Manhours is a single word very commonly used to measure time, cost and effectiveness of supervision. There are lot of books, literatures and theories available in the market but none of them lay down the design basis of calculation of the same. Why dont we put our experience in writing here and find it out to derieve it in a structure way.
I am writing down the same here to start the discussioin rolling:
Based on our experience, we have worked out piping erection MHrs. norms as tabulated below:
Manhours for CS piping erection including fitup:
Take: Size of CS pipe spool: 6", spools: 2 Nos., each of 4 Mtr
Qty of erection: 48 IM, at elevation of 10 Mtr
Sr. No.
Activity
Craft
Qty
Time
(Hrs.)
MHrs
Remarks
1
Scaffolding
Scaffolders
6
8
48
2
Rigging of spool and
placement in place
Foreman: 0.5
Rigger: 4
4
3
12
3
Bevelling of pipe
Gascutter: 0.5
Grinder: 0.5
1
1
1
4
Alignment & Tack welding
Fitter : 1
Helper: 1
Tack welder: 1
3
2
6
5
Contingency @ 20%*
13.4
Total
80.4
For 48 IM
A
MHrs. Per IM:
1.7
*
Contingency for interruptioin in front/ modification / material handling delays etc.
Hope such experience sharing will make our decision backed up by confidence and accurate.
Hi Brij
Thank you for this input - a few queries:
Why stop at tack welding - there should be at least two more passes?
Who takes the scaffolding down?
When does the integrity test happen?
Best regards
Mike Testro
Dear Brij,
Please find out the piping erection on site & also other materails E.g SS316,Duplex, CS Molybdenum etc.
Site Productivity Formula.
Thanks for above information & waiting for other technical information regd the piping norms.
Regd,
Majid
Dear Brij,
This is a good idea and should be added into the dedicated section (Rates).
One comment anyway, I think we should not integrate contingency into the ratio. Usually contingency are added after the MHrs calculation on an overall quatity.
Rgds,
Maxime.
Sameway it can be found out for welding, supporting, testing and structural steel erection activities.