Project description for first poll: A total of 600 hours ($60,000) was invested in flexibility analysis from initial concept through construction administration on a project consisting of 8 piping systems totaling 1200 elements, and 260 load cases.

B31.1 as basis of design, Grade B carbon steel, in heated building, 250 to 350 Deg. F, 150 to 400 psig, pipe sizes ranged from 4” to 24”, with the majority in the 4 to 8” range, with 8 pressure vessel nozzles, 12 pump nozzles. No flange leak checks, low thermal cycles, no seismic or other dynamic loads. Restraints consisted of one-way supports and spring hangers. No expansion joints or ball joints. No structural steel modeling or nozzle modeling. No analysis report to client. No as-built model.

Usually in a full blown project entailing piping layout, design, fab isos, pipe supports etc. an approximation is ~ 25-30% of the piping total.....

I understand you to say flexibility analysis may run 25-30% of the total piping engineering cost. So, in terms of the installed cost of the piping around 3 to 5%?

25-30% of the total pipe design / engineering effort, where you are doing a 3D model, Isos, Pipe Supports etc.

The figure for percentage of construction cost to engineering cost varies widely but is around 15% - 20% of the total construction cost usually, this perecnetage is for all the engineering i.e., Civil Structural, Controls electrical etc.