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IS 2558 Part 1 : 1985Vitreous China Water Closets (Indian Type) - Part 1: Specific Requirements

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EN 997 · ASME A112.19.2 · AS/NZS 1172.1
CurrentFrequently UsedSpecificationBIMMEP · Drainage, Sewerage and Sanitary Fittings
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OverviewValues4InternationalTablesFAQ3Related

IS 2558:1985 Part 1 is the Indian Standard (BIS) for vitreous china water closets (indian type) - part 1: specific requirements. This standard specifies the dimensions, manufacturing tolerances, finish, and performance requirements for vitreous china water closets of the Indian type (squatting pans). It ensures uniform quality, proper flushing performance, and hygiene across sanitary plumbing installations.

Details specific requirements for Indian type vitreous china water closets, including dimensions and performance criteria.

Overview

Status
Current
Usage level
Frequently Used
Domain
MEP — Drainage, Sewerage and Sanitary Fittings
Type
Specification
International equivalents
EN 997:2018+A1:2021 · CEN (European Committee for Standardization)ASME A112.19.2-2023/CSA B45.1-23 · ASME (US) / CSA (Canada)AS/NZS 1172.1:2014 · Standards Australia / Standards New Zealand
Typically used with
IS 2556IS 9140
Also on InfraLens for IS 2558
4Key values2Tables3FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! The pan and the trap are often specified together; ensure compatibility for an effective water seal.
! Check for crazing and warpage during site inspection; defective vitreous china can lead to cracking under load.
! Ensure proper bedding of the squatting pan in sand/concrete to prevent point-loading fractures.
Frequently referenced clauses
Cl. 3Manufacture and FinishCl. 4Dimensions and TolerancesCl. 5Flushing TestCl. 6Water Absorption and Crazing
Pulled from IS 2558:1985. Browse the full clause & table index below in Tables & Referenced Sections.
vitreous chinaceramic

International Equivalents

Similar International Standards
EN 997:2018+A1:2021CEN (European Committee for Standardization)
HighCurrent
WC pans and WC suites with integral trap
Covers performance and construction requirements for all WC types, including squatting WC pans.
ASME A112.19.2-2023/CSA B45.1-23ASME (US) / CSA (Canada)
MediumCurrent
Ceramic Plumbing Fixtures
Specifies material, dimensional, and performance requirements for vitreous china fixtures, including water closets.
AS/NZS 1172.1:2014Standards Australia / Standards New Zealand
MediumCurrent
Sanitary plumbing products, Part 1: Water closets (WCs), pans of 6/3 L capacity or proven equivalent
Focuses on water-saving performance for WCs, including squatting pans, but with different design assumptions.
Key Differences
≠IS 2558 is highly prescriptive, providing detailed dimensional drawings for 'Long Pan' and 'Orissa Pan' types. International standards like EN 997 are performance-based, allowing any design that meets specified flushing and cleaning tests.
≠IS 2558 (1985) was designed for higher flush volumes (typically 10-12.5 litres). Modern international standards mandate low-flush (e.g., 6 L) or dual-flush (e.g., 6/3 L or 4.5/3 L) for water conservation.
≠International standards (e.g., EN 997, ASME A112.19.2) include a more extensive suite of performance tests, such as tests for removing paper loads, plastic balls, and extensive surface washing/rinsing tests, which are not detailed in IS 2558.
≠IS 2558 is specific only to Indian-type squatting pans. International equivalents cover a much broader range of products in a single document, including close-coupled, one-piece, wall-hung, and pedestal WCs.
Key Similarities
≈All standards specify the use of vitreous china, a ceramic material fired at high temperature to make it non-porous and durable.
≈There is a common requirement for a minimum water trap seal depth (typically 50 mm) to prevent the passage of sewer gases into the building.
≈All standards mandate that functional surfaces of the water closet must be covered with a smooth, impervious glaze that is resistant to staining and easy to clean.
≈Material quality tests, such as the crazing resistance test (using an autoclave) and the water absorption test, are present in both the IS code and its international counterparts with very similar test parameters and acceptance criteria.
Parameter Comparison
ParameterIS ValueInternationalSource
Water Absorption (of Vitreous China)Not more than 0.5% of its dry weightShall not exceed 0.5% of the dry weightASME A112.19.2
Minimum Trap Seal Depth50 mmAt least 50 mmEN 997
Crazing Resistance TestNo crazing after one cycle at 345 kPa (3.5 kgf/cm²) steam pressure for 1 hour.No evidence of crazing after one cycle at 50 psi (approx. 345 kPa) steam pressure for 1 hour.ASME A112.19.2
Static Load Bearing Test400 kgf (approx. 3.9 kN) applied on the pan without fracture.3.0 kN applied for 30 minutes without showing cracks or fracture.EN 997
Nominal Full Flush VolumeDesigned for older high-volume cisterns (e.g., 10-12.5 Litres)Defined classes, typically 6 Litres or 4 Litres for full flush.EN 997
Chemical Resistance TestNo visible staining from ink or staining agent.Not to be visibly affected by specified chemical solutions (e.g., N-Amyl-acetate).ASME A112.19.2
⚠ Verify details from original standards before use

Key Values4

Quick Reference Values
max water absorption0.5%
minimum thickness6 mm
typical lengths450 mm, 500 mm, 580 mm, 630 mm
tolerance on dimensions above 75mm± 4 percent

Tables & Referenced Sections

Key Tables
Table 1 - Dimensions of Indian Type Water Closets
Table 2 - Permissible Tolerances
Key Clauses
Clause 3 - Manufacture and Finish
Clause 4 - Dimensions and Tolerances
Clause 5 - Flushing Test
Clause 6 - Water Absorption and Crazing

Related Resources on InfraLens

Cross-Referenced Codes
IS 2556:1982General requirements for water meters - Part ...
→
IS 9140:1996Method for a sampling of vitreous and fire cl...
→

Frequently Asked Questions3

What is the maximum permissible water absorption for vitreous china WCs?+
The maximum water absorption should not exceed 0.5% by mass to ensure durability and hygiene.
What are the standard lengths of Indian type water closets?+
Common standard lengths typically specified are 450 mm, 500 mm, 580 mm, and 630 mm depending on the pattern.
Is the trap an integral part of the pan?+
It can be integral or separate (P or S trap) depending on the specified pattern, but must maintain the required water seal depth.

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