Engineering Manhour Estimate

[sara58sara]

can anybody share a practical guideline for estimation of engineering manhour for different projects?

[sara58sara]

Furthermore, is there any rule for estimation of engineering manhour required in each discipline? Electrical, I&C, Civil, Structure, Piping, etc.?

[DSB123]

Engineering Estimation "norms" are normally known as intellectual property of the various Companies and are not available otherwise another Company could undercut. Always remember the fundamental Rule "a job takes as long as it takes" and the second Rule "don't try and cut corners".

An engineering estimate is as good as the guy preparing the estimate. If he has insufficient experience then the estimate is more like a guesstimate!!!.

Another "golden Rule" is for "nuclear work" estimate as for a normal job then multiply the result by at least a factor of 4 or 5!!!

[gusgon]

As DSB123 pointed out, companies estimate man-hours based on their own experiences. For instance a company like PDVSA, Venezuelan oil company, has a manual (if you speak spanish I could sent you a copy) where stablish for the type of engineering your are going to do (Conceptual, Basic, Detail) the typical documents and drawings required by each discipline. With that, and some criteria of your own, such as determining how many Process Flow Diagrams (PFD´s) for instance might be required to a certain job, you estimate the man-hours. In the company whre I work, a engineering consultant, that is done by senior engineers of each discipline (Process, Mechanical, Electrical, etc). You as coordinator put al the man-hours togheter and estimate the staff hours such as Project Manager, Engineering Coordinator, Planner, Contract Administrator, Cost Estimators, etc. Many of those are full time, some are partial time, as might be the case of cost estiamtor, which is required once youa have sized the main equipment or bill of materials, depending of the type of engineering.
Other thing is determine the categories of required engineers, based on their experience. The more early stage in engineering, the more experienced engineers you required. For instance, for a conceptual engineering, you might require more experienced engineers, as more design criteria is required. Also for man-hours estimates you have to use judgment, as a more experienced engineer can develope some task more quickly and efficiently that a les experienced one, but is more costly.
So my dear friend, there is not a rule of thumb or a clear cut way of estimating man-hours for a project. Even some companies estimate engineering man-hours based on the number and type of equipment. And as DSB123 said, you almost always underestimate. Worst if you are competing against other engineering companies.
Based on you requirements I posted the book Engineering & Construction Project Management - A. Kerridge (Gulf Professional Publishing, 1986), where chapters 14 and 15 explained some methodology for estimating man-hours.
Againg for your benefit, I will be uploading another book with more information, but in a different thread to benefit more people. The book is Planning, Estimating and Control of Chemical Construction Projects (2nd Ed.) - P. Navarrete (Dekker). Look for it.

[carlosdiperna]

Hello, Gusgon. Is at your ability to send me a copy of the PDVSA costs estimating manual. I speak spanish (I'm from Uruguay). My email is carlosdiperna@gmail.com. TThank you very much. Best regards, saludos. Carlos

[ECH1]

Estimado Gugson,

Si puedes enviame una copia del manual de PDVSA a e27081962@yahoo.com.ar
Desde ya muchas gracias

[bzbipin]

Hi,

Also please send the manual to me bzbipin@gmail.com

Thanks in advance

[jlbejaranor]

Dear sara58sara,
There are several ways to calculate what you want. One of them would be to assign a certain quantity of manhours to every document. As an example, these manhours could be from 30 to 50 hours depending on the expertise of the engineering personnel. But then arises the most important question: Estimate the quantity of documents or the structure of the engineering. This depends on the scope and the type of information that is given by your client. So rules of thumb can be useful but can also be very dangerous misguiding you to big mistakes.
Regards,
JLBejarano

[jlgarciatucci]

Hello Sir Gusgon,
Could you help me sending the manual (PDVSA costs estimating manual) to my e-mail? jlgarciatucci@gmail.com
Thank you very much

[memoo5000]

Thanksss

[chuchai]

thank you!

[fantastz]

Gusgon. Is at your ability to send me a copy of the PDVSA costs estimating manual.
My email is: tschens@gmail.com
Thanks