Seaton Approach
Under FAR Part 61, Dispatchers are limited to 8 hours duty. If over 8 hours they must receive at least 8 hours rest, but if they work out side of the US they are allowed to work up to 10 hours.
Thats what the regulations say but my company have obtained a waiver, from the FAA, allowing us to work 12 hour shifts as long as we have one complete 24 hour period off duty every 7 days. Hope that is as clear as mud.