1.1This test method describes measurement of the average velocity of a gas stream for the purpose of determining gas flow in a stack, duct, or flue. Although technically complex, it is generally considered the most accurate and often the only practical test method for taking velocity measurements.
1.2This test method is suitable for measuring gas velocities above 3 m/s (10 ft/s).
1.3This test method provides procedures for determining stack gas composition and moisture content.
1.4The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are for information only.
1.5This test method is applicable to conditions where steady-state flow occurs, and for constant fluid conditions, where the direction of flow is normal to the face tube opening of the pitot tube employed in the method. The method cannot be used for direct measurement when cyclonic or swirling flow conditions are present.
1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.