ISO 25780:2011

Overview

ISO 25780:2011 specifies requirements for glass‑reinforced thermosetting plastics (GRP) systems based on unsaturated polyester (UP) resin used in pressure and non‑pressure water supply, irrigation, drainage or sewerage. The standard applies to GRP‑UP pipes with flexible joints intended for installation using jacking (trenchless) techniques, covering pipes from DN100 to DN4000 for conveying water or sewage at temperatures up to 50 °C. It defines material, geometric and performance characteristics, plus the test parameters for the referenced test methods.

Key topics and technical requirements

• Scope and classification: Applicable to GRP‑UP piping systems (with or without aggregates/fillers) intended for jacking installation; minimum nominal stiffness requirement (pipes intended to have at least SN 20000).
• Pipe properties and construction: Requirements for wall construction, dimensions (OD, ID, mean diameter, laying length), and material specifications for GRP‑UP materials and rubber seals.
• Mechanical tests: Procedures and test parameters for longitudinal compressive strength, initial longitudinal compressive modulus, ring stiffness, resistance to strain corrosion and long‑term properties under wet conditions.
• Jacking performance: Definition and calculation of design and permissible jacking forces (Fj, Fperm,p), ultimate longitudinal load and material safety coefficients; joint deflection capability and joint performance requirements as a function of declared nominal pressure rating.
• Joint requirements: Design, interchangeability and type‑test performance for flexible joints, including leaktightness and deflection tests referenced to other GRP standards.
• Normative annexes: Annex A/B/C provide methods for determining longitudinal compressive properties (prism and spool test‑pieces) and a procedure for calculating permissible jacking force.

Applications and users

ISO 25780:2011 is practical for:

• Manufacturers of GRP‑UP pipes and flexible joints specifying production tolerances, marking and type testing.
• Design engineers and specifiers selecting pipe systems for water supply, irrigation, drainage and sewerage projects requiring trenchless/jacking installation.
• Trenchless contractors and site engineers who need to assess permissible jacking forces, joint deflection and installation limits.
• Testing laboratories and certification bodies conducting mechanical and joint performance tests per the standard.
• Utilities and infrastructure owners evaluating GRP pipe system suitability for buried pipelines and jacked installations.

Related standards

ISO 25780 references and works alongside other GRP standards such as ISO 10466, ISO 10468, ISO 10471, ISO 8639, ISO 10639 and testing and materials standards cited within the normative references to ensure coherent specification and testing of GRP‑UP piping systems.

Keywords: ISO 25780, GRP‑UP, glass‑reinforced thermosetting plastics, unsaturated polyester, jacking techniques, flexible joints, trenchless installation, DN100‑DN4000, water supply, drainage, sewerage.