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1、BRITISH STANDARD BS 7967-2:2005 Carbon monoxide in dwellings and the combustion performance of gas-fired appliances Part 2: Guide for using electronic portable combustion gas analysers in the measurement of carbon monoxide and the determination of combustion performance ICS 13.040.40; 97.100.20 ? Li
2、censed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:39:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 8 December 2005 BSI 8 December 2005 The fol
3、lowing BSI references relate to the work on this British Standard: Committee reference GSE/30 Draft for comment 04/30092714DC ISBN 0 580 47420 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee GSE/30, Gas installations (1
4、st, 2nd and 3rd family gases), upon which the following bodies were represented: Boiler and Radiator Manufacturers Association Ltd British Flue and Chimney Manufacturers Association BSI Consumer Policy Committee Catering Equipment Suppliers Association Centrica plc Council for Registered Gas Install
5、ers Department of Trade and Industry Health and Safety Executive Heating and Ventilating Contractors Association ICOM Energy Association Institute of Domestic Heating and Environmental Engineers Institution of Gas Engineers and Managers LP Gas Association Society of British Gas Industries Co-opted m
6、embers The following bodies were also represented in the drafting of this standard: Advantica Ltd Association of Plumbing and Heating Contractors Council of Gas Detection and Environmental Monitoring Energywatch National Grid Gas plc Amendments issued since publication Amd. No.DateComments Licensed
7、Copy: London South Bank University, London South Bank University, Fri Dec 08 10:39:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2:2005 BSI 8 December 2005 i Contents Page Committees responsibleInside front cover Forewordii 1Scope 1 2Normative references 1 3Terms and definitions 2 4Gas analy
8、sers 3 5Determination of ambient levels of CO and CO2 in dwellings 4 6Determination of the combustion performance (CO/CO2 ratio) of an appliance 7 Annex A (informative) Electronic portable combustion gas analyser 12 Annex B (informative) Multi-hole sample probes 13 Annex C (informative) Flue/draught
9、 diverter configurations for warm air heaters 14 Bibliography 15 Figure B.1 Probe for gas cooker grill 13 Figure B.2 Angled probe 13 Figure C.1 Flue/draught diverter configurations for warm air heaters 14 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:39:59
10、GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2:2005 ii BSI 8 December 2005 Foreword This part of BS 7967 has been prepared under the direction of Technical Committee GSE/30. BS 7967 consists of the following parts. Part 1: Guide for identifying and managing sources of fumes, smells, spillage/l
11、eakage of combustion products and carbon monoxide detector activation. Part 2: Guide for using electronic portable combustion gas analysers in the measurement of carbon monoxide and the determination of combustion performance. Part 3: Guide for responding to measurements obtained from electronic por
12、table combustion gas analysers. Part 4: Guide for using electronic portable combustion gas analysers as part of the process of servicing and maintenance of gas-fired appliances.1) This part of BS 7967 is intended to be used in conjunction with BS 7967-1, BS 7967-3 and the Gas Industry Unsafe Situati
13、ons Procedure 1. This standard has been prepared to provide guidance on the use of electronic portable combustion gas analysers for which no standard has previously been available. This standard has been written for electronic portable combustion gas analysers that are not suitable for measuring amb
14、ient levels of CO2. However, at the time of publication, analysers equipped with direct reading CO2 sensors that may be used for measuring ambient levels of CO2 are becoming available and these will be the subject of a future revision of this standard. Attention is drawn to the following statutory r
15、egulations. The Gas Safety (Installation b) ensure that the analyser has a current proof of calibration; c) ensure that the display is functioning correctly; d) ensure the analyser is zeroed and purged in accordance with the manufacturers instructions; e) ensure that the pump is working; f) ensure t
16、hat filters and water traps are clean and dry; g) ensure that probe tubing is free from leaks or damage. NOTE It is essential that analysers are only used by a person who: a) is competent in their use; and b) has an understanding of the results obtained and an awareness of the necessary safety actio
17、ns and appropriate regulations e.g. GS(I or b) of a type that measures CO and O2 and calculates the CO2 levels from the O2 measured. The accuracy of gas analysers used in the measurement of CO in dwellings should be guaranteed by the manufacturer and the gas analysers should be of a type that measur
18、es and displays CO in ppm. For readings at or below 20 ppm the accuracy should be 3 ppm or better and for above 20 ppm the accuracy should be 5 % or better of the instrument reading. Regardless of which gas analyser is used, the manufacturers written specification should be checked to confirm that t
19、he analyser is accurate to these levels. NOTE 1 When using a gas analyser that performs the functions described in b) to measure CO, it is recommended that the gas analyser is certified by the manufacturer as conforming to BS 7927:1998 including Amendment 1:1999. NOTE 2 Not all gas analysers have th
20、e ability to record the maximum CO reading; some only display the current level. In the latter instance it is necessary to exercise extra vigilance to ensure that a peak value does not pass unobserved. This needs to be kept in mind when selecting the gas analyser. Licensed Copy: London South Bank Un
21、iversity, London South Bank University, Fri Dec 08 10:39:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2:2005 4 BSI 8 December 2005 4.2.2 CO2 in dwellings For the detection of the presence of CO2 in dwellings analysers should conform to BS 7927:1998 including Amendment 1:1999. 4.2.3 Combusti
22、on products from appliances For the determination of CO and CO2 in the combustion products from gas-fired appliances the analyser should conform to BS 7927:1998 including Amendment 1:1999. If the analyser is not labelled as conforming to BS 7927, the analyser manufacturer should be asked to provide
23、written confirmation as to its suitability for the intended purpose. 4.2.4 Sensor cross sensitivity Analyser readings for CO and CO2 can be affected by the presence of other gases and vapours that can, for example, come from cooking activities or common household materials such as cleaning fluids, p
24、olishes and paints. This sensor cross sensitivity can lead to inaccurate readings. The manufacturers instructions for analysers conforming to BS 7927:1998 including Amendment 1:1999 will indicate what substances could interfere with analyser operation or reliability in the short or long term. In the
25、 case of other analysers the gas analyser manufacturer should be consulted. 4.2.5 Multi-hole sample probes Appropriate multi-hole probes are described in Annex B. These may be supplied by the analyser manufacturer. 5 Determination of ambient levels of CO and CO2 in dwellings NOTE Of the two combusti
26、on product gases CO and CO2 it is the former which attracts attention because of its greater toxicity. Therefore, 5.1 to 5.6 have been written emphasising the measurement of CO only. However, in some circumstances the measurement of CO2 can give a better indication of the presence of combustion prod
27、ucts. This is particularly true where the volume of combustion products released is small, the concentration of CO in the combustion products is low or access to the appliance is restricted, e.g. when appliances are fitted in small appliance compartments. Where CO2 is used to check for the presence
28、of combustion products, as a precaution it is essential that CO is monitored as well. 5.1 General The procedures described in 5.2 to 5.6 are not intended to measure the absolute levels of CO within a space. They are intended to measure the increase in CO level (which, for example, could emanate from
29、 a faulty appliance installation) above the outdoor background CO level. Normally these measurements will only be made to provide reassurance to the customer, or where there is still “cause for concern”, after it has been ascertained that appliances have been installed correctly, are in apparent goo
30、d working order, and are operating in accordance with the manufacturers instructions. If an absolute CO level is required it will be necessary to “zero” the analyser with a CO free sample. If the analyser measures absolute CO levels it will be necessary to subtract the outdoor background CO level fr
31、om the level recorded in the building. There are many types of analyser and this standard can only provide general advice. For some analysers that always commence their measurement from a position of absolute zero it is not necessary to “zero” in the outdoor air. The analyser manufacturers instructi
32、ons should always be consulted and followed. Busy roads and car park exits can generate significantly high levels of outdoor background CO and this should be kept in mind when forming the final conclusion to the test. Possible reasons for testing for CO are given in BS 7967-1. 5.2 Preparation of ana
33、lyser for use Switch the analyser on and carry out the relevant “zero” procedure described in the manufacturers instructions in outdoor air at a location as adjacent to the space in the building to be tested as is reasonably possible. The analysers calculate CO2 from an O2 measurement, so it is good
34、 practice to check that the O2 reading in outdoor air is 20.9 %. When CO2 is being determined, the relevant fuel gas should be selected on the analyser. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:39:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2
35、:2005 BSI 8 December 2005 5 Once zeroed, it is essential that the analyser is not switched off during the test. If it is switched off, the analyser will need to be re-zeroed before taking any more readings. If the analyser cannot be zeroed, the manufacturers instructions should be consulted. For exa
36、mple, the analyser may be faulty or its sensors may require recalibration and/or replacement. 5.3 Preparation for testing It is recommended that only persons required to carry out the test work are in the room under test and that these persons do not smoke before or during the tests. Smoking in othe
37、r parts of the building adjacent to the area being tested should be discouraged during the testing procedure as this can also adversely affect results. Position an open ended sampling probe approximately 2 m above floor level in the centre of the room and at least 1 m away from any suspect appliance
38、 installation. Turn off/extinguish all combustion appliances and ventilate the room until the inside and outside CO levels are the same. Close all external doors, windows and customer adjustable ventilation. Record the level of CO over a 15 min period. If the indoor level of CO starts to rise during
39、 this period, check for CO migration from other sources. If there is no rise then proceed to the appropriate test in 5.4 and 5.5. NOTE 1 It should be noted that there may be more than one appliance installation at fault and more than one source of CO in the building. CO can come from sources other t
40、han gas appliances, e.g. solid fuel appliances, smoking, etc. NOTE 2 Information on sources of CO and its movement is given in BS 7967-1. 5.4 Testing 5.4.1 General procedure With only one appliance operating at a time, measure the CO level in the room in accordance with 5.4.3, 5.4.4 or 5.4.5 dependi
41、ng on what type of appliance is being operated. Clearly record the CO level measurements and make the results available in accordance with 5.7. Repeat the measurement for each appliance in turn or in combination until satisfied that the source of CO has been identified or that the original problem h
42、as been resolved. NOTE 1 The generation of negative pressures within spaces may prevent the correct operation of combustion and flue systems or induce CO from other spaces. Consequently, for each test it will be necessary to take account of the effect of mechanical air movement and extraction equipm
43、ent such as cooker hoods, extractor fans, radon ventilation systems, tumble dryers, warm air circulation fans and appliance flue interaction between rooms. Except when carrying out the test for cookers in accordance with 5.4.5.1, when higher intermittent levels are allowed, if at any time the CO rea
44、ding exceeds 30 ppm, stop the test, turn off all appliances, open all windows and doors to ventilate the room and vacate the room under test. NOTE 2 It can be acceptable to continue testing above 30 ppm CO if a risk assessment has been carried out in accordance with the Control of Substances Hazardo
45、us to Health Regulations 1999 (COSHH) 14. Further guidance on COSHH is given in the Health and Safety Commission (HSC) Approved Code of Practice and Guidance, Control of substances hazardous to health The Control of Substances Hazardous to Health Regulations 2002 15. If the CO reading exceeds the le
46、vel(s) given in BS 7967-3, perform the appropriate action recommended in BS 7967-3. 5.4.2 Types of gas-fired appliance The following three types of gas-fired appliances are classified in PD CR 1749 and BS 5440-1. a) Flueless appliances (type A appliances). These are appliances not intended for conne
47、ction to a flue or to a device for evacuating the combustion products to the outside of the room in which the appliance is installed. b) Open flue appliances (type B appliances). These are appliances intended to be connected to a flue that evacuates the combustion products to the outside of the room
48、 containing the appliance. The combustion air is drawn directly from the room. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:39:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7967-2:2005 6 BSI 8 December 2005 c) Room sealed appliances (type C appliances).
49、 These are appliances in which the combustion circuit (air supply, combustion chamber, heat exchanger and evacuation of the combustion products) is sealed with respect to the room in which the appliance is installed. Even where there is purpose built extraction direct to the outside of the building, flueless appliances will release some CO and CO2 into the building. The other types of appliance, when installed and operating in accordance with the manufacturers instructions, wi
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