Can a test report cover several colours or sizes?
Sometimes, but do not assume that a shared model name means shared test coverage. Ask a competent assessor to document which variants the evidence supports, why the tested samples represent them, and where additional tests are needed. Ask Cambridge China Bridge to coordinate factory variant information with its staff in China.
Assess coverage for each test
A report describes the samples and tests recorded in it. Treat coverage of untested variants as a question requiring a documented technical assessment. A shared catalogue range, similar appearance or the factory's assurance is not enough to explain why the results apply.
Separate report authenticity from variant coverage. Use our test-report verification guide to check the document, then commission the assessment below. For the distinction between reports and conformity marking, see our certification guide.
Give the assessor a complete variant register
Start with a register of every model, colour, size and supplied configuration. Against each entry, record materials, pigment or coating references, dimensions, components, accessories, intended use and manufacturing location. Include drawings, photographs, material information and the existing reports. Use the same identifiers in the order and sample labels.
Ask the factory to identify differences explicitly rather than writing 'same except colour'. A colour change might involve a different pigment, coating or plastic formulation. A size change might alter wall thickness, stability, loading or access to parts. Build this information into your product specification.
Request a signed product-family assessment
Commission a laboratory or product compliance specialist competent in the relevant product and test methods. Ask for a dated, signed assessment identifying its author, scope, applicable requirements and standards with their editions, documents reviewed, and the exact variants assessed. Treat 'product family' as a proposed technical grouping whose boundaries need explaining.
For products within the UKCA or CE regimes in Great Britain, government guidance says manufacturers remain responsible for assessing risks, identifying relevant requirements and documenting how they are addressed. Ask the assessor to explain coverage test by test: the representative sample, the reason it represents other variants, assumptions, exclusions and any further evidence needed. If your assessment route involves a conformity assessment body, ask that body to confirm how the proposed grouping fits its assessment.
Identify variants needing additional tests
Ask for a coverage matrix linking each variant to each relevant test or assessment. Record whether existing evidence supports it, further documents are needed, or additional testing is proposed. Require a reason for every decision. A variant may share mechanical evidence while needing separate chemical testing.
Ask which configuration presents the most demanding condition for each test. Do not select the largest size or darkest colour by instinct. Have the assessor justify sample selection using the actual construction and formulation, and specify whether targeted tests or a broader programme would resolve each gap.
| Variant difference | Question to resolve | Possible additional work |
|---|---|---|
| Different pigment, coating or material formulation | Does existing chemical or flammability evidence represent this formulation? | Obtain formulation information and assess targeted testing. |
| Different dimensions or construction | Does the tested sample represent stability, strength and access to hazardous parts? | Compare drawings and assess mechanical testing. |
| Different power supply, motor or enclosure | Does the evidence represent electrical, thermal and interference behaviour? | Review component details and assess relevant electrical tests. |
| Different accessory or intended use | Does the assessment include the supplied combination and its use? | Review the complete configuration and assess additional tests. |
Close gaps before approving production
Agree the test plan before sending samples. Match samples to the variant register, document their construction and keep photographs and dispatch records. Ask the laboratory to identify what it actually tested. If coverage relies on a separate assessment or report addendum, retain it with the report; do not add model names to the report yourself.
Keep the assessment, coverage matrix, reports and approved specification together using our compliance-file guide. Put unresolved variants on hold. Agree that changes to materials, components or construction return to the assessor for review. Cambridge China Bridge's staff in China can coordinate factory information and sample identification for that review.
Frequently asked questions
Do all colours need separate laboratory tests?
Do not assume either way. Give the assessor the formulation and coating differences for each colour and ask for a written decision against each relevant test.
Can testing the largest size cover smaller sizes?
Possibly, but size alone does not justify coverage. Ask the assessor which size presents the most demanding condition for each test and why the results represent the others.
Can the factory add my model to an existing report?
Ask the issuing laboratory about a supported amendment or addendum. Keep any separate assessment with the original report. Do not accept model names added without the issuer's confirmation.
What should a product-family assessment contain?
The exact variants, reviewed documents, relevant requirements and test methods, sample-selection reasons, coverage decisions, exclusions, further tests and the assessor's name, signature and date.