Operational Guidelines and Safety Precautions

CHAPTER 6 — Operational Planning Change A 6-17 operations using MK 16 UBA, MK 25 UBA, Viper VSW UBA, SCUBA, and surface supplied UBA in water temperatures up to 99°F. Diving in water tempera- tures above 99°F should not be attempted without first contacting NAVSEA 00C. 6-6.3.1 Operational Guidelines and Safety Precautions. These guidelines are based on data collected from heat acclimated divers dressed in UDT swim trunks and t- shirts who were well rested, calorically replete, well hydrated, and had no imme- diate heat exposure prior to starting exercise. Exercise rate for the divers replicated a moderate swimming effort. Conditions that contribute to thermal loading such as heavy work rates, significant pre/post dive activities, and various diver dress (dive skins/wetsuits/dry suits) can reduce exposure limits appreciably. Define guidelines for exposure limits based on diver dress are currently being developed by NEDU. Until further guidance is provided regarding the measurable effects of these factors, the limits provided shall serve as maximum levels of exposure. The following precautions apply to all warm water diving operations above 88°F: Weight losses up to 15 lbs (or 6-8% of body weight) due to fluid loss may occur and mental and physical performance can be affected. Divers should hydrate fully (approximately 500 ml or 17 oz) two hours before diving. Fluid loading in excess of the recommended 500 ml may cause life-threatening pul- monary edema and should not be attempted. Hydrating with water or a glucose/electrolyte beverage should occur as soon as possible after diving. Approximately 500 ml should be replaced for each hour of diving. Exposure limits represent maximum cumulative exposure over a 12 hour period. Divers should be hydrated and calorically replete to baseline weight, rested, and kept in a cool environment for at least 12 hours before a repeat exposure to warm water is deemed safe. NOTE This guidance does not change NAVSEA-approved canister duration limits for the MK 16, MK 25, and Viper VSW UBAs. Maximum warm water dive time exposure limits for these UBAs shall always be the lesser of the approved UBA canister duration limits or diver physiological exposure limits. The following guidance is broken down into specific UBAs: MK 25 UBA A diver working at a moderate rate, swimming at 0.8 kts or less (combat swimmer): 88°-94°F - limited to canister/O₂ bottle duration 94°-97°F - limited to three hours based on physiological limits. 97°-99°F - limited to one hour based on physiological limits.