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Quality and evidence

Understanding reference blocks and system checks

Instrument calibration, task-specific setup and ongoing system checks serve different purposes.

2 min readUpdated: Editorial team: NPB NDT Consulting

Keep the terms distinct

In everyday inspection, 'calibration' can refer to several different activities. Verification of instrument characteristics should be distinguished from task-specific setup using suitable references. An instrument certificate also does not replace checks on the actual system of instrument, probes, accessories and inspection sequence.

Connect the reference to its purpose

A reference block must suit the purpose for which it is used. Record its identity, intended use and associated documentation. Selection and required checks follow the agreed method and applicable requirements. This does not justify universal checking intervals or acceptance limits for unrelated tasks.

Define the response to deviations

If a check fails, simply restarting the program is not an adequate organisational response. The agreed process should explain who makes the decision and how potentially affected inspections are identified. Changes to probes or program versions also need technical assessment.

Practical checklist

  • Distinguish instrument verification from task setup
  • Identify reference blocks unambiguously
  • Document inspections and checks
  • Define consequences of deviations and decision ownership

Planning example

Illustrative planning example, not a customer reference.

Planning example: A system check reveals a deviation. The team records the condition, stops further evaluation and establishes which previously inspected items require review under the agreed procedure.

Key takeaway

References and checks support confidence only when their purpose and the consequences of a deviation are defined.

Technical sources

The articles and method descriptions provide general technical orientation. The organisations listed are technical sources, not customers or partners of NPB NDT Consulting. Sources may be in German or English.

These articles provide technical orientation. The specific inspection task and applicable requirements must be assessed for each project.

Would you like to apply this question to your component or process? Start by describing the task in general terms.

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