Page 264 - Improving Machinery Reliability

Machinery Reliability Audits and Reviews 235

procedures for vulnerable turbomachinery trains, and guidelines for upgrading recip-
rocating compressor components.
To appreciate the scope of a well thought out machinery audit effort, a sample of
observations and recommendations dealing with operational practices and proce-
dures influencing reliability is given below:

Operators, at times, may not have sufficient opportunity to review procedures
when under pressure to restart a compressor train; consequently, errors in proce-
dure might occur. It is thus often recommended that critical start up procedures be
provided on laminated plastic cards sized to fit in the operator’s shirt pocket (Fig-
ure 3-107).
For steam turbines, there may well be an awareness that special procedures have to
be employed to avoid component damage from “rotor bows” when restarting after
a short shutdown, but specific steps are often not readily available in written form.
Startup diagrams for normal (‘‘cold start”) and special (‘‘hot restart”) sequence may
have to be developed for field-posting in painted sign or engraved plaque format.
Protective systems are sometimes not being tested “on the run” for fear that they
might cause an inadvertent shutdown. To deal with this and other related problems,
the audit team may leave written recommendation and relevant documents, such as:
-A sample instrument checkout procedure that describes typical on-stream verifi-
cation routines for critical instruments such as compressor suction drum high-
level shutdowns.

Figure 3-107. Shirt-pocket checklists can prevent costly operating errors.