What does the no-decompression limit (NDL) indicate?

The no-decompression limit (NDL) signifies the maximum time that a diver can spend at a specific depth without needing to perform mandatory decompression stops upon ascent. This concept is crucial in preventing decompression sickness, commonly known as "the bends," which can occur if a diver ascends too quickly after spending excessive time at a considerable depth. By adhering to the NDL, divers can ascend directly to the surface without encountering risks associated with nitrogen absorption in their tissues. Understanding the NDL helps divers plan their dives safely, ensuring that they remain within the established time limits for their chosen depth to avoid the need for decompression procedures later.

While the maximum depth for diving and the safety distance near underwater structures are important considerations in diving, those concepts do not accurately capture the essence of what the NDL represents. Similarly, while there is a relationship between dive time and depth, simply stating it as the longest duration for a dive misses the specific nature of decompression requirements.