Lang / Hand factors are based on purch. or delivered equipement cost?

[zaigrata]

Dear all,

Can you please provide confirmation whether the Lang, the Hand and the Wroth factors for preparing cost estimates are based on purchased or on delivered equipment?

Various sources suggest differently:
+James R. Couper suggests in Perry's Chemical Engineers' Handbook ed. 8 that Lang and Hand start with purchased equipment cost while Wroth starts with delivered equipment cost. Note: in the same book, on the same page authors states Lang is based on delivered equipment cost
+ same author James R. Couper suggests in Process Engineering Economics that Lang is based on delivered equipment; Hand is based on purchased equipment costs; later the author summarizes that Lang and Hand methods start with delivered equipment costs, but the Wroth method begins with purchased costs
+ Max S. Peters and Klaus D. Timmerhaus suggest in Plant Design and Economics for Chemical Engineers ed. 5 that Lang is based on delivered equipment cost
+ Gavin Towler / Ray Sinnott suggest in Chemical Engineering Design Principles, Practice and Economics of Plant and Process Design suggests that Lang is based on purchased equipment cost
+ Harry Silla in Chemical Process Engineering Design and Economics suggests that Lang is based on delivered while Hand factor is based on purchased equipment cost

Can you please provide additional information?
If anyone has access to the original publications by Lang, Hand or Wroth, please let me know.

Thank you in advance.

Best regards,
Stan

 

[hahor]

Zaigrata,

you are talking about estimates in the +/-30% range. Don't try to be too accurate on items with small effects on the final number.

The article "Making Sense of your Project Cost Estimate" by J.C. Lagace, CHEMICAL ENGINEERING Magazine of August 2006 might be helpful.

Kind Regards,
hahor

 

[StoneCold]

When I have seen the estimates used, they were stated as delivered, Gulf Coast only. Anything outside of the US would cost more for shipping so that would have to be factored in. Hahor is right that you are not going to get very close with the Lang factors. Most of the time you don't get that close with an initial bid. The devil is always in the details of the projects that come up later anyway.

Regards
StoneCold