Most of us see propane cylinders stored and used on PITs on a daily basis and all of these cylinders are stored and used in their horizontal position. However, the propane cylinder we use at home on our gas grill can NOT be stored or used in its horizontal position. Here why…
Both types of cylinders have a Relief Valve (RV) on what most of us would call the “top” of the cylinder. However, by design, the cylinder designed to be used on PITs has a RV high up on the cylinder head when the cylinder is horizontal and even has an RV stem that extends upward inside the cylinder. See photo below, the RV stem is circled:
On the other hand, the propane cylinder we use on our gas grills are NOT designed to be stored or used horizontally because the head is centered on the tank and when the tank is on its side, the RV is in the LIQUID PHASE and thus will not operate properly AND it is a violation of 1910.110(b)(10)(ix), which states:
Safety relief valves shall have direct communication with the vapor space of the container at all times.
