SIST EN ISO 23856:2021 PDF

Overview

SIST EN ISO 23856:2021 specifies requirements for glass‑reinforced thermosetting plastics (GRP) piping systems based on unsaturated polyester (UP) resin for pressure and non‑pressure water supply, drainage and sewerage. It covers pipes, fittings and joints (DN 50 to DN 4000) primarily intended for direct‑buried installations but also applicable to non‑buried use and rehabilitation methods such as slip‑lining. For the purposes of the standard, UP also includes vinyl‑ester (VE) resins.

Keywords: GRP piping, UP resin, glass‑reinforced plastics, water supply, sewerage, drainage, buried pipelines, DN 50–DN 4000.

Key technical topics and requirements

• Materials & construction
  • Composition: reinforcement (glass fibres), resin (UP/VE), aggregates/fillers, thermoplastic liners, elastomers and metallic components.
  • Wall structure: inner layer, structural (load‑bearing) layer, outer layer.
• Mechanical performance
  • Tests and criteria for initial and long‑term ring stiffness, creep stiffness, tensile strength and ultimate failure resistance in deflected conditions.
  • Hydrostatic pressure design following ISO/TS 20656‑1 and reliability principles in ISO 2394 and EN 1990 (partial safety factors, risk‑based design).
• Joints and fittings
  • Flexible and rigid joint types, sealing rings, adhesives, options for end‑thrust load bearing or non‑bearing joints.
• Durability & chemical resistance
  • Procedures to assess resistance to chemical attack using defined test solutions and strain/failure point methods.
• Testing, marking & conformity
  • Reference conditions (temperature, test water), dimensional measurement, marking and assessment of conformity requirements for manufacturers and suppliers.

Practical applications

• Potable water distribution, raw water, irrigation and cooling systems
• Sewage, drainage collectors, stormwater and wastewater pipelines
• Marine and salt‑water applications, power‑plant penstocks, processing plants
• Trenchless rehabilitation (slip‑lining) and large‑diameter buried mains

Keywords: GRP sewer pipes, GRP water mains, buried GRP pipeline, slip‑lining GRP.

Who should use this standard

• Pipeline designers and civil/mechanical engineers specifying GRP systems
• Manufacturers and fabricators of GRP pipes, fittings and joints
• Utilities and asset owners for procurement and acceptance testing
• Contractors and installers for buried and rehabilitation projects
• Testing laboratories and conformity assessment bodies

Related standards

• ISO/TS 20656‑1 (hydrostatic pressure design guidance)
• ISO 2394, EN 1990 (structural reliability and safety principles)
• ISO 25780 (GRP pipes for jacking installation)

This standard harmonizes material, testing and design practices for durable, large‑diameter GRP piping in water and wastewater infrastructure.