good advice. We used to sixe RO's downstream of valve for 15,000 pounds/hr. Some pipeline companies install upto 8" wide open ball valves under the impression that it was a DOT mandate to empty the contents of the blowdown piping in under 15 secs or 30 or 45 seconds, THEY weren't sure.
They finally allowed me to put in RO's when the land owner threaten to sue them and have them remove the 16,000 HP station if they didn't stop spraying oil all over his land.