Product Quality Inspection Services
Inspection examines a product, process, installation, or service and determines conformity, often using professional judgment rather than a single instrument reading. ISO/IEC 17020:2012 is the governing standard. This domain tests inspection-body types, inspector competence, sampling plans, and reporting.
Inspection body types
- Type A: independent third-party body with no affiliation to the party supplying the inspected item.
- Type B: first-party body that is separate from design and production within its own organization.
- Type C: body that may be part of the same organization, provided reporting lines and records preserve independence of the inspection result.
A Type C body cannot present itself as an independent third party for its own production.
Methods, sampling, and competence
Inspection methods and procedures must be documented and appropriate to the item. Sampling may follow ISO 2859-1 attribute plans using acceptance quality limit (AQL), or scheme-specific rules. Inspectors need relevant qualifications, experience, and knowledge of the applicable code, plus periodic competence review. Equipment used for inspection must be controlled and calibrated where it affects results.
Reporting
Clause 7.4 requires records and reports that are factual and traceable: item identification, inspection scope, method, results, and any nonconformities. Inspector judgment must be documented, not left as an unexplained opinion.
Worked example
A lot of 10,000 units is inspected at general inspection level II with AQL 1.0. The sample size code letter is J, giving n = 80, acceptance number Ac = 2, rejection number Re = 3. Finding two nonconforming units accepts the lot; finding three rejects it. The AQL describes the scheme's acceptance risk, not a guarantee that the lot contains at most 1% defects.
Traps that cost marks
- Using a Type C body as if it were an independent third party for its own output.
- Switching between normal, tightened, and reduced plans without a documented switching rule.
- Treating AQL as a defect-rate promise rather than a sampling scheme property.
- Reporting an inspector's conclusion without the supporting observation.
- Failing to define critical defects separately from major and minor categories.