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.
The Guinness Book of World Records allows divers to hyperventilate for up to 30 minutes with pure oxygen before they submerge for their record attempt. This practice, Discovery News reports, helps the body expel carbon dioxide, buying time before carbon dioxide levels become toxic.