Procedures, Work Instructions and Technical Governance

Learning outcomes

By the end of this chapter, the learner should be able to explain the hierarchy of regulatory, code, standard, specification and internal documents; write a complete ultrasonic procedure framework; derive a job-specific work instruction; manage references, essential variables and departures; and define review and approval evidence.

15.1 Document hierarchy is contractual, not universal

Regulations, legislation, product codes, method standards, client specifications, engineering drawings, procedures and work instructions can all govern an inspection. Their priority depends on jurisdiction and contract. A generic pyramid is useful for teaching but cannot resolve a real conflict. The organisation must identify the controlling documents and obtain formal clarification where requirements disagree.

Method standards commonly describe how examinations are performed. Product codes or specifications may provide acceptance criteria. Some documents contain both. The Level 3 must verify the actual controlled text rather than relying on labels or memory.

15.2 Procedure content

A method procedure should define, as applicable:

• scope, purpose and exclusions;
• normative and supporting references;
• definitions, responsibilities and personnel requirements;
• component materials, product forms, thickness and geometry ranges;
• equipment, probes, wedges, cables, scanners and software controls;
• reference standards and calibration requirements;
• surface condition, access, temperature and couplant controls;
• technique selection, scan plans, coverage and essential variables;
• sensitivity, transfer and evaluation methods;
• interpretation, sizing and recording rules;
• acceptance source and disposition pathway;
• quality checks, drift actions and data retention;
• safety, environmental and post-test requirements;
• qualification evidence, attachments and approval.

The procedure should contain enough control to reproduce the qualified method while leaving job-specific identifiers to the work instruction.

15.3 Work instruction content

A work instruction converts the procedure and job requirements into an executable sequence. It normally identifies the component, drawing, weld or test area, material and dimensions, access, inspection objective, personnel, safety controls, exact equipment, calibration block, probe positions, scan pattern, sensitivity, coverage, recording thresholds, acceptance source, forms and escalation steps.

Instructions should use observable actions: "Verify the 100 mm reference path within the stated tolerance" is stronger than "Calibrate correctly." Diagrams should define coordinate origin, scan direction and component orientation.

15.4 Review and approval

Technical review checks physics, coverage, equipment capability, calculations, references and qualification evidence. Document-control review checks identifiers, revision, approval, issue, distribution and supersession. Operational review checks that competent personnel can execute the instruction safely in the real access conditions.

Approval signatures should represent actual authority. Copying an old approval block into a rewritten manual or procedure does not approve the new content; it merely gives the problem stationery.

15.5 Change and concession control

Revisions must identify technical changes and affected qualifications. Field departures require authorised disposition. A concession should not rewrite acceptance criteria after the result is known; engineering acceptance of a nonconforming condition is a separate controlled decision.

Failure modes and decision control

Weak practice commonly includes assuming the document title defines its authority; citing unverified editions; placing acceptance limits in a method document without an authorised source; producing work instructions that repeat theory but omit positions and tolerances; reusing approval details from a superseded document; and changing essential variables without reviewing qualification.