What are the pressure ratings available for uPVC pipes under IS 4985?

Six classes are specified, from Class 1 (0.25 MPa) up to Class 6 (1.6 MPa). See Clause 4.2.1.

Is lead permitted in the composition of these pipes?

No, the 2021 revision mandates the use of lead-free stabilizers. See Clause 5.1.1.

What is the standard colour for these pipes?

The colour shall be dark grey. See Clause 6.5.

What is the purpose of the reversion test?

The reversion test checks for induced stress during manufacturing by heating a sample. A high reversion value (over 5%) indicates poor processing, which can affect long-term performance. See Clause 7.2.

IS 4985

: 2021

Unplasticized PVC (uPVC) pipes for potable water supplies - Specification

CurrentEssentialSpecificationBIMMEP · Water Supply and Plumbing

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This standard specifies the requirements for unplasticized polyvinyl chloride (uPVC) pipes intended for carrying potable water. It covers the material composition (mandating lead-free stabilizers), dimensions, physical and mechanical properties, and testing methods for pipes of various pressure classes.

Specifies requirements for uPVC pipes intended for conveying potable water under pressure.

Quick Reference Values

Standard pipe colourDark Grey

Maximum reversion percentage5%

Opacity requirement< 0.2% light transmission

Stabilizer requirementLead-free

Standard pipe length6 m (excluding socket length)

Lowest pressure class rating (Class 1)0.25 MPa

Highest pressure class rating (Class 6)1.6 MPa

Practical Notes

The 2021 revision mandates lead-free stabilizers, a critical health and compliance point. Ensure procured pipes meet this latest requirement.

Pipes are classified by working pressure (e.g., Class 1 for 0.25 MPa). Selecting the wrong class for the system's pressure is a common cause of failure.

Pipe marking is a key identifier of compliance. It must include the manufacturer, size, pressure class, 'Potable' designation, and the IS 4985 mark.