1、DEUTSCHE NORM Julv 2000 Crosslinked high-density polyethylene (PE-X) pipes General quality requirements and testing DIN 16892 - ICs 23.040.20 Supersedes March 1985 edition. Rohre aus vernetztem Polyethylen hoher Dichte (PE-X) - Allgemeine Gteanforderungen, Prfung In keeping with current practice in
2、standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker. Contents Foreword 1 5.5 Crosslinking . 4 2 6 Testing . 4 2 Normat 3 Concepts . 2 6.1 Surface finish 4 4 4 Material (moulding material) 2 6.3 Ovality 4 4.1 General
3、Page Page 1 Scope 2 5.6 Heat reversion 4 6.4 Long-term hydrostatic pressure resistance . 5 resistance 2 6.5 Crosslinking . 5 5 Requirements 4 6.6 Heat reversion 6 . 5.1 Form sutmlied 4 6.7 Test certificate . 6 II 5.2 Surface finish 4 5.3 Dimensions and tolerances . 4 notes 7 5.4 Long-term hydrostati
4、c pressure resistance 4 Other relevant standards 7 Foreword This standard has been prepared by Technical Committee Prfverfahren fr Rohre of the Normenausschuss Kunststoffe (Plastics Standards Committee). Amendments This standard differs from the March 1985 edition as follows: a) the long-term hydros
5、tatic pressure curves have been revised; b) the degree of crosslinking for type PE-Xa polyethylene has been reduced; c) requirements for resistance to hydrostatic pressure have been modified; d) ovality testing has been included. Previous edition DIN 16892: 1985-03. Continued on pages 2 to 7 Transla
6、tion by DIN-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text. Q No pari of this translation may be reproduced without the prior permission of Ref. No. DIN 16892 : 2000-07 Sales No. 0107 09.01 DIN Deutsches Institut frNonunge. V., Berlin. Be
7、uth Verlag GmbH, 10772 Berlin, Germany, has the exclusive right of sale for German Standards (DIN-Normen). English price group O7 Page 2 DIN 16892 : 2000-07 All dimensions are in millimetres. 1 Scope This standard specifies requirements and methods of test for seamless pipes of circular cross sectio
8、n made from crosslinked high-density (PE-X) polyethylene. Individual requirements specified here may be superseded by technical delivery conditions for particular ap- plications. NOTE: Any relevant European Standards shall also be observed. 2 Normative references This standard incorporates, by dated
9、 or undated reference, provisions from other publications. These norma- tive references are cited at the appropriate places in the text, and the titles of the publications are listed below. For dated references, subsequent amendments to or revisions of any of these publications apply to this standar
10、d only when incorporated in it by amendment or revision. For undated references, the latest edition of the publica DIN 8075 DIN 16887 DIN 16893 DIN 323-1 DIN 5001 1 - DIN EN 921 on referred to applies. Preferred numbers and preferred number series - Basic, calculated and rounded values Polyethylene
11、pipes - General quality requirements and testing Determination of the long-term hydrostatic pressure resistance of thermoplastics pipes Crosslinked polyethylene (PE-X) pipes - Dimensions Artificial climates in technical applications - Controlled-atmosphere test installations - General concepts and r
12、equirements Thermoplastics pipes - Determination of resistance to internal pressure at constant tem- perature 1 DIN EN 10204 Inspection documents for metallic products (includes Amendment Al : 1995) IEC 60093 Methods of test for insulating materials for electrical purposes -Volume resistivity of sol
13、id electrical insulating materials ISO/TR 9080 : 1992 Thermoplastics pipes for the transport of fluids - Methods of extrapolation of hydrostatic stress rupture data to determine the long-term hydrostatic strength of thermoplastics pipe materials 3 Concepts 3.1 Long-term hydrostatic pressure resistan
14、ce The strength of a pipe required to resist an induced internal hydrostatic pressure, o, in N/mm2, calculated as fo I I ows: d-s o=p- 2s where p is the induced hydrostatic pressure; d is the outside diameter; o is the wall thickness. 3.2 Ovality The difference between the maximum and minimum pipe o
15、utside diameters, at the same cross section (cf. DIN 8075). 4 Material (moulding material) 4.1 General Pipes shall be made from cross-linkable moulding mass manufactured on the basis of high-density poly- ethylene (PE-X). The choice of stabilizers and other additives shall be left to the pipe manufa
16、cturer. Materials of unknown composition shall not be used. 4.2 Long-term hydrostatic pressure resistance In the case of pipes made from crosslinked polyethylene, values for hydrostatic pressure resistance shall lie on or above the time-to-failure curves, as shown in figure 1. The dashed lines apply
17、 for longer exposure times at 110C. Page 3 DIN 16892 : 2000-07 The long-term hydrostatic pressure resistance is to be extrapolated as in DIN 16887 and ISO/TR 8090. The time-to-failure curves for testing at temperatures from 1 O “C to 95 “C are established using equation (2); the curves for testing a
18、t 11 O “C are-not based on this equation. Ig(t) = -1 05,861 8 - (1 8 506,15 / T) . Ig(o) + 57 895,49 / T - 24,799 7 . Ig(o) where t is the time, in hours; T is the temperature, in K; o is the induced hydrostatic stress, in N/mm2. 5 10 25 50 100 Time to failure, in years- 10 10 10 Time to failure, in
19、 hours - Figure 1 : Long-term hydrostatic pressure resistance of pipes made from PE-X Page 4 DIN 16892 : 2000-07 Test temperature, in “C 5 Requirements 5.1 Form supplied Pipe ends should be cut as square as possible to the pipe axis. Pipes shall be free from any blisters and irregularities (includin
20、g foreign matter) which could affect their performance. Pigmentation shall be uniform throughout. Period of stressing (minimum time to failure), t. in hours Proof stress, o, in N/mm2 Exposure medium 5.2 Surface finish Pipes shall be smooth both inside and outside. Minor irregularities and shallow gr
21、ooves are permissible, provided the minimum wall thickness as specified in DIN 16893 is maintained throughout. Sharp-edged grooves are not permissible. 46 4,4 Air or water 5.3 Dimensions and tolerances The pipe outside diameter and wall thickness shall comply with the specifications of DIN 16893. In
22、 the case of pipes of dimensions not covered by preferred number series (cf. DIN 323-1) or international specifications, calculation shall be on the basis of DIN 16893. 165 1 O00 5.4 Long-term hydrostatic pressure resistance When tested in accordance with subclause 6.4 under the conditions specified
23、 in table 1, pipes shall neither fail nor develop any signs of leakage. Table 1: Test conditions for hydrostatic pressure testing 110 Air 2,s 8 7601) I 95 I Air or water I 4,7 I 22 I 95 5.5 Crosslinking When tested as in subclause 6.5, the degree of crosslinking shall be as follows: type a (peroxide
24、 crosslinked) pipes: 70 %; type b (hydrosilicon crosslinked) pipes: 65 %; type c (electron beam crosslinked) pipes: 60 %. 5.6 Heat reversion When testing in accordance with subclause 6.6, the mean relative change in pipe length shall not be greaterthan 3 YO, except where the wall thickness is greate
25、r than 16 mm. 6 Testing 6.1 Surface finish The inside and outside surfaces of the pipe shall be inspected with back light. 6.2 Dimensions The mean pipe outside diameter shall be determined to an accuracy of 0,l mm by circumferential measurement at both pipe ends, at a point at least 0,5 d from the c
26、ut edge. The wall thickness shall be determined to an accuracy of 0,l mm at both ends, at at least four points spaced evenly around the circumference of the pipe. Measurements shall be taken at (23 12) “C. 6.3 Ovality Immediately after production, ovality shall be determined by measuring the minimum
27、 and maximum outside diameters to an accuracy of 0,l mm. Page 5 DIN 16892 : 2000-07 6.4 Long-term hydrostatic pressure resistance General information on testing is given in DIN EN 921. For each proof stress value as given in table 1, three sections of pipe (referred to below as pipes) with a length,
28、 Z, as follows shall be taken as specimens: 2, =3.d+2.Z5+250mm (3) Figure 2: Specimen for hydrostatic pressure resistance test where, in figure 2 and the preceding equation, d is the pipe outside diameter, in mm; 1, is the specimen length, in mm; 1, is the test length, in mm; 1, is the length of pip
29、e affected by the sealing devices being clamped, in mm: 1, = d; 1, is the assessment length, in mm (2, - 2 . 2,); 1, is the free length, in mm (for mounting a sealing device). Along the assessment length, the wall thickness and the outside diameter shall be determined by circumfer- ential measuremen
30、t at eight and three points respectively, to an accuracy of 0,l mm, and the minimum wall thickness, .srnini and the mean outside diameter, d, established. Sealing devices shall be fitted to both ends of the specimen, allowing it free axial movement during the test. The specimen shall be filled with
31、water at the test temperature specified in table 1 (to within I5 K) through an opening in one of the sealing devices, placed in a tank which has been heated to test temperature (maintained to within I 1 K) and left there for at least one hour to reach thermal equalization. If the pipe is filled with
32、 cooler water, it shall be left in the tank for 12 hours. With the pipe remaining in the tank, hydrostatic pressure shall be steadily increased to proof pressure within one minute. The pressure shall be maintained to within 2,5 YO throughout the period specified in table 1 (mini- mum time to failure
33、). The proof pressure, Pe,p, shall be calculated as follows: where d is the mean outside diameter over 1,; smin is the minimum wall thickness over 1,; o, is the proof stress as specified in table 1. Check whether the pipe has failed or developed signs of leakage during the specified period of stress
34、ing. If the pipe has failed within 1, during this period, the results of the test shall not count and the test shall be repeated. 6.5 Crosslinking 6.5.1 General The degree of crosslinking shall be determined by measuring the fraction of PE-X being insoluble in boiling xy I en e. 6.5.2 Sampling Chips
35、 (0,2 I0,02) mm thick shall be taken from the pipe, using a lathe if possible. The width of the chips shall correspond to the pipe wall thickness, and their length shall be at least equal to the pipe circumference. 6.5.3 Procedure Weigh the chips to an accuracy of 1 mg (m,) and place in a wire net o
36、r perforated metal container. Place the container in boiling, technically pure xylene, to which 1 % antioxidant (2,2 methylene-bis-(4-methyl-6-tert- butylphenol) or pentaerythrityl tetrakis (3-(3,5 di-tert.butyl-4-hydroxiphenyl)-propionate) has been added. Leave for 8 h I5 min, then lift the contain
37、er out of the boiling solvent, allow it to cool to ambient temperature and dry it. Page 6 DIN 16892 : 2000-07 Wall thickness, s, in mm Up to 8 The samples shall then be dried for three hours in an oven with forced circulation, at 140 “C. After cooling to ambient temperature, the residue mass, m2, sh
38、all be weighed to an accuracy of 1 mg. 6.5.4 Expression of results The degree of crosslinking, G, expressed as a percentage, is to be calculated using equation (5): Test tempera- Test period, t, ture, in “C in minutes 120I2 60I2 6.6 Heat reversion Specimens shall be three pipe sections, each approxi
39、mately 200 mm long. Gauge marks shall be made on the outside of each specimen, approximately 50 mm from each end, along the pipe axis. The distance between the two reference marks, lo, shall be approximately 1 O0 mm, measured at (23 12) “C to an accuracy of 0,25 mm. The specimens shall be laid conve
40、x side down on a glass plate dusted with talcum so that any change in length will not be hindered. Subsequently, the glass plate shall be placed in an oven with forced air circulation in accordance with DIN 5001 1-1 1, which has been preheated to test temperature, as specified in table 2. Table 2: C
41、onditions for heat reversion test Over 8 up to 16 I 120 I2 120I2 I I After removing the specimens from the oven and allowing them to cool to (23 12) “C in the same position, the minimum distance between the two gauge marks, Imin, shall be measured. The relative change in length, E, shall be calculat
42、ed as follows: hl 100=-10O 10 10 lo - Imin E=- where 1, Imin The arithmetical mean of E, calculated as in equation (6), shall be taken as the mean relative change in length for the tested pipe. 6.7 Test certificate By agreement, the pipe manufacturer shall issue a DIN EN 10204 inspection document. i
43、s the distance between gauge marks before heat treatment, in mm; is the distance between the gauge marks after heat treatment and cooling, in mm; A1 = 1, - Imin. Page 7 DIN 16892 : 2000-07 Density (testing as in DIN 53479) Mean coefficient of linear thermal expansion at temperatures between O “C and
44、 70 “C (testing as in DIN 53752) Explanatory notes This standard is a basic standard and therefore does not coverthe scope of testing, inspection, or requirements relating to special applications. The hydrostatic pressure resistance requirements specified in this standard are based on experiments wh
45、ich have taken the probable service life of the pipes into consideration. These experiments have shown that when crosslinked polyethylene fulfilling the requirements of this standard is tested for resistance to hydrostatic pressure, the result is linear on a log-log scale, unlike common polyolefines
46、, which produce a sharply bent curve. Heat reversion testing provides important information for processing, because heating in order to bend and assembly moulded parts will change the dimensions of the pipes. PE-X pipes cannot be recycled for use as reworked material. The following table gives guide
47、line values for the properties of PE-X pipes specified in this standard. 0,94 g/cm3 1,5. 10-4 K-1 Table: Properties and guideline values Surface resistivity (testing as in IEC 60093) I ProDertv I Guideline value I 1012 I Thermal conductivitv ftestina as in DIN 52612-1) I 0.41 WK-1m-1 I I Minimum mod
48、ulus of elasticity (testing as in DIN EN IS0 178) I 600N/mm2 I Other relevant standards DIN 41 02-1 Fire behaviour of building materials and elements - Classification of building materials - Requirements and testing DIN 41 02-4 Fire behaviour of building materials and elements - Overview and design
49、of classified building materials, elements and components DIN 53752 Determination of coefficient of linear thermal expansion of plastics DIN 5261 2-1 Determination of the thermal conductivity of thermal insulating materials by the guarded hotplate apparatus - Procedure and evaluation DIN 53479 Determination of density of plastics and elastomers DIN EN IS0 178 Determination of the flexural properties of plastics (IS0 178 : 1993) DIN EN IS0 1872-2 Plastics - Polyethylene (PE) moulding and extrusion materials - Part 2: Preparation of test specimens and determination of properties (
