6. Tests and maintenance
Test and maintenance tasks may only be performed by authorised personnel who
have been trained on functional safety.
Test and maintenance equipment has to be calibrated.
Information
Any test/maintenance must be recorded in a test/maintenance report.
Impact of testing/maintenance on relevant devices, equipment or other work must
be evaluated.
6.1. Safety equipment: check
All safety functions within a safety equipment must be checked for perfect functionality
and safety at appropriate intervals.The intervals for safety equipment checks are to
be defined by the plant operator.
The plant operator has to establish a safety schedule for the entire safety lifecycle
of the SIS to avoid systematic faults. Policies and strategies for achieving safety as
well as different activities during the safety life cycle should be defined.
6.2. Proof test (verification of safe actuator function)
The proof test serves the purpose to verify the safety-related functions of the actuator
and actuator controls.
Proof tests shall reveal dangerous faults which might remain undetected until a safety
function is started and consequently result in a potential danger.
For checking the safety-related function, the output of safe end position feedback is
appropriately checked.
Information All installed and used safety functions within the actuator must be checked and all
test steps performed in compliance with the pertaining checklists.
Intervals:
A proof test interval describes the time between two proof tests. Functionality must
be checked at appropriate intervals. The intervals are to be defined by the plant
operator.
In any case, the safety-related functions must be checked after commissioning and
following any maintenance work or repair as well as during the T
proof
intervals defined
in safety assessment.
6.2.1. Preliminary tests
The actuator system has to be subjected to a visual inspection first.The system
should be checked for outside damage and corrosion. Furthermore, the electrical
and mechanical connections should be checked and the actuator inspected for
unusual noises while operating the actuator at least a complete travel from CLOSED
to OPEN and back.
6.2.2. Review and validation of the “Safe end position signal” safety function
Test sequence (check-
list)
1. Operate actuator to end position OPEN – Is the end position OPEN signalled
via Safe end position signal?
2. Unseat actuator out of end position OPEN – Is the safe end position signal
OPEN cancelled?
3. Operate actuator again to end position OPEN – Is the end position OPEN sig-
nalled again via Safe end position signal?
4. Operate actuator to end position CLOSED – Is the end position CLOSED sig-
nalled via Safe end position signal?
5. Unseat actuator out of end position CLOSED – Is the safe end position signal
CLOSED cancelled?
6. Operate actuator again to end position CLOSED – Is the end position CLOSED
signalled again via Safe end position signal?
13
Multi-turn actuators
SA .2 with AC(V) 01.2/AC(V)ExC 01.2 Tests and maintenance
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