IAPMO IGC 241-2019 covers mechanical water flow shut off devices that are designed to shut off the cold water supply to water heater or the water supply to water closets, shower head, sink or bathtub upon actuation and specifies requirements for materials, physical characteristics, performance testing, and markings.This standard applies to mechanical automatic water supply shutoff devices and component(s) (see Part IV, Definitions), hereinafter referred to as systems and component(s) constructed entirely of new, unused parts and materials, which is intended for use with water heaters, bathtubs, shower heads, lavatories, sinks, or water closets.This standard does not cover shut off device installed on water heaters that shall be connected to the thermocouple or gas line within the system.