1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 751-3 : 1997 Incorp
2、orating corrigendum March 1997 The European Standard EN 751-3 : 1996 has the status of a British Standard ICS 83.140.50; 91.140.40; 91.140.60 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family
3、gases and hot water Part 3. Unsintered PTFE tapesBS EN 751-3 : 1997 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 July 1997 BSI 1997 The following BSI references re
4、late to the work on this standard: Committee reference PSE/2 Draft for comment 94/708887 DC ISBN 0 580 27665 1 Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committe
5、e PSE/2, Jointing materials and compounds, upon which the following bodies were represented: Asbestos Information Centre Ltd. British Adhesives and Sealants Association British Compressed Gases Association British Hydromechanics Research Group Chartered Institution of Water and Environmental Managem
6、ent Energy Industries Council Industrial Water Society LP Gas Association Water Services Association of England and WalesBS EN 751-3 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 751-3 3ii BSI 1997 BS EN 751-3 : 1997 National for
7、eword This Part of BS EN 751 has been prepared by Technical Committee PSE/2, and is the English language version of EN 751-3 : 1996 Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases and hot water Part 3: Unsintered PTFE tapes incorporating corrigendum March
8、 1997, published by the European Committee for Standardization (CEN). It supersedes BS 6974 : 1991 which is withdrawn. Cross-references International Standards Corresponding British Standard ISO 7-1 BS 21 Specification for pipe threads for tubes and fittings where pressure-tight joints are made on t
9、he threads (metric dimensions) EN 437 BS EN 437 Specification for test gases, test pressures and categories of appliance, for gas appliances EN 10242 BS EN 10242 Threaded pipe fittings in malleable cast iron Compliance with a British Standard does not of itself confer immunity from legal obligations
10、. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, an inside back cover and a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat:
11、 rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref. No. EN 751-3 : 1996 E EUROPEAN STANDARD EN 751-3 NORME EUROPE ENNE EUROPA ISCHE NORM December 1996 Incorporating Corrigendum March 1997 ICS 21.140; 23.040.80 Descriptors: Pipe fittings, gas pipes, water pipes, hot water
12、, threaded fittings, sealing materials, tapes, classifications, specifications, dimensional tolerances, effectiveness, dimensional measurements, tests, marking English version Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases and hot water Part 3. Unsintere
13、d PTFE tapes Mate riaux de tache ite pour raccords filete se n contact des gaz de la 1e re, 2e me et 3e me famille et de leau chaude Partie 3: Bandes en PTFE non fritte Dichtmittel fu r Gewindeverbindungen in Kontakt mit Gasen der 1., 2. und 3. Famile und Heibwasser Teil 3: Ungesinterte PTFE-Ba nder
14、 This European Standard was approved by CEN on 1996-11-24. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical referen
15、ces concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into
16、 its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Swi
17、tzerland and United Kingdom.Page 2 EN 751-3 : 1996 BSI 1997 Foreword This European Standard has been prepared by Technical Committee CEN/TC 108 , Sealing materials and lubricants for gas appliances and gas equipment, the secretariat of which is held by NNI. This European Standard shall be given the
18、status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 1997, and conflicting national standards shall be withdrawn at the latest by June 1997. This European Standard consists of the following Parts: Part 1: Anaerobic jointing compounds Part
19、 2: Non-hardening jointing compounds Part 3: Unsintered PTFE tapes This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). According to the CEN/CENELEC Internal R
20、egulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdo
21、m. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative references 3 3 Definitions 3 4 Classification of PTFE tapes 3 5 Requirements 4 5.1 Requirements to be met by the PTFE tape as received 4 5.2 Requirements to be met by the PTFE tape after assembly 4 5.3 Re-test 4 6 Test material and doc
22、umentation 4 6.1 Test material 4 6.2 Test documentation 4 7 Test methods 5 7.1 Test methods for PTFE tapes as received 5 7.2 Test of PTFE tapes after assembly 6 8 Marking and instructions 7 8.1 Marking on packages 7 8.2 Instructions 7Page 3 EN 751-3 : 1996 BSI 1997 Introduction This European Standar
23、d specifies requirements and test methods for tapes produced from virgin unsintered polytetrafluorethylene (PTFE) for use with metallic threaded joints. It defines two classes of PTFE tapes, mainly differing in thickness and mass per area, for fine (F) and coarse (G) threads. A universally applicabl
24、e PTFE tape may be used for all gas, potable water, and hot water installations. In respect of potential adverse effects of the jointing compounds covered by this European Standard on the quality of water intended for human consumption this standard provides no information as to whether the jointing
25、 compounds may be used without restriction in any of the Member States of the EU or EFTA. The use and characteristics of the jointing compounds should comply with current regulations, where they exist, depending on the acceptance of verifiable European criteria. Since the application techniques, som
26、etimes due to different pressure limits and safety requirements, differ from country to country, it was rather difficult to harmonize the existing national standards and approval requirements for PTFE tapes. One particular point relates to the adjustment of parts of an installation which sometimes r
27、equire the assembled taper/parallel threaded joints to be turned back up to an angle of 45 . To ensure that PTFE tapes fulfil this requirement in countries where such handling techniques are used, an additional requirement concerning the turn back test was included and such PTFE tapes are additional
28、ly designated with Rp. 1 Scope This European Standard specifies requirements and test methods for unsintered polytetrafluorethylene (PTFE) tapes (hereafter referred to as PTFE tapes) which are suitable for sealing threaded metallic joints as specified in ISO 7-1. The PTFE tapes are typically for use
29、 in installations for 1st family gases (town gas), 2nd family gases (natural gas) and 3rd family gases (liquefied petroleum gases (LPG) up to 5 bar and up to 7 bar for hot water of heating systems (Class A) as well as up to 0,2 bar in gas appliances and their auxiliary equipment (Class B). The maxim
30、um working pressure covered in this European Standard is 20 bar which is relevant to LPG storage (Class C). The temperature range is limited to220 C to 125 C. NOTE. For applications outside the scope of this standard (e.g. compressed gases) the purchaser should consult the manufacturer. Anaerobic jo
31、inting compounds are covered by EN 751-1, non-hardening sealing materials in the form of, e.g. jointing compound paste, are covered by EN 751-2. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references ar
32、e cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest e
33、dition of the publication referred to applies. ISO 7-1 Pipe threads where pressure-tight joints are made on the threads Part 1: Dimensions, tolerances and designation ISO 228-1 Pipe threads where pressure-tight joints are not made on the threads Part 1: Dimensions, tolerances and designation EN 437
34、Test gases Test pressures Appliance categories EN 10242 Threaded pipe fittings in malleable cast iron prEN 10255 Carbon steel tubes suitable for welding or threading prEN 12164 Copper and copper alloys Rod for free machining purposes 3 Definitions For the purposes of this European Standard the follo
35、wing definitions apply: 3.1 PTFE tape Thread sealing tape manufactured from virgin unsintered polytetrafluorethylene (PTFE) without fillers or additives. 3.2 gas family For further information on types of gases see EN 437. 3.3 batch Any quantity of PTFE-tapes manufactured in a single mix at one time
36、. 4 Classification of PTFE tapes There are two classes of PTFE tapes, mainly differing in thickness and mass per area, suitable for fine (F) and coarse (G) threads in accordance with table 1. Table 1. Classification of PTFE tapes Class Thread Nominal size F, Frp 2) ISO 7-1 taper/parallel and taper/t
37、aper DN# 10 1) G, Grp 2) ISO 7-1 taper/parallel and taper/taper 1 0D N#50 1) Class F tapes may also be used for other dimensions when the number of turns of the thread is$ 7,5 cm 21 2) PTFE tapes where limited turning back of taper/parallel threaded joints (R/Rp) is permitted, are additionally marke
38、d with Rp.Page 4 EN 751-3 : 1996 BSI 1997 5 Requirements 5.1 Requirements to be met by the PTFE tape as received 5.1.1 General The PTFE tape shall be free from any inclusions or imperfections visible to the naked eye and shall be free from any surface or edge defects, when tested in accordance with
39、7.1.1. 5.1.2 Tolerances on tape dimensions 5.1.2.1 Length The actual length of the PTFE tape, when tested in accordance with 7.1.2.1, shall not be less than that marked on the spool. 5.1.2.2 Width The actual width of the PTFE tape, when tested in accordance with 7.1.2.2, shall not differ from that m
40、arked on the spool by more than 0,5 mm. NOTE. The preferred width is 12 mm. 5.1.2.3 Thickness The thickness of the PTFE tape, when tested in accordance with 7.1.2.3, shall not differ from the stated value by more than 10 %. 5.1.3 Tolerances on mass per area The mass per area of the PTFE tape, when t
41、ested in accordance with 7.1.3, shall be greater than 90 % of the value declared by the manufacturer. 5.1.4 Residual lubricant content The residual lubricant content of the PTFE tape, when tested in accordance with 7.1.4, shall not exceed 0,1 % by mass. 5.1.5 Wrapping properties When wrapped around
42、the specified thread in accordance with 7.1.5, the PTFE tape shall conform to and hold the thread form. The finishing end of the PTFE tape shall remain in position with no tendency to unwind. During wrapping the PTFE tape shall not break, tear, or split. 5.2 Requirements to be met by the PTFE tape a
43、fter assembly 5.2.1 Sealing properties When tested in accordance with the methods described in 7.2.1 the PTFE tape shall not permit any leakage, when each test assembly is tested in accordance with 7.2.1.2 to 7.2.1.5 in sequence. 5.2.1.1 Soundness When pressurized, within 1 h after preparation all t
44、he joints in the test assemblies shall not leak, when tested in accordance with 7.2.1.2. 5.2.1.2 Soundness after adjustment (additional requirement for Classes FRp and GRp only) After adjusting the test assemblies in accordance with 7.2.1.3 the joint of these test assemblies shall not leak when test
45、ed in accordance with 7.2.1.2. NOTE. This additional requirement is only valid for countries in which a limited turning back of prefabricated taper/parallel (R/Rp) threaded joints is permitted. PTFE tapes fulfilling this requirement should additionally be marked with Rp. 5.2.1.3 Resistance to temper
46、ature cycling The sealing properties of the PTFE tapes shall not be impaired by the temperature cycling test in accordance with 7.2.1.4. 5.2.1.4 Resistance to vibration The sealing properties of the PTFE tapes shall not be impaired by vibration when tested in accordance with 7.2.1.5. 5.2.2 Dismantli
47、ng When dismantling the screwed joints with commercial tools, after all tests in accordance with 7.2.1 have been completed, there shall be no damage or corrosion of the threads. 5.3 Re-test If more than one joint in all test assemblies should fail throughout the tests specified in 7.2.1.2 to 7.2.1.5
48、 no re-test shall be permitted. Should only one joint fail to comply with the requirements of any test, two further test assemblies shall be prepared using PTFE tape from the same production batch and each of them shall comply with the requirements of all tests. If any of the joints in the re-tested
49、 assemblies fails then it shall be deemed that the whole batch of PTFE tape has failed. 6 Test material and documentation 6.1 Test material The manufacturer shall submit 20 spools of the PTFE tape in original packing to the test laboratory. 6.2 Test documentation The following documents shall be submitted to the test laboratory: a) description of the PTFE tape including classification according to table 1, mass per area, and dimensions of the PTFE tape (nominal length, width and thickness); b) application and wrapp
