Mattcaroni,
normally the approach is considering piping "supported somewhere between simple support and fixed support".
These formula are valid for straight pipes. If you have bends, some reduction factors or additional equivalent lenghts have to be considered.
Please check the linear weight (looks a little too low) and do not forget mill tolerance, corrosion, insulation and valve weights if any.
By the way, yes: the theoretical calculated results are "often" overconservative if compared with CAESAR II calculated spans.


To investigate more, some good reference books are:
- Pipe Stress Engineering (Peng)
- Design of piping system (Kellogg)
- Introduction to Pipe stress analysis (Kannappan)

Corrado Vannella
www.vannella.com