What is the maximum permissible water absorption for vitreous china sanitary appliances?

The water absorption shall not exceed 0.5 percent of the dry weight of the test piece.

What are the standard dimensional tolerances for these appliances?

Unless specified otherwise in specific parts, tolerances are ±2 mm for dimensions up to 44 mm, and ±5 percent for dimensions above 44 mm.

What is the minimum modulus of rupture required?

The modulus of rupture of the vitreous china material must not be less than 60 MPa.

How is the crazing test performed?

The sample is subjected to an autoclave test at a steam pressure of 0.34 MPa for 10 hours and then immersed in a dye solution to check for surface cracks (crazing).

IS 2556 Part 1

: 2020

Vitreous Sanitary Appliances (Vitreous China) - General Requirements

CurrentFrequently UsedSpecificationBIMMEP · Plumbing Fixtures and Valves

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This standard lays down the general requirements for material, manufacture, glazing, permissible defects, dimensional tolerances, and physical performance characteristics of vitreous china sanitary appliances.

Covers general requirements, dimensions, and testing of vitreous china sanitary appliances.

Quick Reference Values

water absorption max0.5 % by mass

modulus of rupture min60 MPa

crazing test steam pressure0.34 MPa

crazing test duration10 hours

tolerance up to 44mm± 2 mm

tolerance above 44mm± 5 %

visual inspection distance600 mm

Practical Notes

This is a general standard (Part 1) and must always be read in conjunction with the specific product standard (Parts 2 to 17) for exact dimensions and shapes of individual appliances.

Visual inspection for surface blemishes (such as spots, pinholes, or blisters) should be conducted under daylight or equivalent lighting from a distance of 600 mm.

Strict adherence to the 0.5% maximum water absorption limit is critical to prevent the sanitary ware from absorbing sewage water, which leads to odor and hygiene issues.