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IS 12903:1990 is the Indian Standard (BIS) for non-metallic abrasives for blast cleaning - specification. This standard specifies the requirements, sampling, and test methods for various non-metallic abrasives used in blast cleaning operations for surface preparation. It covers physical properties like hardness and particle size, and chemical properties like limits on water-soluble chlorides to ensure the quality of the prepared surface before coating. This standard has been withdrawn.
Specifies requirements for non-metallic abrasives (e.g., garnet, copper slag) used for blast cleaning of surfaces.
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Painting, Coatings and Surface Finishing
! CRITICAL: This standard has been withdrawn and superseded by the IS/ISO 11126 series. Users must refer to the relevant part of the new series for specific abrasive types (e.g., IS/ISO 11126-10 for garnet).
! Controlling chloride content as per the specified limits is critical to prevent premature coating failure due to osmotic blistering, especially in marine or corrosive environments.
! The standard categorizes abrasives into grades (e.g., Grade 1, 2, 3) based on particle size distribution, which must be selected based on the required surface profile and cleaning speed.
ISO 11126-10:2017ISO (International Organization for Standardization), International
HighCurrent
Preparation of steel substrates before application of paints and related products — Specifications for non-metallic blast-cleaning abrasives — Part 10: Almandite garnet
Both specify physical and chemical requirements for garnet abrasives used in blast cleaning.
SSPC-AB 1:2019SSPC (The Society for Protective Coatings) / AMPP, USA
HighCurrent
Mineral and Slag Abrasives
Both define requirements for cleanliness, sizing, and properties of various non-metallic abrasives.
ISO 11126-1:2018ISO (International Organization for Standardization), International
MediumCurrent
Preparation of steel substrates before application of paints and related products — Specifications for non-metallic blast-cleaning abrasives — Part 1: General introduction and classification
Provides the general framework and classification for abrasives, similar to the introductory sections of IS 12903.
BS 7079-F SeriesBSI (British Standards Institution), UK
HighWithdrawn
Preparation of steel substrates before application of paints and related products. Specifications for non-metallic blast-cleaning abrasives
This series was the British adoption of the ISO 11126 standards, covering the same scope.
Key Differences
≠IS 12903 is a single, consolidated standard covering multiple abrasive types, whereas the equivalent ISO 11126 standard is a multi-part document with a separate part for each specific abrasive type (e.g., slag, garnet, olivine).
≠The permissible limit for free silica in non-siliceous abrasives is higher in IS 12903 (max 2.0%) compared to modern international standards like SSPC-AB 1, which typically mandate less than 1.0% due to heightened health and safety regulations regarding silicosis.
≠The maximum allowable conductivity of aqueous extract is significantly more lenient in IS 12903 (1000 µS/cm) than the commonly specified limit in projects using ISO standards (often 250 µS/cm), indicating a lower stringency on soluble salt contamination.
≠The abrasive grade designations in IS 12903 (e.g., G1, G2, S1, S2) are unique to the Indian standard and do not directly correlate with the sizing nomenclatures used in ISO or SSPC standards.
Key Similarities
≈Both IS 12903 and its international counterparts share the primary objective of defining quality control parameters for non-metallic abrasives to ensure consistent and effective surface preparation.
≈All standards specify requirements for key physical properties that determine abrasive performance, such as minimum hardness on the Mohs scale and minimum specific gravity.
≈There is a common emphasis on controlling water-soluble contaminants, with all standards setting maximum permissible limits for chlorides and sulfates to prevent premature coating failure.
≈All standards mandate particle size distribution analysis (sieve analysis) to classify abrasives into different grades and ensure they are suitable for the intended blasting profile and application.
Parameter Comparison
Parameter
IS Value
International
Source
Free Silica Content (Non-siliceous abrasive)
Max 2.0% by mass
Shall not contain free silica in excess of 1.0% by weight
SSPC-AB 1:2019
Conductivity of Aqueous Extract
Max 1000 µS/cm
Max 250 µS/cm (common requirement)
ISO 11126-1:2018
Water Soluble Chlorides (Garnet)
Max 0.005% by mass (50 ppm)
Max 0.0025% by mass (25 ppm)
ISO 11126-10:2017
Hardness (Garnet)
Minimum 7 on Mohs scale
Minimum 6 on Mohs scale (typical range is 7.5 to 8.5)
ISO 11126-10:2017
Specific Gravity (Garnet)
Minimum 3.4
Minimum 3.3 (typical range is 3.8 to 4.3)
ISO 11126-10:2017
Moisture Content
Max 0.5% by mass
Max 0.2% by mass
ISO 11126-10:2017
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Minimum Mohs Hardness6.0
Maximum Water-Soluble Chlorides0.0025% by mass
Minimum Specific Gravity2.5
Maximum Water-Soluble Sulphates0.01% by mass
Tables & Referenced Sections
Key Tables
Table 1 - Physical Requirements for Non-Metallic Abrasives
Table 2 - Chemical Requirements for Non-Metallic Abrasives
Table 3 - Sieve Analysis for Abrasive Grades
Key Clauses
Clause 3 - Material and Types
Clause 4 - Requirements
Clause 6 - Tests
Annex A - Method for Determination of Water-Soluble Chlorides
No, IS 12903:1990 has been withdrawn. It is replaced by the IS/ISO 11126 series of standards for preparation of steel substrates before application of paints and related products.
What is the minimum required hardness for abrasives under this old code?+
A minimum hardness of 6.0 on the Mohs scale is required as per Table 1.
Why is the chloride content limit so important?+
Low chloride content (max 0.0025% by mass per Table 2) is crucial to prevent contamination of the blasted surface, which can lead to under-film corrosion and premature coating failure.
What types of materials does this standard cover?+
It covers naturally occurring non-metallic abrasives like silica sand and garnet, as well as processed abrasives from slags. The specific material must be agreed upon between the purchaser and supplier.