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 SCUBA on air, recreational diving sets a limit of 40 meters (130 feet) because of the risk of nitrogen narcosis, which is similar to nitrous oxide (laughing gas) intoxication at low levels (30-50 meters) but can cause death at high levels (100 meters).