Maxitrol vent limiting devices eliminate the need to run vent piping to the outside. They are designed for use indoors and in spaces where limiting the amount of gas escapement due to diaphragm failure is critical. Vent limiting devices should not be used outdoors if they are exposed to the environment. Ball check permits unobstructed inhalation for fast regulator diaphragm response on opening cycle, but limits gas escapement to be within ANSI and EN 88 requirements should a diaphragm rupture.