In order to best control all the physical parameters necessary for good orifice metering accuracy,
it is standard practice for custody transfer flowmeter installations to use honed meter runs rather
than standard pipe and pipe fittings. A “honed run” is a complete piping assembly consisting of a
manufactured fitting to hold the orifice plate and sufficient straight lengths of pipe upstream and
downstream, the interior surfaces of that pipe machined (“honed”) to have a glass-smooth surface
with precise and symmetrical dimensions. Such piping “runs” are quite expensive, but necessary to
achieve flow measurement accuracy worthy of custody transfer