S-2.1, r. 4 - Safety Code for the construction industry
3.13.6. A compressed gas cylinder shall be used only under the following conditions:
(a) it shall be placed upright so that the pressure limiting device is in constant and direct contact with the gaseous phase; and
(b) it shall be fastened to a rigid structure or held on a cart designed for the transportation of such cylinder, or on the vehicle it supplies.