commercial catering

Gas Safe Register’s Technical Team set out the standards and competences that are required to work in this specialist field.

The commercial catering sector is a specialist field and gas engineers who are trained and qualified to work in this environment need to know and understand the requirements of both BS 61731 and IGEM/UP/19 Edition 22. These documents do not apply to mobile catering or event catering, which are covered by Liquid Gas UK CoP 24 Part 33 BS 6173 refers to DW 1724 for ventilation systems but the design, installation of the canopies, extract and supply air is usually undertaken separately by a specialist heating and ventilation contractor.

Ventilation

BS 6173 covers the installation of kitchen equipment and how catering areas shall be ventilated to provide air for combustion, and to remove combustion products and steam from the cooking process.

In 2001, new requirements were added that gas installations in commercial kitchens must be interlocked. The standard recognises the fact that the extraction/ventilation of products acts in the same way as any other mechanical fan-assisted flue for gas appliances and so is a safeguard to prevent appliances operating in the event of mechanical failure.

The standard was reviewed and published again in 2009, adding a requirement to carry out air-quality sampling in commercial kitchen areas.

More detail on how interlocking and air testing should be carried out is given in IGEM/UP/19.

IGEM/UP/19 Ed 2 – Design, construction and equipment used for interlock systems

The requirement for any interlock of a catering installation is to ensure adequate air quality and to prevent appliance operation should an air extraction or supply component fail. Interlocks shall:

• Be reliable and suitable for their intended duty and consider maintenance and testing requirements of the devices, where applicable

• Be independent of other functions unless their safety function cannot be affected by such other functions

• Be compatible with other components, equipment, and functions

• Provide suitable and reliable protection: that is, fail-safe modes, redundancy, diversity, and self-diagnosis

• Be able to monitor the correct air provision and/or quality conditions as required and cause shutdown condition of the system, requiring a manual

Carbon dioxide monitoring

– used to ensure a safe working environment, where combustion products are emitted into the kitchen area and provide further proof of fan performance. IGEM/ UP/19 specifies the installation of CO2 monitoring in new kitchens (including their location and height) and that they shall only be used in conjunction with either an air flow, air pressure or fan power monitoring interlock, irrespective of whether the appliance is flued or flueless.

The actuation of the CO2 alarm when the level is above 2800ppm shall cause visual or audible warning. If the level rises above 5000ppm, the interlock will cause lockout of the gas system.

Industry Standard Update 115 highlights the main changes in IGEM/UP/19 Edition 2. You can read and download Industry Standard Updates by logging into your online account at www.GasSafeRegister.co.uk/sign-in reset upon a failure occurring

• Control systems shall comply with BS EN 60730-1:20165 and automatic gas valves shall comply with BS EN 1616 They shall not incorporate any override.

Interlock systems are described as:

Air flow monitoring – simply, a vane switch that has a pre-determined weight adjustment in the flow of air and products of combustion.

Air pressure monitoring

– interlock system that senses the correct operation of fans using differential pressure sensing.

Fan power monitoring

– monitors the power or current consumption of the fan motor(s) to ensure that they are within a specific tolerance of the commissioned values. They are less prone to failure caused by grease affecting the sensing element.

Air quality testing

Air testing shall be carried out when:

• A new gas and or ventilation system is installed and commissioned

• When working on gas equipment for the first time, carrying out service/ maintenance on gas or ventilation system, including installing additional or replacement gas appliance or part of gas-fired item

• Following replacement of fan motors or other ventilation equipment

• If you suspect that the extract system is not performing correctly, such as working environment issues reported by staff (high heat or condensation). Analysers conforming with BS EN 505437 are used for direct reading of CO2 when undertaking air testing.

Important: Most electronic portable combustion gas analysers are not suitable as they do not measure CO2 directly.

Air testing is carried out with appliances operating under maximum load condition and without utensils. Ventilation systems shall be operating normally. With demand-controlled kitchen ventilation (DCKV – known previously as variable-speed drives), the test shall be performed at the lowest setting and throughout variable speed settings. The measurement of CO2 is taken at three points within the kitchen work area(s) at a height of 2m above floor level and the average of the readings is taken. CO2 readings below 2800ppm are usually considered safe. EH408 sets a maximum exposure limit of CO2 at 5000 ppm/8 hour time-weighted average.

Using IGEM/G/11 – the Gas Industry Unsafe Situation Procedure – CO2 of between 2800ppm and 5000ppm is classified as At Risk, while readings above 5000ppm are Immediately Dangerous. ■

Bibliography

1 BS 6173 – Installation & maintenance of gas-fired catering appliances for use in all types of catering establishments (2nd and 3rd family gases) –Specification

2 IGEM/UP/19 Edition 2 – Design and application of interlock devices and associated systems used with gas appliance installations in commercial catering establishments.

3 Liquid Gas UK CoP 24 Part 3 –Use of LPG for Commercial Catering Events, Street Food and Mobile

Catering

4 DW 172 – Specification for kitchen ventilation systems

5 BS EN 60730-1 – Automatic electrical controls - Particular requirements for automatic electrical pressure sensing controls including mechanical requirements

6 BS EN 161 – Automatic shut-off valves for gas burners and gas appliances

7 BS EN 50543 – Electronic portable and transportable apparatus designed to detect and measure carbon dioxide and/or carbon monoxide in indoor ambient air. Requirements and test methods

8 EH40/2005 Workplace exposure limits, HSE Books