I searched for fly casting competition rules. The World Championship and the Best of the West Competitions use WF fly lines. The ACA Tournament uses a shooting head and running line.
World Casting Championship Rules
Under Trout distance competition.
"2. Fly line: Scientific anglers mastery expert distance competition WF5F (orange, 120 ft.). The line shall not be modified in any way.'
Best of the West Competition Rules
ISE Sportsman Competitions
"Line: 90 ft, weight forward, floating"
American Casting Association Tournament Rules
Pg 25 under Angler Fly Distance rules:
a) Shooting head shall be no longer than thirty-one (31) feet nor shorter then twenty-eight (28) feet and shall weigh not more then three hundred ten (310) grains.
b) Running line - Unrestricted except that the diameter shall not be less than 0.015 inches.'