Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 104:2017 is the Indian Standard (BIS) for ready mixed paint, brushing, zinc chrome, priming, for steel - specification. This standard prescribes the requirements and methods of sampling and testing for ready mixed zinc chrome brushing paint. It is primarily used by engineers and painting inspectors as an anti-corrosive primer coat for the protection of structural steelwork and iron surfaces.
Specifies requirements and methods of test for ready mixed, brushing, zinc chrome priming paint for steel, Type 1 and Type 2.
Overview
Status
Current
Usage level
Frequently Used
Domain
Materials Science — Painting, Coatings and Surface Finishing
! Proper surface preparation (e.g., abrasive blast cleaning to Sa 2.5 or thorough manual wire brushing) is essential before applying zinc chrome primer to ensure proper adhesion.
! Although formulated primarily for brushing to ensure penetration into surface pores, it can often be sprayed if appropriately thinned.
! Do not leave the primer exposed to the environment without a suitable topcoat for extended periods, as it is designed as a base coat, not a weathering finish.
TT-P-645BU.S. General Services Administration (US)
HighWithdrawn
Primer, Paint, Zinc-Chromate, Alkyd Type
Specifies a solvent-borne, alkyd-based zinc chromate primer for the protection of ferrous metals.
DEF STAN 80-15/3UK Ministry of Defence (UK)
HighWithdrawn
Paint, Priming, Zinc Chromate, Lead Free
Specifies requirements for a lead-free zinc chromate priming paint for military equipment and steelwork.
AS K145-1965Standards Australia (AU)
MediumWithdrawn
Zinc Chromate-Iron Oxide Primer for Steel (Excluding Marine Applications)
Specifies a primer based on zinc chromate and iron oxide in an alkyd vehicle for general steelwork.
ISO 12944-5:2019ISO (International)
LowCurrent
Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 5: Protective paint systems
A performance standard that lists generic paint system types (including alkyds) but does not prescribe specific formulations.
Key Differences
≠IS 104:2017 is a current standard, whereas most direct international equivalents (e.g., TT-P-645B, DEF STAN 80-15) have been withdrawn for many years due to the classification of zinc chromate (a hexavalent chromium compound) as a carcinogen and its strict regulation in North America and Europe.
≠IS 104 is a prescriptive compositional standard, defining required percentages of pigment and zinc chrome. Modern international standards like ISO 12944 are performance-based, specifying required durability (e.g., corrosion resistance) for a given environment rather than dictating the paint's recipe.
≠IS 104 specifies a minimum of 30% zinc chrome in the pigment portion. Withdrawn standards like TT-P-645B had different types with varying requirements, such as Type I with a minimum of 87% zinc chromate, indicating different formulation strategies.
≠Modern standards place heavy emphasis on low Volatile Organic Compound (VOC) content. IS 104 specifies mineral turpentine oil as the primary solvent, a formulation with high VOCs that would not be compliant with current environmental regulations in many Western countries.
Key Similarities
≈The core chemistry across IS 104 and its historical international equivalents is identical: an anti-corrosive primer based on zinc chromate pigment in an alkyd resin binder.
≈All standards define a product intended for the same purpose: a primary protective coating on prepared steel surfaces to inhibit corrosion, typically as part of a multi-layer paint system.
≈The specified physical characteristics, such as viscosity and flow, are formulated to allow for conventional application methods like brushing and spraying, ensuring ease of use in typical fabrication or site environments.
≈All are single-component, air-drying paints that cure through a combination of solvent evaporation and oxidative cross-linking of the alkyd vehicle. They specify similar tests for determining drying stages like surface dry and hard dry.
Parameter Comparison
Parameter
IS Value
International
Source
Drying Time (Hard Dry)
Not more than 24 hours
Not more than 18 hours
TT-P-645B
Zinc Chromate in Pigment (min % by mass)
30%
87% (for Type I) or 40% (for Type II)
TT-P-645B
Total Pigment in Paint (% by mass)
35 - 45%
Minimum 45%
TT-P-645B
Fineness of Grind
Not more than 25 microns (Hegman 6)
Minimum Hegman 4 (approx. 50 microns)
TT-P-645B
Flexibility and Adhesion (Mandrel Bend)
Passes 6 mm mandrel
Passes 1/8 inch (3.2 mm) mandrel
TT-P-645B
Consistency / Viscosity
100-140 sec by Flow Cup No. 4 at 30°C
63-73 Krebs Units (KU) at 25°C
TT-P-645B
⚠ Verify details from original standards before use