SIST EN 1228:1997

Overview

EN 1228:1996 (CEN) specifies laboratory methods for determining the initial specific ring stiffness of glass-reinforced thermosetting plastics (GRP) pipes used in plastics piping systems. The standard gives two equivalent test methods and applies to pipes of any diameter, with the caveat that each method is valid only within the specified deflection limits set by the standard. EN 1228:1996 is intended to provide a consistent basis for measuring ring stiffness for quality control, product certification and structural design input.

Key topics and technical requirements

• Scope and applicability: Measurement of the initial specific ring stiffness for GRP (glass‑reinforced thermosetting plastics) pipes across all diameters.
• Two standardized methods: The document defines two laboratory procedures; within the standard’s deflection limits both are equally valid. (EN 1228:1996 does not prioritize one method over the other.)
• Initial specific ring stiffness: Focus on determining the pipe’s resistance to radial deformation under controlled loading - a key mechanical property for buried and supported piping systems.
• Deflection limits: Tests are valid only while deflection remains within the limit ranges specified in the standard (users must follow those limits to compare results reliably).
• Repeatability and comparability: By prescribing standard test methods, EN 1228 improves the repeatability of results between laboratories and manufacturers.
• Documentation and reporting: Test results should be reported in accordance with the standard’s specifications so results can be used for compliance, certification, and design.

Practical applications and users

EN 1228:1996 is used by:

• Manufacturers and quality control teams to verify production compliance and control material/process variations.
• Independent testing laboratories for product type testing and certification testing.
• Pipeline and civil engineers who need standardized stiffness values for structural design, bedding calculations and load-bearing assessments.
• Specifiers and procurement professionals writing technical specifications or selecting GRP pipes for municipal, industrial, drainage and sewer applications.
• Regulatory bodies and certification agencies for harmonized acceptance criteria and performance verification.

Practical benefits:

• Ensures consistent, comparable stiffness data for design and compliance
• Supports product selection and lifecycle performance assessment
• Reduces disputes by providing standardized test procedures and reporting formats

Related standards

• EN 1228:1996 is part of the suite of CEN plastics piping system standards for GRP materials. For complete design and installation guidance, consult adjacent CEN/ISO standards covering long‑term mechanical properties, jointing, installation and design verification.