19 (1) Where an oxygen supply system is to be used in a diving operation, the diving contractor who conducts the diving operation shall use or permit to be used only an oxygen supply system the design of which complies with the requirements that:
[...]
(f) quick-shut-off valves not be installed in the oxygen supply system except for one-quarter-turn valves that are connected to lines with reduced oxygen pressure and that may be used in an emergency.
