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1、BRITISH STANDARD CONFIRMED JANUARY 1986 BS 1747-5: 1972 Methods for The measurement of air pollution Part 5: Directional dust gauges UDC 628.5:551.510.42:551.508.91 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:30:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1747-5:1972 This British
2、Standard, having been approved by the Solid Fuel Industry Standards Committee, was published under the authority of the Executive Board on 22 June 1972 BSI 03-1999 The following BSI references relate to the work on this standard: Committee references SFE/21 and SFE/21/4 Draft for comment 70/38715 IS
3、BN 0 580 07473 0 Co-operating organizations The Solid Fuel Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Consulting EngineersG
4、as Council* British Cast Iron Research AssociationGreater London Council* British Coke Research AssociationHeating and Ventilating Contractors British Ironfounders AssociationAssociation British Mechanical Engineering Institute of British Foundrymen ConfederationInstitute of Fuel* British Steel Indu
5、stry*Institution of Gas Engineers* Chamber of Coal TradersInstitution of Heating and Ventilating Chemical Industries AssociationEngineers* Coal Utilisation CouncilInstitution of Mechanical Engineers* Coke Oven Managers AssociationLow Temperature Coal Distillers Combustion Engineering AssociationAsso
6、ciation of Great Britain Ltd. Council of Ironfoundry AssociationsNational Coal Board* Department of the Environment*Society of British Gas Industries Department of Trade and Industry*Water-tube Boilermakers Association Domestic Solid Fuel Appliances Approval Womens Advisory Council on Solid Fuel Sch
7、eme Electricity Council, the Central Electricity Generating Board and Area Boards in England and Wales* The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted
8、with the preparation of this British Standard: Association of Municipal CorporationsDepartment of Trade and Industry Association of Public Health InspectorsWarren Spring Laboratory British Railways BoardInstitution of Electrical Engineers Department of Employment Factory Institution of Municipal Eng
9、ineers InspectorateLondon Transport Executive Department of Trade and Industry National Society for Clean Air Laboratory of the Government Chemist Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:30:33 GMT+00:00 2006, Uncontrolled Cop
10、y, (c) BSI BS 1747-5:1972 BSI 03-1999i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction1 1 Scope 1 2 Apparatus 1 3 Siting 2 4 Operation 2 5 Examination of deposit 3 Appendix A Absorptiometric measurement 4 Figure 1 Typical wooden supports for directional dust gaug
11、e 5 Figure 2 Directional dust gauge, typical assembly 6 Figure 3 Collecting head for directional dust gauge 7 Figure 4 Squeegee for directional dust gauge 8 Figure 5 Absorptiometer assembly for dust measurement 9 Figure 6 Circuit diagram for obscuration measurements 10 Table 1 Relation between scale
12、 reading and obscuration 4 British Standards 12 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:30:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1747-5:1972 ii BSI 03-1999 Foreword In order to keep abreast of progress in the industries concerned, British Standards are subject to periodi
13、cal review. Suggestions for improvements will be recorded and in due course brought to the notice of the committees charged with the revision of the standards to which they refer. A complete list of British Standards, numbering over 9,000, fully indexed and with a note of the contents of each, will
14、be found in the BSI Catalogue which may be purchased from BSI Sales Department. The Catalogue may be consulted in many public libraries and similar institutions. This standard makes reference to the following British Standard: Serious damage or reduction of amenity may be caused by polluting materia
15、ls discharged into the atmosphere from various sources. Such emissions can adversely affect agricultural land and crops, can soil clothing and buildings, can corrode metal installations and can have a harmful effect on the health of the community. It was suggested, therefore, by interested authoriti
16、es that, to assist those engaged in dealing with this national problem, the British Standards Institution should undertake the standardization of apparatus for the measurement of air pollution. It was further suggested that such apparatus should be convenient for use by technical colleges and simila
17、r institutions in order to promote widespread knowledge of the extent of air pollution. The pollutants emitted into the air may be arbitrarily classified as follows. 1) Particulate material, liquid or solid, coarse enough to settle out fairly rapidly under the influence of gravity or as a result of
18、impingement upon any projection from the Earths surface. The quantity of such material may be assessed by the method described in Part 1 or that in Part 5 of this standard. 2) Finer material which tends to remain suspended in the air but can be collected by filtration; such material is commonly know
19、n as “smoke”. A method of quantitative assessment will be found in Part 2 of this standard. 3) Gaseous impurities, which can be separated from the air by chemical means. An example of such impurities is sulphur dioxide, which causes corrosion and presents a health hazard. A method for the determinat
20、ion of this pollutant will be found in Part 3 of this standard and the determination of some other harmful gaseous constituents of the atmosphere is dealt with in Part 4 of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Stan
21、dards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. BS 2751,Vulcanized butadiene/acrylonitrile rubber compounds. Summary of pages This document comprises a front cover, an inside front cover, pages i and i
22、i, pages 1 to 12, 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. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:30:33 GMT+00:00 20
23、06, Uncontrolled Copy, (c) BSI BS 1747-5:1972 BSI 03-19991 Introduction Methods of assessing the deposition of coarse particulate material were considered before those for fine materials and gaseous impurities and a specification covering the construction and use of deposit gauges was issued in 1951
24、. Experience with these gauges has shown that they collect only very coarse dust adequately under light wind conditions, but are inefficient collectors at higher wind speeds and may even lose some of their previously collected dust under strong wind conditions. They do not adequately take account of
25、 the fact that pollution by dust, particularly of vertical surfaces, takes place even with fairly strong winds. A different type of gauge, which until recently has been known as the C.E.R.L. Directional Dust Gauge, has been developed and is the subject of this Part of this standard. The gauge measur
26、es the tendency of objects to become dirty in a dusty atmosphere. It collects the dust that is likely to impinge on objects on the Earths surface (and does not collect fine material as defined in 2) above). If the measurement of the collected dust and any associated liquid is made by absorptiometer
27、then the “covering power”, i.e. the tendency of the dust to soil objects near ground level, is assessed. Alternatively, the collected solid matter can be filtered off, dried and weighed, and an analysis of both residue and filtrate can be carried out, if required. The period of exposure of the gauge
28、 for long term measurements is commonly a calendar month, but this may conveniently be expressed in terms of 10 day periods1). The gauge may also be used in certain circumstances for individual short term measurements. The gauge will, in fact, only measure the dust pollution at its own position. If
29、the result is intended to be representative of an area rather than the measurement at a point, then the position chosen should be as typical as possible of the area and buildings or other elevated objects should be at typical distances. The deposition of dust can vary considerably over distances of
30、10 100 m and results can only be representative of an area in a statistical sense. The precise measurement of the particulate material at any particular site is difficult and it should be noted that the amount collected and retained in the gauge is influenced by factors such as the height of the gau
31、ge above ground, the nature of the site and the meteorological conditions, e.g. wind force and rainfall. These factors have to be borne in mind when any comparison is made of the quantity of the deposit measured at different sites or even on the same site under varying weather conditions, although s
32、uch comparisons may be valid in relation to known circumstances, especially when results are averaged over several months. The wind direction is also an important factor and it is a feature of the new type of gauge that its results can be interpreted in terms of direction, which is of value when the
33、 gauge is used for diagnostic purposes. 1 Scope This part of this British Standard covers the construction, installation and use of the directional dust gauge for the collection and measurement of atmospheric impurities that are deposited by their own weight or inertia, or are brought down by natura
34、l precipitation. 2 Apparatus 2.1 Assembly. The complete directional dust gauge outfit shall comprise the following: 1) one vertical supporting post (with stand, if required); 2) four collecting heads; 3) eight collecting bottles; 4) one squeegee; 5) one wash bottle. 2.2 Support. The collecting heads
35、 may be attached to a post driven directly into the ground, or to a post that can be supported by three or four legs on surfaces not easily penetrable, and shall be situated so that their tops are 1.5 0.1 m above ground level. Driven posts may be of wood, as shown in Figure 1 a, straight grained wit
36、hout knots or flaws, not less than 75 mm in diameter or side of square, or of metal tube, about 50 mm in diameter or about 40 mm square, at least 1.6 mm wall. 1) D.H Lucas and D.J. Moore. J. Inst .Air Wat. Poll., Pergamon Press, 1964 , 8 , 441. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24
37、03:30:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1747-5:1972 2 BSI 03-1999 If the gauges are mounted on a post to be supported on legs, the legs should be of steel strip at least 20 mm by 3 mm, as shown in Figure 2 (or of wood, as shown in Figure 1b, or tubular metal of equivalent strength), m
38、eeting the post at an angle of 45 about 150 mm above ground level. The legs should be linked to each other about 50 mm above ground level or may be affixed to a base plate. In order that the gauges attached to a post supported on legs may withstand severe wind forces (e.g. up to 40 m/s), a sufficien
39、t mass should be added to the legs or base plate as follows: 1) to prevent overturning 40 kg; 2) to prevent sliding (e.g. on asphalt or smooth concrete) 80 kg. The support may, however, be fastened down with screws or bolts and may also be used on soft surfaces if anchored by long pins. Suitable pro
40、tective treatment should be given to all wood and metal parts, not only to reduce corrosion but also to ensure that corrosion products do not enter the collecting heads. The complete assembly (see Figure 2) consisting of post, collecting heads with bottles and legs, if any, shall have a sighting dev
41、ice to assist in orientation. 2.3 Collecting heads. The collecting heads shall be made of chemically resistant plastics material, e.g. PVC, and shall be to the dimensions shown in Figure 3. The four heads shall be firmly attached to the post at 90 to each other. If birds are found to create a nuisan
42、ce, means may be employed to prevent this, provided that the access of naturally deposited material to the apertures is not impeded. 2.4 Collecting bottles. The bottles shall be made of suitable plastics material, preferably translucent (e.g. high density polyethylene), or of glass. They shall be at
43、tached to the collecting heads so that water running from the collecting head runs into the bottle. The capacity of the bottle should be such that it will not completely fill with rain (and washing water) in the situation where it is to be used. In most cases a capacity of one litre is adequate. Eac
44、h bottle should be indelibly marked with a code that identifies both the site on which it is used and the direction in which the aperture of its collecting head points. 2.5 Squeegee. The squeegee shall be made from an aluminium rod, 12 mm diameter and 800 mm long, to which is attached at one end, by
45、 welding or by a suitable adhesive (e.g. epoxy resin), a disc of 35 50 mm diameter and 3 to 5 mm thick. To this is attached by a suitable impact adhesive a 150 segment of a concentric rubber disc, 3 mm thick and 75 1 mm in diameter. This rubber disc is of nitrile rubber to BS 2751, Grade BAS (see Fi
46、gure 4). 2.6 Wash bottle. A wash bottle of the type used in chemistry laboratories, filled with distilled water, is desirable for washing dust from the collecting head into the bottle and for washing the collected material out of the bottle into the measuring system. 3 Siting The directional dust ga
47、uge shall be sited with the post vertical and, whenever possible, in an open space. The gauge stand, if used, should be securely fixed to the surface on which it stands so that individual orifices always face the preselected directions. If necessary the gauge may be sited above ground level, provide
48、d that the foregoing considerations are observed. Gauges to assess nuisance should obviously be sited at the point of complaint; when required to assess source behaviour, a single assembly can be used or several can be distributed at convenient distances and directions from the source. 4 Operation 4
49、.1 Preliminary. The gauge shall be put into operation on the chosen site as described in Clause 3 on the first day of a calendar month. If for any reason an operation is not carried out on the first day of the month, the fact shall be stated in the report. If light is prevented from reaching the contents of the collecting bottle algae should not develop, but it may be desirable to add a suitable inhibitor2) to each of the collecting bottles in order to discourage the development of fungi or similar growths. 4.2 Final. On the first day of th