This document specifies tests and requirements for the excess flow valve, a liquefied natural gas fuel system component intended for use on the types of motor vehicles defined in ISO 3833. This document is applicable to vehicles using natural gas in accordance with ISO 15403-1 (mono-fuel, bi-fuel, or dual-fuel applications). It is not applicable to the following:a) fuel containers;b) stationary gas engines;c) container mounting hardware;d) electronic fuel management;e) refuelling receptacles.It is recognized that miscellaneous components not specifically covered herein can be examined to meet the criteria of this document and tested according to the appropriate functional tests.All references to pressure in this document are to be considered gauge pressures unless otherwise specified.This document is based upon a working pressure for natural gas as a fuel of 1,6 MPa (16 bar1). Other working pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio). For example, a 2 MPa (20 bar) working pressure system will require pressures to be multiplied by 1,25. 1 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2.