Page 25 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

List of Lessons Learned
8.3: Using cartridge seal assemblies has resulted in Chapter 10 The Post Shipment Phase
significantly higher seal MTBFs.
8.4: All cartridge seals should be statically pressure tested Installation, Pre-Commissioning,
prior to installation. Commissioning and Start-up Lessons
8.5: Use of un-pressurized dual seals has exposed plant and Learned
personnel to potential losses.
8.6: Failure to monitor seal chamber pressure has caused 10.1: Plant life safety and reliability is directly connected to
low mechanical seal MTBFs. the project construction phase.
8.7: Checks all seal system components every time the seal 10.2: Delayed machinery start-ups are often caused by
is replaced to optimize MTBF. insufficient preservation programs.
8.8: Low seal MTBFs have been caused by incompatible 10.3: Vendor site visits are not effective unless detailed site
external flushes. details are sent in advance.
8.9: Use external flushes instead of flush line strainers and 10.4: Installing machinery without a proven foundation
cyclone separators. procedure will reduce MTBF.
8.10: Failure to monitor the operation of seal quench systems 10.5: Failure to use epoxy grout for all machinery
has caused low seal MTBFs. installations will reduce MTBFs.
8.11: Failure to monitor performance is the major contributor 10.6: Improper process piping attachment will significantly
to pump component failure. reduce machine MTBFs.
8.12: Process fluid will leak from dual un-pressurized seal 10.7: Most oil flush procedures take too long and are not
systems if the vent line is closed. effective.
8.13: Lack of a mechanical seal installation procedure has 10.8: Failure to check operation of auxiliary systems prior to
caused low seal MTBFs. start results in start-up delays.
10.9: Failure to perform an inert gas run exposes the plant to
reduced safety and reliability.
10.10: Not performing commissioning driver solo runs
Chapter 9 Dry Gas Seal Lessons exposes the plant to revenue losses.
Learned 10.11: Failure to obtain detailed component baseline
conditions reduces unit reliability.
9.1: Failure to consider plant operating conditions has 10.12: Lack of operator machinery awareness will reduce
resulted in low dry gas seal MTBFs. machinery safety and reliability.
9.2: Double dry gas seal systems have fewer components 10.13: Lack of an effective site predictive maintenance
than tandem seal systems. (PDM) program reduces MTBF.
9.3: Failure to monitor secondary seals has exposed plant
and personnel to safety issues.
9.4: Labyrinth separation seal nitrogen consumption is too
great to justify their usage. Chapter 11 Preventive and Predictive
9.5: The use of ‘bone dry’ N 2 (dew points below e30 C) has Maintenance Lessons Learned

resulted in low seal MTBFs.
9.6: Seal gas conditioning does not ensure reliability in 11.1: PM (time based) programs do not increase machinery
saturated process gas applications. reliability and are costly.
9.7: Many failures occur where the flare header can exceed 11.2: Short pump unit bearing bracket oil change intervals
the seal gas supply pressure. (13e26) weeks reduce MTBFs.
9.8: Dry gas seal separation systems do not prevent 11.3: Lack of a pump changeover program results in
carryover of oil into the seal chamber. significantly lower MTBFs.
9.9: Failure to include a seal gas conditioning unit has 11.4: Control valve replacement during plant operation
resulted in low seal reliability. exposes the plant to shutdowns.
9.10: Tandem seals with a seal chamber pressure above 0.5 11.5: Yearly oil lubricated coupling PMs expose the plant to
barg have higher MTBFs. unnecessary shutdowns.
9.11: A primary orifice bypass device in high suction pressure 11.6: Oil system transient tests performed during
services increases reliability. a turnaround are not accurate.
9.12: Tripping on high primary vent conditions only can cause 11.7: Failure to trend machinery operating points reduces
excessive plant shutdowns. machinery safety and reliability.
9.13: Never connect bearing housing vents if dry gas seals are 11.8: PM-heavy maintenance programs produce lower
used in the compressor. machinery MTBFs.
9.14: Not using a delta pressure controller for the separation 11.9: Reliability groups not using operations and process
seal has caused gas releases. input produce lower MTBFs.
9.15: Lack of personnel awareness of DGS system function 11.10: Operations and process groups need increased
reduces seal MTBFs. machinery functional awareness.

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