Inspection as conformity assessment: role, responsibilities and distinctions

Inspections involve examining product designs, products, services, manufacturing or testing processes, or installations, and carrying out the corresponding conformity assessment.

Conformity is assessed either against specific requirements based on standards or other normative documents, or against general requirements using expert judgement. The results are documented in an inspection report.

Scope and methods of inspection

The scope of accreditation is set out in the accreditation certificate, which lists the procedures for which the inspection body’s competence has been confirmed. When inspecting processes, such as automated non-destructive testing (NDT) processes, the assessment may cover personnel, facilities and equipment, and the methods applied. The examination methods used are varied and may include audits or calculations as well as testing. The responsible specialists are known as inspectors.

Inspection is inherently a significantly more complex form of conformity assessment than testing. It differs particularly in that it includes expert judgement. While testing primarily aims to determine individual characteristics, inspection encompasses a holistic assessment, often considering operating conditions, interactions and requirements that are not fully defined by standards.

Requirements for inspection bodies

Accredited inspection bodies must fulfil comprehensive technical, organisational and quality management requirements. These include, in particular:

• suitable facilities and equipment for performing inspections,
• performing contracted services themselves wherever possible; subcontracting is permitted but limited,
• an effective quality management system.

Particular emphasis is placed on personnel qualifications.

Competence of inspectors

The employees of an inspection body responsible for performing inspections are called inspectors. The requirements for their work go beyond conventional testing. Alongside technical expertise, broader system knowledge is essential. This includes:

• manufacturing processes,
• application and operating conditions,
• typical defect patterns and their effects,
• normative and regulatory requirements.

Sound expert assessments are possible only on this basis.

Independence and impartiality

Independence and impartiality are central to accredited inspection bodies. The standard distinguishes three types of inspection body:

• Type A: a completely independent and impartial body. Neither the organisation nor its inspectors are involved in manufacturing, designing or using the items it inspects. Its services must be accessible without discrimination.
• Type B: part of an organisation that manufactures, designs or uses the items inspected by the inspection body. However, the inspection body is clearly separated organisationally and is not involved in manufacturing, designing or using the inspected items. Services may be provided only to its own organisation.
• Type C: directly involved in manufacturing, designing or using the items it inspects. This requires a clear separation of responsibilities within the organisation.

This classification is closely related to the first-, second- and third-party concepts in DIN EN ISO/IEC 17000.

Comparison with the testing laboratory

Compared with DIN EN ISO/IEC 17025, DIN EN ISO/IEC 17020 places significantly higher demands on personnel competence, independence and impartiality, and organisational integrity. This directly reflects the greater complexity of inspections and the need for expert assessments that go beyond requirements explicitly defined by standards.

Key areas of inspection work

The core activities of an accredited inspection body comprise:

• examination of products, services, processes or installations using accredited procedures,
• evaluation of results for conformity with specific or general requirements,
• a decision on conformity, usually without a separation between those who evaluate and those who decide,
• preparation of an inspection report containing the corresponding statement of conformity.

The statement of conformity applies exclusively to the specific inspected item and the time of inspection. It may not be extended to other objects or future points in time.

A typical practical question

A typical question for an accredited inspection body is: “Is this component’s strength sufficient for it to function reliably under typical operating conditions?” In this case, the inspection involves not only testing strength, but also technically defining and evaluating “typical” and “reliably” in the relevant application context.

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Further information: Part 5 of the series “Conformity assessments in materials testing”: “Conformity assessment by certification bodies: processes and requirements”.(opens in new tab)