Talk:Permeation

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Units in Simple Approximation[edit]

Is there any reason why the units are described as being 'American' rather than 'Imperial' or 'European' rather than SI? —Preceding unsigned comment added by ClimberTom (talk • contribs) 16:36, 5 May 2010 (UTC)[reply]

Units of Measurement[edit]

I think this article should explain the measurement of permeation rate in mol･m/m2･s･Pa, as used in various ANSI standards. --Westwind273 (talk) 00:10, 23 March 2012 (UTC)[reply]

There are two distinct definitions of permeability relating to gas transport. Permeability through porous solids by fluid flow, as governed by Darcy's law, is measured in m^2. Permeability through diffusion of gas in solids, as governed by Fick's law, is measured in SI units of mol･m/m2･s･Pa or mol･/m･s･Pa (cancelling the meter term). This article incorrectly links to intrinsic permeability as defined by Darcy's law. The units of m^2 for permeability are for Darcy's law and are incorrect. The book Whittington's Dictionary of Plastics, Third Edition By James F. Carley (https://books.google.ie/books?id=791DhiI-D88C&pg=PA353&lpg=PA353&dq=darcy+mol+m+s+pa&source=bl&ots=tybSucKvuF&sig=I_P1p4OT03qtsCXSqbpAMckw7hI&hl=en&sa=X&ved=0ahUKEwizs4TTwrPJAhVDJQ8KHQ7bBLIQ6AEIIDAA#v=onepage&q&f=false) defines the difference between the two. Mike f 109.76.45.4 (talk) 18:11, 28 November 2015 (UTC)[reply]