Piping cost estimates (pt 3)

Continuing our series on estimating the costs of pipework and piping projects (see p19 in September and October 1999), this month we present the first of a number of graphical representations of the costs of fabricating various types of pipework on process sites.

When using the graphs the following notes should be borne in mind:

Figure 1 - Cutting carbon steel pipes: the scope here refers only to straight-cutting by flame or by machine, except for 40mm dia pipe which includes hand-cutting and dressing pipe-ends. Mitre cuts should be taken as 1.5 times the manhours for the above.

Figure 2 - Cutting and threading carbon steel pipes: again, this refers to cutting and threading by machine, except 40mm dia which includes work by hand and dressing ends of pipe.

Figure 3 - `V' bevel carbon steel pipes: the scope here is cutting by flame or machine and dressing pipe-ends by hand.

Figure 4 - `U' bevel carbon steel pipes: the scope here is as for Fig 3.

All the graphed manhour norms in Figs 1-4 are based upon direct labour working in an established site workshop provided with all the facilities, tools and so on for the fabrication of pipework, as would be expected in any factory. PE

If there is one part of a process plant that sets it apart from other manufacturing plants, it is the pipework that links all the process units. The design and specification of piping systems is an integral part of process engineering, but too often the actual mechanics of turning the designs into reality takes a back seat.

Piping fabrication is a skilled task and should be taken into account in any project cost estimate. The graphs here (and following ones in coming months) give a guide to fabrication costs for a variety of pipework. The data is based on work carried out in the North West of England at various chemical and petro-chemical sites, with average labour efficiency and good site conditions.