BS 7967:2015

This standard BS 7967:2015 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 is classified in these ICS categories:

• 13.040.40 Stationary source emissions
• 97.100.20 Gas heaters

1.1

This standard provides guidance for gas operatives on:

1. 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;

   NOTE 1 This standard assumes that a portable combustion gas analyser [often referred to colloquially as a “flue gas analyser” (FGA)] of the type specified in BS EN 50379‑3 or BS 7927:1998 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 Clause 4 for further information on competence.

   NOTE 2 BS EN 50379‑3 superseded BS 7927:1998 incorporating Amendment No. 1:1999 on 1 March 2007. However, electronic portable combustion gas analysers conforming to BS 7927:1998 incorporating Amendment No. 1:1999 remain acceptable for the purposes of this standard.

2. the use of such an electronic portable combustion gas analyser to determine ambient levels of carbon monoxide (CO) and, in certain circumstances (see Notes 4 and 5, and Commentary on 8.1), detect the presence of carbon dioxide (CO₂) in dwellings;

   NOTE 3 A definition of a dwelling is given in 3.7.

   NOTE 4 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].

   NOTE 5 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).

3. 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:

   1. flueless appliances (type A appliances);

   2. open-flue appliances (type B appliances);

   3. room-sealed appliances (type C appliances); and

   4. all appliances for which the gas appliance manufacturer has provided a purpose-designed sampling point or specific sampling instructions;

   NOTE 6 Type A, type B and type C classification of gas-fired appliances is described in PD CEN/TR 1749 and in 3.21.

4. the use of an electronic portable combustion gas analyser as a diagnostic instrument to assist a gas operative:

   1. in confirming safe and/or efficient operation at the time of commissioning, in accordance with gas appliance instructions;

   2. in determining the level of servicing required for a gas-fired appliance;

   3. in confirming satisfactory combustion following servicing in accordance with gas appliance instructions; and

   4. in confirming satisfactory combustion following maintenance.

   NOTE 7 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).

   NOTE 8 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.

1.2

This standard gives recommendations on:

1. combustion performance action levels; and

2. 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.

1.3

This 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].

1.4

This standard does not:

1. cover the obligations of an emergency service provider (ESP) in responding to a gas emergency or procedures for investigating incidents that are reportable under Section 11(1) of the Reporting of Injuries, Diseases and Dangerous Occurrence Regulations (RIDDOR) 2013 [5] and the Gas Safety (Management) Regulations (GSMR) 1996 [6];

2. make recommendations arising from the determination of ambient CO₂ levels; or

3. 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].