This document refers to UGLDs (ultrasonic gas leak detectors). This document is applicable to ultrasonic gas leak detection equipment intended to provide an indication, alarm or other output function for the purpose of initiating automatic or manual protective action(s). This document specifies general requirements for design, testing and performance, and describes test methods that apply to UGLD. The following items are considered in this document: Leak rates to be used to verify the detection range of UGLD Test gas to be used (nitrogen, methane, helium, etc.) Nozzle shape and size used at all tests leak rate tests Gas pressure used at all leak rate tests Time duration of each leak rate test Test leak nozzle height from solid ground Test leak nozzle angling relative to test UGLD UGLD angle relative to the leak (field of coverage of the UGLD) Wind speed, air temperature and humidity at day of test Minimum distance to solid structures (walls, etc.) at test site Wind velocity and direction Installation height relative to the ground Texture of solid ground between leak and UGLD Background noise sources, known to interfere with UGLDs, Specification of detection radius in 3 dimensions Environmental limitations e.g. temperature limits on sensors Operational requirements such as temperature, ingress protection, hazardous area classification, vibration, etc. This document is also applicable when an equipment manufacturer makes any claims regarding any special features of construction or superior performance that exceed the minimum requirements of this document. This document prescribes that all such claims are verified, and that the test procedures are extended or supplemented, where necessary, to verify the claimed performance. The additional tests are agreed between the manufacturer and test laboratory and identified and described in the test report. This document does not apply to Gas Detectors using non-ultrasonic measurements to detect a gas leak.