ISO 13953:2001

Overview

ISO 13953:2001 specifies a standardized tensile test method for evaluating butt-fused joints in polyethylene (PE) pipes and fittings. The standard applies to butt-fused joints between PE pipes with a nominal outside diameter of ≥ 90 mm and is intended to determine the tensile strength and tensile failure mode of machined test pieces taken through the fused joint. Results are used, together with other test methods, to assess butt-fusion quality.

Key topics and requirements

• Scope and applicability: Method for butt-fused PE pipe assemblies, nominal OD not less than 90 mm.
• Test temperature: Tests are carried out at 23 °C ± 2 °C.
• Apparatus: Controlled test room, tensile-testing machine capable of 5 mm/min ± 1 mm/min cross-head speed, clamping device and measuring tools.
• Test-piece preparation:
  • Test pieces are machined from fusion joints following templates for Type A (wall thickness < 25 mm) or Type B (wall thickness ≥ 25 mm).
  • The waist is formed by drilling specified holes to align the joint with the centre of the reduced cross-section. Fusion beads may be removed.
• Sampling: Number of test pieces depends on pipe nominal diameter (e.g., 2 pieces for 90 ≤ d < 110 mm; 4 for 110 ≤ d < 180 mm; 6 for 180 ≤ d < 315 mm; 7 for d ≥ 315 mm). One piece must be taken at the position of maximum misalignment.
• Conditioning: Minimum 6 hours at 23 °C ± 2 °C immediately prior to testing; testing must not start less than 24 hours after fusion.
• Test procedure:
  • Measure width and thickness (for cross-sectional area).
  • Apply tensile load perpendicular to the joint at prescribed speed until failure.
  • Record maximum force and characterize failure mode as ductile or brittle (only failures at the butt-fusion joint are considered).
  • Calculate tensile strength = maximum force / (width × thickness).
• Test report: Must include reference to ISO 13953, pipe identification, fusion procedure, test-piece type, test temperature, failure type and tensile strength per specimen, observations and laboratory details.

Applications and users

ISO 13953 is used to:

• Verify weld quality and joint integrity for PE water, gas and sewer pipelines.
• Support quality control in PE pipe manufacturing and fusion operations.
• Provide evidence for acceptance testing by utilities, contractors and inspection bodies. Typical users: pipe manufacturers, fusion equipment suppliers, testing laboratories, utilities, construction contractors and certification/inspection agencies.

Related standards

• Normative reference: ISO 11414:1996 (preparation of PE pipe test-piece assemblies by butt fusion).
• Developed by ISO/TC 138 (Plastics pipes, fittings and valves).

Keywords: ISO 13953:2001, polyethylene PE pipes, butt-fused joints, tensile strength, failure mode, tensile test, butt fusion, PE pipe testing.