EN ISO 5167-2:2003

Foreword
Introduction
1 Scope
2 Normative references
3 Terms, definitions and symbols
4 Principles of the method of measurement and computation
5 Orifice plates
   5.1 Description
   5.2 Pressure tappings
   5.3 Coefficients and corresponding uncertainties of
        orifice plates
   5.4 Pressure loss, delta[omega]
6 Installation requirements
   6.1 General
   6.2 Minimum upstream and downstream straight lengths
        for installation between various fittings and the
        orifice plate
   6.3 Flow conditioners
   6.4 Circularity and cylindricality of the pipe
   6.5 Location of orifice plate and carrier rings
   6.6 Method of fixing and gaskets
Annex A (informative) Tables of discharge coefficients
         and expansibility [expansion] factors
Annex B (informative) Flow conditioners
Bibliography

ISO 5167-2:2003 specifies the geometry and method of use (installation and operating conditions) of orifice plates when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit.It also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1.ISO 5167-2:2003 is applicable to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with D and D/2 pressure tappings. Other pressure tappings such as vena contracta and pipe tappings have been used with orifice plates but are not covered by ISO 5167-2:2003. ISO 5167-2:2003 is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow. It does not cover the use of orifice plates in pipe sizes less than 50 mm or more than 1 000 mm, or for pipe Reynolds numbers below 5 000.