TDS vs COA vs SDS: Which Lubricant Document Answers Which Question in a Purchase Order
A Technical Data Sheet (TDS) answers "will this product fit my equipment spec?" with typical, non-batch-specific values. A Certificate of Analysis (COA) answers "did the batch I am receiving actually meet spec?" with measured, batch-tied results. A Safety Data Sheet (SDS) answers "how do I store, handle, and transport this safely?" — it is a hazard document, not a quality document. Confusing these three is one of the most common documentation errors in a lubricant purchase order, and it can lead to disputes at receiving inspection that were preventable at the RFQ stage.
This article breaks down what each document actually certifies, which standards govern it, and when to request each one in a B2B lubricant transaction.
What is a TDS and what question does it answer?
A Technical/Product Data Sheet is issued by the manufacturer or blender to describe a product's typical, or nominal, properties. It is a specification-fit document, not a shipment-specific one — the values on a TDS represent what the formulation is designed to deliver, not a guarantee of any particular production batch.
Typical properties reported on a lubricant TDS include:
- Kinematic viscosity at 40°C and 100°C (ASTM D445; an ISO 3104 equivalent test also exists, though the specific edition referenced can vary by document)
- Viscosity Index, or VI (ASTM D2270)
- Flash point, tested by either the Cleveland Open Cup or Pensky-Martens Closed Cup method (ASTM D92 COC or D93 PMCC) — the method used should always be stated on the sheet, since the two are not interchangeable
- Pour point (ASTM D97)
- Total Base Number, or TBN (ASTM D2896, potentiometric titration is the method most commonly cited on a fresh-oil TDS; a separate method, ASTM D4739, is used mainly for in-service/used-oil analysis and can produce numerically different results — buyers should confirm which method a given document is citing before comparing numbers across sheets)
- Noack volatility (ASTM D5800)
- Density (ASTM D4052 is the modern method; older documents may reference D1298, a hydrometer-based method)
Because the TDS describes the formulation in general, it is the correct document for a pre-purchase technical fit check — comparing viscosity grade, VI, flash point, and other properties against equipment or OEM specification requirements before a purchase order is placed.
What is a COA and how is it different from a TDS?
A Certificate of Analysis is a batch- or lot-specific document. Where a TDS shows what the product is designed to be, a COA shows what a specific production batch was actually measured to contain, tested against the product's own spec limits and tied to a batch or lot number.
The COA is issued by the manufacturer's quality-control laboratory; in some contracts, an independent third-party laboratory is used instead, and which is required depends on the individual supplier agreement — buyers should confirm this arrangement directly with the supplier.
A critical distinction: a document titled "Certificate of Analysis" that shows only "Typical" values instead of actual measured results for the batch in question is not a valid batch COA. It is effectively a relabeled TDS. A genuine COA states real, measured figures against each spec parameter, for the specific batch being shipped.
The COA is the only document that proves what a specific shipment actually measured. It matters for:
- Incoming-goods quality control at receipt
- Contractual conformance disputes (proving whether a shipment met the agreed spec)
- Traceability back to a specific production lot
What is an SDS and why is it not a quality document?
A Safety Data Sheet — formerly called an MSDS (Material Safety Data Sheet) — is a standardized, 16-section hazard and safety communication document. It is governed by chemical hazard classification frameworks, not by product-performance standards, and it does not confirm quality or performance in any section.
The 16-section format, at a high level, covers:
- Identification
- Hazards identification
- Composition/ingredients
- First-aid measures
- Firefighting measures
- Accidental release/spill measures
- Handling and storage
- Exposure controls/PPE
- Physical and chemical properties (this section may restate values such as flash point or appearance that also appear on a TDS, but its purpose here is hazard characterization, not spec verification)
- Stability and reactivity
- Toxicological information
- Ecological information
- Disposal considerations
- Transport information (including UN number and classification pointers)
- Regulatory information
- Other information
The governing frameworks behind this format include the UN Globally Harmonized System (GHS), administered by UNECE, currently at Revision 11 (2025) on its standard two-year revision cycle. Which specific revision a given live SDS actually follows varies by jurisdiction and by when the document was last updated — this should always be checked on the document itself rather than assumed.
Regional implementations layer on top of the UN GHS baseline:
- In the United States, OSHA's Hazard Communication Standard (HazCom 2012, 29 CFR 1910.1200) is aligned to GHS Revision 3. A 2024 OSHA final rule moves the standard toward alignment with a later GHS revision (GHS Rev.7); buyers relying on a US-market SDS should verify the applicable effective date.
- In the European Union, the CLP Regulation (EC) No 1272/2008 governs classification and labeling, and REACH Annex II sets the 16-section SDS format itself. Since 1 January 2023, EU SDSs follow the format as revised by Commission Regulation (EU) 2020/878.
Because the SDS is a hazard document, it never confirms performance or quality — it should never be treated as evidence that a product meets a technical specification or that a shipped batch conforms to anything.
TDS vs COA vs SDS: comparison table
| TDS | COA | SDS | |
|---|---|---|---|
| Purpose | Describes typical/nominal product properties | Confirms measured results for one specific batch | Communicates hazards, handling, and safety information |
| Batch-specific? | No — typical values, not a guarantee of any batch | Yes — tied to a specific batch/lot number | No — product-level, not batch-level |
| Answers which buyer question? | "Will this meet my equipment/OEM spec?" | "Did the batch I received actually meet spec?" | "How do I store, handle, and transport this safely?" |
| Issued by | Manufacturer/blender | Manufacturer's QC lab (or an independent lab, depending on the supplier contract) | Manufacturer/supplier, formatted to GHS/regional hazard-communication requirements |
| Confirms quality/performance? | Describes design intent, not a guarantee | Yes — the only document that proves actual shipment quality | No — never a quality or performance document |
Common mistakes and misconceptions
Treating the TDS as proof of the actual shipment. The TDS describes what the product is formulated to be. It does not prove what any specific batch measured. Only a COA does that.
Assuming the SDS proves quality or performance. The SDS is a hazard-communication document. Its presence, or its content in section 9 (physical and chemical properties), says nothing about whether a batch conforms to a purchase specification.
Expecting an OEM approval to appear as a field on the TDS or COA. OEM approval is a formal, separate approval relationship — for example, one obtained and licensed through a system such as API's Engine Oil Licensing and Certification System — and it is documented in its own approval letter or license, not printed as a line item on a technical or quality sheet. If a supplier claims OEM approval, request that separate approval document directly.
Confusing "meets spec" with "OEM-approved." These are two different claims. "Meets spec" refers to property or grade conformance shown on a TDS/COA. "OEM-approved" refers to a formal, documented approval relationship with the equipment manufacturer. They are never interchangeable, and one does not imply the other.
What to request via RFQ and when
Different documents are relevant at different stages of a purchase order:
- At the spec/technical-fit stage: request the TDS to compare properties against equipment or industry specification requirements.
- If an OEM approval or category license is being relied on: request the separate approval letter or license document — do not accept a claim without it.
- Before or at shipment: request the batch COA tied to the exact lot number of the shipment being received. This is the document that proves conformance for that specific delivery.
- For handling, storage, and transport planning: request the current SDS, and confirm its revision date and that it is specific to the product in question rather than a generic or outdated version.
Altonex Global is a B2B trade platform that connects buyers with registered suppliers for these transactions; it does not issue, verify, or certify TDS, COA, or SDS documents itself. Buyers should request these documents directly from the supplier through the RFQ process and evaluate them against their own equipment and regulatory requirements before finalizing a purchase order.