6 minute read

Technical

Next Article
News focus

News focus

What’s cooking in commercial catering?

In this article, Gas Safe Register Technical Support Officer Steve Lombard takes a look at commercial catering standard BS 6173 and reviews some of the changes that have evolved since its first publication in 1982.

Industry standards are periodically revised, usually every five to 10 years. They are often updated to reflect changes in equipment, materials, best practice and changes to associated standards. But, more importantly, they are updated to improve the overall safety of installations.

The latest edition of BS 61731 , published in March 2020, applies to new installations and when improvements are made to existing installations. The standard is not applied retrospectively and, as per IGEM/G/11 (the Unsafe Situations Procedure), when considering the safety of any existing catering installation, the overall safety will be based on a risk assessment outlined in the IGEM/UP/192 risk assessment protocol.

Earlier editions of BS 6173 (1982 and 1990) were not as detailed as they are today. Previously, for instance, in the event of an emergency, only a manual valve was required to be turned off. Ventilation was simply described as being of a specialist nature and having to be adequate.

Prove the ventilation is safe

In 2001, the standard was revised to place much greater emphasis on proving the safety and operation of the ventilation system. The ventilation system does not simply provide air for combustion, removal of combustion products, and removal of steam, etc, from working operations, but also to provide a safe working environment for people working in the kitchen, providing clean, cool air, and to remove excess fumes and hot air from cooking processes.

Catering system installations require interlocking to prevent the catering equipment from being used if the ventilation should fail. Unlike interlocking boilers in plant rooms, where appliance gas valves can be prevented electronically from operating, catering equipment can be prevented from being used by interlocking the gas supply via an automatic isolation valve (AIV) interlocked with the extraction.

The 2020 edition of BS 6173 has further implications on the safety of existing catering equipment. The previous version had stated that, where possible, all new and existing appliances are required to have flame safety devices (FSDs) fitted to all burners. These prevent gas from passing through open gas taps and burners following any shutdown, followed by restoration of the gas supply. Technical Bulletin 0433 was introduced to provide guidance on upgrading FSD controls on older existing catering equipment and referenced in the standard. Note: A revised TB 043 was published to coincide with the publication of BS6173 2020. Where appliances could not be upgraded with an FSD approved by the catering appliance manufacturer to all burners, a proving system would be required to prevent the gas passing through any open burners following restoration of the gas supply.

Now, the current 2020 version of BS6173 states: “All burners on new appliances shall have flame failure devices fitted” and that “many older appliances are not fitted with safeguards that are currently required, eg, flame supervision devices, water failure systems or mechanical protection

Situation

15. Commercial catering

Cat Notes

15.1 Existing kitchen installation containing gas-fired appliance(s) where there are safety concerns with: 1. Fixed ventilation (make up/air inlet) 2. Mechanical ventilation systems (make up/air inlet), for example, those with no interlock with the gas supply or those fitted with a manual override See Notes 3. Mechanical extraction systems, for example, those with no interlock, those fitted with a manual override or those without the provision for make-up/air inlet) 4. Atmosphere readings that indicate excessive levels of carbon dioxide (CO2) or other products of combustion (complete or incomplete) 5. Air quality within the working environment, ie, very hot working condition, high levels of condensation, catering staff complaining about the working environment. Following a risk assessment, as set out in the Risk Assessment Protocol for dealing with gas-fired catering appliances outlined in IGEM/UP/19 – Application of interlock

devices and associated systems used with gas appliance installations in

commercial catering – apply the relevant category and actions (ID, AR or as defined by IGEM/UP/19).

Note: It may be possible, with permission of the responsible person, to carry out remedial work to reduce risk levels, for example, improve ventilation, service filters/ fans, etc, or reduce cooking load/isolate appliances.

Source: IGEM/G/11

BS 6173:2020: Overview of updates to the standard

• All new and previously used appliances to be fitted in a kitchen shall have flame failure devices fitted on all burners • A manual isolation valve shall be fitted on the installation pipework and a test point fitted within 300mm downstream of the manual valve to facilitate tightness testing • Automatic isolation valve – provided to facilitate interlocking. In large catering facilities, separate groups of appliances can operate with dedicated independent ventilation/extract canopy systems and have independent AIV fitted upstream to each group of appliances. This enables localised shutdown within the catering area while other equipment can remain in use • Emergency situations – Notices. At locations where either a manual gas isolation valve or AIV can be re-set, a suitably worded notice shall be affixed. There are now two versions of the labelling to be used at either the MIV or emergency stop buttons or both.

What’s cooking in commercial catering?

At a glance

• BS 6173 was first introduced in 1982

• Revision in 2001 requiring interlocking and air testing – proving operation of ventilation and confirming safe environment

• While older installations might not meet the requirements of the current standard, a risk assessment shall be carried out to determine the overall safety of an existing catering installation

• New installations and upgrades to existing installations must meet the current requirements • When installing new and previously used catering equipment, FSDs must be fitted on all burners.

systems. Alternative components can only be used if specified by the appliance manufacturer.” Emergency stop buttons –A solenoid valve (AIV) must be fitted to enable interlocking of the gas supply, which means that the supply can also be turned off electronically using stop buttons in an emergency. This could be used as an alternative to or in addition to an emergency manual isolation valve. Air testing – To prove the adequacy of the ventilation following commissioning and maintenance of catering installation, the carbon dioxide (CO2) levels must be checked with an analyser to confirm safe working conditions.

Note: Air testing should only be carried out using a direct-reading CO2 analyser.

The methods of interlocking to prove the operation of the ventilation system, along with the method for carrying out air testing, are described in more detail in IGEM/UP/19. n

Changes and references added to BS 6173

1982 1990 2001 2009 2020

Manual isolation valve

Ventilation – required to be adequate Automatic isolation valve Catering information sheet CAIS 10 Ventilation design DW/171 then 172 Ventilation – interlocking requirement Catering information sheet CAIS 23 FSD on appliances with enclosed burners FSD required on all burners – TB043 Gas proving system Yes Yes Yes Yes Yes

Yes Yes Yes Yes Yes

* * Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes

*Automatic isolation valve (AIV) originally installed as alternative (pipe entry into kitchen inaccessible for manual valve operation in event of emergency)

Bibliography

1 BS 6173 – Installation and maintenance of gas-fired catering appliances for use in all types of catering establishments (2nd and 3rd family gases) – specification 2 IGEM/UP/19 +A: 2015 – Design and application of interlock devices and associated systems used with gas appliance installations in commercial and catering establishments 3 Technical Bulletin 043 – Electrical work on gas appliances

This article is from: