053-9 Wyo. Code R. § 9-2
(a) Vapor lines shall be connected between the liquid CO2 containers so that pressure is equalized.
(b) Only hose approved for use with CO2 shall be used.
(c) Hose shall be inspected prior to use for damage to the external cover or braid. Defective hose shall be removed from service.
(d) Hose which exhibits visible damage shall not be used until it has been pressure tested. If it proves to be defective, it shall be removed from service.
(e) All discharge lines shall be securely staked or anchored.
(f) A check valve shall be installed in the discharge line of each pump prior to CO2 entering a common line, or a manifold trailer which has a check valve installed in it shall be used.
(g) A shutoff (plug) valve and two (2) check valves shall be installed on a CO2 line upstream of a commingling tee or manifold.
(h) A shutoff (plug) valve and a check valve shall be installed on a liquid line upstream of a commingling tee or manifold.
(i) Two (2) shutoff (plug) valves and a choke valve shall be installed on the release line with the shutoff valves located upstream of the choke valve.
053-9 Wyo. Code R. § 9-2