What are the standard 'K' classes for DI pipes?

The primary classes are K7 and K9. The K-class determines the pipe's wall thickness and pressure rating. (Annex B)

What is the standard length of a single DI pipe?

The standard effective lengths are 5.5 meters or 6.0 meters. (Clause 5.3)

What is the minimum required tensile strength for the ductile iron material?

The minimum tensile strength must be 420 MPa, and the minimum elongation is 10%. (Table 2)

What type of internal lining is required for DI pipes carrying water?

A factory-applied cement mortar lining is required to prevent tuberculation and maintain water quality. (Clause 9.1)

IS 15365

: 2003

Ductile iron pressure pipes for water and sewage - Specification

CurrentFrequently UsedSpecificationBIMWater Resources · Water Supply and Plumbing

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This Indian Standard specifies the requirements for ductile iron pressure pipes, including their joints and accessories, intended for conveying water or sewage. It covers material properties, dimensions, mechanical characteristics, works tests like hydrostatic pressure testing, and requirements for internal cement mortar linings and external protective coatings.

Specifies requirements for ductile iron pipes intended for use as pressure pipes for water and sewage.

Quick Reference Values

Minimum Tensile Strength420 MPa

Minimum Elongation at break10 %

Standard Pipe Length5.5 m or 6.0 m

Hardness (Brinell)Max 230 HB

Common Pressure ClassesK7, K9

Minimum Cement Mortar Lining Thickness (for DN 100)3.0 mm

Practical Notes

The 'K' class (e.g., K7, K9) is crucial; K9 is robust and commonly used for underground water mains, while K7 is suitable for less onerous conditions.

Always ensure rubber gaskets used for jointing conform to IS 5382 and are compatible with the pipe's joint type (e.g., push-on Tyton joint).

Upon delivery, visually inspect pipes for damage to the external zinc/bitumen coating and the internal cement mortar lining, as these are critical for long-term corrosion protection.