Barrer or Barrer
Barrer or Barrer :
ACGS unit of gas permeability for membranes, contact lenses, and similar thin materials. Permeability is defined to be the gas flow rate multiplied by the thickness of the material, divided by the area and by the pressure difference across the material. To measure this quantity, the barrer is the permeability represented by a flow rate of 10-10 cubic centimeters per second (volume at standard temperature and pressure, 0oC and 1 atmosphere), times 1 centimeter of thickness, per square centimeter of area and centimeter of mercury difference in pressure. That is, 1 barrer = 10-10cm2 s-1 cmHg-1, or, in SI units, 7.5005 x 10-18 m2 s-1 Pa-1. The unit, often capitalized, honors the New Zealand chemist Richard M. Barrer (1910-1996), who was a leader in research on the diffusion of gases
