INTRODUCTION This Data Item presents information on the pressure drop in ducts across round-wire gauzes (or screens) normal to a fluid flow. The pressure drop is dependent upon the gauze geometry@ and the velocity@ density@ Reynolds number and Mach number of the flow. The data are presented in the form of non-dimensional pressure drop coefficients and apply to the flow of liquids and gases. For liquids@ the effect of compressibility (or Mach number) can be ignored.