มอก. (TIS) — the Thai national standards that touch fasteners and coatings, and how to check a มอก. claim

Scope — and what it does not cover

มอก. (TIS) are the Thai national standards published by the Thai Industrial Standards Institute — สมอ. / TISI — under the Ministry of Industry. A มอก. NUMBER identifies a standard document; a มอก. LICENCE is a different thing entirely: permission granted to one factory to mark one product. For fasteners and their finishes, TIS has adopted a family of documents that line up with the ISO originals — mechanical properties, stainless properties, thread tolerances, electroplated and zinc flake coatings, hydrogen-embrittlement testing, quality assurance. It does NOT replace the customer drawing, does not certify a subcontract process, and for general industrial fasteners is not a compulsory requirement for sale in Thailand.

Standards are copyrighted documents. We explain scope, intent and practical application in our own words; obtain the current edition from ISO, ASTM, DIN or your national standards body.

What actually bites in production

• 1There are two different มอก. worlds. มอก.บังคับ (compulsory) applies to listed products that may not legally be sold without a licence. Everything else is voluntary: the standard exists, a maker may apply for a licence, but nobody is obliged to.
• 2A มอก. licence belongs to a product made in a named factory. It is not a process certificate, so a heat treatment or plating subcontractor cannot hold a มอก. mark for someone else's bolt. If a supplier shows you a มอก. mark, ask which product and which factory it names.
• 3Most fastener TIS documents are adoptions of the ISO originals, so the technical requirement behind a Thai drawing is usually familiar: มอก. 171-2530 is the mechanical-properties document for bolts, screws and studs, and มอก. 2453 เล่ม 1-2552 is its stainless counterpart.
• 4Thread tolerances are มอก. 339, published in several parts — including two that exist specifically for threads that have to mate after hot dip galvanizing, which is the Thai equivalent of the coating-fit problem.
• 5Coatings have their own numbers: มอก. 2416-2551 for electroplated coatings on fasteners, มอก. 2408-2551 for non-electrolytic zinc flake, มอก. 2443-2552 for hot dip galvanized fasteners, and มอก. 2444-2552 for the preloading test that detects hydrogen embrittlement.
• 6The year in a มอก. number is a Buddhist-era year, so มอก. 171-2530 is 1987. An old adoption can lag the current international edition, which is a reason to state the edition you mean rather than the number alone.
• 7ISO 9001:2015 is published in Thailand as มอก. 9001-2559. They are the same requirements in two publications, and a certificate issued to ISO 9001:2015 is a management-system certificate — not a product มอก. licence for anything.

What to write on the drawing or PO

• The document AND the edition you mean — "มอก. 171-2530 ชั้นคุณภาพ 8.8", or the ISO number, but not both in a way that leaves it ambiguous.
• Whether you require a มอก.-licensed product or simply conformity to the technical content of the standard. Those are very different commercial requirements.
• The coating requirement with its own TIS or ISO number, the minimum local thickness and the corrosion criterion.
• Which tests are wanted per lot and whether a report must accompany the delivery.
• For an export order, whether the receiving country's standard (ISO, JIS, DIN, ASTM) governs instead — a Thai number is not automatically recognised abroad.

What goes wrong when it is cited loosely

• Reading a มอก. mark on one product as approval of a whole factory, or of a subcontracted process. The licence is product-specific and factory-specific.
• Writing "ตามมาตรฐาน มอก." with no number. It is the same as writing "to standard" — there is nothing to inspect against.
• Assuming the Thai adoption is identical to the newest ISO edition. Several TIS fastener documents date from the 1980s.
• Expecting a plating or heat treatment subcontractor to supply a มอก. certificate. What a process shop can supply is a test report and a quality-management certificate; the product licence belongs to whoever puts the product on the market.