commonly used compressibility calculation is American Gas Association Report No. 8, detail characterization. Thread sizing standards Residential, commercial and industrial gas meters have their own standard thread sizes. The gas meter is connected to customer piping through a swivel and nut, which has a dedicated set of thread sizes. These thread sizes were originally named for the amount of gas designed to flow through them in terms of gas lamps, for example a 30-Lt. meter can provide enough gas for 30 lights and was referred to in the late 19th century as a 30-light-gas-meter. These sizes are typically 10Lt, 20Lt, 30Lt, 45Lt, or 60Lt, though smaller and larger sizes are available. The thread sizes are slightly, about , larger than the nearest size NPT size, in order to accommodate the appropriate inner diameter within the swivel. See also Automatic Meter Reading Flow conditioning#Effects on flow measurement devices Electricity meter Flow measurement Gas flow computer Gas meter prover Meter-Bus Julius Pintsch Smart meter Thermal mass flow meter Turnaround document (way of collecting data from) Utility submeter Water meter References Flow meters Gas technologies Natural gas safety Public services