Section R. 408.41873 - L.P. safety devicesRule 1873.
(1) Every container and every vaporizer shall be provided with 1 or more approved safety relief valves or devices. These valves shall be arranged to afford free vent to the outer air with discharge not less than 5 feet away, horizontally, from any opening into a building which is below such a discharge.(2) Shutoff valves shall not be installed between the safety relief device and the container, or the equipment or piping to which the safety relief device is connected, except that a shutoff valve may be used where the arrangement of this valve is such that the full required capacity flow through the safety relief device is always afforded.(3) Container safety relief devices and regulator relief vents shall be located not less than 5 feet in any direction from air openings into sealed combustion system appliances or mechanical ventilation air intakes.Mich. Admin. Code R. 408.41873