【BS英国标准】BS EN 761-1995 Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes Determination of the creep factor under dry condi

british standard bs en761:1995bs 2782-12: method1214d:1995plastics pipingsystems glass-reinforced thermosetting plastics (grp) pipes determination of the creep factor under dry conditionsthe european standard en 761:1994 has the status of abritish standardbs en 761:1995committees responsible for thisbritish standardthe 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 plcbritish plastics federationbritish plumbing fittings manufacturers association british valve and actuator manufacturers association department of the environment (british board of agreement)department of the environment (building research establishment) department of the environment (property and buildings directorate) department of transportelectricity associationfederation of civil engineering contractorshealth and safety executive institute of building control institute of materials institution of civil engineers institution of gas engineersinstitution of water and environmental managementnational association of plumbing, heating and mechanical servicescontractorspipeline industries guildplastics land drainage manufacturers associationsociety of british gas industries society of british water industries water companies associationwater services association of england and walesthe following bodies were also represented in the drafting of the standard, through subcommittees and panels:this british standard, having been prepared under the direction of the sector board for materials and chemicals, was published under the authority of the standards board and comes into effect on15 july 1995 bsi 11-1999the following bsi references relate to the work on this standard:committee reference pri/61draft for comment 92/43170 dcisbn 0 580 24229 3association of consulting engineersengineering equipment and materials users associationinstitution of mechanical engineersrapra technology ltd. water research centreamd. no.datecommentsamendments issued since publicationbs en 761:1995contentspage committees responsibleinside front cover national forewordiiforeword21scope32normative references33definitions34principle45apparatus46test piece57conditioning68procedure69calculation610test report7annex a (informative) equal increments of lg (time)8figure 1 schematic diagram of the apparatus5table a.1 times compromising equal increments of lg th 8list of referencesinside back cover bsi 11-1999ibs en 761:1995national forewordthis british standard has been prepared by technical committee pri/61 and is the english language version of en 761:1994 plastics piping systems glass-reinforced thermosetting plastics (grp) pipes determination of the creep factor under dry conditions, published by the european committee for standardization (cen).it is incorporated into bs 2782 methods of testing plastics part 12: reinforced plastics pipes, fittings and valves, as method 1214d:1995, for association 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 reinforced plastics piping systems and components. it has been implemented to enable experience of the method 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 that standard/specification has been amended or revised to make reference to this method and adjust any requirements as appropriate.cross-referencespublication referred to corresponding british standarden 705:1994bs en 705:1995bs 2782-12: methods 1220a, b and c:1995 plastics piping systems glass-reinforced thermosetting plastics(grp) pipes and fittings methods of regression analysis and their usenote reference is also made to en 1228 prior to its publication. when that is published it is intended that the corresponding british standard will carry the references bs en 1228 andbs 2782-12: methods 1214a and b.a british standard does not purport 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.summary of pagesthis 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.this standard has been updated (see copyright date) and may have had amendments incorporated. this will be indicated in the amendment table on the inside front cover. bsi 11-1999iieuropean standard norme europenneeuropische normen 761april 1994udc 621.643.2-036.067.5:620.1:539.3descriptors: pipelines, plastic tubes, reinforced plastics, glass reinforced plastics, thermosetting resins, creep properties, deflection, tests, computationenglish versionplastics piping systems glass-reinforced thermosetting plastics (grp) pipes determination of the creep factor under dry conditionssystmes de canalisations plastiques tubes en plastiques thermodurcissables renforc de verre (prv) dtermination du coefficientde fluage en condition schekunststoff-rohrleitungssysteme rohre aus glasfaserverstrkten duroplastischen kunststoffen (gfk) bestimmung des kriechfaktors im trockenen zustandthis european standard was approved by cen on 1994-04-27. 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 references 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 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, switzerland and united kingdom.ceneuropean committee for standardization comit europen de normalisation europisches komitee fr normungcentral secretariat: rue de stassart 36, b-1050 brussels 1994 copyright reserved to cen membersref. no. en 761:1994 een 761:1994forewordthis european standard was prepared by cen/tc 155, plastics piping systems and ducting systems.this standard is based on document n 129 glass reinforced thermosetting plastics (grp) pipes and fittings test method for the determination of creep factor of pipes under dry conditions prepared by working group 1 of subcommittee 6 of technical committee 138 of the international organization for standardization (iso). it is a modification of document iso/tc 138/sc 6/wg 1 n 129 for reasons of possible applicability to other test conditions and alignment with texts of other standards on test methods.the modifications are: test parameters are omitted; material-dependent requirements are not given; editorial changes have been introduced. the material-dependent test parameters and/orperformance requirements are incorporated in thereferring standard.annex a, which is informative, is given to assist the scheduling of data measurement.no existing european standard is superseded by this standard.this standard is one of a series of standards on test methods which support system standards for plastics piping and ducting systems.in accordance with the common cen/cenelec rules, 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 kingdom.7 bsi 11-19991 scopethis european standard specifies a method for determining the dry creep factor of glass-reinforced plastics pipes.it is applicable to pipes with an initial specific ring stiffness of not less than 630 n/m, when determined by the method specified in the referring standard.note for this purpose plates or beam bars are considered to be equally valid for loading the test piece up to a relative deflection of 28 %. when it is expected that the relative deflection will be more than 28 %, then the test is to be conducted using beam barswheree is the apparent modulus of elasticity as determined in the ring stiffness test, in newtons per square metre;i is the moment of inertia (the second moment of area) in the longitudinal direction per metre length, expressed in metres to the fourth power per metre, i.e.:3ie(see 8.3).2 normative references=where-12this european standard incorporates by dated or undated references, provisions from other publications. these normative references are 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 edition of the publication referred to applies.en 1228, plastics piping systems glass-reinforced thermosetting plastics pipes determination of the initial specific ring stiffness1).en 705, plastics piping systems glass-reinforced thermosetting plastics pipes and fittings methods for regression analyses and their use.3 definitions3.1specific ring stiffness (s)a physical characteristic of the pipe which is a measure of the resistance to ring deflection under external loadthis characteristic is determined by testing and is defined, in newtons per square metre, by the equation:s = ei-d3meis the wall thickness of the pipe, in metres;dmis the mean diameter (see 3.2) of the pipe, in metres.3.2mean diameter (dm)the diameter of the circle corresponding with the middle of the pipe wall cross sectionit is given, in metres, by either of the following equations:dm = di + e dm = de ewherediis the average of the measured internal diameters, in metres;de is the average of the measured external diameters, in metres;eis the average of the measured wall thicknesses of the pipe, in metres.3.3initial specific ring stiffness (s0)the specific ring stiffness when measured 3 min after beginning of loadingit is expressed in newtons per square metre3.4compressive load (f)a load applied to the horizontal pipe to cause a vertical deflectionit is expressed in newtons1) at present pren 1228.3.5vertical deflection (y)the vertical change in diameter of a pipe in a horizontal position in response to a vertical compressive load (see 3.4)it is expressed in metres3.6initial deflection (y3 min)the vertical deflection caused by the compressive load and measured 3 min (i.e. 0,05 h) after the beginning of loadingit is expressed in metres3.7long-term vertical deflection under dryconditions (yx, dry)the estimated vertical deflection after x years, obtained by extrapolation of long-term deflection measurements at a constant load under dry conditionsit is expressed in metres3.8dry conditionsthe test environment in air at the prevailing humidity3.9dry creep factor (!x, dry)the factor given by the following equation:the creep factor under dry conditions is determined from the relationship between the initial deflection and the deflection after x years of the same test piece (see 3.7 and 3.8).note 1 if it is required to predict the deflection at 50 years this requires extrapolating approximately 2,5 decades (2,5 increments of lg t, where t is time in hours). in order to improve the reliability of the prediction the creep test may be extended beyond 1 000 h.note 2 it is assumed that the following test parameters are set by the standard making reference to this standard:a) the time to which the values are to be extrapolated(see 3.6, 3.7, 3.9 and clause 9);b) the length of each test piece (see 6.1);c) the number of test pieces (see 6.2);d) if applicable, the conditioning atmosphere and period(see clause 7);e) the test temperature and relative humidity (see 8.1);f) the periods of test pieces under load (see 8.4).5 apparatus5.1 compressive loading machine, comprising a system by means of which one or more test pieces can be compressed by compressive load determined to an accuracy of 1 % of the maximum indicated applied value via two parallel load application surfaces conforming to 5.2.note care may be necessary to ensure that the applied load is not affected by friction effects.5.2 load application surfaces5.2.1 general. the surfaces shall be provided by a pair of plates conforming to 5.2.2, or a pair of beam bars conforming to 5.2.3, or a combination of one!x, dry =wherey3 min- yx, dryfx- f3 minsuch plate and one such bar, with their major axes perpendicular to and centred on the direction ofapplication of load f by the compressive loading machine, as shown in figure 1. the surfaces to be inx indicates a specified period of time, in years;f is the applicable deflection coefficient.3.10deflection coefficient (f)the coefficient which takes into account the second order theory and of which the value is given by the following equation:f = 1860 + (2500 y/dm) 1054 principlea cut length of pipe is subjected to a constant load along its length to compress it diametrically for a period of not less than 1 000 h. its deflection is measured at intervals. the deflection after a specified time of x years is estimated by extrapolation.contact with the test piece shall be flat, smooth, clean and parallel.5.2.2 plate. each plate shall have a length at least equal to the length of the test piece (see 6.1), a width of at least 100 mm and a thickness such that no visible bending or deformation of the plate shall occur during the test.5.2.3 beam bar. each beam bar shall be rigid, have rounded edges and shall have a length at least equal to the length of the test piece (see 6.1). for pipes with a nominal size of not more than 300 the width of the bar shall be (20 5) mm. for pipes with a nominal size greater than 300 the width of the bar shall be (50 5) mm. each bar shall be so constructed and supported that other surfaces of the beam bar structure shall not come into contact with the test piece during the test.5.2.4 dimensional measuring devices, capable of determining the necessary dimensions (length, diameters, wall thickness) to an accuracy of within 1 % and of determining the change in diameter of the test piece in the vertical direction during the test to an accuracy of within 1 % of the maximum value of the measured change.note the maximum value of the change to be measured depends upon the relative deflection specified in the referring standard.6 test piece6.1 preparationthe test piece shall be a complete ring cut from the pipe to be tested. the length of the test piece shall be as specified in the referring standard, with permissible deviations of 5 %.the cut ends shall be smooth and perpendicular to the axis of the pipe.straight lines shall be drawn on the inside or the outside along the length of the test piece and repeated at 60 intervals around its circumference, to serve as reference lines.6.2 numberthe number of test pieces shall be as specified in the referring standard.figure 1 schematic diagram of the apparatus6.3 determination of the dimensions6.3.1 lengthmeasure the length of the test piece along each reference line to an accuracy of 0,5 %.calculate the average length, l, of the test piece, in metres.reject or correct the test piece if it does not conform to .2 wall thicknessmeasure to within 1 % the wall thickness of the test piece at each end of each reference line.calculate the mean wall thickness, e, as the average of the measured values.6.3.3 mean diametermeasure to an accuracy of within 1,0 % either of the following:a) the internal diameter, di, of the test piece between each diametrically opposed pair of reference lines at their mid-lengths, e.g. by means of a calliper;b) the external diameter, de, of the test piece which includes the mid-points of the reference lines, e.g. by means of a circumferential wrap steel tape.determine the mean diameter, dm, of the test piece by calculation using the averaged values obtained for wall thickness and for either the average internal or the average external diameter at the mid-point of the six reference lines (see 6.