Two-stage Regulator

A Two-Stage Regulator System is defined in NFPA 58 as, “An LP-Gas vapor delivery system that combines a first-stage regulator and a second-stage regulator(s), or utilizes a separate integral two-stage regulator.” In section 6.10.2, the requirements for this type of system are covered. In short, a two-stage system or 2-psi regulator system is required on all fixed piping systems and mobile food facilities that serve 1/2 psig appliance systems. Single-stage regulators on fixed piping systems have not been legal since June 30,1977. The only exception for single-stage regulator use is on small portable appliances and outdoor cooking appliances with input ratings of 100,000 btu/hr or less. If you work on a system that has a single-stage regulator installed, then you must upgrade this system to a two-stage system.

Why is this important? The following information helps to answer this and is pulled from the Fisher LP-31 Education & Guidance section.