Page 40 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 1 .9 Project Best Practices
Bearings – surface speed, load and experience Review of typical arrangement drawings
Thrust balance (reaction and hybrid types) List of experienced system sub-suppliers
Shaft seals Review of proposed dry gas seal supplier information
Transient torsional response experience review 5. Scope of supply for compressor train (all components and
(synchronous motors) auxiliaries) review
Control and protection system 6. Compressor train (all components) exceptions to specification
3. Gear experience (if applicable) (vendor to include necessary 7. Meeting summary and action required
reference charts, tables etc.) Note: Based on machinery risk, the following ‘design checks’
Gear box experience review and review of layout drawing may be required:
Review of gear data sheet Aero-dynamic
Gear calculation review (in accordance with API 613) Thermodynamic
Bearings – surface speed, load and experience Rotor response
Thrust loading – single helical gears Stability analysis
Pitch line velocity review Seal balance
4. Auxiliary system experience (lube, dry gas seal and control Thrust balance
oil system) Bearing loading
Review of P&IDs Control system simulations
Review of API 614 data sheets System layout maintenance accessibility

Best Practice 1.9

Require from the EP&C (contractor) effective bid tabula- A vendor selection that will not result in the highest level of plant
tions that minimize project time and assure machinery safety, reliability and revenue for the life of the process unit
selection based on life cycle cost.
Input required bid tabulation details to project team management Benchmarks
for review and transmittal to the EP&C early in the FEED phase (Front I have used this approach since 2007 in all critical equipment bid tab-
End Engineering Design). ulations, and have gained approval from project teams for its use. As the
Require the bid tabs to be minimized in size, but include the critical size of plants (mega) and daily revenue has increased significantly in
items necessary for evaluating bids on a life cycle cost basis. recent years, end user clients have seen the advantages in this ap-
Use the ‘typical bid tab’ format contained in this section as a guide. proach over the “standard industry bid tabulations” that were used in the
past. This approach has been used in the following projects since 2007:
Lessons Learned Upstream – gas plant booster compressor project
Use of the EP&C typical bid tabulation format extends the LNG plant feed gas compressor project
bid cycle and evaluates only on a capital cost and not life LNG plant mixed refrigeration gas compressor project
cycle cost basis. Proposed Bio – Fuels compression equipment project
Using this format will result in the following issues: One of the projects mentioned above allowed the selection of
a machine with a capital cost of þ25% based on yearly revenue, power
Extension of the bid cycle time by 2 or more weeks
cost and maintenance savings equal to the capital cost increment.
Evaluation based on technical items but on their capital cost only

B.P. 1.9. Supporting Material However, it has been my experience that the contractor bid
tabulation is usually nothing more than a scope of supply
list, and not a true technical comparison of the offered
Bid evaluations equipment.
As noted in B.P. 1.8, if the pre-bid meetings are conducted
It is an established fact that the contractor will prepare the bid correctly, the scope and the vendor exceptions to specifications
tabulation and present it to the end user for acceptance. will be essentially the same. Based on my experience, I require

Table 1.9.1 Bid tabulation key fact list
- The end user should review the contractor proposed bid tab format
- A technical check list should be included to quickly identify advantages
- Carefully consider the weight given to power costs and their tendency to influence selection of equipment of lower availability
- Detail exceptions to specifications and require vendors to list only exceptions specific to the project
- Encourage contractor to minimize size of the bid tabulation since scope should be equal based on pre-bid meeting results