Page 45 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 1 .12 Project Best Practices

Best
Best Practice 1.12Practice 1.12Practice 1.12
Best
Determine in the pre-bid project phase if and when design conducted design audits were either not performed or conducted too
audit meetings are required. late in the project.
Determine the critical machinery risk class as soon as the project is
announced, in the pre-feed phase, using the guidelines contained in Benchmarks
the supporting material section of this B.P. It may be necessary to use The above approach has been used in critical equipment projects since
design audits in the pre-feed phase as a means of vendor acceptability 1990, and particularly since 2000 when MEGA projects became
screening. common in the industry. This approach has resulted in projects free of
Determine if vendor sub-supplier audits are required (carefully safety and reliability issues, without significant cost adders or schedule
review ‘new international country sources’– China, Middle East, etc.). delays. Design audits were performed in compressor trains for the
The machinery industry has recently experienced poor quality sub- following recent projects:
supplier work from ‘new countries’ entering into sub-supplier work. Refinery hydrocracker recycle compressor
LNG mixed refrigerant compressor
Lessons Learned Methanol MAC and BAC air separation train
Failure to conduct design audits at the proper time in Ethylene refrigeration compressor
a project can lead to significant start-up delays, and life- The anticipated revenue savings from properly timed and conducted
long machinery safety and/or reliability problems. design audits can easily reach $60m, or much greater if based on a $1m
Since 1990 FAI has been involved with many field troubleshooting per-day-plant. Design problems that are not determined during an audit
assignments (RCFAs). These were required because properly can easily cause field delays in excess of two months.

B.P. 1.12. Supporting Material

Design and manufacturing audits Machining capabilities (max, size capability)
Balancing capabilities (Low speed and/or high speed, max rotor
size)
The need for design and manufacturing audits, as previously Size of assembly area
stated, depends on the equipment risk class, vendor and sub- Shop load status
supplier design, and manufacturing experience level. These audits Testing capabilities (gas test, full load test, power limits)
can be conducted at any phase of the project, but the sooner the Handling capabilities (max lift, laydown area)
better. Prototype equipment requires that audits be conducted Shipping capabilities
during the pre-FEED or FEED phase of the project. Today, most
projects are defined as MEGA projects, since the process units are Fig 1.12.2 Manufacturing audit guidelines
the largest size ever built and most probably will incorporate single
equipment trains that are prototype in nature. Therefore, many
projects require that design audits (pre-screening) should be Table 1.12.1 Suggested design audit activity
conducted as soon as the project starts. Planning and conducting
effective supplier design and manufacturing audits requires pre- Suggested design audit activity
planning and a significant amount of work, but it is certainly worth
the effort in terms of increased profits and reduced project 1. Risk type 1 2 3 4
schedule. These salient points are noted in Figure 1.12.1. 2. Design checks
When supplier or sub-supplier manufacturing audits are re- ■ Aero-dynamic X X ? *
quired, suggested action is shown in Figure 1.12.2. ■ Thermodynamic X X ? *
■ Rotor response X X ? *
In Table 1.12.1 I have presented a suggested list of what the ■ Stability analysis (if applicable) X X ? *
design audit should include, depending on the risk classification. ■ Seal balance X X ? *
■ Thrust balance X X ? *
■ Bearing loading X X ? *
■ Train lateral analysis X X ? *
Detailed agenda, well in advance ■ Torsional analysis (if applicable) X X ? *
Design audit at vendor's offices with follow-up at end user’s ■ Transient torsional (if req’d) X X ? *
offices ■ Control system simulations X X X X
Manufacturing audit at vendor's and/or sub-supplier’s plants ■ System layout – accessibility X X X X
End user specialists must participate
Conduct preliminary end user in-house checks prior to the design Key 1 = Prototype X = Required
audit if possible 2 = Multiple component inexperience ? = Optional
3 = Single component inexperience * = Not required
4 = Proven experience for all components.
Fig 1.12.1 Vendor audit requirements

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