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IS 4321:1992 Part 1 is the Indian Standard (BIS) for concrete roofing tiles - part 1: plain tiles. This standard lays out the specification for materials, manufacture, dimensions, and testing of plain concrete roofing tiles intended for use on pitched roofs.
Specifies requirements for plain concrete roofing tiles.
! Ensure strict adherence to dimensional tolerances; irregular tiles lead to improper overlapping and potential roof leaks.
! When colored tiles are required, only durable, weather-resistant mineral pigments should be used so they do not degrade the structural integrity of the concrete.
! Proper curing of the manufactured tiles is crucial to achieve the desired transverse strength and to prevent excessive efflorescence.
EN 490:2011+A1:2017CEN (European Committee for Standardization), Europe
HighCurrent
Concrete roofing tiles and fittings for roof covering and wall cladding - Product specifications
Covers product specifications for concrete roofing tiles and fittings, including plain tiles.
BS EN 490:2011+A1:2017BSI (British Standards Institution), United Kingdom
HighCurrent
Concrete roofing tiles and fittings for roof covering and wall cladding - Product specifications
The UK's national adoption of the European standard EN 490, making it identical in technical content.
AS 2049-2002Standards Australia, Australia
MediumCurrent
Roof tiles
Covers both concrete and terracotta roof tiles, with many similar performance requirements.
JIS A 5402:2002JISC (Japanese Industrial Standards Committee), Japan
HighCurrent
Concrete roofing tiles
Specifies requirements for concrete roofing tiles, including testing for bending strength and water absorption.
Key Differences
≠The Indian standard (1992) is significantly older than its European counterpart EN 490 (2011, amended 2017), and thus lacks requirements related to modern manufacturing controls and performance metrics.
≠EN 490 includes mandatory freeze-thaw resistance testing for tiles used in specific climates, a requirement not present in IS 4321, which is tailored for the predominantly non-freezing Indian climate.
≠IS 4321 specifies dimensional tolerances as a percentage (e.g., ±2% for length), whereas EN 490 uses more precise absolute values (e.g., ±2 mm), reflecting stricter manufacturing control.
≠The water permeability test in IS 4321 is a simple pass/fail observation over 24 hours, while EN 490 uses a quantitative impermeability test, resulting in a calculated factor for better performance classification.
Key Similarities
≈Both standards are fundamentally based on similar materials, specifying the use of Portland cement, aggregates (sand), water, and optional pigments.
≈A core performance requirement in both standards is the transverse breaking strength test to ensure tiles can withstand physical loads from handling, installation, and maintenance.
≈Both IS 4321 and its international equivalents mandate tests to limit water ingress, either through a water absorption test, a permeability test, or both, to ensure weather tightness.
≈The general scope of both standards is to define the geometric, mechanical, and physical characteristics of concrete plain tiles to ensure their fitness for purpose as a roof covering.
Parameter Comparison
Parameter
IS Value
International
Source
Transverse Breaking Load (Plain Tiles)
Minimum average 450 N (no single tile < 400 N) on a 267 mm span.
Method dependent; typically requires a minimum of 600 N to 1200 N depending on class and test method.
EN 490:2011+A1:2017
Water Absorption
Maximum 10% by mass after 24-hour immersion.
No limit specified in the standard; value is declared by the manufacturer, typically under 8% in practice.
EN 490:2011+A1:2017
Water Permeability / Impermeability
No water shall drip from the underside after 24 hours under a static head of water.
Quantitative test. A factor 'I' is calculated based on water absorption over time. For Category 1 (highest), I ≤ 0.5.
EN 490:2011+A1:2017
Dimensional Tolerance (Length)
± 2% of the specified length.
± 2 mm of the declared working length (an absolute value).
EN 490:2011+A1:2017
Dimensional Tolerance (Width)
± 3 mm from specified width.
± 2 mm of the declared working width.
EN 490:2011+A1:2017
Mass Variation
± 5% of the specified nominal mass per tile.
Average mass of 20 tiles shall not deviate by more than ±10% from the declared mass.
EN 490:2011+A1:2017
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
Permeability test duration24 hours without water drop formation on underside