Talk:Barrer

SI version
I removed the "SI value" given (1 Barrer = 7.5005×10-18 m2 / s Pa) because it's not true SI for what it represents. Permeability is quantified as the amount of matter flowing through a given area of material with a given thickness over a given period of time under a given pressure/partial pressure differential, so SI units should be moles*m^-2*m*s^-1*Pa^-1, i.e. moles*(m*s*Pa)^-1.

The original version uses units of volume (cm^3) to describe what's really a molar quantity, and it looks as if the editor who supplied the 'SI' version simply translated these to m^3, but a proper SI version should use moles (or, if using volume, incorporate pressure, temperature, and the universal gas constant). --144.53.251.2 (talk) 23:49, 16 June 2008 (UTC)

SI conversion
In my opinion, 1 barrer in SI units is 1E-10/(8314.472 * 273.15 / 100000)*76/101325/10000 = 3.30264E-19 kmol /m /s /Pa. This is using the current IUPAC definition of STP (1e5 Pa, 273.15 K). You get just about 3.348E-19 with the alternative computation: 1E-10/(8314.472 * 273.15 / 100000)*76/100000/10000 which is incorrect because it transforms cmHg in Pa using 100000/76 rather than 101325/76. In some references you find the alternative conversion to 1E-10*76/101325/10000 = 7.50062E-18 m3STP/m/s/Pa. I agree that you should not simplify m3STP and m since the former is a (practical but confusing) unit of molar amount. Baolog (talk) 22:36, 13 January 2011 (UTC)

Useful changes
Is the higher the the result, the more moles can pass into or through the material at the conditions given? More straightforward and empirical information in addition to the theory would be helpful to students and people outside this field. — Preceding unsigned comment added by 50.37.104.204 (talk) 23:21, 6 April 2017 (UTC)

Pronounciation
How is "Barrer" pronounced? 173.184.135.28 (talk) 01:31, 28 June 2021 (UTC)

An amusing explanation
For an amusing explanation of how the barrer is derived, see the You Tube video "Cursed Units 2: Curseder Units" by Joseph Newton: https://www.youtube.com/watch?v=Zg7xe8MkJHs 2A00:23C8:728A:2501:A4C9:2A71:C989:6CE6 (talk) 23:34, 17 June 2024 (UTC)