Define the scope and reference documents
List the machine, zones, drawings, safety requirements, software versions and design calculations included in the validation.
- Control document revisions
- Record exclusions and third-party interfaces
- Confirm access to required equipment and test points
Create a test for every requirement
Each safety function should be tested in relevant modes and from each applicable access point.
- Normal protective demand
- Reset and restart behaviour
- Multiple-device and sequence conditions
Include fault tests
Test practicable faults in sensors, wiring, logic inputs and final elements according to the design.
- Open and short-circuit conditions where appropriate
- Device misalignment or actuator removal
- Contactor, valve or feedback faults
Record results and close deviations
Validation is not complete while unexplained failures, temporary overrides or undocumented changes remain.
- Record actual result and evidence
- Assign corrective actions
- Retest after modification and capture final status
Apply the guidance to the specific machine.
This guide supports early decision-making but does not replace a project-specific risk assessment, safety-system design or validation. Machine condition, tasks, controls and modification scope can change the correct solution.
Questions
Direct answers.
Is a checklist enough for validation?+
A checklist is useful only when it is tied to defined safety requirements and includes expected results, fault tests and clear evidence.
Should stopping time be measured?+
Where protective-device location or safe access depends on stopping performance, measurement may form an important part of validation.
Who signs the validation report?+
The organisation should define competent reviewers and approval responsibilities appropriate to the project and its governance.
