Analox Sensor Technology

If you can`t stand the CO2, get out of the kitchen - part 1

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Courtesy of Analox Sensor Technology

There are two potentially dangerous types of gas in a commercial kitchen: 1) the flammable ones used for cooking (e.g. methane/natural gas; propane/liquefied petroleum gas); and 2) the noxious, gaseous products of combustion such as carbon monoxide, carbon dioxide and hydrocarbons. It would be good to know how to avoid them. But a search for advice on kitchen ventilation threatens to drown the investigator in a sea of acronyms. The roll call includes the BSI, CEDA, CESA, HSE, HVCA, IGEM and the unabbreviated but no less formidable Gas Safe Register. The bewildering flotsam of regulations can be equally difficult to navigate.

Of the two separate themes above—1) flammable fuel gas and 2) poisonous combustion gas—it is only the latter we consider here. The safety legislation on gas-fired appliances is well-established and unambiguous; gas engineers are subject to strict legal constraints and are monitored by the Gas Safe Register. Besides, Analox is not in that industry. Our interest lies in gases created as by-products of combustion (the ‘cooking process’) with particular reference to carbon dioxide (CO2). And the CO2 in a commercial kitchen is not only a potential hazard in itself—it is also an indicator of how well the kitchen ventilation system is performing.

Elevated CO2 levels in the atmosphere of a commercial kitchen can be an indication that the ventilation is inadequate. This could be due, for example, to blocked filters in a cooker-hood or insufficient fresh ‘make-up’ air being introduced. Whatever the cause, this is a dangerous situation. Whereas normal air contains a safe level of 400 parts per million CO2 (0.04%), an increase to 15,000ppm CO2 (1.5%) may cause drowsiness, headache and increased breathing. A level of 30,000ppm CO2 (3%) may cause dizziness. If the concentration approaches or exceeds 100,000ppm CO2 (10%) this may lead to unconsciousness or even death.

Kitchen ventilation manufacturers increasingly integrate CO2 sensors with their products in order to provide ‘demand-based ventilation’: a built-in CO2 sensor is used to constantly monitor the air and switch on or off the ventilation (cooker-hood, extract fans, etc.) according to pre-configured settings. If it is well designed and installed this arrangement can provide automatic control of the ventilation appropriate to the level of cooking activity. It can also help to minimise the energy used, by ensuring that the ventilation system is only operating when it needs to—i.e. when the carbon dioxide level indicates an unhealthy atmosphere.

During the last 15 years a number of standards, specifications and technical bulletins have been published by various organisations. These documents were undoubtedly well-intentioned yet some were criticised by industry experts; some documents were subsequently either withdrawn, superceded or revised. The list below is not necessarily exhaustive, it is simply an attempt to demonstrate how the technical literature has changed and evolved. Nevertheless, it may prove useful to anyone who is seeking guidance on gas detection solutions for commercial kitchen ventilation. If we review the events from 2000 to 2015, we can see that:

  • in February 2000 the British Standards Institute (BSI) publishes ‘BS EN 45544-3:2000 Workplace atmospheres. Electrical apparatus used for the direct detection and direct concentration measurement of toxic gases and vapours. Performance requirements for apparatus used for measuring concentrations well above limit values’;
  • in May 2001 the British Standards Institute (BSI) publishes ‘BS 6173:2001 Specification for installation of gas-fired catering appliances for use in all types of catering establishments (2nd and 3rd family gases)’;
  • in December 2005, the Heating and Ventilating Contractors’ Association (HVCA) publishes ‘DW172: Specification for Kitchen Ventilation Systems’;
  • in February 2007 the Health & Safety Executive (HSE) publishes ‘Information Sheet No. 23 (Revision 1) Gas safety in catering and hospitality’;
  • in July 2007 the British Standards Institute (BSI) publishes ‘BS 8494:2007 Electronic portable and transportable apparatus designed to detect and measure carbon dioxide in indoor ambient air. Requirements and test methods’;
  • in August 2009 the British Standards Institute (BSI) publishes ‘BS 6173:2009 Specification for installation and maintenance of gas-fired catering appliances for use in all types of catering establishments (2nd and 3rd family gases)’;
  • in October 2010, the UK Government publishes ‘Building Regulations 2010 Approved Document F1 Means of ventilation’. This is subsequently amended in April 2013′;in April 2011 the British Standards Institute (BSI) publishes ‘BS EN 50543:2011 Electronic portable and transportable apparatus designed to detect and measure carbon dioxide and / or carbon monoxide in indoor ambient air. Requirements and test methods’. This replaces ‘BS 8494:2007;
  • in April 2012 the Gas Safe Register publishes ‘Technical Bulletin 140 Guidance on ventilation and extract requirements for commercial catering installations, Edition 1’. This is intended to clarify ‘HSE Information Sheet No. 23’. It is prepared by IGEM and published by Gas Safe Register. Subsequently both the Catering Equipment Distributors Association (CEDA) and the Catering Equipment Suppliers Association (CESA) voice their concerns about this Technical Bulletin and ask for it to be withdrawn;
  • in April 2012 the British Standards Institute (BSI) publishes ‘BS EN 50379-3:2012 Specification for portable electrical apparatus designed to measure combustion flue gas parameters of heating appliances. Performance requirements for apparatus used in non-statutory servicing of gas fired heating appliances’;
  • in June 2013, the Health and Safety Executive (HSE) publishes ‘Research Report RR973, Review of alarm setting for toxic gas and oxygen detectors’
  • in July 2013 the Health & Safety Executive (HSE) publishes ‘Information Sheet No. 23 (Revision 2) Gas safety in catering and hospitality’;
  • in June 2014, the Gas Safe Register publishes ‘Technical Bulletin 140 Guidance on ventilation and extract requirements for commercial catering installations Edition 2’. This supercedes Edition 1;
  • in October 2014, the Institution of Gas Engineers & Managers (IGEM) publishes ‘IGEM/UP/19 Design and application of interlock devices and associated systems used with gas appliance installations in commercial catering establishments’. This is jointly published by IGEM and CEDA, and is intended to replace the ‘Technical Bulletin 140 Guidance on ventilation and extract requirements for commercial catering installations Edition 2’, published by the Gas Safe Register;
  • in February 2015 the British Standards Institute (BSI) publishes ‘BS EN 45544-3:2015 Workplace atmospheres. Electrical apparatus used for the direct detection and direct concentration measurement of toxic gases and vapours. Performance requirements for apparatus used for general gas detection’. This replaces BS EN 45544-3:2000.

In Part 2 of this article, we will summarise the industry’s current ‘best practice’ as recommended by some of the more recent legislation—with an emphasis on the monitoring of carbon dioxide in commercial kitchens.

In the meantime, if you would like to discuss CO2 monitoring for commercial kitchens, please contact us today, we’d be happy to discuss your requirement.

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