What is the maximum allowable ascent rate recommended for diving?

The maximum allowable ascent rate recommended for diving is typically set at 30 feet per minute. This rate is suggested to help divers reduce the risk of decompression sickness, or "the bends," which can occur when ascending too quickly from depth. A controlled ascent allows nitrogen, which has been absorbed into the body tissues during the dive, to be safely expelled without forming bubbles that can cause injury.

During a dive, as the diver spends time at depth, the body's tissues become saturated with nitrogen based on the surrounding pressure. If a diver ascends too quickly, the decrease in pressure can lead to the formation of nitrogen bubbles. By maintaining an ascent rate of around 30 feet per minute, divers can ensure a safer transition to the surface, allowing them to stop and allow their bodies time to off-gas any excess nitrogen, particularly at designated safety stops.

In contrast, ascent rates higher than this limit may not provide sufficient time for safe off-gassing, increasing the risk of decompression sickness. Therefore, adhering to the recommended ascent rate is crucial for diver safety.