IS 13871 Explained: India's Powder Coating Standard
IS 13871 is the Indian Standard for thermosetting powder coatings. First published in 1993 by the Bureau of Indian Standards and revised in 2021, it classifies powder coatings into three grades by gloss, sets minimum performance requirements for each, and specifies the IS 101 test methods used to verify them. If you are buying or specifying powder coating in India, this is the standard your specification should reference, and almost nobody explains it.
What IS 13871 covers
The standard's scope is narrow and worth knowing precisely: it prescribes requirements and test methods for thermosetting powder coatings on mild steel components, aimed at protective and decorative use in domestic appliances, automotive and two-wheeler applications. It does not cover thermoplastic powders, and it is not an architectural aluminium standard: for that, European specifications such as QUALICOAT are the usual reference.
The three grades
IS 13871 classifies powder coatings by specular gloss measured at 60°, not by chemistry. A grade tells you the finish, not the resin system.
| Grade | Finish | Gloss at 60° |
|---|---|---|
| Grade A | Glossy | Above 80 |
| Grade B | Semi-glossy | 10 to 80 |
| Grade C | Matt | Below 10 |
The requirements, in full
These are the properties IS 13871 requires, with the value specified for each grade and the IS 101 test method that verifies it.
| Requirement | Grade A | Grade B | Grade C | Test method |
|---|---|---|---|---|
| Dry film thickness | 50–60 µm unless otherwise specified | IS 101 (Part 3/Sec 2) | ||
| Finish | Smooth | IS 101 (Part 3/Sec 4) | ||
| Gloss at 60° | Above 80 | 10–80 | Below 10 | IS 101 (Part 4/Sec 4) |
| Scratch hardness, 3000 g | No scratch showing bare metal | IS 101 (Part 5/Sec 1) | ||
| Flexibility, 6.25 mm mandrel | No visible damage or detachment | IS 101 (Part 5/Sec 2) | ||
| Erichsen cupping / adhesion | 8.0 mm | 3.0–7.0 mm | 3.0 mm | IS 101 (Part 5/Sec 2) |
| Impact, direct and reverse | 250 kg/cm | 150 kg/cm | 150 kg/cm | IS 101 (Part 5/Sec 3) |
| Corrosion protection, 1000 h | No blistering, rusting or loss of adhesion | IS 101 (Part 6/Sec 1) | ||
| Humidity resistance | No blistering, rusting or loss of adhesion | IS 101 (Part 6/Sec 1) | ||
| Boiling water, 30 min at 100 °C | No blisters, no gloss change, no adhesion loss | IS 101 (Part 7/Sec 1) | ||
| Lubricating oil, SAE 30 | Pass | IS 101 (Part 7/Sec 2) | ||
| Petrol resistance | Pass | IS 101 (Part 7/Sec 2) | ||
| Heat resistance, double bake | No appreciable colour change or property loss | IS 101 (Part 7/Sec 3) | ||
| Resistance to bleeding | Pass | IS 101 (Part 7/Sec 4) | ||
| Detergent resistance | Pass | Annex B | ||
| Acid and alkali resistance | Pass | Annex C | ||
Storage and shelf life
IS 13871 specifies storage in a cool, dry place not exceeding 25 °C and not more than 65 % relative humidity, away from direct heat or sunlight, with a storage life of not less than six months under those conditions. This clause matters more in India than the number suggests: a monsoon-season godown regularly exceeds 65 % RH, and powder stored above 25 °C can sinter into soft lumps that show up later as poor fluidisation and orange peel.
The ECO Mark provisions
The standard also carries optional ECO Mark criteria restricting volatile organic compounds and capping toxic metals, lead, cadmium and hexavalent chromium, at 0.1 % or below. Powder coatings are 100 % solids with no solvent, so the VOC criterion is generally satisfied by the technology itself.
How to read your supplier's test data against IS 13871
This is where most specifications go wrong. A supplier's data sheet quoting ASTM and ISO results is not an IS 13871 compliance statement, and treating it as one is a mistake in both directions. Three things to check before you assume equivalence:
- The film thickness the test was run at. IS 13871 assumes 50–60 µm unless agreed otherwise. Most suppliers test at 70–80 µm. A thicker film generally improves corrosion results, so the numbers are not directly comparable.
- The test method, not just the property name. IS 13871 calls for impact to IS 101 (Part 5/Sec 3) in kg/cm. ASTM D2794 reports in kg·cm² using different geometry. These are different tests measuring related but not identical things, you cannot convert one into the other.
- Corrosion is the clause that actually separates products. IS 13871 requires no blistering, rusting or loss of adhesion after 1000 hours. Many general-purpose powders on the Indian market are formulated to 500–750 hours. That is a perfectly good coating for indoor service. It simply is not an IS 13871 corrosion pass.
Worked example: Oracle Industries' own published data
We publish all eight of our laboratory reports in full, so we can work this through honestly rather than in the abstract. Mapping our tested gloss values onto the IS 13871 grade bands:
| Oracle product | Gloss at 60° | IS 13871 grade band | Salt spray as tested | Against the 1000 h corrosion clause |
|---|---|---|---|---|
| Pure Polyester Glossy | 90–93 GU | Grade A | 500–750 hrs | Below 1000 h at 75–80 µm |
| Epoxy Polyester Glossy | 88–90 GU | Grade A | 500–750 hrs | Below 1000 h at 75–80 µm |
| Pure Polyester Satin | 60–70 GU | Grade B | 500–750 hrs | Below 1000 h at 75–80 µm |
| Epoxy Polyester Satin | 55–60 GU | Grade B | 500–750 hrs | Below 1000 h at 75–80 µm |
| Pure Polyester Matt | 9–11 GU | Straddles B/C boundary | 500–750 hrs | Below 1000 h at 75–80 µm |
| Epoxy Polyester Matt | 8–10 GU | Grade C | 500–750 hrs | Below 1000 h at 75–80 µm |
| Pure Epoxy Dead Matt | 5–8 GU | Grade C | 1000–1300 hrs | Meets 1000 h at 75–80 µm |
| Polyurethane | Per finish | A, B or C by finish | ≥1200 hrs | Meets 1000 h at 70–80 µm |
Read that table carefully, because the honest answer is more useful than a marketing one. Two of our four chemistries, Pure Epoxy and Polyurethane, reach the 1000-hour corrosion durability that IS 13871 calls for. Two, Epoxy Polyester and Pure Polyester, are formulated to 500–750 hours, which is the right specification for indoor decorative work and for exterior applications where UV stability matters more than salt spray, but is below the IS 13871 corrosion clause.
Two important caveats on that comparison. Our salt spray testing is run to ASTM B117 / ISO 9227, not IS 101 (Part 6/Sec 1), and at a film thickness of 70–80 µm rather than the 50–60 µm the standard assumes. So this is a like-for-like indication, not a certified compliance statement. Oracle Industries does not hold a BIS licence for IS 13871 and does not claim one.
What this means when you write a specification
- Reference the grade, not just "matt" or "glossy". "IS 13871 Grade B" is unambiguous; "semi-gloss" is not.
- State the film thickness you want. If you leave it out, the 50–60 µm default applies and you may not get the corrosion life you assumed.
- If corrosion protection is the point, say so explicitly and ask for salt spray data at your specified thickness. Do not infer it from the grade, grade is a gloss classification and carries no corrosion information.
- Ask which test method produced each number. A supplier who can tell you immediately is a supplier who tests. One who cannot, is not.
- For exterior architectural aluminium, IS 13871 is the wrong reference. Its scope is mild steel components. Specify UV performance separately.
Frequently asked questions
Is IS 13871 mandatory in India?
No. IS 13871 is a voluntary standard, not a compulsory BIS certification scheme for powder coatings. It becomes contractually binding only when a purchase specification references it.
What is the difference between IS 13871:1993 and IS 13871:2021?
The 2021 revision, published on 25 October 2021 by BIS committee CHD 20, supersedes the 1993 edition. Buy the current edition from BIS before writing it into a contract, and reference the year explicitly in your specification.
Does IS 13871 cover powder coating on aluminium?
Its stated scope is thermosetting powder coatings on mild steel components. For architectural aluminium, exterior durability specifications such as QUALICOAT or EN 12206 are the more usual reference.
Does IS 13871 specify a curing schedule?
No. The standard states that powder reactivity and the curing schedule are to be agreed between supplier and purchaser, which is why the cure schedule belongs in your purchase specification, expressed as metal temperature and dwell time, not oven set-point.
Are Oracle Industries' powder coatings IS 13871 certified?
No. We hold no BIS licence and make no certification claim. We test every product line in our own laboratory to ASTM and ISO test methods and publish every report in full, so you can compare our data against IS 13871 yourself. Which is what the table above does.
Sources
- IS 13871 (1993): Powder Coatings, Specification, Bureau of Indian Standards. Full text available via the Public Resource India standards archive.
- IS 13871: 2021: Powder Coatings, Bureau of Indian Standards, committee CHD 20, published 25 October 2021.
- Oracle Industries laboratory reports OI/QC/PC/2026-0147 to OI/QC/PP/2026-0154, issued 31 May 2026, published in full on our Technical Documents page.
Need help matching a powder coating specification to IS 13871 grades and your actual service environment? Contact Oracle Industries we will work through your requirement with you, including telling you when our product is not the right one.