Today I bring to my colleagues some statistics resulting from Max S. Peters & Klaus D. Timmerhaus on typical percentages of pipes with respect to the type of process. Information as you find them in our course “Advanced Cost Estimation – Process piping“
Rough estimate of the piping costs for various types of chemical processes1
- The cost for piping covers labor, valves, fittings, pipe, supports, and other items involved in the complete erection of all piping used directly in the process.
- This includes raw-material, intermediate-product, finished-product, steam, water, air, sewer, and other process piping.
- Since process-plant piping can run as high as 80 percent of purchased-equipment cost or 20 percent of tied-capital investment, it is understandable that accuracy of the entire estimate can be seriously affected by the improper application of estimation techniques to this one component.
- Piping estimation methods involve either some degree of piping take-off from detailed drawings and flow sheets or using a factor technique when neither detailed drawings nor flow sheets are available.
- Factoring by percent of purchased- equipment cost and percent of fixed-capital investment is based strictly on experience gained from piping costs for similar previously installed chemical-process plants.
Piping around pumps – ISBL
- Table below presents a rough estimate of the piping costs for various types of chemical processes.
- Labor for installation is estmated as approximately 40 to 50 percent of the total installed cost of piping.
- Material and labor for pipe insulation is estimated to vary from 15 to 25 percent of the total installed cost of the piping and is influenced greatly by the extremes in temperature which are encountered in the process streams.
(1) PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS – By Max S. Peters & Klaus D. Timmerhaus