Large industrial and institutional users of argon,nitrogen,and helium need storage units on their premises with greater capacity than that provided by manifolded cylinders. These bulk supply systems are an assembly of storage containers,pressure regulators,pressure relief devices (PRDs),vaporizers,manifolds,interconnecting piping,and,where present,liquid transfer equipment. The inert gases are stored as gas or liquid in either stationary or portable containers. The bulk system terminates at the point where gas at service pressure enters the supply line.