Structured-Wall Plastics Piping Systems for Non-Pressure Drainage and Sewerage - Specification, Part 2: Pipes and Fittings with Non-Smooth External Surface, Type B
2013 Edition

According to IS 16098 Part 2:2013, the minimum wall thickness for pipes and fittings must be equal or greater than specified values depending on the nominal diameter. Fabricated fittings should have wall thicknesses meeting or exceeding those of the pipes, with allowances for reductions only if they comply with Table 12 requirements. For example, for DN 75, the pipe body minimum thickness (e4) is 1.0 mm and the socket/spigot thickness (e5) is 0.85 mm, with a minimum socket length of 27 mm. These values increase with pipe size, ensuring structural strength and leak resistance. For pipes longer than 6 meters, socket lengths should be increased accordingly.

IS 16098 Part 2 defines Nominal Ring Stiffness (SN) as the minimum required ring stiffness expressed in kN/m² that a pipe or fitting must have. Pipes with nominal diameters up to 500 mm are classified into SN 4, SN 8, and SN 16 stiffness classes, while those above 500 mm may include SN 2 as well. The standard stipulates that the average ring stiffness of the socket and spigot must be at least equal to the pipe's SN value, ensuring mechanical integrity. Manufacturer-guaranteed stiffness values between SN grades can be accepted for pipes with DN up to 500 mm, but markings must reflect the lower SN class.

The standard specifies jointing methods that ensure watertight connections, primarily utilizing coupler and spigot/socket joints with elastomeric sealing rings. Pipes have corrugated outer layers at the socket end where a rubber ring is positioned on the first corrugation valley to provide a locking and sealing function. Before assembly, pipe ends and gaskets must be cleaned and lubricated with approved lubricants. Proper alignment is essential, with insertion guided by homing marks on pipes. Leak-tightness is verified by hydrostatic pressure testing under specified conditions, with any leakage indicating joint failure requiring remedial action.

Per IS 16098 Part 2 Clause 5.2, only clean, reprocessable material generated from the manufacturer's own production process using the same raw material is permitted for reuse in manufacturing pipes and fittings. The use of reprocessable materials sourced externally or recycled materials from other origins is explicitly prohibited to maintain quality and consistency. This approach ensures the integrity and performance of the final products.

IS 16098 Part 2 mandates a suite of tests for mechanical performance and hydrostatic pressure resistance. PE fittings undergo thermal stability (oxidation induction test), water tightness, and flexibility tests. PP pipes require resistance tests to internal hydrostatic pressure at 4.2 MPa for 165 hours and 2.5 MPa for 1000 hours, creep ratio evaluation, thermal stability testing, water tightness, elastomeric joint tightness, and combined temperature cycling with external load resistance. Hydrostatic pressure testing for fabricated assemblies requires maintaining 0.5 bar pressure for at least one minute. These rigorous tests confirm the pipes' durability, pressure endurance, and joint integrity.