Can anyone sujest me the manhour for piping welding( inch dia )??? (PLS HELP ME>>>am new in planning)

Hi FRDS,

                    Can anyone give me a hand in this.

           * I want to assign manhours to a piping project. So I want to know the ratio btween piping works (welding, installation, insulation etc ) with manhour. I know it varies with several condition & different companies has different standards. Any way....can anybody help me in this case? Presently I calculation the total joints for our project and from that the total inch dia also.... So can any one tell me the manhour taking for 1 inch dia????? Also other works also like...installation, insulation etc.............

           Pls help me................

 Regards

 ARUN R