How to calculate forces in piping manually

I gather you really should be designing to an applicable, current piping code, perhaps ASME B31.3

For smaller piping systems, manual calculations are not a problem, however they are very rigorous and involved as you get into larger systems and computer programs such as Caesar II are used.

Having said that, before you use a computer analysis, you really need to understand the theory behind it.

For all aspects of "Code" work:
- Process Piping: The Complete Guide to ASME B31.3, 2nd Ed by Dr. Charles Becht IV
- CASTI Guidebook to ASME B31.3 Process Piping 4th Ed, by Glynn E. Woods, and Roy B. Baguley

Good references for piping stress analysis are:

ASME B31.3 Appendix S
"Piping Stress calculations Simplied", Spielvogel (rare, out-of-print and very difficult to get a hard copy)
"Introduction to Pipe Stress Analysis", Kannappan
5th edition "Piping Handbook" (other editions have omitted the good stress analysis chapter, but do have the basics)
"Piping Design and Engineering",by Grinnell
"Design of Piping Systems", by Kellogg
"Piping and Pipe Support Systems" by, Paul R. Smith & Thomas J. Van Laan
"Pipe Hanger Design and Engineering", by Anvil

Also - I believe there is some very basic calculations in "Handbook of Mechanical Engineering Calculations", by Hicks; but I don't have access to my copy right now.

thanks a lot..Indeed that i should know the principle first before engaging into software such as CAESAR II. I'll try to get a copy of ASME B31.3. Other books mentioned might be pretty hard to find especially here in the Philippines.. thanks anyway.. cheers.