This standard, ""Earthquake-Actuated Automatic Gas Shutoff Devices (ASCE 25-97)"", provides minimum functionality requirements for earthquake-actuated automatic gas shutoff devices and systems meant to include mechanical devices consisting of a sensing means and a means to shut off the flow of gaseous fuels. It basically applies to single-family or multi-family structures of three stories or less. The seismic performance requirements established by this Standard are based upon data from recent earthquakes, primarily in Southern California.