Section 197.312 - Breathing supply hoses(a) Each breathing supply hose must-(1) Have a maximum working pressure that is equal to or exceeds-(i) The maximum working pressure of the section of the breathing supply system in which used; and(ii) The pressure equivalent of the maximum depth of the dive relative to the supply source plus 100 psig;(2) Have a bursting pressure of four times its maximum working pressure;(3) Have connectors that- (i) Are made of corrosion-resistant material;(ii) Are resistant to accidental disengagement; and(iii) Have a maximum working pressure that is at least equal to the maximum working pressure of the hose to which they are attached; and(4) Resist kinking by- (i) Being made of kink-resistant materials; or(ii) Having exterior support.(b) Each umbilical must-(1) Meet the requirements of paragraph (a) of this section; and(2) Be marked from the diver or open bell end in 10-foot intervals to 100 feet and in 50-foot intervals thereafter.