The Iranian threat, of course, is real, but its immediacy gets turned on and off by the Prime Minister like a faucet. In this tube the coals were placed, and when the water in the urn was hot, it could be drawn off by means of a faucet at the side. The drip-drip of water from the faucet sounded loud in the quiet.
After multiple dives per day or multiple days of diving, a minimum surface interval of 18 hours is recommended. If you had to do a decompression stop during a dive, the recommended time to wait before flying is a bit more of a gray area.
Technical Diving: Divers are limited by the number of tanks they use during the dive. Some exceptional dives have been for over 18 hours. Clearly a great deal of planning is required for these types of dives. More routinely Technical Divers often go to 150-250 ft with durations around 90-120 minutes. Rebreather Diving: A rebreather (as described here) removes the gas limitation, but imposes a limit on the duration of the scrubber material. Based on the construction of the rebreather, this is usually between 3 and 11 hours.