1、BRITISH STANDARD BS EN 744:1996 BS 2782-11: Method 1108C:1996 Plastics piping and ducting systems Thermoplastics pipes Test method for resistance to externalblows by the round-the-clock method The European Standard EN 744:1995 has the status of a British Standard ICS 23.040.20BSEN744:1996 This Briti
2、sh Standard, having been prepared under the directionof the Sector Board for Materials and Chemicals, was published under the authority ofthe Standards Board and comesinto effect on 15 February 1996 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference PRI
3、/61 Draft for comment 92/413382 DC ISBN 0 580 25149 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee PRI/61, Plastics piping systems and components, upon which the following bodies were represented: British Gas plc Briti
4、sh Plastics Federation British Plumbing Fittings Manufacturers Association British Valve and Actuator Manufacturers Association Department of the Environment (British Board of Agrment) Department of the Environment (Building Research Establishment) Department of the Environment (Property and Buildin
5、g Directorate) Department of Transport Electricity Association Federation of Civil Engineering Contractors Health and Safety Executive Institute of Building Control Institute of Materials Institution of Civil Engineers Institution of Gas Engineers Institution of Water and Environmental Management Na
6、tional Association of Plumbing, Heating and Mechanical Services Contractors Pipeline Industries Guild Plastics Land Drainage Manufacturers Association Society of British Gas Industries Society of British Water Industries Water Companies Association Water Services Association of England and Wales The
7、 following bodies were also represented in the drafting of the standard, through subcommittees and panels: ERA Technology Ltd. Engineering Equipment and Materials Users Association RAPRA Technology Ltd. Amendments issued since publication Amd. No. Date CommentsBSEN744:1996 BSI 07-1999 i Contents Pag
8、e Committees responsible Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Definition 3 3 Principle 3 4 Apparatus 3 5 Test pieces 6 6 Conditioning 6 7 Procedure 6 8 Expression of results 7 9 Test report 8 Annex A (informative) Evaluation of results from isolated batches 9 Figure 1 Typic
9、al falling weight testing machine 4 Figure 2 Dimensions of strikers 5 Figure 3 Number of test pieces for 10% TIR (at 90% confidence level) 8 Table 1 Dimensions for the nose of the striker 3 Table 2 Mass of strikers 3 Table 3 Number of equidistant lines to be drawn on the test pieces 6 Table 4 Condit
10、ioning periods 6 Table 5 Expression of TIR at 10% depending on the number of blows and failures 7BSEN744:1996 ii BSI 07-1999 National foreword This British Standard has been prepared by Technical Committee PRI/61 and is the English language version of EN 744:1995 Plastics piping and ducting systems
11、Thermoplastics pipes Test method for resistance to external blows by the round-the-clock method, published by the European Committee for Standardization (CEN). It is incorporated into BS 2782 Methods of testing plastics Part 11: Thermoplastics pipes, fittings and valves, as Method 1108C:1995 for ass
12、ociation with related test methods for plastics materials and plastics piping components. This test method has been prepared for reference by other standards under preparation by CEN for specification of plastics piping systems and components. It has been implemented to enable experience of the meth
13、od to be gained, and for use for other fresh applications. It is also for use for the revision or amendment of other national standards as practicable, but it should not be presumed to apply to any existing standard or specification which contains or makes reference to a different test method until
14、that standard/specification has been amended or revised to make reference to this method and adjust any requirements as appropriate. In particular, attention is drawn to the fact that because of e.g.differences in striker geometry, this methodis not expected to give identical results to those obtain
15、ed by reference to BS 2782-11:Method 1108A:1989, the use of which should be restricted to its current applications. Pending any related amendment of EN 744:1995, attention is drawn to the requirement in clause6 to use a bath of water and ice for conditioning at0 C, which may inhibit the use of equip
16、ment where the bath liquid temperature is controlled by passage through or past a heat exchanger operating at a lower temperature. WARNING NOTE. This British Standard, which is identical with EN 744:1995, does not necessarily detail all the precautions necessary to meet the requirements of the Healt
17、h and Safety at Work etc.Act 1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for the
18、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2 to 10 and a back cover. This standard has been updated (see co
19、pyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 744 April 1995 ICS 23.040.20 Descriptors: Plastic tubes, thermoplastic resins, mechanical tests, impact test, shock res
20、istance English version Plastics piping and ducting systems Thermoplasticspipes Test method for resistance to external blows by the round-the-clock method Systmes de canalisations et de gaines en plastiques Tubes thermoplastiques Mthode dessai de rsistance aux chocs externes par la mthode du cadran
21、Kunststoff-Rohrleitungs- und Schutzrohrsysteme Rohre aus Thermoplasten Prfverfahren fr die Widerstandsfhigkeit gegen uere Schlagbeanspruchung im Umfangsverfahren This European Standard was approved by CEN on 1995-02-06. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
22、stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standa
23、rd 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 its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national bodies
24、 of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secreta
25、riat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members Ref. No. EN 744:1995 EEN744:1995 BSI 07-1999 2 Foreword This European Standard was prepared by CEN/TC 155, Plastics piping systems
26、 and ducting systems, of which the secretariat is held by NNI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 1995, and conflicting national standards shall be withdrawn at the latest by
27、October 1995. According to the CEN/CENELEC Internal Regulations, 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, United
28、Kingdom. This standard is based on ISO/DIS 3127:1992 Unplasticized polyvinyl chloride (PVC) pipes for the transport of fluids Determination and specification of resistance to external blows, prepared by the International Organization for Standardization (ISO). It is a modification of ISO/DIS 3127:19
29、92 for reasons of applicability to other plastics materials and/or other test conditions and alignment with texts of other standards on test methods. The modifications are: no pipe material is mentioned; test parameters, except those common to all plastics, are omitted; no material-dependent require
30、ments are given; editorial changes have been introduced. The material-dependent parameters and/or performance requirements are incorporated in the system standard(s) concerned. Annex A, which is informative, gives guidance on sampling. No existing European Standard is superseded by this standard. Th
31、is standard is one of a series of standards on test methods which support system standards for plastics piping systems and ducting systems.EN744:1995 BSI 07-1999 3 1 Scope This standard specifies a method for determining the resistance to external blows of thermoplastics pipes with circular cross se
32、ctions by using the round-the-clock method. The method is intended to be applied to isolated batches of pipe. For type testing and audit testing,0 C and/or 20 C are applicable. NOTEPipes made from polypropylene homopolymer (PP-H) which principally can not conform to impact requirements at0 C or lowe
33、r temperatures are permitted to be tested at(23 2) C under the condition that PP-H pipes are intended for use for soil and waste discharge and bear an additional marking indicating that they are not to be installed below+5 C. 2 Definition For the purposes of this standard, the following definition a
34、pplies. true impact rate (TIR) the total number of failures divided by the total number of blows, inpercent, as if the whole batch had been tested NOTEIn practice, test pieces are drawn at random from the batch and the result is only an estimate of the TIR for that batch. 3 Principle Test pieces com
35、prising cut lengths of pipe, representative of a batch or a production run from an extruder, are subjected to blows from a falling weight dropped from a specified height on to specified positions around the circumference of the pipe. The incidence of failure is estimated as the true impact rate (TIR
36、) of the batch, or production run, where the maximum value for TIR is10%. NOTE 1The severity of this test method can be adjusted to suit different specification needs by changing the mass of the falling weight and/or by changing the fall height. It is not technically correct to vary the severity of
37、the test by choosing other values of TIR than that specified in this method. NOTE 2It should be appreciated that a completely definitive result can only be reached by testing the whole batch, but in practice a balance is necessary between the statistical possibility of a definitive result and the co
38、st of further testing. NOTE 3It is assumed that the following test parameters are set by the standard making reference to this standard: a) the type of striker and striker mass seeb) of clause4 and itema)of7.1; b) the drop height for the striker see d) ofclause4 and7.2, 7.3 and/or 7.4 as applicable;
39、 c) the method of sampling see5.1 and c)ofclause9; d) if appropriate, the number of test pieces to be used (see5.2 andclause7); e) the test and conditioning temperature and the conditioning medium (seeclause6); f) if applicable, any alternative or additional criterion for failure seed)of7.1. 4 Appar
40、atus A falling weight testing machine incorporating the following basic components (seeFigure 1): a) main frame, with guide rails or a guiding tube rigidly fixed in the vertical position to accommodate a striker seeb) and release it to fall vertically and freely such that the speed of the striker at
41、 the moment of hitting the pipe is not lessthan95% of the theoretical speed; b) striker, having a nose comprising all or part of a hemispherical form combined with a cylindrical stem atleast10mm long and having dimensions conforming toTable 1 and Figure 2, depending upon the mass of the striker. The
42、 mass of the striker, including any associated weights, shall be selected fromTable 2. Below the stem, the nose shall be of steel with a minimum wall thicknessof5mm and the striking surface shall be free from imperfections which can influence the results. c) rigid test piece support, consisting of a
43、120 vee-block atleast200mmlong, positioned so that the axis of the line of fall of the nose of the striker shall intersect the axes of the vee to within 2,5mm(seeFigure 1). The support construction shall be sufficiently rigid not to cushion the effect of the impact. d) release mechanism, such that t
44、he falling weight can fall from a height which can be adjusted up to atleast2m, as measured from the top surface of the test piece. Table 1 Dimensions for the nose of thestriker Table 2 Mass of strikers Type R s d d s a mm mm d25 50 25 a a d90 50 90 a a a Not specified, to allow design freedom. Mass
45、esinkilograms Mass of striker 0.005 kg Type d25 Type d90 0,25 0,5 0,8 1,0 1,25 1,6 2,0 2,5 3,2 4,0 5,0 6,3 8,0 10,0 12,5 16,0EN744:1995 4 BSI 07-1999 Figure 1 Typical falling weight testing machineEN744:1995 BSI 07-1999 5 Figure 2 Dimensions of strikersEN744:1995 6 BSI 07-1999 5 Test pieces 5.1 Prep
46、aration The test pieces shall be cut from pipes selected at random from a batch or from a product run from an extruder. For each test piece, the length shall be(200 10)mm. The cut ends shall be square to the axis of the pipe, clean and free from damage. For pipes with outside diameters greaterthan40
47、mm, a number of longitudinal lines conforming toTable 3 shall be drawn with equidistant spacing around the pipe. EXAMPLE.A straight line may be drawn along the length of the test piece at a random position. Further lines are drawn at successive equidistant intervals from one another (i.e.the last on
48、e is equidistant to the first one). Table 3 Number of equidistant lines to be drawn on the test pieces 5.2 Number Taking into account that the number of test pieces necessary will depend upon: any applicable product sampling requirements(see5.1); the size of the pipe under test; whether or not each
49、test piece may be subject to more than one impact(seeTable 3 and clause7); the results obtained(see7.5); The number of test pieces shall be sufficient to enable at least one determination to be made in accordance with clause8 (seeTable 5 and the equations (1) and (2) as to whether the results obtained lie in region A, B or C. The number of test pieces shall enable atleast25 blows to be applied. 6 Conditioning The test pieces shall be conditioned in a bath of water and
