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1、INTERNATIONAL STANDARD IS0 13479 First edition 1997-05-01 Palyolefin pipes for the conveyance of fluids - Determination of resistance to crack propagation - Test method for slow crack growth on notched pipes (notch test) Tubes en polyokfines pour le transport des fluides - RBsistance 21 la propagati
2、on de la fissure - Mkthode dessai de ia propagation lente de la fissure dun tube entail6 (essai dentaille) This material is reproduced from IS0 documents under International Organization for Standardization (ISO) Copyright License number IHSIICCH996. Not for resale. No part of these IS0 documents ma
3、y be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyright law of the country of use, or with the prior written consent of IS0 (Case postale 66,1211 Geneva 20, Switzerland, Fax +41 22 734 10 79), IHS or the IS0 Licensers members. - - (g a=4OOnet; p=iso;
4、 o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- I
5、NTERNATIONAL STANDARD 0 IS0 IS0 13479: 1997(E) Polyolefin pipes for the conveyance of fluids - Determination of resistance to crack propagation - Test method for slow crack growth on notched pipes (notch test) 1 Scope This International Standard specifies a method of test for determining the resista
6、nce to slow crack growth of polyolefin pipes, expressed in terms of time to failure in a hydrostatic pressure test on a pipe with machined longitudinal notches in the outside surface. The test is applicable to pipes of wall thickness greater than 5 mm. 2 Normative references The following standards
7、contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to inves
8、tigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 161-1:1996, Thermoplastics pipes for the conveyance of fluids - Nominal outside diameters and nominal pressures - Pa
9、rt 1: Metric series. IS0 1167:1996, Thermoplastics pipes for the conveyance of fluids - Resistance to internal pressure - Test method. IS0 6108:1978, Double equal angle cutters with plain bore and key drive. IS0 11922-l :1997, Thermoplastics pipes for the conveyance of fluids - Dimensions and tolera
10、nces - Part 7: Metric series. 3 Definitions For the purposes of this International Standard, the definitions given in IS0 161-l and IS0 11922-1 apply. 4 Principle Lengths of pipe with four machined longitudinal external notches are subject to a constant-pressure hydrostatic pressure test whilst imme
11、rsed in a water tank at 80 “C. The time to failure is recorded. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without licens
12、e from IHS -,-,- IS0 13479: 1997(E) IS0 5 Apparatus 5.1 Pipe pressure-testing equipment, as specified in IS0 1167. 5.2 Notch-machining equipment, i.e. a milling machine with a horizontal mandrel rigidly fixed to the bed to enable the pipe to be securely clamped to give a straight test piece. The man
13、drel shall support the pipe bore beneath and along the full length of the notch to be machined. The milling cutter mounted on a horizontal arbor shall be a 60”included-angle “V-cutter conforming to IS0 6108, having a cutting rate of (0,010 otherwise a minimum free length of greater than or equal to
14、1 000 mm shall be used. 6.2 Notch location Positions shall be marked for machining four notches equally spaced around the pipe circumference (see figure 1). 6.3 Machining the notches 6.3.1 If the wall thickness of the test piece is greater than 50 mm, the material shall be machined with a slot drill
15、 of 15 mm to 20 mm diameter to leave approximately 10 mm to be removed by the “V-cutter used in accordance with 6.3.2. 6.3.2 Each notch shall be machined by climb milling to a depth so as to produce a pipe wall ligament of thickness between 0,78 and 0,82 times the minimum wall thickness, as specifie
16、d in IS0 11922-l) for the diameter and pressure series of the pipe as shown in table 1 (see note). The ends of each notch shall be aligned circumferentially as shown in figures 1 and 2. The length of each notch, at full depth, shall be equal to the pipe nominal outside diameter + 1 mm. For pipes wit
17、h a free length of pipe of less than (3 dn + 5) mm, the length of each notch, at full depth, shall be equal to the free length minus (500 + 1) mm. NOTE - To achieve a remaining ligament within the required tolerance range, it is advisable to aim for a remaining ligament at the top of the tolerance r
18、ange. This is because the pipe wall can move due to release of residual stresses, resulting in a deeper than anticipated notch. 6.3.3 The test piece shall have end caps fitted which ensure that any longitudinal internal pressure load will act fully on the pipe (e.g. as shown for the type A arrangeme
19、nt in IS0 1167). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 13479:1997(E) Copyright In
20、ternational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 13479: 1997(E) Q IS0 Ligament thickness: 0,X to 0.82 ti
21、mes minimum IS0 wall thickness Figure 1 - Pipe test piece 60 double equal Notch length (I x d,) centred on test piece Figure 2 - Notching method 6.4 Number of test pieces Prepare a minimum of three test pieces unless specified otherwise in the referring standard. 7 Conditioning The test pieces shall
22、 be filled with water, immersed in a water tank at 80 “C and allowed to condition for 24 h for pipes of wall thickness up to 25 mm and 48 h for greater wall thicknesses. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards
23、1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- Q IS0 IS0 13479:1997(E) 8 Procedure 8.1 Hydrostatic-pressure testing Pressurize the test piece with water in accordance with IS0 1167 at a test temperature of 80 92, applying an
24、d maintaining the pressure specified in the referring standard. During the procedure of applying the pressure, ensure that the pressure is increased smoothly and progressively, and the required pressure is not exceeded. Maintain the pressure until either the test piece ruptures or a specified minimu
25、m time to failure has elapsed, whichever occurs first. Record the time under pressure to the nearest hour. In the case of failure, record the location of the failure for each test piece. NOTE - Table A.1 gives applicable pressure levels, dependent on material type and pipe series. 8.2 Notch-depth me
26、asurement On completion of the pressure test, remove the test piece from the water tank and allow to cool to ambient temperature. Cut a section of pipe out from round the position of each notch. Open up the notch to give clear access to one of the machined surfaces of the notch. Measure the width of
27、 the machined surface of the notch to an accuracy f 0,l mm with a microscope or equivalent means, e.g. as shown in figure 3. If required by the referring standard, measure the depth of penetration of the crack. Notch depth, N Width L of machined r I /- surface of notch i Ligament thickness Figure 3
28、- Measurement to calculate notch depth Calculate the notch depth N, in millimetres, using the following equation: where H=0.5(dem-J d em is the measured mean pipe outside diameter, in millimetres. Calculate the ligament thickness from the notch depth and the individual average wall thickness alongsi
29、de each notch position. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 13479:1997(E) IS0 9
30、 Test report The test report shall include the following information: 4 W 4 4 4 f) 9) t-0 0 0 k) a reference to this International Standard and to the referring standard; all details necessary for complete identification of the pipe (manufacturer, type of pipe, production date); the cutter size and
31、number of teeth; the cutter speed, in revolutions per minute, and traverse speed, in millimetres per minute; the mean pipe outside diameter, in millimetres; the ligament thickness for each notch; the notch depth and percentage notch depth for each notch, and location of any failed notch; the test pr
32、essure; the time under pressure or the time to failure, in hours, as applicable; details of any factors which may have affected the results, such as any incidents or any operations not specified in this International Standard; the date of the test. Copyright International Organization for Standardiz
33、ation Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- Q IS0 IS0 13479: 1997(E) Annex A (informative) Test-pressure levels and recommended specifications
34、 for polyethylene NOTE - The test is applicable to other polyolefin materials such as polypropylene, but test parameters and specifications have not been developed. A.1 Test-pressure levels For a notch test for slow crack growth in polyethylene (PE) pipe, at the test temperature of 80 “C the applica
35、ble pressure levels depend on the material type and pipe series as given in table A-1. Table A.1 - Test-pressure levels Test pressure, p bar SDR S PE 80 PE 100 41 20 2 2,3 33 16 2,5 2,88 26 12,5 32 3,68 21 10 4 4,6 17,6 893 4,82 554 17 8 5 5,75 13,6 693 6,35 7,3 11 5 8 92 9 4 IO 11,5 794 3,2 12,5 14
36、,38 6 23. 16 18,4 NOTE - These pressure levels are calculated to give nominal plain-pipe hydrostatic stress levels of 4,0 MPa in PE 80 materials and 4,6 MPa in PE 100 material by use of the following equations: 10a l-J=-y or 200 =(SDR-1) where u is the hydrostatic stress, in megapascals; S is the pi
37、pe series; SDR is the standard dimension ratio. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,-
38、 IS0 13479: 1997(E) 0 IS0 A.2 Recommended minimum requirements It is recommended that at least three tests be performed, and no failure time should be less than the applicable minimum time given in table A.2. Table A.2 - Minimum failure times Material type Minimum failure time h PE 80 (MRS 8) 165 PE
39、 100 (MRS 10) 165 NOTE - MRS (minimum required strength) as classified in accordance with IS0 12162. I Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction
40、 or networking permitted without license from IHS -,-,- Q IS0 IS0 13479:1997(E) Annex B (informative) Bibliography I IS0 12162:1995, Thermoplastics materials for pipes and fittings for pressure applications - Classification and designation - Overall service (design) coefficient. Copyright Internatio
41、nal Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 13479:1997(E) Q IS0 ICS 23.040.20 Descriptors: fluid pipelines,
42、 pipes (tubes), thermoplastic resins, polyolefins, plastic tubes, cracking (fracturing), crack propagation, tests, cracking tests, determination, crack strength, test report sheets. Price based on 9 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/23/2007 19:48:13 MDTNo reproduction or networking permitted without license from IHS -,-,-