Is IS 12903 still in use?

No, IS 12903:1990 has been withdrawn.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.

IS 12903

: 1990

Non-Metallic Abrasives for Blast Cleaning - Specification

CurrentSpecializedSpecificationMaterials Science · Painting, Coatings and Surface Finishing

Download PDF BIS Portal Google

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 This standard has been withdrawn.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.

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

Practical Notes

CRITICAL: This standard has been withdrawn and superseded by the IS/ISO 11126 series.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.