Dear eng-tips members:

In plant systems involve horizontal, vertical, long/short distance, inclined and gas/liquid two phase pipe line. The
pressure losses due to bend, valve, and fittings may cause
part of total friction loss. Therefore, engineers have to
get a proper pressure drop limit criteria for all kind of
fluid in any shape of pipe.   
 
  I encounter a line sizing dilemma when sizing the flow rate for
this pipe. This 2" hydrogen purge gas(operating pressure is 22kg/cm2g) line to reactor (operating pressure is 21kg/cm2g).
I use the pressure drop about 0.34kg/cm2 as criteria for this situation, but our leader said this should not so large.
So, I used other Bechtel process standard.

The standard is as follows

"Column overhead line" operating pressure above 50 pisg,

->Maximum recommended pressure drop is 5 psi total.
normal recommended velocity is 40~60 ft/sec.

But,
1. Is this overhead line criteria could use any gas line situation ?


2. The maximum recommended pressure drop 5 psi in this standard. Is this 5 psi means the pressure drop per 100m or just 0.05 psi per 1 m?



Thank you very much for your kindly help and suggestion.