Accuracy of the Modified TFCF for Conceptual and

ACCURACY OF THE MODIFIED TFCF FOR CONCEPTUAL AND CHECK ESTIMATES 

As mentioned in section 19.11 the total field cost factor (TFCF) can be modified and adapted to facilities that differ from those in the original study. The modified factor is developed by adjusting each of its cost components (see Table 19.36) to meet the requirements of specific cases. This approach can be very useful for conceptual estimating as well as for the quick checking of estimates prepared by others. 

This Appendix illustrates the use of this technique in two actual cases. Since they were the only ones available that justified the modification of the TFCF, the results must be confirmed with more cases. However, the results were so good that I don t hesitate to recommend that all project engineers/managers include the procedure in their tool box. I pray that some readers will be interested enough to dig into their files and check the procedure against their completed projects to confirm these results. 

Small 100% carbon steel plant handling simple non-toxic hydrocarbons with minimal instrumentation and by pressurizing vessels rather that pumping. 

The final cost was distorted and rendered meaningless by several major scope changes, so the procedure was evaluated against each of the three key estimates of the project preliminary, appropriation, and definite. 

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Accuracy of the Modified TFCF for Conceptual and Check Estimates... 

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