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IS 657:1982 is the Indian Standard (BIS) for materials for use in the manufacture of magnesium oxychloride flooring compositions. This standard specifies the requirements for materials such as calcined magnesite, magnesium chloride, fillers, and aggregates used in the manufacture of magnesium oxychloride (magnesite) flooring compositions. It is used by engineers to ensure quality control for materials going into heavy-duty, jointless flooring installations.
Materials for Use In The Manufacture of Magnesium Oxychloride Flooring Compositions
Overview
Status
Current
Usage level
Rare
Domain
Materials Science — Flooring, Wall Finishing and Roofing
Covers the binder (magnesite), aggregates, and resulting mortar, making it highly comparable to the Indian standard's intent.
Key Differences
≠The most significant difference is that IS 657:1982 remains an active Indian Standard, whereas its key international counterparts like BS 776 and ASTM C275 were withdrawn decades ago, reflecting the decline of magnesium oxychloride flooring in Western markets.
≠IS 657:1982 explicitly lists 'Asbestos Fibre' as a permissible fibrous filler. The use of asbestos is now strictly prohibited or heavily regulated in most countries covered by the equivalent standards, making this a major point of divergence from modern safety and material standards.
≠While testing similar properties like setting time and strength, the specific test methods, specimen dimensions, and apparatus can vary. For example, the transverse strength test in IS 657 uses a specific prism size and loading rate which may differ from the methods referenced in the withdrawn BS or ASTM standards.
≠The purity requirements for magnesium chloride solution (gauging solution) in IS 657 are specified based on a Baumé hydrometer reading (20 to 24°Bé), a practice which is less common in modern standards that typically prefer specifying specific gravity or molar concentration directly.
Key Similarities
≈All standards (IS 657, BS 776, ASTM C275) identify calcined magnesite as the primary binder and specify critical quality control parameters for it, including fineness, setting time, soundness, and strength.
≈Both IS 657 and its direct equivalent BS 776 cover the full suite of materials required for the flooring composition, including the binder (magnesite), gauging solution (magnesium chloride), and various types of fillers and aggregates.
≈The standards share a common goal of controlling dimensional stability by placing limits on linear change (expansion and contraction) of the set cement over time to prevent cracking or warping of the finished floor.
≈All standards recognize the detrimental effect of excess active lime (CaO) on the final product's durability and therefore place a maximum permissible limit on its content in the calcined magnesite.
Parameter Comparison
Parameter
IS Value
International
Source
Fineness of Calcined Magnesite (Residue on 150-micron sieve)
Not more than 8% by mass
Not more than 10% by mass
BS 776:1972
Initial Setting Time
90 min (min) to 300 min (max)
60 min (min) to 240 min (max)
BS 776:1972
Final Setting Time
180 min (min) to 600 min (max)
Not more than 420 min (7 hours)
BS 776:1972
Transverse Strength at 7 days (Modulus of Rupture)
Not less than 2.8 N/mm²
Not less than 3.1 N/mm²
BS 776:1972
Linear Change at 7 days (Expansion)
Not more than 0.25%
Not more than 0.20%
BS 776:1972
Active Lime (CaO) Content in Calcined Magnesite
Not more than 2.0% by mass
Not more than 2.5% by mass
BS 776:1972
Loss on Ignition of Calcined Magnesite
Not more than 8.0% by mass
Not specified directly; controlled via other parameters like MgO content.
ASTM C275-61
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
Magnesium chloride specificationMust conform to IS 254
Calcined magnesite minimum MgO content87% by mass (typical requirement for standard structural magnesite)
Fineness of calcined magnesiteShould pass through 90-micron IS sieve