1、BS 1123:2006Fusible plugs for steam boilers and compressed air applications SpecificationICS 13.240; 97.120NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the
2、document was last issued. BSI 2006ISBN 0 580 48468 8The following BSI references relate to the work on this standard:Committee reference PVE/12Draft for comment 05/30029968 DCPublication historyFirst published, July 1943Second edition, February 1950Third edition, July 1961Fourth edition, October 197
3、6Fifth edition, as Part 1, February 1987Sixth edition, July 2006Amendments issued since publicationAmd. no. Date Text affectedBS 1123:2006 BSI 2006 iBS 1123:2006ContentsForeword ii1 Scope 12 Normative references 13 Terms and definitions 14 Construction 15 Materials 26 Marking 27 Instructions 2AnnexA
4、nnex A (informative) Installation and safe use 3Bibliography 4Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover.ii BSI 2006BS 1123:2006ForewordPublishing informationThis British Standard was published by
5、BSI and came into effect on 20 July 2006. It was prepared by Technical Committee PVE/12, Safety devices. SupersessionIt supersedes BS 1123-1:1987, which is withdrawn. Information about this documentIt has been prepared to:1) consolidate requirements for fusible plugs from BS 759-1:19841)and BS 1123-
6、1:1987 into one standard;2) remove potential overlap with BS EN ISO 4126-1:2004. This British Standard provides requirements for the design and guidance on the installation of fusible plugs for the steam boiler and compressed air industries for which a European or international standard does not cur
7、rently exist. Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. 1)At the time of publication
8、 BS 759-1:1984 is being revised and the new edition will not cover fusible plugs. BSI 2006 1BS 1123:20061 Scope This British Standard specifies design requirements for fusible plugs for use in steam boilers and compressed air installations.Guidance on installation is included in Annex A.NOTE Fusible
9、 plugs do not provide protection against excessive pressure, i.e. they do not remove the requirement for a safety device(s).2 Normative referencesThe following referenced document is indispensable for the application of this document. For dated references, only the edition cited applies. For undated
10、 references, the latest edition of the referenced document (including any amendments) applies.BS 21, Specification for pipe threads for tubes and fittings where pressure-tight joints are made on the threads (metric dimensions)3 Terms and definitionsFor the purposes of this British Standard, the foll
11、owing term and definition apply.3.1 fusible plugtemperature-activated non-closing pressure relief device, containing fusible metal designed to melt at a pre-determined temperature4 Construction 4.1 Steam boiler applications Fusible plugs for steam boiler applications shall consist of an outer body w
12、ith a central passage, which may be either parallel or conical. The smallest diameter of the central passage shall be not greater than 13 mm for plugs suitable for pressures up to 7 bar, and be not greater than 10 mm for pressures exceeding 7 bar. The passage shall be closed with a central core secu
13、red by an annular lining of fusible metal, designed to allow the core to drop clear if the lining melts.NOTE A portion of the body carrying the fusible metal may be detachable from the base to allow easy replacement without removing the whole fitting from the boiler.4.2 Compressed air applications F
14、usible plugs for compressed air applications shall consist of a holder with a central passage closed by fusible metal. The outlet shall be provided with a diffuser cap capable of arresting and containing the ejected metal. The inlet connection of the holder shall be threaded not less than R3/8 in ac
15、cordance with BS 21.BS 1123:20062 BSI 20065 Materials5.1 GeneralThe manufacturer shall take into account the full details of the application in order for the correct materials to be selected.NOTE Details may include: temperature;pressure;fluid;pressure vessel material.5.2 Non-fusible components Non-
16、fusible components of the plug shall be of copper alloy, except where this is incompatible with the application criteria in 5.1 eg. fluid chemical compatibility.5.3 Fusible component For steam boiler applications the fusible component of the plug shall be of a metal which melts readily at a temperat
17、ure not less than 90 C and not greater than 200 C in excess of the saturated steam temperature at the design pressure of the boiler. For compressed air applications the fusible component of the plug shall be of metal with a melting point to suit the application. 6 Marking The melting temperature or
18、temperature range in C shall be permanently marked on the fusible plug. NOTE Where the fusible plug is too small to permit the temperature to be marked, a suitable traceable code may be used.7 Instructions The manufacturer shall provide clear written instructions relating to the installation of fusi
19、ble plugs and their safe use.NOTE Guidance on the installation and safe use of fusible plugs is given in Annex A. BSI 2006 3BS 1123:2006Annex A (informative) Installation and safe useA.1 GeneralDischarge through fusible plugs should not be used to provide over pressure protection i.e. they do not re
20、move the requirement for a safety device(s).Consideration should be given to the positioning of the fusible plug to ensure that the discharge does not cause damage or injury to persons and property.It is essential that fusible plugs are installed the correct way round, otherwise during operation the
21、 core could jam in the passageway and render the device useless.A.2 Steam boiler applicationsFusible plugs should be fitted at a sufficient height and in such a position as to give an early warning in the event of shortage of water to all parts of the boiler liable to damage by the direct applicatio
22、n of furnace heat. Fusible plugs should be installed so that their discharge is directed onto the source of heat. However, they should also be installed so that as far as practical they are shielded from the path of direct flames.It is essential that fusible plugs are installed the correct way round
23、. A fusible plug may be designed to be installed from the “fire-side” or may be designed to be installed from the “water-side”. It needs to be installed in the attitude it was designed for i.e. with the pressure on the appropriate side of the fusible plug.A.3 Compressed air applicationsFusible plugs
24、 should be fitted between the compressor and the after-cooler (if any), or between the compressor and the receiver. They should be fitted as close to the compressor outlet as practicable, and situated so that the discharge from the plug cannot cause injury or damage to persons or property.On compres
25、sed air vessels the fusible plug should be fitted at or near the top of the vessel.A.4 Safe useFusible plugs should be cleaned and inspected regularly to assure continued protection, for example fusible plugs on steam boilers can be affected by scale and other deposits and should be cleaned and repl
26、aced as necessary.BS 1123:20064 BSI 2006BibliographyStandards publicationsFor dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.BS EN ISO 4126-1:2004, Safety devices for protection against excess
27、ive pressure Part 1: Safety valvesFurther readingBS EN ISO 4126-2, Safety devices for protection against excessive pressure Part 2: Bursting disc safety devicesBS EN ISO 4126-4, Safety devices for protection against excessive pressure Part 4: Pilot operated valvesBS EN ISO 4126-5, Safety devices for
28、 protection against excessive pressure Part 5: Controlled safety pressure relief systems (CSPRS)This page deliberately left blankBS 1123:2006BSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Euro
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