NIST developed a cryogenic flow loop; it is the only internationally-recognized facility for calibrating flow meters operating with liquid nitrogen. (After calibration, the meters are often used to measure flows of liquefied natural gas.) The loop operates with mass flows of 0.95 kg/s to 9.5 kg/s (corresponding to volume flows of 1.26 L/s to 12.6 L/s) and it achieves a mass flow calibration uncertainty of 0.17 % at a 95 % confidence level. Customer calibrations and research activities are now conducted at CEESI’s site in Nunn Colorado under a Cooperative Research and Development Agreement. The objectives of the research are to reduce the cost and the necessity of cryogenic flow calibrations for metering liquefied natural gas.