46 C.F.R. § 197.322 Surface-supplied helmets and masks.
Title 46 - Shipping
(a) Each surface-supplied helmet or mask must have— (1) A nonreturn valve at the attachment point between helmet or mask and umbilical that closes readily and positively; (2) An exhaust valve; and (3) A two-way voice communication system between the diver and the dive location or bell. (b) Each surface-supplied air helmet or mask must— (1) Ventilate at least 4.5 ACFM at any depth at which it is operated; or (2) Be able to maintain the diver's inspired carbon dioxide partial pressure below 0.02 ATA when the diver is producing carbon dioxide at the rate of 1.6 standard liters per minute.
Title 46: Shipping
PART 197—GENERAL PROVISIONS
Subpart B—Commercial Diving Operations
equipment
§ 197.322 Surface-supplied helmets and masks.
