The ascent time (ASC TIME) is the minimum amount of time needed to reach the surface in a decompression dive. It includes:
•the time needed at the deep stop
•the time needed to ascend to the ceiling at an ascent rate of 10 m/33 ft per minute. The ceiling is the shallowest depth to which you should ascend
•the time needed at the ceiling
•the time needed at the Mandatory Safety Stop (if any)
•the time needed to reach the surface after the ceiling and Safety Stops have been completed
WARNING YOUR ACTUAL ASCENT TIME MAY BE LONGER THAN DIS- PLAYED BY THE INSTRUMENT! The ascent time will increase if you:
•remain at depth
•ascend slower than 10 m/33 ft per minute
•make your decompression stop deeper than at the ceiling
•do not use optimal decompression gas
These factors will also increase the amount of gas required to reach the surface.
Ceiling, ceiling zone, floor and decompression range
When in decompression, it is important that you understand the meaning of ceiling, floor, and decompression range.
•The ceiling is the shallowest depth to which you should ascend when in decompression. At this depth, or below, you must perform all stops
•The ceiling zone is the optimum decompression stop zone. It is the zone between the minimum ceiling and 1.2 m/4 ft below the minimum ceiling
•The floor is the deepest depth at which the decompression stop time will not increase. Decompression will start when you pass this depth during your ascent
•The decompression range is the depth range between the ceiling and floor. Within this range, decompression takes place. However, it is important to remember that the de- compression will be very slow at, or close to, the floor
The depth of the ceiling and floor will depend on your dive profile. The ceiling depth will be fairly shallow when you enter the decompression mode, but if you remain at depth, it will move downward and the ascent time will increase. Likewise, the floor and ceiling may change upwards while you are decompressing.
When conditions are rough, it may be difficult to maintain a constant depth near the surface. In such cases, it is more manageable to maintain an additional distance below the ceiling, to make sure that the waves do not lift you above the ceiling. Suunto recommends that decompression takes place deeper than 4 m/13 ft, even if the indicated ceiling is shallower.
NOTE | It will take more time and more gas to decompress below the ceiling |
| than at the ceiling. |
29
