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BS 7967:2015



The latest, up-to-date edition.

Guide for the use of electronic portable combustion gas analysers for the measurement of carbon monoxide in dwellings and the combustion performance of domestic gas-fired appliances

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Hardcopy , PDF



Published date


1 Scope
2 Normative references
3 Terms and definitions
4 Competence
5 Gas analyser
6 Investigation of reports of fumes, smells
   and spillage/leakage of combustion
   products in dwellings
7 Reacting to activation of CO detectors
8 Determining ambient levels of carbon
   monoxide (CO) in a room
9 Information on levels of CO
10 Determination of the combustion
   performance of an appliance
11 Procedure for commissioning, servicing
   and maintenance using a gas analyser
12 Combustion action levels
13 Completion and leaving the property
14 Reports
Annex A (informative) - Gas analyser
Annex B (informative) - Movement of CO in
Annex C (normative) - Multi-hole sample
Annex D (informative) - Flue/draught diverter
        configurations for warm air heaters
Annex E (informative) - Background to the
        use of a gas analyser in regular
Annex F (informative) - Dwelling investigation report
Annex G (informative) - Gas appliance investigation report

Explains guidance for gas operatives on: the general use of an electronic portable combustion gas analyser conforming to BS EN 50379-3 and BS 7927:1998 incorporating Amendment No. 1:1999.

1.1This standard provides guidance for gas operatives on: the general use of an electronic portable combustion gas analyser conforming to BSEN50379‑3 and BS7927:1998 incorporating Amendment No. 1:1999; NOTE1 This standard assumes that a portable combustion gas analyser [often referred to colloquially as a “flue gas analyser?? (FGA)] of the type specified in BSEN50379‑3 or BS7927:1998 incorporating Amendment No. 1:1999 is available to the gas operative and the operative is competent in its use and the interpretation of any reading obtained. This competence can be demonstrated by satisfactory completion of the relevant ACS assessments, which cover the use of electronic portable combustion gas analysers. See Clause4 for further information on competence. NOTE2 BSEN50379‑3 superseded BS7927:1998 incorporating Amendment No. 1:1999 on 1 March 2007. However, electronic portable combustion gas analysers conforming to BS7927:1998 incorporating Amendment No. 1:1999 remain acceptable for the purposes of this standard. the use of such an electronic portable combustion gas analyser to determine ambient levels of carbon monoxide (CO) and, in certain circumstances (see Notes4 and 5, and Commentary on 8.1), detect the presence of carbon dioxide (CO2) in dwellings; NOTE3 A definition of a dwelling is given in 3.7. NOTE4 One of the main combustion products from gas appliances is CO2, which is mainly regarded as an asphyxiant, but is also a toxic substance which could be present in the air in sufficient quantity to prove harmful. For guidance on the occupational health considerations of CO2, reference can be made to the HSE Guidance note on Workplace exposure limits, EH40/2005 [8]. NOTE5 Electronic portable combustion gas analysers that calculate CO2 levels from an oxygen (O2) measurement are: well proven for calculating CO2 levels in combustion gases in the flue of an appliance; not suitable for measuring ambient levels of CO2 in dwellings; and able to detect increases in the ambient CO2 levels in ambient atmospheres and such increases in CO2 will provide an early indication of increasing build-up of products of combustion in the room (see Commentary on 8.1). the use of an electronic portable combustion gas analyser to measure CO and CO2 in combustion products from the following types of gas-fired appliances: flueless appliances (type A appliances); open-flue appliances (type B appliances); room-sealed appliances (type C appliances); and all appliances for which the gas appliance manufacturer has provided a purpose-designed sampling point or specific sampling instructions; NOTE6 Type A, type B and type C classification of gas-fired appliances is described in PD CEN/TR1749 and in 3.21. the use of an electronic portable combustion gas analyser as a diagnostic instrument to assist a gas operative: in confirming safe and/or efficient operation at the time of commissioning, in accordance with gas appliance instructions; in determining the level of servicing required for a gas-fired appliance; in confirming satisfactory combustion following servicing in accordance with gas appliance instructions; and in confirming satisfactory combustion following maintenance. NOTE7 At the time of installation of a new appliance it is not necessary to carry out tests to measure the level of combustion products in the flue, unless the gas appliance instructions specify that a test be carried out (see 11.2). NOTE8 Electronic portable combustion gas analysers are not to be used as a substitute for normal service and maintenance carried out in accordance with gas appliance instructions. This standard describes the options of how they can be used in conjunction with gas appliance instructions. 1.2This standard gives recommendations on: combustion performance action levels; and actions to be taken when CO is detected in dwellings. This standard is for use with appliances using 2nd or 3rd family gases. NOTE The general recommendations for 3rd family installations contained within this standard also apply to gas installations supplied with LPG/air mixtures used in the Channel Islands or the Isle of Man, provided: any installed gas equipment has been appropriately converted and is suitable for the gas being supplied, and the provisions of the standard do not conflict with local regulations or authorized local custom and practice. 1.3This standard gives references to further information on the effects of CO. NOTE Information on the effects of CO can be found in the Institute for Environment and Health’s IEH assessment on indoor air quality in the home (2): Carbon monoxide [9]. 1.4This standard does not: cover the obligations of an emergency service provider (ESP) in responding to a gas emergency or procedures for investigating incidents that are reportable under Section11(1) of the Reporting of Injuries, Diseases and Dangerous Occurrence Regulations (RIDDOR) 2013 [5] and the Gas Safety (Management) Regulations (GSMR) 1996 [6]; make recommendations arising from the determination of ambient CO2 levels; or deal with the measurement of combustion products such as nitrogen oxides and aldehydes. NOTE Combustion products from gas appliances also contain oxides of nitrogen (NOx), predominantly nitrogen monoxide (nitric oxide, NO) and nitrogen dioxide (NO2). Although this standard does not cover the measurement of these substances, quantities of such products could be present in the air and could cause harm and irritation to humans. For guidance on the health considerations associated with these combustion products, see the Institute for Environment and Health assessment on indoor air quality in the home: Nitrogen dioxide, formaldehyde, volatile organic compounds, house dust mites, fungi and bacteria [10].

Supersedes BS 7967-1(2005), BS 7967-2(2005), BS 7967-3(2005), BS 7967-4(2007) & 14/30258585 DC. (03/2015)
British Standards Institution

BS 7927:1998 Heating appliances for domestic applications. Portable apparatus designed to detect and measure specific combustion flue gas products. Requirements
BS EN 50291-2:2010 Electrical apparatus for the detection of carbon monoxide in domestic premises Electrical apparatus for continuous operation in a fixed installation in recreational vehicles and similar premises including recreational craft. Additional test methods and performance requirements
BS 7860:1996 Specification for carbon monoxide detectors (electrical) for domestic use
BS 3632:2005 Residential park homes. Specification
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
BS 5546:2010 Specification for installation and maintenance of gas-fired water-heating appliances of rated input not exceeding 70 kW net
BS EN 50292:2013 Electrical apparatus for the detection of carbon monoxide in domestic premises, caravans and boats. Guide on the selection, installation, use and maintenance
PD CEN/TR 1749:2014 European scheme for the classification of gas appliances according to the method of evacuation of the combustion products (types)
BS EN 721:2004 Leisure accommodation vehicles. Safety ventilation requirements

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