Commissioning a Third-Party Test: Scope, Samples, Standards, Turnaround

Scenario: you want an independent lab to test samples of a cutting edge. Direct answer: write a brief that states the question, the samples, the method and the report you want, and ask the lab to confirm each in writing. A vague brief gets a vague answer. This checklist is general; the lab will tell you which methods and standards it offers.

Checklist for the brief

1. The question

• [ ] What decision will the result support: accept a lot, compare suppliers, investigate a failure?
• [ ] What result would change the decision?

2. The samples

• [ ] How many pieces, and how were they chosen: random from a lot, or specific parts?
• [ ] How are they labelled, packed and sent, and who holds the retained samples?
• [ ] Are reference samples, such as a known good part, included?

3. The methods

• [ ] Which tests, and to which standard or method, as offered by the lab?
• [ ] Where on the part is each test done?
• [ ] Are any tests destructive, and does that matter for the samples you send?

4. The report

• [ ] Raw readings or only pass or fail?
• [ ] Test conditions, equipment and date included?
• [ ] Photographs where relevant?
• [ ] A statement on measurement uncertainty, if the lab provides one?

5. Commercial terms

• [ ] Price, currency and what is included.
• [ ] Turnaround time and what causes delays.
• [ ] Confidentiality, and who owns the data.
• [ ] What happens to the samples afterwards.

After the result

Ask the lab to explain anything unclear before you act. Keep the report with the purchase record and note which decisions it informed.

Common pitfalls

The most common pitfalls are sending too few samples to say anything about a lot, asking for tests the lab does not run, and receiving a report with only a pass or fail. Ask the lab what a typical report looks like before you buy. Check that the samples sent are the ones you mean to test, and keep identical retained samples in case a second opinion is needed.

Boundary: No test method or standard is recommended here; the lab will say which methods it offers and whether they answer your question.