IS 101 is the umbrella standard for sampling and testing paints, varnishes and related products, split into many parts and sections — each test method in its own part/section. Part 5 covers mechanical tests on the dried paint film; Section 1 deals with film hardness. Because the parts are separate, you must cite the exact part/section for the property tested (e.g. drying time is Part 3 Sec 1; hardness is Part 5 Sec 1).
Key Requirements
•Identify the correct IS 101 part/section for the property being tested — the parts are not interchangeable
•Part 5 Sec 1 = mechanical tests / hardness of the dried film; drying time = Part 3 Sec 1; sampling = Part 1
•Tests are run on a film applied and dried on a standard test panel under conditioned conditions (see the test-panel clause)
•Results feed acceptance against the relevant paint product specification, not IS 101 itself
Reference Tables
IS 101 — common parts/sections (cite the exact one)
Part / Section
Subject (indicative)
Part 1
Sampling, general test conditions
Part 3 Sec 1
Drying time (surface-dry / hard-dry)
Part 5 Sec 1
Mechanical tests on films — hardness
Part 5 (other sec)
Other mechanical-film tests (flexibility, adhesion, etc.)
Indicative mapping — confirm the exact part/section and edition against the current BIS publication.
Practical Notes
✓The single biggest IS 101 error is citing 'IS 101' generically — always cite the exact part and section, because each property has its own method.
✓All film tests presuppose a correctly prepared, correctly dried test panel — the result is invalid otherwise (see the test-panel clause).
Common Mistakes
⚠Citing 'IS 101' without the part/section, making the requirement ambiguous and unenforceable.
⚠Running a film test before the film has properly dried/cured to the required state.
⚠Confusing the drying-time method (Part 3 Sec 1) with the hardness method (Part 5 Sec 1).