The required surface interval between two separate dives is _____; the recommended minimum surface interval is ______.

The required surface interval between two dives is established to allow for the elimination of inert gases, primarily nitrogen, from the body, reducing the risk of decompression sickness. A minimum surface interval of 10 minutes is generally advised for safety in many diving situations.

The recommended minimum surface interval of 1 hour is suggested to provide an additional safety margin, allowing divers to off-gas more effectively. This recommendation also accounts for varying factors, such as the depth and duration of the dives, which can influence how much nitrogen a diver has absorbed.

This approach emphasizes the importance of planning and considering individual dive profiles to ensure optimal safety. In essence, while the required surface interval aims to mitigate immediate risks, the recommended minimum is a best practice to promote overall well-being during consecutive dives.