Relief Valves:

Sometimes external valves are used to protect gas systems from accidental over-pressuring. This drawing shows a typical relief valve installation. The relief valve may be recognized as the one connected to a discharge pipe extending upward, usually with a rain cap on the end. Most companies install a standard shut-off valve below the relief valve with a lock to keep it in an open position. The lock keeps unauthorized persons from closing the valve and rendering the relief valve ineffective.

A relief valve venting gas to the atmosphere is performing its proper function. It should never be shut off or restricted until a gas company employee arrives and makes corrections.

Anyone who sees or hears a relief valve venting gas to the atmosphere should call the gas company immediately and should not take any action that would keep the relief valve from venting gas to the atmosphere.