The 1992 edition of IS 654 outlines the standards for Mangalore pattern clay roofing tiles, popular in southern India. It details specifications including tile dimensions, permissible variances, physical and mechanical characteristics, classifications, and testing protocols to guarantee product reliability and longevity. This code is essential for producers, distributors, and inspectors handling these interlocking clay tiles for roofing.
Overview
The 1992 edition of IS 654 outlines the standards for Mangalore pattern clay roofing tiles, popular in southern India. It details specifications including tile dimensions, permissible variances, physical and mechanical characteristics, classifications, and testing protocols to guarantee product reliability and longevity. This code is essential for producers, distributors, and inspectors handling these interlocking clay tiles for roofing.
Audience
Contents
Structure
IS 654 sets forth the standards for burnt clay roofing tiles of the Mangalore design, specifying size ranges and quality classifications. Tile sizes (length and width) and maximum batten spacing are detailed, including allowances for overlap adjustments. Quality classes (Class AA and Class A) define maximum water absorption percentages and minimum breaking load values. Test results are to be rounded according to IS 2:1960.
This section provides detailed classification tables outlining water absorption limits and breaking load minimums for different tile sizes. It also includes dimensional data for various tile sizes and notes on overlap adjustments to accommodate batten spacing. Rounding rules per IS 2:1960 for test results are emphasized to ensure consistency.
Terminology aligns with IS 2248:1991 related to clay roofing tiles. Tile sizes and classifications are reiterated with explanations on sizing tolerances and quality classes. Notes on rounding and measurement practices are included to clarify the standard's intent.
The roofing tiles are categorized into Class AA and Class A based on their physical properties, primarily maximum permissible water absorption and breaking load thresholds. Dimensions associated with each class are specified, and overlap adjustments are described to maintain structural integrity.
Sampling procedures and allowable defect limits are provided for various lot sizes. Tiles are examined for shape, dimensions, and weight. Acceptance of a lot depends on conformity with specified limits for water absorption, breaking load, and dimensional accuracy. The section outlines the criteria for lot acceptance or rejection.
Detailed tile size specifications and maximum batten spacings are given. Measurement methods for tolerances involve arranging three tiles tightly interlocked on a flat surface and measuring combined length or width. Overlap minimums for lengthwise and widthwise directions are included. Procedures for removing defects before measurement and rounding off values are also described.
Sampling sizes are defined based on lot quantity, with corresponding limits on the number of defective tiles permitted. Tiles selected for sampling undergo examination for shape, size, and weight. The section details how to determine conformity, including rounding requirements and the acceptance formula.
Minimum breaking load values are specified for both average and individual tiles across different sizes and classes. Testing protocols involve loading tiles until failure with results compared against these thresholds. The section underscores the necessity for all samples to meet individual minimums and the collective average to meet the class requirement, ensuring adequate tile durability.
This part describes the protocol if tiles fail testing, including retesting a second sample and criteria for lot rejection if failures persist. Sampling sizes and permissible defects are reiterated. The rounding off of test values according to IS 2:1960 is also emphasized to maintain accuracy.
Tiles must bear the manufacturer's name or trademark in a clear and permanent manner, with an optional BIS Standard Mark. The marking area should not exceed 5% of the tile's surface to avoid impairing function or appearance. This ensures traceability and consumer confidence in products conforming to IS 654.
The water absorption percentage is calculated by weighing dry specimens and after 24 hours of submersion in cold water. Acceptance criteria involve computing the average and range of test results and ensuring that the combined value does not surpass prescribed limits. The procedure mandates using oven-dried samples for accuracy.
Permeability testing ensures no water penetrates the tile under specified conditions. Six tiles are tested following the detailed procedure, which includes preparing clean, dry specimens and applying water under controlled pressure. Passing the permeability test is mandatory alongside water absorption compliance.
Breaking load tests require applying force to six tile specimens until failure, recording individual and average loads. All individual specimens must exceed minimum breaking loads, and the average must also meet minimum class requirements. The annex outlines the methodology and consequences of test failures.
Frequently Asked
Standard tile sizes for Mangalore pattern clay roofing tiles include 410 x 235 mm, 420 x 250 mm, and 425 x 260 mm. Measurement of tolerances is conducted by selecting three tiles, removing surface defects, and tightly interlocking them lengthwise or widthwise on a level surface. The combined length or width of these tiles must fall within specified ranges: 630-650 mm for 410x235, 670-690 mm for 420x250, and 690-710 mm for 425x260. Minimum overlap requirements are 60 mm lengthwise and 25 mm widthwise. These measures ensure consistency and proper fit according to IS 654.
Breaking load is assessed by soaking six tiles in water at 27 ± 2°C for 24 hours, then supporting them on bearers spaced 25 cm apart. A load is applied perpendicular to the tile span at a constant rate of 450–550 N/min until the tile breaks. Minimum breaking loads vary by tile size and class; for example, 410x235 mm Class AA tiles require an average breaking load of at least 1.0 kN and individual minimum of 0.90 kN. If any tile fails in the initial sample, a second sample is tested; persistent failure leads to rejection of the lot. This test ensures tiles meet strength requirements for safe use.
IS 654 categorizes Mangalore pattern clay roofing tiles into two classes: Class AA and Class A. Class AA has stricter limits, featuring a maximum water absorption of 18% and higher minimum breaking loads (1.0 kN average for 410x235 mm tiles). Class A allows up to 20% water absorption and slightly lower breaking load requirements (0.80 kN average for the same size). This classification helps determine suitable tiles based on durability and structural demands.
Water absorption testing involves measuring the weight difference of six tiles before and after 24-hour water immersion. The acceptance criterion is that the average absorption plus half the range must not exceed the limits specified, generally 18% for Class AA and 20% for Class A tiles. Permeability testing ensures no water penetrates the tile under defined conditions. All tested tiles must pass this test to confirm impermeability and durability as per IS 654.
Tiles must bear the manufacturer's name or trademark in a clear, permanent manner, occupying no more than 5% of the tile surface area. Optionally, the BIS Standard Mark may be included to indicate conformity with Indian Standards. Markings should be legible and resistant to weathering and handling to maintain traceability and consumer confidence.
Ask AI about any clause, requirement, or provision in IS 654. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required