Page 381 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 7 .5 Lube, Seal and Control Oil System Best Practices

Best Practice 7.5Practice 7.5Practice 7.5
Best
Best
Always perform a design audit of system and component competitively select sub-vendors for auxiliary systems. Care must be
sizing early in the engineering phase for ‘bad actor’ con- taken to ensure the selected sub-vendor is an experienced, quality
soles (more than one shutdown per year), to ensure the shop.
highest possible level of critical machinery reliability.
Two factors which play a great part in attaining a reliable auxiliary Lessons Learned
system are communication and revenue. Frequently, auxiliary systems Failure to design audit new and ‘bad actor’ oil system and
are sub-contracted by the original equipment manufacturer to a spe- component design has caused many start-up delays and
cialty auxiliary system facility. The communication between the original trips of critical (un-spared) compressor trains.
equipment manufacturer (OEM) and the sub-vendor is not always ef- Even at the present time (2010), a design audit of oil systems is not
ficient. After receipt of an order to manufacture an auxiliary system, common. Failure to conduct an audit can result in shop testing, start-
confirmation of scope of supply should be obtained with the end up delays and troublesome low reliability oil consoles.
manufacturer of the system involved.
The other factor is the cost of the critical equipment and the price Benchmarks
charged for it. In the real world of competition, original equipment This best practice has been used since the early 1980s to ensure
vendors often sell the equipment for less than originally anticipated. optimum oil console design and component selection, and has
Therefore, costs are high and profit decreases. In an effort to minimize resulted in critical machine reliability exceeding 99.7%.
cost, sub-systems can suffer in terms of design and quality. OEMs will

B.P. 7.5. Supporting Material Data sheet review
The system data sheet should be complete and be thoroughly
Design audit agenda reviewed at this point, including specific component details and
desired manufacturers of major components. This review goes
In this section, we will deal with specific areas important to both ways; that is, vendor required information and user in-
the confirmation of good auxiliary system design and man- formation must be detailed and correct on the data sheets.
ufacture. To ensure maximum effectiveness of these re- Frequently, utility and site information is not complete. This
views, it is recommended that a prior agenda, mutually absence can only lead to reliability and communication prob-
agreed upon between OEM and user, be generated and lems in the field. As with any meeting, detailed minutes should
supplied to both parties well in advance of any meetings. In be kept and every effort should be expended to resolve all open
addition to detailing the subjects of discussion, the agenda items prior to its conclusion. Postponing decisions only creates
should also define the attendees of the meeting. A well inefficiencies.
defined meeting is still ineffective if the participants are not
familiar with the subject or have a minimum amount of Exceptions to specifications
experience.
All vendor exceptions to specifications must be reviewed and
either accepted or rejected. The final, mutually agreed to list of
Confirmation of scope vendor exceptions should become part of the job specification.

For the reasons mentioned above, scope review approxi- Component sizing audit
mately one to two months after auxiliary system order
placement is recommended. The major areas of scope review A typical component sizing audit form is included at the end of
are: this B.P. We will now review the major areas of this audit form.

- Schematic review
- Data sheet review System requirements
- Exceptions to specification The first subject of discussion concerns confirmation of auxiliary
system flow rates, pressures and heat loads required. This in-
formation determines the size of all major system components.
Schematic (P&ID) review
It must be correct and not modified during the design of the
The original system schematic (P&ID) (console and unit) as equipment. The component sizing agenda should emphasize the
contained in the equipment specification should be reviewed at need to have all required information supplied and confirmed by
this point, to confirm all system logic and instrumentation is as each critical equipment vendor. Attention is drawn to compar-
specified. That is, the schematic should be reviewed in the ing values noted. If significant discrepancies appear, question
framework of a P&ID (process and instrument diagram). All them! Remember all critical equipment components are
comments should be noted and the system schematics equivalent orifices, and at a specified pressure will only pass
corrected. a given flow. If the component oil flow specified is greater than

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