Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Gas Flowmeter Calibrations With the Working Gas Flow Standard



John D. Wright, Jean-Phillipe Kayl, Aaron N. Johnson, Gina M. Kline


The Working Gas Flow Standard (WGFS) uses critical venturis, critical nozzles, or laminar flowmeters as working standards to calibrate customer flowmeters. The working standards are periodically calibrated with primary standards: the 34 L, 677 L, or 26 m3 PVTt standards, or a static gravimetric standard. The WGFS is used to calibrate flowmeters with low pressure drop, in dry air, at flows from 0.001 L/min to 70000 L/min with uncertainty of 0.15 % or less. At flows less than 2000 L/min, calibrations in other non-hazardous and non-corrosive gases are available.In this document, we provide an overview of the gas flow calibration service and the procedures for customers to submit their flowmeters to NIST for calibration. We also document the flow calculation algorithms and uncertainties of the WGFS.
Special Publication (NIST SP) - 250-80
Report Number


calibration, critical nozzle, critical ventrui, flow, flowmeter, gas flow standard, laminar, uncertainty, working standard


Wright, J. , Kayl, J. , Johnson, A. and Kline, G. (2009), Gas Flowmeter Calibrations With the Working Gas Flow Standard, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 21, 2024)
Created November 23, 2009, Updated November 10, 2018