ISO 13953 pdf download.Polyethylene (PE) pipes and fittings — Determination of the tensile strength and failure mode of test pieces from a butt-fused joint
1 Scope
This International Standard describes a test method for determination of the tensile strength and tensile failure mode of butt-fused polyethylene (PE) pipe assemblies. The method is applicable to butt-fused joints between PE pipes with a nominal outside diameter of not less than . The method may be used, together with other test methods, to evaluate the quality of the butt-fused joints.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1 1 41 4:1 996, Plastics pipes and fittings — Preparation of polyethylene (PE) pipe/pipe or pipe/fitting test piece assemblies by butt fusion .
3 Principle
A test piece machined from a butt-fused PE pipe joint to give a waisted section is subjected to a tensile stress at constant speed. When loading the test piece in a tensile-testing machine, the stress is concentrated through the jointed region and ultimate failure is in the vicinity of the joint. The failure mode and tensile strength are used as criteria for the evaluation of the butt-fused joint.
4 Apparatus
4.1 Room, which can be controlled at a temperature of . 4.2 Tensile-testing machine, capable of sustaining between its clamping jaws a constant speed of , and equipped with means for recording the consequent applied force, and a device to detect test piece failure. 4.3 Clamping device, equipped with bars fitting into traction holes machined in the test piece. 4.4 Measuring devices, capable of determining the width and thickness of the test piece to within (see 7.1 ). 4.5 Template with the geometry of the test piece (see Figures 1 and 2), to mark the shape of the test piece to be machined.
5 Test pieces
5.1 Sampling The pipes used to produce the test piece shall be obtained by sampling as specified in the product standard. 5.2 Preparation 5.2.1 General The butt-fused PE pipe joints shall be prepared in accordance with the manufacturer’s instructions or the instructions specified in the relevant standards (e.g. ISO 1 1 41 4). For each test piece required, a strip shall be machined out along the longitudinal direction of the pipe, across the joint. The strip shall be further machined to prepare a test piece with dimensions conforming to: a) Table 1 and Figure 1 for pipes with wall thickness (type A); b) Table 1 and Figure 2 for pipes with wall thickness (type B); using a template to ensure that the joint interface will be aligned with the cross-section of the centre of the waist of the test piece of type A or type B, as applicable. The fusion beads may be removed. 5.2.2 Type A test piece The dimensions and shape of the type A test piece shall conform to Figure 1 and Table 1 .
7 Procedure
7.1 Measure the thickness of the test piece as the thickness of the pipe wall and the width of the test piece as the distance between the two holes drilled at the joint ( ) for test pieces of type A (see Table 1 and Figure 1 ) or as the width of the narrow portion ( ) for test pieces of type B (see Table 1 and Figure 2). 7.2 Place the test piece in the clamping device of the tensile-testing machine, so that the direction of the force applied to the test piece is perpendicular to the butt-fusion joint. 7.3 Apply tension to the test piece with a cross-head speed of . 7.4 Record the force applied during extension until complete failure of the test piece. 7.5 Record the maximum force applied (in newtons) and the type of failure as ductile or brittle, as characterized by the ductile and brittle failure modes shown in Figure 3. Only failures at the butt-fusion joint shall be taken into account. 7.6 Calculate the tensile strength as the maximum recorded tensile force (in newtons) divided by the cross- sectional area of the centre of the test piece (i.e. width thickness, as measured in accordance with 7.1 , in square millimetres).