What is the difference between IS 780 and IS 14846?

IS 780 covered valves up to 300 mm, while IS 2906 covered sizes above 300 mm. Both were amalgamated and replaced by IS 14846:2000, which covers sizes from 50 mm to 1200 mm.

What are the standard pressure ratings for sluice valves in this code?

They are classified into PN 1.0 (max working pressure 1.0 MPa / ~10 kg/cm2) and PN 1.6 (max working pressure 1.6 MPa / ~16 kg/cm2).

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

The body is tested hydrostatically at 1.5 MPa (1.5 times working pressure) and the seat is tested at 1.0 MPa (Table 3).

IS 780

: 1984

Sluice Valves for Waterworks Purposes (50 to 300 mm size) - Specification

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This specification covers the requirements for inside-screw, non-rising stem type cast iron sluice valves up to 300 mm in size used for waterworks. Note that this standard was officially amalgamated with IS 2906 (larger valves) and superseded by IS 14846 in the year 2000, though it remains frequently referenced in legacy project documents.

Specifies requirements for cast iron sluice valves of 50 to 300 mm nominal size for waterworks.

Quick Reference Values

size range covered50 mm to 300 mm

pressure rating PN 1 01.0 MPa (Maximum working pressure)

pressure rating PN 1 61.6 MPa (Maximum working pressure)

body test pressure PN 1 01.5 MPa (Hydrostatic)

seat test pressure PN 1 01.0 MPa (Hydrostatic)

body test pressure PN 1 62.4 MPa (Hydrostatic)

seat test pressure PN 1 61.6 MPa (Hydrostatic)

Practical Notes

Although formally superseded by IS 14846, IS 780 is still commonly cited in legacy government tenders and older BOQs in India.

Ensure proper alignment of flanges and use the correct gasket thickness to avoid uneven stress during tightening, which can crack the cast iron body.

Always check whether the system requires PN 1.0 or PN 1.6 valves depending on the maximum hydraulic head of the pipeline.