ISO/IEC 17020

Inspection is the determination of the conformity of a product, facility or process to defined requirements through observation, measurement and PROFESSIONAL JUDGEMENT. What distinguishes it from testing is that the decision rests largely on the competence of the inspection personnel and on assessment carried out on site.

This difference has an important consequence. A test standard, if sufficiently defined, gives the same result in different laboratories. In inspection, the experience of the personnel, the quality of observation and their competence in making decisions directly affect the result. In inspection bodies, personnel qualification, the authorisation matrix and continuing training are therefore as central a subject as equipment calibration.

The activity is mostly carried out ON SITE, and this brings its own difficulties: ambient conditions cannot be controlled, access may be limited, equipment must be transported and the decision is often made on the spot. Pre-shipment inspection, in-process checks during manufacture, periodic equipment inspection, inspection of lifting equipment and pressure vessels, weld inspection and non-destructive examination fall within this scope.

The competence of an inspection body is assessed under ISO/IEC 17020, and the body's TYPE OF INDEPENDENCE (A, B, C) determines the context in which the inspection will be accepted. A type A body is entirely independent; a type B body is a separate unit inspecting the parent organisation's own products; a type C body sits within the same organisation as design, manufacturing or maintenance activity. In some areas of legislation only inspection by an independent type A body is accepted; an inspection report issued without reading this distinction may be rejected.

PERIODIC INSPECTION is an obligation arising from legislation and is the backbone of the occupational safety field. Lifting equipment, pressure vessels, electrical installations, fire installations, ventilation systems and construction machinery are inspected at defined intervals. The intervals are defined in legislation or in the relevant standards and keeping the records is the employer's responsibility.

Non-destructive testing (NDT) is the most technical sub-body of the field and has its own personnel qualification system. Radiography, ultrasonic examination, penetrant, magnetic particle and visual examination methods are sensitive to different defect types; the method is chosen according to the defect being sought, and one method "finding no defect" does not mean another method would find none.

An inspection report is NOT A PRODUCT CERTIFICATE; it is the record of an assessment made at a particular time within a particular scope. The scope, the requirement applied, the inspection date and the identity of the sample or equipment appear clearly in the report. The report says nothing about a part that was not inspected, and this boundary is stated in the report.

Pre-shipment inspection also carries a commercial function. The buyer has to pay without seeing the goods; confirmation of quantity, packaging, marking and visible quality by an independent inspection body reduces that risk and can form part of the terms of a letter of credit.