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a) 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NOTE 2 BS EN 50379‑3 superseded BS 7927:1998 incorporating Amendment No. 1:1999 on 1 March 2007.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.
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b) 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).
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c) 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.
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d) 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.
