ISO-3127-1994.pdf
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1、INTERNATIONAL STANDARD IS0 3127 Second edition 1994-l Z-01 Thermoplastics pipes - Determination of resistance to external blows - Round-the-clock method Tubes en mat it is called the round-the-clock method. This method is applicable to isolated batches of pipe tested at 0 “C (information is also giv
2、en for sampling from the continuous production of pipe). NOTE 1 If testing below 0 “C is required, a temperature of - 20 “C is recommended. 2 Definitions For the purposes of this International Standard, the following definitions apply. 2.1 true impact rate (TIR): The total number of failures divided
3、 by the total number of blows, as a percentage, as if the whole batch had been tested. NOTE 2 In practice, test pieces are drawn at random from the batch and the result is only an estimate of the TIR for that batch. 2.2 failure: Unless otherwise specified in the product standard, shattering or any c
4、rack or split on the inside of the pipe that was caused by the impact and that can be seen by the naked eye (lighting devices may be used to assist in examining the specimens). Indentation of the test piece is not considered a failure. 3 Principle Test pieces are subjected to blows from a falling st
5、riker, of specified mass and shape, dropped from a known height onto specified positions around the circumference of the test piece. The true impact rate (TIR) of the batch, or production run from an extruder, is estimated. The severity of this test method can be adjusted by changing the mass of the
6、 striker and/or by changing the drop height. It is not technically correct to vary the severity of the test by choosing values of the TIR other than those specified below. The maximum value acceptable for the TIR is taken to be 10 %. NOTE 3 It should be appreciated that a completely definitive resul
7、t can be reached only by testing the whole batch, but in practice a balance is necessary between the statistical possibility of a definitrve result and the cost of further testing. 4 Apparatus 4.1 Falling-weight testing machine, incorporating the following basic components (see figure I). 4.1.1 Main
8、 frame, with guide rails or a guiding tube rigidly fixed in the vertical position, to accommodate a striker (4.1.2) and release it to fall vertically and freely. When calibrated, the speed of the striker at the moment of impact shall be not less than 95 % of the theoretical speed. 4.1.2 Striker, hav
9、ing a nose comprising all or part of a hemisphere, combined with a cylindrical stem at least 10 mm long, and having dimensions conforming to figure 2 and table 1, depending upon the mass of the striker. The mass of the striker, including any associated weights, shall be selected from the values give
10、n in table 2. Below the stem, the nose shall be of steel with a minimum wall thickness of 5 mm and the striking surface shall be free from visible imperfec- tions such as scratches or dents which may influence the results. 1 Copyright International Organization for Standardization Provided by IHS un
11、der license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:58:09 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 - F! A Dlmenslons In metres - Guide - Graduated scale, vertically adjustable for different sizes of pipe - Channel s
12、ection A Enlarged view Striker / 120 V-block Solid base Figure 1 - Diagrammatic representation of impact-testing machine Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:58:09
13、MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 IS0 3127:1994(E) Dlmenslons In mllllmetres a) Type d25 (for strikers of mass 0.5 kg and 0.8 kg) b) Type d90 (for strikers of mass equal to or greater than Ikg) Figure 2 - Noses of the strikers (see table I) Strikers with 0
14、,5 kg and 0,8 kg mass shall have a type d25 nose. Strikers with greater masses shall have a type d90 nose. Table 1 -Dimensions for the nose of the striker Dimensions In mllllmetres Table 2 - Recommended masses of strikers Masses In kllograms a 3 Copyright International Organization for Standardizati
15、on Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:58:09 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3127:1994(E) 4.1.3 Rigid test support, consisting of a 120” V-block at least 200 mm long, positio
16、ned so that the vertical projection of the point of impact of the falling striker is within 2,5 mm of the axis of the V-block (see figure 1). 4.1.4 Release mechanism, such that the striker can fall from a variable height which can be adjusted to any height up to at least 2 m, as measured from the to
17、p surface of the test piece, with an accuracy of f 10 mm. 5 Test pieces Test pieces of length 200 mm f 10 mm shall be cut from pipe selected at random from the batch, or the production run from an extruder. The cut ends shall be square to the axis of the pipe, clean and free from damage. For pipes w
18、ith outside diameters greater than 40 mm, a straight line shall be drawn along the length of each test piece at a random position. Further lines shall be drawn at equal distances around the pipe so that each test piece has the number of lines given in table 3. The number of blows required is given i
19、n clause 6. For 0 IS0 pipes with outside diameters less than or equal to 40 mm, only one blow per test piece shall be made. Table 3 - Number of equidistant lines to be drawn on test pieces Nominal outside diameter of pipe Number of equidistant lines to be drawn mm =z 40 - 50 3 63 3 75 4 90 4 110 6 1
20、25 6 140 8 160 8 180 8 200 12 225 12 250 12 280 16 a315 16 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/22/2007 20:58:09 MDTNo reproduction or networking permitted without license fro
21、m IHS -,-,- 0 IS0 IS0 3127:1994(E) 888 800 700 I 600 400 500 40 1 2 3 4 5 678910 15 20 30 40 506070 90 120 Numberoffailures - Boundaries between regions are calculated using the following equations: S g,c = np+0,5+uJnpo where u = 1,282 (10 % one-sided) p = 0,lO (TIR) n number of blows NOTE - It IS n
22、ecessary to have achieved at least 25 blows without failure before the test is discontinued. Figure 3 - Number of test pieces for 10 % TIR (at 90 % confidence level) 5 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/
23、9972545001 Not for Resale, 04/22/2007 20:58:09 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3127: 1994(E) 0 IS0 Number of blows Number of failures Accept Continue Reject test Number of blows Number of failures Accept Continue test Reject 25 0 1 to3 4 75 3 4to10 11 26
24、 0 1 to4 5 76 3 4to 10 11 27 0 1 to4 5 77 3 4to 10 11 28 0 1 to4 5 78 3 4to10 11 29 0 1 to4 5 79 3 4to 10 11 30 0 1 to4 5 80 4 5to10 11 31 0 1 to4 5 81 4 5to11 12 32 0 1 to4 5 82 4 5to11 12 33 0 1 to 5 6 83 4 5to11 12 34 0 1 to 5 6 84 4 5tot1 12 35 0 1 to 5 6 85 4 5to11 12 36 0 1 to 5 6 86 4 5to 11
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