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.
For many agencies 40 meters is the limit in depth. There are. however certifying agencies such as CMAS which have a air limit. (56 meters depth) but this fringes on Technical Diving. In Tech Diving there are two limits: 1) Air limit -> 56 - 65 meters aprox. 2) Trimix -> No real limits.