S-2.1, r. 13 - Regulation respecting occupational health and safety
312.20. Buddy diving: While buddy diving, the divers must
(1) establish a communication code by hand signals to be used in case of emergency or failure of the voice communication system;
(2) maintain constant visual contact with each other during the entire dive;
(3) terminate the dive immediately if one of the divers begins to ascend;
(4) apply the emergency measures in the dive plan if one of the divers does not respond to a signal; and
(5) be tethered to the surface by a cord attached to a buoy, which must be constantly visible and monitored so that immediate help may be provided to the divers in case of emergency.