Carbon monoxide in
dwellings and the
combustion performance
of gas-fired appliances –
Part 4: Guide for using electronic
portable combustion gas analysers as part
of the process of servicing and
maintenance of gas-fired appliances
This part of BS 7967 gives guidance on the use of an electronic portable
combustion gas analyser as a diagnostic instrument to assist a gas
operative:
a) in determining the level of servicing required for a gas-fired
appliance;
b) in confirming satisfactory combustion following servicing in
accordance with manufacturer’s instructions;
c) in confirming satisfactory combustion following maintenance.
This standard is intended to ensure the safe and efficient operation, in
dwellings, of:
1) flueless gas-fired appliances (type A gas-fired appliances),
e.g. cooking appliances, space heaters.
2) open flued appliances (type B gas-fired appliances).
3) room sealed appliances (type C gas-fired appliances).
NOTE 1 Types A, B and C classifications of gas-fired appliances are
described in PD CEN/TR 1749.
This standard is for use with appliances using 1st, 2nd or 3rd family
gases.
This standard deals with the measurement of carbon monoxide (CO),
the determination of carbon dioxide (CO2) and their ratio in combustion
products from gas-fired appliances.
NOTE 2 This standard does not cover the use of an analyser during
commissioning. However, an appliance manufacturer may specify the
need for a combustion test during commissioning. If this is called for, and
if either due to the absence of the necessary equipment or through lack of
expertise, the manufacturer’s methods and figures cannot be applied, the
appliance needs to be turned off, disconnected and labelled as an uncommissioned
appliance until such time as either the necessary
equipment and/or expertise is available.
NOTE 3 Following a landlord’s gas safety check in accordance with
regulation 36(3) of The Gas Safety (Installation and Use) Regulations
1998 [1], an electronic portable combustion gas analyser can also be used
in accordance with this standard as a diagnostic instrument to determine
the need for further work.
NOTE 4 Combustion products from gas appliances will contain nitrogen
oxides (NOx), predominantly nitrogen monoxide (nitric oxide, NO) and
nitrogen dioxide (NO2). This standard does not deal with the
measurement of combustion products such as nitrogen oxides and
aldehydes. Such products could be present in the air in sufficient
quantities to prove an irritant and could be harmful. For guidance on the
occupational health considerations associated with these combustion
products, reference can be made to the following documents.
a) The Institute for Environment and Health’s IEH assessment on
indoor air quality in the home: Nitrogen dioxide, formaldehyde,
volatile organic compounds, house dust mites, fungi and bacteria
[7].
b) The Health and Safety Executive’s (HSE’s) Chemical Hazard Alert
Notices, CHAN 28 on nitrogen monoxide [8] and CHAN 29 on
nitrogen dioxide [9]. Please note that these CHANs refer to
occupational levels specifically related to the workplace situation.
For further guidance refer to the HSE1).