Describes velocity area methods for measuring flow in swirling or asymmetric flow conditions in circular ducts by means of current meters or Pitot static tubes. Specifies the measurements required, the precautions to be taken, the corrections to apply and describes the additional uncertainties which are introduced when a measurement in asymmetric or swirling flow has to be made. Although methods of using velocity area integration techniques to measure flow rate under conditions where there is swirl and/or asymmetry in the flow are described, every effort should nevertheless be made to choose a measuring section in the pipe where the swirl or asymmetry is as small as possible. Only flows with a negligible radial component are considered.

BS 1042-2(1964) : LATEST

BS ISO 7194 : 2008