BES Ltd Gas Meter Union – BS 746 Thread Conversion Chart

BS 746 is the specification that applies specifically to Gas Meter Installations. The size name refers to the internal bore size of the meter unions and the ECV (main gas cock), not the thread diameter. To ensure you order the correct fittings, please measure the thread diameter of the male thread on your meter or ECV in millimetres, and then use the chart below to identify the BS 746 size.