Fabricated PVC-U Fittings for Potable Water Supplies - Specification, Part 5: Specific Requirements for Equal Tees
2009 Edition

According to IS 10124 Part 5, the minimum dimension B (length of the fitting) is calculated using the formula:

[ B = 1.45 \times \text{Nominal Outside Diameter} + 6 \text{ mm} ]

The minimum wall thickness (t) for the equal tee is defined as 90% of the minimum wall thickness of the corresponding pipe size and pressure rating, rounded up to the nearest 0.1 mm. The standard provides detailed tables indicating these values for various nominal sizes and pressure classes. Additionally, reducing tees can be customized as per client requirements. The fittings are typically solvent welded or welded using welding rods, reinforced with fiberglass strips measuring 40 mm in width and 3 mm in thickness, ensuring compatibility and mechanical strength for pressures up to 1.25 MPa.

IS 10124 Part 5 specifies five pressure classes for fabricated PVC-U equal tees, each associated with a distinct color for easy identification on site:

This color scheme facilitates quick recognition of the pressure rating of the fitting during installation and inspection.

Fabricated PVC-U equal tees must be clearly and permanently marked with the following information:

• The manufacturer’s name or unique identification mark.
• The size of the equal tee.
• The pressure class or working pressure rating as per IS 4985.
• The color corresponding to the pressure class (Blue, Green, Brown, Yellow, or Black).

Optionally, fittings may also display the BIS Standard Mark if authorized. These markings provide traceability, verify pressure ratings, and ensure compliance with relevant standards.

IS 10124 Part 5 guarantees compatibility with IS 4985 PVC pipes by aligning the dimensions, pressure classes, and material specifications of fabricated PVC-U fittings with those defined in IS 4985:2000. The fittings' outside diameters, wall thicknesses, and pressure ratings correspond precisely with the pipe specifications, ensuring seamless assembly and leak-proof joints. The standard explicitly references IS 4985 to maintain uniformity across potable water supply systems, facilitating interchangeability and consistent performance.

To comply with IS 10124 Part 5, manufacturers must adhere to the general material, dimensional, testing, sampling, and conformity requirements specified in IS 10124 Part 1. Key points include using approved materials, maintaining strict dimensional tolerances, performing mechanical and chemical testing, and conducting representative sampling as prescribed. The manufacturing process should ensure uniformity and defect-free products. Specific provisions also cover the production and inspection of caps and other accessory fittings to maintain overall system integrity.