What is the maximum exposure time allowed before a defined repet dive?

The maximum exposure time allowed before a defined repetitive dive is 12 hours. This time frame is crucial in managing nitrogen levels in the diver's body and preventing decompression sickness. When a diver completes a dive, nitrogen is absorbed into the body tissues. After the dive, the body starts to eliminate this nitrogen, a process influenced by the duration of the surface interval before the next dive.

The 12-hour rule is significant because it serves as a guideline to give the body enough time to off-gas the nitrogen absorbed during the previous dive, especially if it was a deeper or longer dive. By allowing this time, divers can reduce the risks associated with successive dives, maintaining safety and health.

Other time frames like 10 minutes or 1 hour do not provide sufficient intervals for nitrogen levels to be adequately reduced before a subsequent dive, increasing the risk of decompression sickness. A 24-hour period, while longer than necessary, may be overly cautious and not representative of standard diving practices where repetitive dives are commonly performed within the 12-hour frame. Thus, 12 hours stands as the maximum exposure time recommended before diving again.