Operation Condition - Rig Floor  Alarm Condition  Sufficient self-contained breathing apparatus sets should be kept on the rig floor for all personnel likely to be immediately affected. The equipment will be rechecked at this stage.  Tests with a Draeger gas detector must be made immediately. For this reason, a portable H2S detectors must be available on the rig floor (driller house) at all times, with an adequate supply of extra tubes. The driller will notify the drilling superintendent, or tool-pusher. Check for gas with mud logging unit and start degasser. Recheck your choke and kill manifold for correct line up. Derrick man and shaker hand will be notified and instructed to check and prepare breathing apparatus. Have bug blower at shale shaker and pump room run at this stage. Have bug blower on top of draw works run. Check "hang off" tools and safety valves and have everything ready for circulating gas. At least one P-tank with Barite will always be on pressure and ready for use. Personnel in connection with the mud system will wear breathing equipment at least 20 minutes prior to bottoms up. Breathing apparatus will be worn at least 20 minutes, or 15 stands, in advance of core barrel on surface and retrieving core. Crane operator Crane driver and safety man will check: Safety Equipment  Breathing equipment for roustabouts and A.B.'s. With Captain check "safe briefing area" and whether breathing equipment and recharging equipment will have to be moved to other "safe briefing areas". With person in charge of breathing equipment and have all  equipment rechecked. Crane driver will place bug blowers: One at each entrance door to sack material stores, blower facing in  to sack stores. One at starboard side of shale shaker building so that air can be  blown into the shaker area from starboard. Two at front end of cellar deck - facing towards aft end of deck. Crane driver will check with electrician re electrical connections of bug blowers. Crane driver will open both doors on port side of shaker house, as well as all windows inside. Crane driver and boatswain will close all watertight hatches in columns, namely: Number 1 and 4 Starboard columns Number 1 and 4 Port columns Crane driver will check with rig floor for further instructions. And will see that safety equipment will be taken to the "safe briefing area".