IS 6623 BIS Certification for High Strength Structural Nuts
High Strength Structural Nuts made, imported or sold in India must be certified against IS 6623 under an ISI mark licence (Scheme-I). What the standard covers, how testing works and how to get the licence.
About IS 6623
| Standard | IS 6623 : 2004 |
|---|---|
| Title | High Strength Structural Nuts |
| Product covered | High Strength Structural Nuts |
| Category | Bolts, Nuts and Fasteners |
| Scheme | ISI mark licence (Scheme-I) |
| Notified under | Bolts, Nuts and Fasteners (Quality Control) Order, 2023, S.O. 3267(E), dated 21st July 2023 · Order PDF |
Editions and amendments of IS 6623
| Edition | Published | Status |
|---|---|---|
| IS 6623:2004 High Strength Structural Nuts | Current, next review 25 Jun 2030 |
Amendments:First Amendment (2020). Test reports must reflect the standard with its amendments.
Marking fee for IS 6623
BIS charges an annual minimum marking fee for the ISI mark under IS 6623, set by unit size, plus a per-unit rate once production passes the minimum:
| Unit size | Minimum marking fee (per year) |
|---|---|
| Large | ₹48,000 |
| Medium | ₹39,000 |
| Small | ₹24,000 |
| Micro | ₹9,600 |
Unit rate: ₹13.35 per ton. Source: BIS marking fee schedule for Scheme-I products, September 2026.
Sampling and key tests for IS 6623
From the BIS product manual for IS 6623, which BIS officers and applicants follow for certification:
Sample quantity:drawn, 2 nos. should be before galvanizing for dimensional
Tests BIS can carry out in a day during factory inspection:
- Dimension and tolerance (Cl.4.1)
- Thread requirement (Cl.4.2)
- Mechanical Properties (Cl.5)
- Finish (Cl.6.2)
- Hot dip galvanizing (Cl.6.2)
- Surface Discontinuities (Cl.7.1)
The full type test covers every clause of IS 6623; the list above is what can be checked on site.
ISI licences under IS 6623
BIS records 34 operative licences (35 including deferred, cancelled or under stop marking). Most licensed factories are in Punjab (26), Tamil Nadu (2), Haryana (2), Dadra & Nagar Haveli (1), Maharashtra (1).
Testing against IS 6623
BIS inspects the factory and has samples tested to the full Indian Standard at a BIS or BIS-recognised laboratory. After grant, the factory keeps testing production under the Scheme of Inspection and Testing, and BIS draws factory and market samples.
The test report has to cover every clause of IS 6623 that applies to the product, in the edition current on the date of testing. When BIS revises IS 6623 or replaces it with a new edition, existing licence holders move to the new edition by the date BIS sets in its notification.
How to get an ISI mark licence under IS 6623
The licence is granted to the manufacturer for a specific factory and product. Indian factories apply under Scheme-I; overseas factories apply under the Foreign Manufacturers Certification Scheme (FMCS) and must nominate an Authorised Indian Representative.
- Confirm the exact Indian Standard and the varieties to cover
- Get the product tested at a BIS-recognised lab (simplified procedure) or arrange BIS sampling
- Apply on Manak Online with factory, quality-control and test documents
- BIS factory inspection and sample verification
- Grant of licence, then marking with the ISI mark and CM/L number
Timeline. BIS targets 30 days under the simplified procedure (applying with a recent lab test report) and 90 days under the normal procedure. Overseas factories under FMCS typically take around 6 months.
Fees. Application fee ₹1,000 and annual licence fee ₹1,000, inspection charges of ₹7,000 per man-day, testing charges, and an annual minimum marking fee set for each Indian Standard (with concessions for micro and small units).
Mark. Certified products carry the ISI Standard Mark with the IS number and the CM/L-XXXXXXXXXX licence number.
Frequently asked questions
What does IS 6623 cover?
IS 6623 : 2004: High Strength Structural Nuts. BIS has made certification against it compulsory for high strength structural nuts.
Is BIS certification under IS 6623 mandatory?
Yes, for high strength structural nuts, under the Bolts, Nuts and Fasteners (Quality Control) Order, 2023, S.O. 3267(E). The product needs a valid BIS licence (ISI mark) and must carry the ISI Standard Mark with the IS number and the CM/L-XXXXXXXXXX licence number.
Where is a product tested for IS 6623?
BIS inspects the factory and has samples tested to the full Indian Standard at a BIS or BIS-recognised laboratory. After grant, the factory keeps testing production under the Scheme of Inspection and Testing, and BIS draws factory and market samples.
How long does IS 6623 BIS certification take?
BIS targets 30 days under the simplified procedure (applying with a recent lab test report) and 90 days under the normal procedure. Overseas factories under FMCS typically take around 6 months.
Other standards in Bolts, Nuts and Fasteners
- IS 204 2 products
- IS 281 Mild Steel Sliding Door Bolts for Use with Padlocks
- IS 1284 Wrought Aluminium Alloy Bolt and Screw Stock for General Engineering Purposes
- IS 1363 3 products
- IS 1364 2 products
- IS 2681 Non-ferrous Metal Sliding Door Bolts (aldrops) for Use with Padlocks
- IS 3757 High Strength Structural Bolts
- IS 4621 Indicating Bolts for Use in Public Baths and Lavatories
- IS 5187 Flush Bolts
- IS 7534 Sliding Locking Bolts for Use with Padlocks
Source: BIS lists of products under compulsory certification (Scheme-I, Scheme-II), checked October 2026. See the full BIS product list or all Indian Standards.
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