ISO 18851-2015 PDF

Full title and description

ISO 18851:2015 — Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes and fittings — Test method to prove the structural design of fittings. This International Standard specifies type-test methods to demonstrate the structural design and mechanical performance of GRP fittings (bends, branches, reducers, tapers and similar fittings) used in pressure and non‑pressure drainage, sewerage and water supply piping systems.

Abstract

ISO 18851:2015 defines destructive type-test procedures to prove the structural design of GRP fittings for buried and non-buried applications, applicable to fittings of all nominal sizes specified in the referring system standards. The standard is intended for type testing (tests are damaging to the test piece) and does not cover connecting joint systems. Test conditions address hydraulic end thrust considerations where relevant.

General information

• Status: Published.
• Publication date: 2015-03 (Edition 1).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 23.040.20 (Plastics pipes).
• Edition / version: Edition 1, 2015-03.
• Number of pages: 7.

Scope

ISO 18851:2015 applies to fittings of any form (bends, branches, tapers, reducers, etc.) made from glass‑reinforced thermosetting plastics (GRP) intended for use in plastics piping systems for pressure and non‑pressure drainage, sewerage or water supply. It provides test methods to prove structural design (type testing) and is not intended for joint systems; it assumes fittings may be subjected to hydrostatic end thrust depending on the referring system standard. The tests are suitable for fittings intended for buried and non‑buried applications and for the range of nominal sizes covered by the applicable system standards.

Key topics and requirements

• Type-test procedures to prove structural design of GRP fittings (destructive tests — test pieces are not suitable for reuse).
• Applicability to bends, branches, reducers, tapers and other shaped fittings produced by various manufacturing methods (filament winding, tape winding, contact moulding, compression moulding or fabrication from straight pipes).
• Tests cover fittings for buried and non‑buried installations and consider hydrostatic end thrust where relevant.
• Test procedures specify loading, support and acceptance criteria for structural performance (static and relevant loading sequences used in type testing).
• Intended to be referenced by or used alongside system standards that define material, dimensional and performance requirements for GRP piping systems.

Typical use and users

Used by GRP fittings manufacturers for type‑testing and design validation, independent testing laboratories and certification bodies performing conformity assessment, pipeline and utilities engineers specifying or approving GRP fittings, and standards committees and technical specifiers referencing type-test evidence for procurement and product standards. Test houses and R&D teams use it to validate structural performance during product development and quality control.

Related standards

ISO 18851 is part of the GRP (glass‑reinforced plastics) piping family. Relevant related standards include ISO 23856:2021 (systems for water, drainage and sewerage — GRP UP), ISO 10639 (earlier GRP systems standard, replaced by later publications), ISO 25780 (GRP pipes for jacking installation), ISO 16611 (non‑circular GRP pipes for non‑pressure drainage/sewerage) and ISO 17885 (mechanical fittings for pressure piping systems). These documents together cover system requirements, joint and pipe design, installation considerations and associated test methods that complement the fitting‑design tests in ISO 18851.

Keywords

GRP, glass‑reinforced thermosetting plastics, fittings, pipes, structural design, type test, test method, plastics piping systems, water supply, drainage, sewerage, hydrostatic end thrust.

FAQ

Q: What is this standard?

A: ISO 18851:2015 is an ISO International Standard giving test methods to prove the structural design of GRP (glass‑reinforced thermosetting plastics) fittings used in plastics piping systems for water, drainage and sewerage.

Q: What does it cover?

A: It covers destructive type tests and associated procedures that demonstrate the structural integrity and mechanical performance of fittings (bends, branches, reducers, tapers, etc.) made from GRP for buried and non‑buried applications; it is not a joints standard and is intended for type testing.

Q: Who typically uses it?

A: Manufacturers of GRP fittings, independent testing laboratories, certification bodies, design engineers and utilities that specify or approve GRP fittings and standards committees preparing or referencing GRP piping system requirements.

Q: Is it current or superseded?

A: ISO 18851:2015 was published in March 2015 (Edition 1). According to ISO's lifecycle information the publication was reviewed and confirmed (remains current as of the last systematic review noted on the ISO record). Users should check the ISO catalogue for any later amendments or revisions when specifying the standard.

Q: Is it part of a series?

A: Yes — ISO 18851 sits within a broader set of ISO documents addressing GRP piping systems (system standards, joint and pipe requirements and related technical specifications) such as ISO 23856, ISO 10639 (historic), ISO 25780, ISO 16611 and ISO 17885, which together address materials, pipes, joints, fittings and installation design.

Q: What are the key keywords?

A: GRP, fittings, plastics piping systems, structural test, type testing, hydrostatic end thrust, buried installations, non‑buried installations, filament winding, contact moulding.