PSV Pipeline Exit Pressure Drop 1

[spudton]

I'm trying to calculate the pressure drop in a PSV discharge line. The set pressure is low so the pressure drop allowable is low to meet back pressure limitations. For the pipe exit to atmosphere, crane quotes a k-value of 1.0. For a 10" pipe this adds a lot to the equivalent length (~14m) versus a straight pipe length of only ~3m. This takes me over the allowable presure drop. Should I be including this K-value in the calc, or is the frictional pressure drop recovered by kinetic energy gain across the fitting, and thus the pressures are the same? Would appreciate any insight into this problem.

 

[EVERYDAYSaSCHOOLday]

Hello guys!
Thank you all for the continued responses. The set pressure in this case 2.4 barg, with an accumulation of 16%. We have 2 valves in parallel with 1 spare (2 duty, 1 spare/out of service).
Each valve has the same discharge piping configuration, which is a very simple, 0.559m horizontal pipe, 90º LR elbow and then 2m vertical pipe.
The issue has arisen where the pressure drop down this line is quite small and falls below the 16% allowable back pressure (2 x PRVs so 16% not 10%!). However, if you include the pipe exit losses also, with a K=1, then the total static pressure is greater than 16%, and this is where the confusion has set in. Do we include the pipe exit loss, or ignore it as it is not frictional loss, and is velocity/acceleration loss only.
Regards,
Everyday's a school day