DIN EN 1120-1996 Plastics piping systems - Glass-reinforced thermosetting plastics (GRP) pipes and fittings - Determination of the resistance to chemical attack from the inside of .pdf

1、DEUTSCHE NORM Julv 1996 DIN EN 1120 Glass-reinforced thermosetting plastics (GRP) pipes and fittings Determination of the resistance to chemical attack from the inside of a section in a deflected condition English version of DIN EN 11 20 - ICs 23.040.20; 23.040.45 Descriptors: Plastics, pipes, fitti

2、ngs, testing. Supersedes DIN 53769-5, April 1989 edition. Kunststoff-Rohrleitungssysteme; Rohre und Formstcke aus glasfaserverstrkten duroplastischen Kunststoffen (GFK); Ermittlung der Widerstandsfhigkeit gegen Chemikalieneinwirkung von der Innenseite eines Abschnittes im verformten Zustand European

3、 Standard EN 1120:1996 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been prepared by CEN/TC 155. The responsible German body involved in its preparation was the Normenausschu Kunststoffe (Plastics Standards Committee), Technical Committ

4、ee Rohre und Rohrleitungsteile aus Reaktionsharzformstoffen. Amendments DIN 53769-5, April 1989 edition, has been superseded by the specifications of DIN EN 1120. Previous edition DIN 53 769: 1989-04. EN comprises 13 pages. Beuth Verlag GrnbH, Berlin, has the exciusive right of saie for German Stand

5、ards (DIN-Normen). 01.97 DIN EN 7 720 Engl. Price group 7 Sales No. 11 07 EUROPEAN STANDARD NORME EUROPENNE EUROPKISCHE NORM EN 1120 March 1996 ICs 23.040.20; 23.040.45 Descriptors: Plastics, pipes, fittings, testing. English version Plastics piping systems Glass-reinforced thermosetting plastics (G

6、RP) pipes and fittings Determination of the resistance to chemical attack from the inside of a section in a deflected condition Systmes de canalisations plastiques; Kunststoff-Rohrleitungssysteme; Rohre tubes et raccords en plastique thermodur- und Formstcke aus glasfaserverstrkten cissable renforc

7、de verre (PRV); dtermi- duroplastischen Kunststoffen (GFK); Er- nation de la rsistance une attaque chimi- mittlung der Widerstandsfhigkeit gegen que par lintrieur dun tronon de tube Chemikalieneinwirkung von der Innenseite soumis dflexion eines Abschnittes im verformten Zustand This European Standar

8、d was approved by CEN on 1995-10-14. CEN members are bound to comply with the CENKENELEC 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 nat

9、ional 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 n

10、otified 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 Kin

11、gdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-IO50 Brussels O 1996. CEN -All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 1120:1

12、996 E Page 2 EN 1120:1996 Foreword This European Standard has been prepared by Technical Committee CEN/TC 155 lPlastics piping systems and ducting systems1, the Secretariat of which is held by NNI. This standard is based on document N 191 *IGlass reinforced thermosetting plastics (GRP) pipes and fit

13、tings - Test method for resistance of a pipe in a deflected condition to chemical attack from the inside“, prepared by working group 1 of subcommittee 6 of technical committee 138 of the international Organization for Standardization (ISO) . It is a modification of ISO/TC 138/SC 6/WG 1 N 191 for rea

14、sons of applicability to other test conditions and alignment with texts of other standards on test methods. Following a request from some experts in the committee this standard contains a concept for structural failure as an alternative failure mode to the traditional weep failure (see note 2 to cla

15、use 1). The extension of the failure modes will be considered in a future revision following consideration of results of tests performed using these criteria. The modifications are: - concept of a second failure mode (structural failure) is added; - test parameters are omitted; - material-dependent

16、requirements are not given; - editorial changes have been introduced. The material-dependent test parameters and/or performance requirements are incorporated in the referring standard. This standard is one of a series of standards on test methods which support System Standards for plastics piping sy

17、stems and ducting systems. This standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 1996, and conflicting national standards shall be withdrawn at the latest by September 1996. According to the CEN/CENELE

18、C Internal Regulations, the following countries are bound to implement this standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Page 3 EN 1120:1996 1 Scope This s

19、tandard specifies a method or determining the chemical resistance properties of glass-reinforced thermosetting plastics (GRP) pipes and fittings in a deflected condition for nominal sizes DN 100 and larger. In conjunction with EN 705 this standard provides a method or evaluating the effect of a chem

20、ical environment on the interior of a pipe or fitting after a specified period of time. NOTE 1: It has been found that the effect of chemical environments can be accelerated using strain induced by deflection, hence it is frequently referred to as strain corrosion. NOTE 2: To study the applicability

21、 of the method to testing the pipe or fitting with regard to structural failure (where structural failure becomes apparent by a sudden reduction in the load applied of at least 20 % of the initial load) then where #weep failure“ is referred to in this standard substi tute “structural failure“. A str

22、uctural failure can be caused by conditions such as: - interlaminar separation; - cracks in or through the structural layer of the wall; - tensile failure of the glass reinforcement; - if applicable, separation of a thermoplastics liner from the structural wall. For such studies, data from “structur

23、al failure“ results will be analyzed separately from “weep failure“ results. 2 Normative references This standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed

24、 hereafter. For dated references, subsequent amendments to, or revisions of, any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 705 Plastics piping systems - Glas

25、s-reinforced thermosetting plastics (GRP) pipes and fittings - Methods for regression analyses and their use Page 4 EN 1120:1996 3 Definitions For the purposes of this standard, the following definitions apply: 3.1 mean diameter (d,): The diameter of the circle corresponding with the middle of the p

26、ipe wall cross section. It is given, in millimetres, by either of the following equations: where : di is the internal diameter, in millimetres; de is the external diameter, in millimetres; e is the wall thickness of the pipe, in millimetres. 3.2 weep failure: Failure which becomes apparent by the pa

27、ssage of the test liquid through the pipe wall. 4 Principle The interior of a test piece is exposed to a corrosive test liquid at a specified temperature while being maintained in a fixed diametrically deflected condition. The test is repeated at several deflection levels, using a fresh test piece e

28、ach time and recording the time to weep failure at each deflection. The results are used to calculate an extrapolated deflection value for a specified period of time. Alternatively the extrapolation can be performed using calculated or measured strains. Strain can be measured by the use of strain ga

29、uges. NOTE 1: Use of strain allows testing using test pieces of variable thickness and stiffness classes. Deflection and strain are interrelatable by calculation. NOTE 2: It is assumed that the following test parameters are set by the Standard making reference to this standard: a) the composition of

30、 the test liquid (see clause 5); b) the number and length of test pieces (see clause 7); c) if applicable, the conditioning to be applied (see clause 9); d) the test temperature (see 10.1 or 11.1) ; e) if failures do not occur (see 10.11 or 11.11) the specified deflection levels and related minimum

31、time intervals; Page 5 EN 1120:1996 f) the time to which the data have to be extrapolated (see clause 12) . 5 Test liquid The test liquid shall be as specified in the referring standard. The quantity shall be sufficient to achieve the specified depth within the test piece (see 10.7 or 11.7). 6 Appar

32、atus 6.1 Loading frame, comprising two parallel steel sections, with or without bearing plates, and threaded rods which can maintain a constant deflection of the test piece (see figure 1). The surfaces in contact with the test piece shall be hard, flat, smooth and clean. The sections and bearing pla

33、tes shall be sufficiently stiff such that visible bending or deformation of the sections or plate does not occur during the compression of the test piece. Each section or plate shall have a length at least equal to the length of the test piece plus 30 mm and a width of at least 100 mm. Threaded rod

34、Bearing plate (optional) Test y strain I gauge(s) Figure 1: Typical test arrangement 6.2 Dimeneiona measurement devices, capable of determining: - the dimensions (length, diameter, wall thickness) to an accuracy of within 0,5 %; Page 6 EN 1120:1996 - the change in diameter of the test piece in the v

35、ertical direction to an accuracy of within e is the mean wall thickness of the test piece at bottom, in millimetres; yav is the average deflection, in millimetres; d, is the mean diameter of the test piece (see 3.11, in millimetres. The calculation assumes that the neutral axis is at the test piece

36、wall mid point. For test piece wall constructions that produce an altered neutral axis position, evaluate the results substituting 2 x z for e, where z is the distance from the inside pipe surface to the neutral axis. The neutral axis position shall be determined using strain gauge couples. 10.7 Wit

37、hin 2 h of reaching the selected deflection (see 10.4) introduce the test liquid between the dams to a depth of between 25 mm and 50 mm and record the time as the zero time. NOTE: The time permitted between loading the test piece and the zero time is chosen to minimize differences arising from stres

38、s relaxation. This time has also been chosen to facilitate preparation of the test piece. 10.8 Maintain the depth of the test liquid at not less than 25 mm until weep failure occurs or the test is stopped. For the duration of the exposure of the test piece, periodically check using suitable analytic

39、al methods and, if necessary, adjust the test solution to maintain it within i 5 % of the specified concentration. NOTE 1: Failure by strain corrosion is characterized by a sudden fracture through the pipe wall in the area of greatest strain, parallel to the axis of the pipe, with the fibre reinforc

40、ement cleanly broken at the edge of the fracture. Visual evidence of surface etching or pitting may or may not be present. NOTE 2: Some solutions become more concentrated by the evaporation of water. It can be necessary, with some reagents, to periodically clean the deflected test piece and replace

41、the test solution with a fresh solution. 10.9 Unless otherwise specified inspect the test piece visually, without magnification, for signs of weep failure at the intervals given in table 2, subject to the permitted deviations given in column 3. NOTE: When a test solution is being replaced by a fresh

42、 solution an intensive examination of the wet area can be made. Page 10 EN 1120:1996 Time since Table 2: Inspection intervals Inepection Permitted deviations interval on inspection interval I Column 1 I Column a I Column 3 I O to 10 10 to 600 600 to 6000 after 6000 every 1 h 0,25 h every 24 h f 6h e

43、very 72 h - + 10 h every week f 1 day To improve visibility of weep failure, if necessary, prepare the outer surface of the test piece by coating with a lime wash. 10.10 Record the time to failure for each test piece. 10.11 In the event that failures do not occur, implement the deflection procedures

44、 detailed in the referring standard. 11 Test procedure using strain measurement WARNING: Precautions should be taken to contain any fragmentation or leakage that can occur during the test. 11.1 During the following procedure, maintain the temperature as specified in the referring standard. 11.2 Sele

45、ct the range of estimated strains such that the times to failure of at least 18 test pieces are distributed between 01 h and over 10000 h and the distribution of failure times of at least ten values conforms to the limits given in table 1. 11.3 Carefully align and attach three strain gauges on the i

46、nvert of the test piece in the circumferential direction to measure initial circumferential strain. Place the gauges equally spaced along one of the lines of the test piece. The adhesive used to attach the gauges shall, in total, not cover more than 37 % of the test piece length along the invert. Ze

47、ro the gauges while the test piece is circular in shape. NOTE: It is recommended that the test piece be placed with its ais vertical to maintain roundness when the bridge is balanced to zero the instrument. 11.4 After installing the strain gauges, place the test piece in the test arrangement (see fi

48、gure 1) with the strain gauges at the bottom. Page 11 EN 1120:1996 Take extreme care to ensure that the gauges are located at the point of maximum strain (6 oclock position), and that the lines on the test piece are parallel to and centred on the axes of the plates or sections. NOTE: Alignment of th

49、e test piece within the loading frame is cri ti cal . 11.5 Apply force to the apparatus to deflect the test piece while keeping the top and bottom plates or sections of the apparatus as parallel as possible. When the desired strain level is reached, lock the apparatus to maintain the test piece in the deflected condition. Read the gauges as soon as the apparatus is locked. Record the initial strain within 2 min after locking the apparatus. To validate the test condition, check that at least two gauges give readings within 5 % of each other. If any gauge reads