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.