1、BRITISH STANDARD BS 6680:1985 Specification for Flameproof equipment for diesel engines for use in coal mines and other mines susceptible to firedamp UDC 621.436-758.364:614.83/.84:622.812BS6680:1985 This British Standard, having been prepared under the direction of the Mining and Quarrying Requisit
2、es Standards Committee, was published under the authority of the Board of BSI and comes into effect on 31 December1985 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference MQE/27 Draft for comment 83/79918 DC ISBN 0 580 14924 2 Committees responsible for
3、this British Standard The preparation of this British Standard was entrusted by the Mining and Quarrying Requisites Standards Committee (MQE/-) to Technical Committee MQE/27 upon which the following bodies were represented: Association of British Mining Equipment Companies British Internal Combustio
4、n Engine Manufacturers Association Health and Safety Executive Institution of Mining Electrical and Mining Mechanical Engineers National Coal Board Amendments issued since publication Amd. No. Date of issue CommentsBS6680:1985 BSI 07-1999 i Contents Page Committees responsible Inside front cover For
5、eword ii 1 Scope 1 2 Definitions 1 3 General requirements 1 4 Joints within the flameproof enclosure 2 5 Air inlet system 3 6 Exhaust and conditioning system 3 7 Flame traps 4 8 Fuel systems 4 9 Engine shut-down 5 10 Condition monitoring 5 11 Electrical apparatus 5 12 Verification testing 5 13 Maint
6、enance literature 6 14 Marking 6 Appendix A Stage 1 type testing of the flameproof enclosure 7 Appendix B Stage 2 type testing of the complete engine and ancillary fittings 7 Appendix C Fire/flame resistance of non-metallic materials 10 Appendix D Guidance on information to be supplied by the flamep
7、roof equipment supplier with equipment to be tested 11 Figure 1 Relationship between length and gap for flamepaths 3 Figure 2 Derivation of pressure rise time 8 Table 1 Maximum adjusted volumetric concentrations of CO and NO xpermitted in the undiluted exhaust gases 4 Publications referred to Inside
8、 back coverBS6680:1985 ii BSI 07-1999 Foreword This British Standard has been issued under the direction of the Mining and Quarrying Requisites Standards Committee. It is intended that the standard will replace the diesel engine flameproofing requirements currently contained in Testing Memorandum12,
9、 published by the Health and Safety Executive. Although not part of the specification, notes are included for guidance, on the information normally required to be supplied by a flameproof equipment supplier, when submitting equipment for independent test (Appendix D). A British Standard does not pur
10、port 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. Attention is drawn to the Health and Safety at Work etc. Act1974, the Mi
11、nes and Quarries Act1954, the Regulations made under these Acts, and also any other appropriate statutory requirements or byelaws. These place responsibility for complying with certain specific safety requirements on the manufacturer and the user. Summary of pages This document comprises a front cov
12、er, an inside front cover, pages i and ii, pages1 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 theinside front cover.BS6680:1985 BSI 07-1999 1 1 Scope This
13、British Standard specifies requirements for flameproof equipment attached to, or forming part of, a diesel engine for use in coal, and other, mines susceptible to firedamp. The use of diesel engines in such mines imposes environmental constraints on the equipment and these constraints are detailed i
14、n the standard. The tests which the diesel engine and its ancillary fittings are required to undergo to prove compliance with this standard are detailed in the appendices. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purpo
15、ses of this British Standard the following definitions apply. 2.1 firedamp a flammable gas, consisting mainly of methane, found naturally in mines 2.2 flameproof equipment supplier the supplier of equipment, attached to or forming part of a diesel engine, that is claimed to comply with this standard
16、 2.3 flameproof enclosure an enclosure that can withstand the pressure developed during an internal explosion and that prevents the transmission of the explosion to the atmosphere surrounding the enclosure. The flameproof enclosure includes all the gas passages associated with the inlet air, the eng
17、ine combustion chambers and the exhaust gases between the inlet flame trap and the exhaust flame trap assemblies 2.4 flame trap a passage into or out of the flameproof enclosure through which gases are designed to pass in the normal mode of operation and beyond which flame will not propagate 2.5 fla
18、meproof joint the place where the surfaces of two parts of a flameproof enclosure come together and prevent the transmission of an internal explosion to the atmosphere surrounding the enclosure 2.6 flame path the shortest path through a flameproof joint from the inside to the outside of the flamepro
19、of enclosure 2.7 diluting air air extracted from the general body of the mine atmosphere and mixed with the engine products of combustion before any such products are discharged into the general body of the mine atmosphere 2.8 particulates airborne materials present in the exhaust gases which are re
20、tained when the gases are passed, at a temperature not exceeding 52 C, through a Whatman GF/A or equivalent filter paper 3 General requirements 3.1 Light metals 3.1.1 External components 3.1.1.1 Except as provided by 3.1.1.2, the metals used in the construction of any external component shall not co
21、ntain: a) more than 15% (m/m) in total of aluminium, magnesium and titanium; b) more than 6% (m/m) in total of magnesium and titanium. 3.1.1.2 When external components are only available with metals used in their construction that contain more than the limits of aluminium, magnesium and titanium spe
22、cified in 3.1.1.1, the use of such components shall be permitted provided that: a) the flameproof equipment supplier identifies these components and demonstrates that no alternative components in metals complying with3.1.1.1 are available; b) the components are protected by means of a steel enclosur
23、e, permanently attached or retained by fixings, shrouded in accordance with3.5; c) any openings in the enclosure are such that it is not possible for a straight test bar of 13mm diameter to enter the enclosure and contact the protected metal. 3.1.2 Paints and coatings. Paints and coatings containing
24、 any of the metals aluminium, magnesium, titanium shall not be used. 3.2 Non-metallic materials 3.2.1 Pipes and hoses. All non-metallic pipes and hoses shall be made from fire resistant materials which meet the flammability test requirements of BS5173-3 and in which the average duration of flame aft
25、erglow following withdrawal of the flame does not exceed 30s. Such pipes and hoses shall be protected and shielded from any heat source hot enough to cause impairment of their properties.BS6680:1985 2 BSI 07-1999 3.2.2 Thermal insulation. Thermal insulating materials shall not be used on any part of
26、 the engine or exhaust system. 3.2.3 Wedge type transmission belts. Wedge type transmission belts shall comply with BS3790. 3.2.4 Transmission belts other than wedge type. Transmission belts other than wedge type (see3.2.3) shall satisfy the electrical resistance requirements of BS2050 and the fire
27、resistance requirements of BS3790. 3.2.5 Electrical cables. See11.3. 3.2.6 Other non-metallic components. Non-metallic components other than those specified in 3.2.1 and3.2.3 to 3.2.5 shall satisfy the electrical resistance requirements of BS2050 or BS2044, as appropriate, and the fire resistance ac
28、ceptance criteria specified in C.2 when tested in accordance with C.1. 3.3 Filling points All fluid filling points and dip sticks shall be provided with screwed or lockable caps to prevent fluid spillage in the event of the engine assuming any attitude away from its normal operating position. Fillin
29、g points shall be designed to avoid spillage during filling operations and shall be clearly and durably marked to indicate their contents. 3.4 Cooling systems for liquid cooled engines 3.4.1 Air release. The cooling system shall be so designed that air is automatically released from the system. 3.4.
30、2 Venting. Facilities for safely venting excess pressure to atmosphere shall be provided within the engine cooling system. 3.4.3 Caps. All radiator filler or pressure caps shall be secured to prevent accidental loss when removed from their operational position and shall be so arranged that the norma
31、l working pressure can be safely released. 3.5 Screwed fasteners in flameproof enclosures Fasteners and associated counterbores or shrouds shall comply with the requirements of BS5501-5. 3.6 Surface temperature The external surface temperature of any part of the equipment shall not exceed 200 C at a
32、ny time during the type tests in B.3.4 or B.3.5, except when the equipment is for use in coal mines, when this temperature shall not exceed 150 C when subjected to the same test conditions. 3.7 Engine breather The discharge from any engine breather shall not be connected to the air intake system of
33、the engine and shall be directed away from hot surfaces in such a way that the external surfaces of the engine and exhaust system do not become fouled with oil. 3.8 Metallic flexible pipes Flexible metallic pipes shall only be used within the flameproof enclosure to avoid stresses which might ruptur
34、e a solid pipe. When a metallic flexible pipe is used, then either: a) means shall be provided for detecting leakage of gas at any point along the pipe, or b) the pipe shall be of a type which has a fatigue life of at least 1 10 7cycles of vibration at the expected service amplitude, when assembled
35、in the service configuration. 4 Joints within the flameproof enclosure 4.1 Designation Each joint within the flameproof enclosure shall be designated as either a “closed joint” or an “open joint”. A “closed joint” shall comply with 4.2. An “open joint” shall comply with 4.3. NOTEThe joint between a
36、flame trap and the flameproof enclosure is classed as an “open joint”. 4.2 Closed joints All closed joints shall be capable of withstanding: a) the hydraulic test pressure, determined as a result of stage1 testing (see12.2.2) without permanent deformation; b) the maximum internal operating pressure,
37、 without leakage, for the operational time interval between maintenance checks on the joint. NOTEThe manufacturer should state any conditions which impose a limit upon the joint and should provide clear instructions and data for the manner in which the joint is to be serviced at the end of each serv
38、ice interval or at any intervening time when the joint has been disturbed. 4.3 Open joints Any linear and continuous open path between the flameproof enclosure and the surrounding atmosphere shall be within the dimensions of length versus gap shown in Figure 1. When the path is not linear and contin
39、uous, the flamepath length shall be determined by reference to BS5501-5. Having determined the flamepath length, the corresponding maximum gap shall be determined from Figure 1. Threaded joints shall comply with 4.2 and Table 5 of BS5501-5:1977.BS6680:1985 BSI 07-1999 3 5 Air inlet system 5.1 Air cl
40、eaner The air inlet system shall be fitted with an air cleaner, preferably of the dry type. Where the use of a wet filter is proposed, passage of the wetting medium through the combustion chamber during operation of the engine shall not affect the ability of the engine to pass stage2 type testing as
41、 described in Appendix B. 5.2 Flame traps Each air inlet shall be fitted with a flame trap, complying with clause7, located between the air cleaner and the inlet manifold. 5.3 Inlet air shut-off valves Inlet air shut-off valves shall not be used as a primary means of stopping the diesel engine. If a
42、n inlet air shut-off system is fitted as a secondary means of stopping the engine, the joints in the intake system shall be such that the engine cannot continue to run because of inward leakage of air. 6 Exhaust and conditioning system 6.1 Flame trap The exhaust system shall be fitted with a flame t
43、rap complying with clause7. 6.2 Spark arrester The exhaust system shall prevent the emission of sparks into the surrounding atmosphere when tested in accordance with B.3.8. 6.3 Water-based conditioning systems 6.3.1 Where a water-based conditioning system is utilized it shall be manufactured from ma
44、terials which will withstand the fluid contained within the system, the products of combustion present in the exhaust gases and any products of combination. 6.3.2 The fluid capacity of any water-based conditioning system, including any capacity make-up system, shall provide at least 90min continuous
45、 running when the engine is being operated to the test conditions given in B.3.4 h) but see alsoB.3.4 b). 6.4 Exhaust emissions 6.4.1 The exhaust gases immediately before dilution shall not contain adjusted volumetric concentrations of carbon monoxide (CO) and oxides of nitrogen (NO x ) exceeding th
46、e limits given in Table 1, on a dry basis, when the engine is operating to the test conditions stated in B.3.4, B.3.5 andB.3.6. The percentage V/V adjusted volumetric concentration shall be calculated as the numerical equivalent of: Figure 1 Relationship between length and gap for flamepaths 0.2QV P
47、 corr -BS6680:1985 4 BSI 07-1999 Table 1 Maximum adjusted volumetric concentrations of CO and NO xpermitted in the undiluted exhaust gases where 6.4.2 At the point of discharge into the surrounding atmosphere, and after dilution, the exhaust gases shall not contain average measured volumetric concen
48、trations of carbon monoxide (CO) or oxides of nitrogen (NO x ) exceeding, on a dry basis, 0.015% and 0.007%, respectively when the engine is being tested to the test conditions given in B.3.4 j). 6.4.3 Means shall be provided for sampling the undiluted exhaust gases immediately before dilution, with
49、out infringing the flameproof enclosure. 6.5 Exhaust gas temperature The temperature of the exhaust gases at the point of discharge into the surrounding atmosphere, and after dilution, shall not exceed 70 C when the engine is operating in any of the conditions given inB.3.5. 7 Flame traps Each flame trap shall be so mounted that it will not be damaged during normal operation of the engine. It shall be removable as a complete unit for inspection, cleaning and overhaul without the need for special lifting equipment. The inlet flame traps shall no
