During a 30' O2 stop, how long is the air break allowed?

In the context of air diving operations, the purpose of an oxygen (O2) stop at a depth of 30 feet is primarily to assist in reducing nitrogen levels in divers' bodies during the ascent phase. The air break refers to a period where divers can breathe air while still allowing for the beneficial effects of the O2 stop.

The correct duration for the air break during a 30-foot oxygen stop is 5 minutes. This duration is considered adequate to allow for safe ventilation of nitrogen while maximizing the effectiveness of the O2 stop. Diving protocols emphasize the importance of this break being kept brief. If it lasts too long, it could potentially negate some of the benefits of the oxygen therapy being employed at that depth.

The other options suggest longer breaks that could be detrimental to the purpose of the O2 stop. Ensuring that the air break adheres to established guidelines helps maintain the safety and health of divers during their operations.