1、STD-BSI BS EN 50303-ENGL 2000 m Lb24bb 087957b 192 m BRITISH STANDARD Group I, Category M1 equipment intended to remain functional in atmospheres endangered by firedamp and/or coal dust The European standard EN 50303:2000 has the status of a British Standard ICs 29.260.20 NO COPYING WITHOUT BSI PERM
2、ISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN i0303:2000 STD.BSI BS EN 50303-ENGL 2000 H Lb24667 0879577 027 BS EN 603032000 National foreword This British Standard is the officiai English ianguage version of EN 50303:2. The UK participation in its preparation was entrusted to Technid Committee
3、GEy31, Electrid apparatus for use in explosve atomspheres, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the - monitor related internationai and European developments and prom and b) more than 6 % in total of
4、 magnesium, titanium and zirconium. O BSI 11-2000 STD.BSI BS EN 50303-ENGL 2000 E Lb24669 0879585 JT Page 8 EN 50303:2000 4.6.2 No exposed external parts of equipment shall be painted or coated with preparations containing, in metallic form, aluminium, magnesium, titanium or zirconium. 4.6.3 Light m
5、etal components, not forming part of the external enclosures, shall be so contained or guarded as to prevent abrupt stress and impact from other extraneous metallic objects during normal operation of the equipment. 4.7 Enclosures constructed of plastics or other materials susceptible to being charge
6、d by static electricity, for: - non-fixed equipment (e.9. portable, hand-held, rotating parts, cooling fans); or - fixed equipment which is likely to be charged by high velocity dust laden air (e.9. equipment intended to be located inside ventilating ducting); Prevention of dangerous electrostatic c
7、harges having a surface area normal conditions of electrostatic charges is projected in any direction of more than 100 ct? shall be so designed that under use, maintenance and cleaning, the danger of ignition of firedamp due to avoided. This requirement shall be satisfied by either: - suitable selec
8、tion of material so that the insulation resistance of the enclosure, measured according to the methods given in EN 50014 and prEN 13463-1, does not exceed 1 CB at (23 f 2) “C and (50 f 5) % relative humidity; or - by virtue of the size, shape and layout of the enclosure, or other protective methods
9、utilized, such dangerous electrostatic charges are not likely to occur. NOTE By virtue of its omission from this text and 7.4.2 of prEN 13463-1, the option described in 7.3.1 of EN 50014 of aiiachinga warning label, is not a permissible arrangement for Category Ml equipment. 4.8 Electric cables 4.8.
10、1 General 4.8.1.1 Electric cables, forming part of Category M1 equipment, shall be assessed for compliance as part of the equipment to which they are connected. Where cables are incorporated into an intrinsically safe circuit, the integrated equipment shall comply with EN 50020 Category ia“. NOTE At
11、 the present time, the explosion protection standards listed in clause 2 do not apply to electric cables because they ae not within their scope. The following clauses therefore deal with electric cables protected by virtue of containing circuits that ae safe with two faults. They repeat the requirem
12、ents previously incorporated in annex 111 of European Directive 82/13/EEC and may be amended or revised at a later date when a Group I Intrinsically Safe Systems Standard is published. 4.8.1.2 Electric cables, cable entries and connections shall be constructed according to good engineering practice
13、and provide ingress protection at least equal to that of the equipment to which they are connected. 4.8.2 Cables containing intrinsically safe circuits shall not contain any non-intrinsically safe circuits. Cables containing intrinsically safe circuits 4.8.3 4.8.3.1 Where a multicore cable contains
14、more than one intrinsically safe Category ia“ circuit its insulation shall have a radial thickness appropriate to the diameter of the conductor. In the case of polyethylene this shall be a minimum radial thickness of 0,2 mm. Additional requirements for cables containing more than one intrinsically s
15、afe circuit OBSI 11-2000 STD.BSI BS EN 50303-ENGL 2000 LbZ4bb9 087958b 031, m Page 9 EN 50303:2000 4.8.3.2 Before the multicore cable leaves the manufacturers works, the multicore cable shall have been submitted to at least one of the dielectric tests described below and the voltage withstand capabi
16、lity of the insulation confirmed in a document supplied by the cable manufacturer: dielectric test performed before the conductor cores are assembled into the cable: each core shall be tested at a voltage equal to 3 O00 V (rms) + (2 O00 times the radial thickness of the insulation in mm) V (rms). Th
17、e assembled cable is then firstly tested at a voltage value (rms) equal to 500 V applied between all armourings, or screens, of the cable joined together electrically and the bundle of all cores joined together electrically, and secondly at a voltage value (rms) equal to 1 O00 V applied between a bu
18、ndle comprising one half of the cable cores and a bundle comprising the other half of the cores. If the cable manufacturer decides otherwise, the dielectric tests may be performed using a d.c. voltage multiplied by a factor of 1,4 on the a.c. values. - dielectric test performed on an assembled cable
19、: a voltage equal to 1 O00 V (rms) is applied between all the armourings andlor screens of the cable joined together electrically and the bundle of all of the conductor cores joined together electrically. It is then tested at a voltage equal to 2 O00 V (rms) applied in succession between each conduc
20、tor core of the cable and the bundle formed by all of the other cores joined together electrically. If the cable manufacturer decides otherwise, the dielectric tests may be performed using a d.c. voltage multiplied by a factor of 1,4 on the a.c. values. 4.8.3.3 Where the above dielectric tests use a
21、n a.c. voltage, it shall be substantially of sinusoidal wave form and be at a frequency between 48 Hz and 62 Hz, supplied from a transformer of sufficient power taking account of the cable capacity. In the case of the dielectric tests on an assembled cable, the voltage shall be increased steadily to
22、 the specified value in a period not less than 10 seconds and then maintained for at least 60 seconds. 4.8.4 Assessment of equipment having multicore cables containing one or more intrinsically safe circuits 4.8.4.1 In assessing the suitability of a multicore cable containing intrinsically safe Cate
23、gory “ia“ circuits, a fault between the cores can be ignored if one of the two following requirements are satisfied: - the cable has successfully met the requirements of the dielectric tests above and each individual circuit is enclosed in a conducting screen providing at least 60 % coverage. - the
24、cable has successfully met the requirements of the dielectric tests above, is effectively protected against mechanical damage and each circuit within the cable has a peak voltage of equal to or less than 60 V in normal operation. 4.8.4.2 Where a multicore cable has successfully met the requirements
25、of the dielectric tests, but faults between cores cannot be ignored (by virtue of not meeting 4.8.4.1 above), then: NOTE The eventual connection of the screen to earth or frame will be specified in the installation rules. - in the case of a cable containing circuits forming part of a single intrinsi
26、cally safe system - faults shall be considered between up to 4 cores of the cable in addition to the intrinsically safe system being considered as though it is a single item of intrinsically safe Category “ia“ apparatus conforming with EN 50020; and - in the case of a cable containing circuits formi
27、ng parts of different intrinsically safe electrical systems - each intrinsically safe circuit contained in the cable shall have a safety factor of at least four times that required if it is considered as being a single item of intrinsically safe Category “ia“ apparatus conforming with EN 50020. 4.8.
28、4.3 Where a multicore cable has neither successfully met the requirements of the dielectric tests, nor the requirements of 4.8.4.1 above, all possible combinations of faults between cores of the cable shall be taken into account in addition to each of the circuits being considered as if they were si
29、ngle items of Category “ia“ apparatus conforming with EN 50020. O BSI 11-2000 STD.BS1 BS EN 50303-ENGL 2000 m Lb24bb 0879587 T78 m Dielectric test Screen (60 %) 4.8.3.2 Yes Yes Yes No Yes No Page 10 EN 50303:2000 Additional conditions Faults to be considered None None Fixed and protected, None S60V
30、None Yes (see 4.8.4.2) 4.8.4.4 The documents produced by the manufacturer of the equipment or intrinsically safe system containing the multicore cables and circuits shall specify the conditions of use resulting from the assessment described in 4.8. No Core insulation 4.8.3.1 Yes No None Yes (see 4.8
31、.4.3) 4.9 4.9.1 External pipesloptical fibres 4.9.1.1 The total energy, capable of being converted into an ignition capable heated surface or hot particle, delivered by any pipe or fibre intended for continued operation in an explosive atmosphere, shall be restricted to a level incapable of igniting
32、 firedamp or an explosive dust cloud in the event of its release, for example, by damage to the pipe or fibre. External pipesloptical fibres and electromagnetic radiation from equipment 4.9.1.2 In the case of optical radiation, which is, or could be directed onto coal dust particles or other particl
33、es suspended in the air, either in normal operation or as a result of damage to the conducting medium, the radiated power shall be limited to: - a radiated power of less than 150 mW, or - a peak radiation flux of less than 20 mW/mm*. NOTE The above values are derived from levels shown to be safe whe
34、n optical radiation impinges on dust particles suspended in methandair mixtures in the form of an explosive atmosphere. They do not apply if the optical radiation can impinge on a coal dist layer and cause local heating in excess of 150 OC. In such cases, the maximum radiation values will have to be
35、 determined by tests which are outside the scope of this standard dealing with atmospheres. 4.9.1.3 Where the optically radiated power is not limited by means of an infallible energy source, or by the use of an infallible limiting device, and the optically radiated power is carried in a transmission
36、 medium (e.9. an optical fibre cable) which can, if damaged, for example by guillotining, expose the optically radiated power to a potentially explosive coal dust atmosphere, an interlock shall be provided which cuts off the radiated power at the transmitter, if either the transmission medium, or th
37、e energy received at the remote receiver becomes interruptedilost. 4.9.2 Radio-frequency radiation from equipment The amount of radio-frequency radiated power from equipment shall not exceed 6 W. NOTE Member State Governments may impose stricter limits for radiated power output for reasons other tha
38、n the risk of igniuonof firedamp andlor coal dust. For example the avoidance of radio frequency ignition of electroexplosive devices (commonly known 83 detonators) by radio transmitters. 4.10 Protection of cells or batteries 4.10.1 Only cells or batteries meeting the requirements of EN 50020 Categor
39、y ia“ in full (as described in clause 5) are permissible. Q BSI 1 1-2000 STD.BSI BS EN 50303-ENGL 2000 lb24bb 0879588 904 9 Page 11 EN 50303:2000 4.10.2 Cells or batteries intended to be re-charged in an explosive atmosphere shall be designed so that they can only be recharged from an intrinsically
40、safe circuit conforming to Category “ia“ in EN 50020. 5 Category MI equipment having the requisite level of protection in the event of two faults occurring independently of each other 5.1 General Where equipment is constructed to be safe with two faults, it shall comply with any relevant explosion p
41、rotection concept standard listed in clause 2 (see 9.1 relating to type testing). NOTE At the present time only intrinsically safe ia“ equipment constructed in accordance with EN 50020 meets this requirement. 5.2 Intrinsically safe Category M1 electrical equipment shall meet the requirements of Intr
42、insically safe apparatus and associated apparatus as specified in EN 50020 Category ia“. Two examples of equipment that are safe with two faults are shown below in Figures 1 and 2. Intrinsically safe Category M1 electrical equipment Iw Marking relating to the method of explosin protection see 10.2 e
43、) IM1 EEx ia I I Figure I - Category “MI“ intrinsically safe “ia“ equipment O BSI 1 1-2000 STD.BSI BS EN 50303-ENGL 2000 Ib24bb9 0879589 840 Page 12 EN 50303:2000 Intrinsically safe “ia“ Power supply Y Marking relating to the method of explosion protection see 10.2 e) I o IM1 EEx ia Figure 2 - Categ
44、ory “MI“ intrinsically safe “ia“ battery power supply 6 Category MI equipment having the requisite level of protection using a second independent means 6.1 General Where equipment is protected by two independent means of explosion protection, as described in 3.6 a), both forms of protection shall fu
45、lly comply with the relevant explosion protection concept standard, as listed in clause 2, to which they are constructed (see 9.2.1 relating to type testing). It shall be possible to check each type of protection individually. If two protection measures are combined which both rely on the integrity
46、of an enclosure, one of the following requirements shall be met. a) There shall be two independent enclosures, each satisfying the requirements for the relevant type of explosion protection; or b) There shall be a single enclosure, satisfying the requirements for both types of explosion protection a
47、nd additionally capable of passing the mechanical impact test in EN 50014 at a value of 20 J; or c) There shall be a single enclosure, satisfying the requirements for both types of explosion protection (including the relevant mechanical strength tests according to EN 50014, specified for unprotected
48、 locations), but with a restriction on use to locations which provide protection against mechanical damage. In this case the equipment is marked “X“ and information provided in the instructions. 6.2 6.2.1 Temperature rise limits For equipment utilizing an outer enclosure as the second independent me
49、ans of protection: Requirements for an outer enclosure as the second independent means - the surface temperature of the first independent means (inner apparatus) shall not exceed the temperature values stated in 4.5.1 during normal working; and - the outer enclosure shall not exceed the temperature values stated in 4.5.1 with the most arduous fault applied to the inner apparatus. d BSI 11-2000 STD.BS1 BS EN 50303-ENGL 2000 1624669 0877590 562 Page 13 EN 50303:2000 6.2.2 Where the second independent means of protection is an enclosure and free space exists around the first
