User Manual
SAFETY 
 Safety handbook        page - 10 -   
PNSPO
3.4 Validation  
The purpose of validation is to determine the level of conformity of the safety-related 
parts of the control system to their specification within the overall safety requirements 
specification of the machinery. Validation consists of executing tests and applying 
analysis in accordance with the validation plan. 
The design of the safety-related parts of the control system shall be validated. 
The validation shall demonstrate that each safety-related part meets: 
-  All the requirements of the specified category 
-  The specified safety characteristics for that part, as set out in the design rationale. 
The validation of the safety-related parts of control systems should contain the 
following elements: 
- 
Selection of the validation strategy (a validation plan); 
-  Management and execution of validation activities (test specifications, testing 
procedures, analysis procedures); 
-  Documentation (auditable reports of all validation activities and decisions). 
The prEN 954-2 (Safety of machinery – Safety related parts of control systems – 
Part 2: Validation ) defines the procedure of Validation and contains possible validation 
for mechanical, pneumatic, hydraulic and electrical systems. 
The principle of validation can be illustrated in a flow chart. 
List of faults 
PrEN954-2, 
clause 6 
START 
General consideration 
during design 
EN954-1, clause 4 
Documents 
PrEN954-2
,
 clause 3.3
Criteria for fault 
exclusion 
PrEN954
-
2, clause 6
Validation plan
prEN954-2, clause 3.3
Validation 
guidelines
prEN954-2, 
clause 3.1 
Analyse 
prEN954-2, clause 4
Is the 
analyse 
sufficient
?
Test 
prEN954-2, 
clause 5 
Report 
prEN954-2, 
clause 3.4 
Test 
complete
?
END
NO 
YES 
YES 
NO 










