DOCUMENTATION
SDS vs TDS: which document answers which question
Buyers ask for “the data sheet” and mean one of two documents that overlap almost nowhere. One tells you whether the material is safe to have on site. The other tells you whether it will work. Asking for the wrong one costs a week.
1 · What a safety data sheet is for
A safety data sheet exists to let people handle, store, transport and dispose of a substance without being harmed by it, and to let emergency services act if something goes wrong. It carries hazard classification and labelling, composition information for the hazardous constituents, first aid and firefighting measures, exposure controls and protective equipment, physical and chemical properties, stability and reactivity, toxicological and ecological information, disposal, and transport classification.
It is a regulatory document with a prescribed structure, and in the EU it is supplied because the law requires it, not as a courtesy. It is written for the safety officer, the warehouse and the carrier.
What it will not tell you is whether the material suits your job. Nothing in it is a performance statement.
2 · What a technical data sheet is for
A technical data sheet is the manufacturer’s description of how the product behaves and how to use it: recommended substrates and preparation, mixing ratios and pot life, application method, film thickness, coverage, flash and recoat windows, cure schedule, and the performance figures the manufacturer is prepared to publish.
It is a commercial and technical document rather than a regulatory one. Its structure varies by manufacturer, and so does how much it discloses — two products with similar claims can have very different amounts of evidence behind them.
This is the document that decides whether a material is a candidate. It is also the one buyers most often forget to ask for until after they have committed.
3 · Where buyers get caught
Assuming the SDS proves suitability. It proves nothing of the kind. A material can be entirely benign and completely wrong for your substrate.
Assuming a TDS is a specification. Published figures are obtained under the manufacturer’s stated test conditions. If your process differs — different substrate, different film build, different cure — they are indicative rather than guaranteed.
Assuming the documents are interchangeable between grades. A surface-treated grade and an untreated one from the same product family can differ in both documents. The sheets must match the grade actually delivered.
Leaving language until the delivery arrives. The SDS has to be usable by the people who will handle the goods. If that means a particular language, it is an enquiry-stage requirement, not a post-delivery one.
4 · What to ask for, and when
At enquiry, ask for the TDS: it tells you whether the material is worth pursuing before anyone spends time on price. At quotation, ask for the SDS for the specific grade quoted, and say whether it must be in a particular language and whether it must travel with the goods rather than follow by email.
If your QA process requires anything beyond these two — a declaration against a sector standard, a certificate of analysis for the batch, a statement about a restricted substance — name it in the first message. Those come from the manufacturer and sometimes only for certain grades, so it is far better to learn that early.
NEXT STEP
Tell us which documents your process requires when you send a pigment or coating requirement, and we will confirm what the manufacturer provides before you commit to anything.