A practical method for assessing and managing the risk of noise induced hearing loss for divers in high-noise underwater environments

The purpose of this study was to develop a method to assessing and managing the risk of noise induced hearing loss (NIHL) to commercial divers operating within or nearby sites with high underwater sound levels. Our method involves using a transfer function to convert underwater sound levels to airborne sound levels at the diver’s ear inside a helmet, which can then be assessed against the 85 dB LAeq (8 hour) exposure limit for NIHL. We measured this transfer function for a standard commercial diving helmet (Kirby Morgan 37) during nearby impact piling using a Soundtrap hydrophone in the water and Brüel and Kjær sound level meter with a type-1 microphone at the ear position. We then used the results to calculate a time limit for a diver to be in the water before the in-ear sound levels exceed the NIHL exposure limit.