What are the standard pressure ratings covered by IS 780?

The standard covers PN 1.0 (1.0 MPa) and PN 1.6 (1.6 MPa) pressure ratings.

What is the hydrostatic test pressure for a PN 1.0 valve?

The body must be tested at 1.5 MPa and the seat/closed valve at 1.0 MPa.

What materials are allowed for the valve body?

The body can be made of Cast Iron (conforming to IS 210) or Ductile Iron (conforming to IS 1865).

What is the minimum duration for hydrostatic testing?

The test pressure must be maintained for a minimum of 5 minutes without leakage or sweating.

IS 780

: 2016

Sluice valves for waterworks (cast iron or ductile iron body) - Specification

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This standard covers the specifications for inside screw, non-rising stem type sluice valves with cast iron or ductile iron bodies used in waterworks. Engineers use this code to define the dimensions, materials, pressure ratings, and hydrostatic testing requirements for valves in municipal and industrial water supply networks.

Specifies requirements for sluice valves of various sizes suitable for waterworks applications.

Quick Reference Values

nominal pressure PN1.01.0 MPa

nominal pressure PN1.61.6 MPa

hydrostatic body test PN1.01.5 MPa

hydrostatic seat test PN1.01.0 MPa

hydrostatic body test PN1.62.4 MPa

hydrostatic seat test PN1.61.6 MPa

test duration5 minutes (minimum)

Practical Notes

Ensure the selected PN rating (PN 1.0 or PN 1.6) exceeds both the maximum working pressure and potential surge pressures in the pipeline.

Non-rising stem valves are standard for underground installations as they save space and protect the stem from damage.

Always verify flange dimensions and drilling against connecting pipe flanges, which typically conform to IS 1538 for cast iron fittings.

Standard closing direction is clockwise, but anti-clockwise closure can be specified if required by the purchaser. This must be clearly marked on the handwheel or cap.