should give the staff and occupants a visual display of the conditions within the room by means of a traffic light system to notify them if the ventilation should be increased.

The CO2 Monitors can be used to automatically control the ventilation in some situations, but where this is not practical or possible then the monitors can be used just to give indication and then the occupant can act accordingly to reduce the levels of carbon dioxide in the area, for example increasing natural ventilation by means of opening windows and doors etc.


Building Bulletin 100 is a document which discusses fire safety in educational establishments and explains the requirements for science laboratories, kitchens and school boiler rooms.

Building Bulletin 100 states that school plant rooms (where they are part of the main building) should be classed as a high fire risk and therefore recommends the following precautions –

  • An emergency knock-off button should be installed at the entrance of the boiler room and connected up to the isolation valve so there is a way of isolating the gas supply in the event of a emergency.
  • Heat detectors should be included over each boiler. If the boiler was ever to catch fire, the heat detector would automatically alarm and cause the gas solenoid valve to shut off.
  • The gas solenoid valve can be automatically reset in the event of a power failure to reduce the risk of frozen pipework in cold periods, however in the event of a genuine alarm the system must be manually reset to restore the gas supply.
  • Gas Detectors are recommended to be connected to a gas detection system, in the event where a gas is detected then this should cause the system to give out an audible alarm and shut off the fuel supply in the boiler room. The most common detectors used are carbon monoxide and natural gas. However, for LPG installations an LPG detector should be considered.

The detectors should be fitted at the following locations –

Natural Gas – 300mm from the ceiling

Carbon Monoxide – 1700mm from the floor

LPG – 300mm from the floor



If automatic flame safe guards are not fitted on all appliances, in the event of a closure of a gas solenoid valve, the Automatic Isolation Valve shall not be allowed to automatically reset until the downstream pipework is checked. If a gas booster or compressor is installed, then it recommends “It is normal good practice to fit a low pressure cut off switch or transducer to comply with such a requirement.”


BS 6644

A means of gas isolation must be incorporated at the entrance to the boiler room.
If it’s not practical to fit a manually operated valve, in an easily accessible position, then an electronic control valve can be fitted with an emergency knock-off button. (Such as the Merlin 500s with S&S Gas Solenoid Valve & Remote Emergency Stop)