What is the goal of using a safety stop at 15 feet?

The primary goal of using a safety stop at 15 feet is to facilitate gas exchange in the body. As divers ascend from deeper depths, they experience a reduction in pressure, which can lead to the formation of nitrogen bubbles if a rapid ascent occurs. By conducting a safety stop at 15 feet, divers allow additional time for nitrogen that has been absorbed into the tissues during the dive to be safely eliminated from the body as they ascend slowly. This practice reduces the risk of decompression sickness, also known as "the bends," which can occur if a diver ascends too quickly without giving the body adequate time to off-gas the excess nitrogen.

While refreshing air supply and initiating buoyancy control may be actions taken by divers, these are not the primary reasons for a safety stop. Safety stops are specifically aimed at promoting safe ascent practices and ensuring the body has the opportunity for proper gas exchange to mitigate the risk of complications associated with changed pressure. Additionally, the goal of increasing dive depth does not align with the purpose of a safety stop, as this procedure is performed during ascent.