man-hours estimate for piping & equipment design 1

[hahor]

Hi folks,

what is your approach to estimating man-hours for piping and equipment designers? Is there any realistic chart available?

Kind Regards,
Hahor

 

[Hagedoorn]

You can use a factor for calculating the engineering work out of the total construction cost (10% and 35% for example)(12% till 15% for petroplant grass root) (revamp 25% en 35%)(fine chemical 17% till 25% grass root).
You can break that down in 30% for project spec and 70% for detail design.
When you know an average manhour rate (all inclusive) divide it to the cost of engineering and you know rough the amout of manhours.

It is a rough system but it will help you to get an 25% acurate estimate.

Raymond Hagedoorn
Cost Engineer

 

[harz2000]

for petro-chemical plants business whre i am...

i use 8-12 as FEC ratio (Factor Engineering to Total Cost), ie engineering is in a range of 1/8 to 1/12 of total project cost (small/revamp closer to 8, large/grassroot closer to 12)

mech/piping take about 1/3 of that engineering cost, so 1/24 to 1/36 of total project


regards,
javier
project controls