Flowserve LPS Series Heavy-Duty Actuators - Manual (Page 4)

4 Expected Lifetime
Actuator lifetime (for which failure rates indicated in Par. 5
are ensured) strongly depends on operating conditions and
on materials of construction.
For normal service conditions, LPS Actuators can be in good
conditions also after 25 years, with planned maintenance,
according to Par. 6.4.
5 Failure Modes and Estimated
Failure Rates
Failure
Mode
Estimated Dangerous Failure Rate

D
[1/h]
Failure on demand 6,39 E-08
Failure Modes and estimated Failure rates –
Actuators Series LPS/SA
Failure
Mode
Estimated Dangerous Failure Rate

D
[1/h]
Failure on demand 7,68 E-08
Failure Modes and estimated Failure rates –
Actuators Series LPS/DA
NOTE: no internal diagnostics is included in the device.
6 Periodic Test and Maintenance
Requirements
6.1 General
Please consider that the information in this paragraph are
relevant only in regards of Reliability Tests; please refer to
the Document “IOM MANUAL” (“Installation, Operation and
Maintenance Manual”, doc. n° LFENIM0001) for detailed
information about product maintenance, handling and
storage.
Diagnostic tests may be made to increase the system
reliability (Full stroke or Partial stroke Test).
“On site” tests depend on Project/Plant facilities/
requirements; however, a functional test must be executed
on site, before Valve usage.
6.2 Full Stroke Test
The “Full Stroke Test” (“On-line”) must be performed
to satisfy the PFDAVG (average probability of failure on
demand) value.
The full test frequencies will be defined from the final
integrator, in relation to the defined SIL level to achieve.
Procedure:
• Operate the Actuator/Valve assembly for an open/close
complete cycle, with complete opening - closing of the
valve.
• Verify the Correct performing of open – close manoeuvre
(e.g. check locally, or automatically, via Logic solver, the
correct movement of the actuator/valve).
Considering the application of the above described
Full Stroke Test procedure, the “Test Coverage” can be
considered 99%.
6.3 Partial Stroke Test
The “Partial Stroke Test” (“On-line”) can be performed to
improve the PFDAVG value.
A typical partial stroke value is 15% of the stroke.
The “Partial Stroke Test” (“On line”) can be performed
to satisfy PFDAVG (average probability of failure on
demand) value.
Recommended Test Interval = 1 – 3 months.
Procedure:
• Operate the Actuator/Valve assembly for in an open/close
cycle, with 15% of the stroke;
• Verify the Correct performing of partial stroke manoeuvre
(e.g. check locally, or automatically via Logic solver, or via
the PST system, the correct movement of the actuator/
valve till 15% of the stroke).
The above parameters will depend on the available partial
stroke test system.
Considering the application of the described Partial Stroke
Test procedure, the “Diagnostic Coverage” is >90 %.
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LPS Series Heavy-Duty Actuators FCD LPS-SM-00 – 1/14