ISO 8639:2023

Overview

ISO 8639:2023 specifies test methods for the leaktightness and structural proof of flexible socket-and-spigot joints with elastomeric sealing elements used in buried and aboveground glass‑reinforced thermosetting plastics (GRP) pipes and fittings. The standard defines type-testing procedures that subject joints to combinations of longitudinal extension (draw), angular deflection, compression/deformation perpendicular to the pipe axis and internal pressure, including negative (vacuum), cyclic and elevated static pressures. Tests are destructive and intended to prove the joint design for both pressure and non‑pressure applications across all nominal sizes.

Key topics and technical requirements

• Test scope: Flexible non‑thrust resistant socket-and-spigot joints for GRP pipelines; applicable to pressure and non‑pressure systems.
• Loading modes: Draw, total draw (including effects of angular deflection), angular movement (degrees), deformation (step caused by transverse load) and internal pressure.
• Pressure regimes: Negative (sub‑atmospheric), cyclic, and positive static pressures; leakage monitoring during pressurized tests.
• Apparatus & measurements:
  • Hydrostatic pressure source and vacuum pump for negative pressures.
  • Pressure gauges (accuracy ±2 %) and force measurement device (accuracy ±5 %).
  • Supports, straps/cradles and end‑sealing devices arranged per the test figures.
• Test pieces & conditioning:
  • Assembly of two pipe pieces joined by the joint under test; total effective length per referring standard.
  • Conditioning at test temperature for at least 24 h unless otherwise specified.
  • Typical testing uses one test piece for type tests.
• Inspection & reporting: Visual or alternative leakage detection (e.g., cameras, tracer dyes) where required; full test report required.

Practical applications

• Type testing and design verification for joint manufacturers to demonstrate that flexible GRP joints meet leaktightness and structural requirements.
• Independent test laboratories and certification bodies performing destructive tests to validate joint performance.
• Pipeline designers, specifiers and asset owners who need assurance that joints will perform under combined mechanical movements and pressure conditions encountered in buried and aboveground installations.
• Manufacturers of GRP pipe systems and fittings for product development and compliance evidence.

Who should use ISO 8639:2023

• GRP joint and seal designers
• Test laboratories and conformity assessment bodies
• Pipeline engineers and project specification authors
• Manufacturers seeking type‑approval or to support product standards compliance

Related standards

ISO 8639:2023 is intended to be referenced by product and application standards that define nominal size, pressure class, total effective length and test temperature for specific GRP systems. The document was prepared by ISO/TC 138 (Plastics pipes, fittings and valves for the transport of fluids).