IS 101:1986 Part 1/Sec 1 is the Indian Standard (BIS) for methods of sampling and test for paints, varnishes and related products: part 1 tests on liquid paints (general characteristics) section 1 sampling, preparation of test panels, etc.. This part of IS 101 specifies the procedures for sampling liquid paints, varnishes, and related products, and establishes standard methods for preparing test panels. It is essential for QA/QC engineers and material laboratories to ensure that extracted samples are representative and applied to uniform surfaces for accurate and reproducible testing.
Specifies methods for sampling, preparing test panels, determining consistency, volatile matter, mass per 10 litres, spreading power and finish of liquid paints.
What each part tests — call up part + section.
| Reference | Value | Clause |
|---|---|---|
| Part 1 | Liquid paints — general (sampling, drying time, flash point) | Part 1 |
| Part 2 | Liquid paints — physical (fineness, viscosity, density) | Part 2 |
| Part 3 | Paint film formation (flexibility, adhesion, hardness) | Part 3 |
| Part 4 | Optical (colour, gloss, opacity) | Part 4 |
| Part 5 / 6 / 7 | Mechanical / durability / environmental tests | Parts 5-7 |
| Part 8 | Tests for pigments and other solids | Part 8 |
| Acceptance rule | Test on standard panels; gloss/colour by instrument | Cl. |
IS 101 — Methods of sampling and test for paints, varnishes and related products — is the test-method backbone behind every paint and protective-coating acceptance on an Indian project. It is a *multi-part* series; this entry stands for the IS 101 family, and high search traffic spans its Parts 2, 3 and 4. Whenever a painting specification or a product standard (synthetic enamel, primer, exterior emulsion) calls for an acceptance test, the *method* comes from IS 101.
It is read with the painting and product codes it serves:
IS 101 splits the work by *what* is being tested:
A correct acceptance call-up names the *part and section* (e.g. 'gloss per IS 101 Part 4/Sec 4') — not just 'IS 101'.
Scenario: an exterior synthetic enamel delivered against IS 2932 — build the IS 101 acceptance sequence.
Step 1 — sampling (Part 1): draw a representative sample from the batch and prepare standard test panels with the specified substrate prep.
Step 2 — liquid-state checks: consistency/viscosity (Part 1/2), drying time — surface-dry and hard-dry classes (Part 1); these screen a stale or off-spec batch immediately.
Step 3 — film optical (Part 4): measure 60° gloss with a glossmeter and colour against the IS 5 reference — not by eye.
Step 4 — film mechanical (Part 3): cross-cut/bend adhesion and scratch hardness on the cured panel.
Step 5 — verdict: compare every measured value with the IS 2932 acceptance limits; one failed mandatory property fails the batch. Record on a test sheet — the ISI mark is not an acceptance test.
1. Calling up 'IS 101' generically. It is a large multi-part series — specify the exact part/section for each property or the lab and contractor will pick the easiest interpretation.
2. Wrong panel/substrate preparation. Adhesion and drying results are dominated by surface prep; testing on an unspecified or contaminated panel makes the result meaningless.
3. Judging gloss and colour by eye. Gloss is a glossmeter number and colour is against the IS 5 chip — visual calls are not IS 101 results and don't survive a dispute.
4. Ignoring drying-time classes. Recoat and handling intervals depend on the IS 101 drying classification; over-coating before hard-dry traps solvent and fails the film.
5. Mixing edition/part numbering. IS 101 has been re-organised across revisions — quote the current part/section, and confirm the product standard references the same.
The IS 101 series is reaffirmed but old, and global manufacturers' datasheets increasingly quote ASTM D / ISO equivalents (e.g. ASTM D523 gloss, D3359 adhesion) alongside IS 101. For acceptance on Indian projects IS 101 remains the contractual method, so the right practice is to specify IS 101 part/section as primary and accept the ISO/ASTM equivalent only where explicitly cross-referenced.
The live regulatory pressure is VOC and lead content — lead-limit rules now constrain decorative paints and many specifications add a VOC ceiling that classical IS 101 does not itself address; capture these as separate call-ups. Because this single IS 101 page aggregates the search traffic of Parts 2/3/4, treat it as the hub: specify the right part for the property, prepare the panel exactly, and measure with instruments — that is where paint disputes are actually won or lost.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Laboratory Sample Size | Not less than 250 ml. | To be agreed between parties; typically 500 ml or 1 litre to allow for multiple tests. | ISO 15528:2020 |
| Sampling Levels in Large Containers | From top, middle and bottom levels. | Specified levels: 10% from the surface, middle of the container, and 10% from the bottom. | ISO 15528:2020 |
| Standard Mild Steel Panel Thickness | Approximately 1.25 mm thick (18 BG). | Typically 0.8 mm ± 0.07 mm for cold-rolled steel (references ISO 3574). Emphasis on consistency. | ISO 1514:2022 |
| Panel Cleaning Solvent | A suitable hydrocarbon solvent (like mineral turpentine). | Specifies suitable aromatic hydrocarbons (xylene) or aliphatic/aromatic mixtures, and explicitly prohibits chlorinated solvents. | ISO 1514:2022 |
| Time Limit for Testing | As soon as possible, but not later than seven days after receipt. | No maximum holding time specified; focuses on conditioning the sample at standard temperature (23 ± 2)°C for a defined period (e.g., 24h) before testing. | ISO 1513:2022 |
| Sample Container Material | Clean, dry, wide-mouthed containers of glass or tinplate. | Containers made of material that will not react with the sample (e.g., glass, certain plastics, lacquered metal), with considerations for light sensitivity. | ISO 15528:2020 |