1、BRITISH STANDARD BS 3841-1: 1994 Determination of smoke emission from manufactured solid fuels for domestic use Part 1: General method for determination of smoke emission rate UDC 662.62:697.243.3:683.93:662.613.5BS3841-1:1994 This British Standard, having been prepared under the directionof the Sol
2、id Mineral Fuels Standards Policy Committee, was published underthe authority of the Standards Board and comesintoeffect on 15 May 1994 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference SFC/11 Draft for comment 92/58574 DC ISBN 0 580 21835 X Committees
3、 responsible for this British Standard The preparation of this British Standard was entrusted by the Solid Mineral Fuels Standards Policy Committee (SFC/-) to Technical Committee SFC/11, upon which the following bodies were represented: Association of British Solid Fuel Appliances Manufacturers Brit
4、ish Coal Corporation British Foundry Association Department of Health Department of the Environment (Her Majestys Inspectorate of Pollution) Department of Trade and Industry (Warren Spring Laboratory) Low Temperature Coal Distillers Association of Great Britain Ltd. METCOM Solid Smokeless Fuels Fede
5、ration Amendments issued since publication Amd. No. Date CommentsBS3841-1:1994 BSI 08-1999 i Contents Page Committees responsible Inside front cover Foreword ii Introduction 1 Scope 1 2 References 1 3 Definitions 1 4 Principle 2 5 Apparatus 2 6 Test chimney and setting 2 7 Open fire and gas ignition
6、 burner 5 8 Gas supply to ignition burner 9 9 Fuel sample preparation and bulk density determination 9 10 Procedure 10 11 Modifications to the procedure for long briquettes 12 12 Calculation of results 12 13 Test report 12 Annex A (informative) Basis of test method 13 Figure 1 Test chimney 4 Figure
7、2 Test setting for installation of 400 mm inset open fire 5 Figure 3 Test appliance: 400 mm (nominal) inset open fire 6 Figure 4 Air inlet plate for use with 400 mm inset open fire 7 Figure 5 Aerator/flow restrictor device for natural gas ingnition burner 8 Figure 6 Monitoring of gas supply to natur
8、al gas ignition burner 8 List of references Inside back coverBS3841-1:1994 ii BSI 08-1999 Foreword This Part of BS 3841 has been prepared under the direction of the Solid Mineral Fuels Standards Policy Committee. Together with BS 3841-2:1994 it supersedes BS 3841:1972 which is withdrawn. The Clean A
9、ir Act 1956 1, modified and extended by the Clean Air Act 1968 2, was introduced to control air pollution in the United Kingdom. Under Section 11 of the 1956 Act, local authorities are empowered, subject to confirmation by the Minister, to set up smoke control areas in which it is an offence to emit
10、 smoke from a building. The only defences against prosecution under the Act are that the smoke is produced from an authorized fuel, that authorized fuels are not available or that the smoke is from an exempted appliance. An exempted appliance is defined by Section 11(4) of the 1956 Act as one which
11、can be operated for burning a fuel other than an authorized fuel without producing any smoke or a substantial quantity of smoke. An authorized fuel is defined in Section 34(1) of the 1956 Act as a fuel declared by regulations of the Minister to be an authorized fuel for the purposes of this Act. In
12、1956 a number of classes of solid smokeless fuel, both manufactured and natural, which pre-dated the Act were declared to be authorized fuels. Subsequent development of other types of manufactured smokeless fuel for domestic purposes demonstrated the need for a standard procedure to establish their
13、potential for smoke emission and to assess whether such fuels were suitable for authorization within the terms of the 1956 Act. For this revision, BS 3841 has been divided into two Parts, Part 1 covering the fuel combustion procedure and Part 2 describing the smoke measurement equipment and its use.
14、 The main technical changes from the previous edition are as follows: a) extension of the test procedure to cover brown coal, lignite, peat and wood fuels; b) widening of the permitted tolerance in the second radiation peak for valid tests; c) modification of the refuelling procedure for long brique
15、ttes; d) provision of a suitable aerator to enable the gas ignition burner to burn natural gas; e) inclusion of the form of test report required; f) specification of a sampling method in a dilution tunnel as an alternative means of smoke measurement to the electrostatic precipitator; g) change of or
16、ganic solvent for cleaning the precipitator; h) change of procedure for conditioning the precipitator; utilizing a constant temperature room (hot room); i) inclusion of safety precautions relating to the use of high voltage and of organic solvent in the operation of the precipitator. A British Stand
17、ard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover,
18、an inside front cover, pages i and ii, pages1 to 14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS3841-1:1994 BSI 08-1999 1 Introduction S
19、moke is defined in Section 34(1) of the Clean Air Act 1956 1 as “including soot, ash, grit and gritty particles emitted in smoke”. This definition is modified by the 1968 Act 2 by the inclusion of fume. None of these terms is precisely defined within the Acts and therefore they are of little technic
20、al significance. It is clear from other parts of the Acts and related Statutory Instruments that smoke is to be assessed on the basis of its optical properties: it is often qualified by the use of “dark” or “black”. However, assessment of smoke emissions purely on the basis of light obscuration depe
21、nds on many parameters including the particle size distribution of the emitted particles, their chemical composition and the lighting conditions at the time when the assessment is made (if it is in the open air). Assessment in these purely subjective terms is clearly unsatisfactory. Therefore, BS 38
22、41 describes the gravimetric measurement of the particulate emission rate during a test carried out with the fire at an average radiation heat output chosen to be reasonably representative of normal domestic usage. Subseqently, an emission limit in gravimetric terms of 5 g h was set by the Governmen
23、t. The current test procedure relates particularly well to solid fuels manufactured from relatively high grade constituents. During recent years there have been many applications for the authorization of lower grade solid fuels such as peat, brown coal and fuels derived from waste materials such as
24、wood waste, straw and paper. This Part of BS 3841 describes a test procedure to provide the information necessary for a judgement to be made on the suitability of the fuel for classification as an authorized smokeless fuel on the basis of the 5 g/h emission limit and, if necessary, in terms of the c
25、oncentration of particulate material emitted. The procedure for authorization of a solid fuel is now well established. When a new solid smokeless fuel intended for use in a smoke control area has been developed, application is made to the Department of the Environment for authorization as a smokeles
26、s fuel. At this stage the smoke emission characteristics of a representative sample of the fuel would be determined in accordance with the procedure described in BS 3841. The average result of replicate determinations is compared with the emission limit. The method is not suitable as a day-to-day qu
27、ality control procedure because of its time-consuming nature and the expense incurred. Other procedures which are quicker and easier to carry out but possibly less precise have been developed for quality control purposes. Such methods are not absolute: the relationship between any such method and th
28、e reference method described in BS 3841 has to be determined and periodic checks and calibrations have to be carried out for each fuel. 1 Scope This Part of BS 3841 describes a general method of carrying out a smoke emission test from a sample of a manufactured solid fuel intended for use in domesti
29、c fires. 2 References 2.1 Normative references This Part of BS 3841 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated ref
30、erences, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this Part of BS 3841 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any a
31、mendments. 2.2 Informative references This Part of BS 3841 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Defin
32、itions For the purposes of this Part of BS 3841 thedefinitions given in BS 1846-1:1968, BS 6100-1.5.1:1984 and BS 3323:1992 apply.BS3841-1:1994 2 BSI 08-1999 4 Principle A specified ignition charge of the prepared fuel, the mass depending upon its bulk density, is charged into a standard design of o
33、pen fire setting and ignited with gas. As the fuel burns the radiation heat output rises to a maximum (the first radiation peak) and then starts to drop. When it has fallen to a specified level a refuelling charge, again the mass depending upon the bulk density of the fuel, is added. The radiation h
34、eat output again rises to a maximum (the second radiation peak) and then starts to drop. The setting of the air control system of the fire is adjusted so that the value of the second radiation peak falls within the range 1.80 kW to2.30 kW. When the radiation heat output has fallen to a specified lev
35、el after the second radiation peak a second refuelling charge, equal in mass to the first, is added to the fire. If the bulk density of the fuel is below 480 kg/m 3 , a third refuelling charge, of the same mass as the first and second, is added after the radiation heat output has fallen to a specifi
36、ed level after the third radiation peak. The mass of smoke emitted during the burning of the two, or three, refuelling charges is determined by one of the methods described in BS 3841-2 or by any other method which has been demonstrated to give equivalent results. The duration of the test period is
37、taken as the time interval between the addition of the first refuelling charge and the falling of the radiation heat output to the level which is specified for refuelling, after the third or fourth radiation peak (depending upon whether there have been two or three refuelling charges). The result is
38、 expressed as the mass of smoke emitted per unit time, averaged over the duration of the test period. NOTEFurther information on the basis of the test method is given in Annex A. 5 Apparatus 5.1 Smoke measurement equipment, as required for the method of measurement of smoke emission rate (see 10.3.3
39、). 5.2 BCURA (British Coal Utilization Research Association) quadrant radiometer 1) , for measuring the radiation heat output from the fire. The radiometer shall consist of the upper section of a hemispherical cage fitted with a matched set of radiometer elements. The calibration factor F, in kilowa
40、tts per millivolt, is initially provided by the supplier of the radiometer and shall be redetermined at intervals not exceeding 24 months. 5.3 Balance, for weighing the fuel, with a capacity of at least 10 kg and an accuracy of 0.01 kg. 5.4 Calibrated dry gas meter, for measuring the total volume of
41、 gas supplied to the ignition burner, with an accuracy of 0.1 dm 3 . The calibration shall be traceable to national standards and shall be carried out under the pressure conditions of the test. 5.5 Indicating gas flowmeter, for checking the rate of flow of gas supplied to the ignition burner, with a
42、 range of 0.04 dm 3 /s to 0.4 dm 3 /s. 5.6 Manometer, for measuring the pressure of the gas supply to the ignition burner, with a range covering 0 kPa to 2.5 kPa and an accuracy of 0.0025 kPa. 5.7 Thermocouple or other temperature measurement device, for measuring the temperature of the gas supply t
43、o the ignition burner, with a calibration traceable to national standards. 5.8 Poker, for de-ashing the fire, with a diameter of not more than 10 mm at the end which is inserted into the fire. 5.9 Timing device, accurate to within 1 s over the duration of the test. 6 Test chimney and setting 6.1 Tes
44、t chimney The test chimney shall be constructed in accordance with Figure 1. The chimney shall terminate within the test laboratory at a height of 4570 mm 25 mm above finished hearth level. An extraction system shall be provided for collecting the flue gas from the top of the chimney and discharging
45、 it to outside air. NOTEThe design of the system depends on the method of smoke measurement: the arrangements when using the electrostatic precipitator and dilution tunnel methods are described in 3.2.1 and 4.2.11 respectively of BS 3841-2:1994. 6.2 Test setting The test setting shall be constructed
46、 as shown inFigure 2. The fireback shall conform to BS1251:1987. NOTE 1The number of parts of the fireback is left to individual choice. The rear surface of the throat shall be formed above the fireback in the manner shown in Figure 2, i.e.without a smoke shelf. The line of the upper surfaceof the f
47、ireback shall be followed for approximately100 mm and the throat then sloped off at an angle of approximately 45 to meet the brickwork at the rear of the chimney, yielding a throat width of approximately 115 mm. 1) For information on the availability of BCURA radiometers and calibrated radiometer el
48、ements write to Customer Services, Information, BSI, Linford Wood, Milton Keynes MK14 6LE.BS3841-1:1994 BSI 08-1999 3 NOTE 2This may be done by the use of either brick with a lime mortar lining or precast concrete. A fireplace surround comforming to BS 1251:1987 shall be fitted, of overall size 1 m
49、high by 1 m wide by 50 mm thick and with the fireplace opening measuringwide andhigh. The surround shall be flat, i.e. the back of the surround at its periphery and around the fireplace opening shall be in the same plane. The front of the surround shall be faced with light-coloured matt tiles. Directly and centrally in front of the chimney the concrete hearth shall be faced with light-coloured matt tiles or finished in a light-coloured matt paint, to match the front of the fireplace surround, over a sufficient area to cover a semicircle of 760 mm r
