What are the standard pressure ratings for GRP pipes under this code?

The standard pressure classes (PN) are 0.1, 0.25, 0.4, 0.6, 1.0, and 1.6 MPa (Clause 5.1.1).

What is the basis for accepting a batch of pipes on-site?

Acceptance is based on conformity to dimensional checks, short-term hydrostatic tests, stiffness tests, and other performance requirements as specified in the sampling plan (Annex E).

Is this code applicable for hot water or sewage?

No, this standard is specifically for potable water supply, which implies cold water. Different standards and resin systems are required for sewage or hot water applications.

How is the long-term strength of the pipe determined?

The code requires a regression analysis of hydrostatic test data to predict a 50-year strength, which is validated by a 10,000-hour sustained pressure test (Annex B).

IS 12709

: 1994

glass-fibre reinforced plastic (GRP) pipes joints and fittings for use in potable water supply

CurrentSpecializedSpecificationBIMWater Resources · Plastic Piping System

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This standard specifies the requirements for glass-fibre reinforced plastic (GRP) pipes, joints, and fittings up to 2000 mm nominal diameter. It covers material properties, dimensions, performance criteria like pressure (PN) and stiffness (SN) classes, and associated testing methods for their use in potable water supply systems.

glass-fibre reinforced plastic (GRP) pipes joints and fittings for use in potable water supply

Quick Reference Values

Standard Pressure Classes (PN)0.1, 0.25, 0.4, 0.6, 1.0, and 1.6 MPa

Standard Stiffness Classes (SN)2500, 5000, and 10000 N/m²

Short-Term Rupture Test Pressure4 x PN (for pipes up to 300mm) or 3.5 x PN (for pipes >300mm)

Short-Term Hydrostatic Test Pressure (Type Test)2 x PN for 1 hour

Minimum Barcol Hardness90% of the value of a fully cured un-reinforced resin casting

Water Absorption LimitMax 0.2% by mass

Long-term Hydrostatic Strength Test Duration10,000 hours

Practical Notes

GRP pipe handling requires care to avoid impact damage, which can cause micro-cracking not visible to the naked eye. Use wide fabric slings for lifting.

Jointing is a critical activity. Ensure elastomeric rings are clean, properly lubricated, and correctly seated as per the manufacturer's instructions to prevent long-term leakage.

Verify the compatibility of the resin system with specific water treatment chemicals (e.g., high chlorine concentrations) that might be used, as the standard primarily covers standard potable water.