Difference between revisions of "Vapor permeability"
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== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| − | + | Dampfdurchlässigkeit (Deut.); perméabilité à la vapeur (Fr.); water vapor permeability | |
== Authority == | == Authority == | ||
| − | * | + | * Richard S. Lewis, ''Hawley's Condensed Chemical Dictionary'', Van Nostrand Reinhold, New York, 10th ed., 1993 |
| − | * | + | * Matt Roberts, Don Etherington, ''Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology'', U.S. Government Printing Office, Washington DC, 1982 |
* ''Van Nostrand's Scientific Encyclopedia'', Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976 | * ''Van Nostrand's Scientific Encyclopedia'', Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976 | ||
Revision as of 06:56, 24 July 2013
Description
The ability of a material to transmit a vapor or gas. Vapor permeability is measured using water vapor or solvent vapors. Variable partial pressures of the measured component are established on each side of the test material and changes are monitored over time. Vapor permeability is usually given in the units of grams per square meter per day (g/m2.d). This indicates the number of grams of vapor that will pass through a square meter of the test material in one day. The thickness of the test material must be specified. A typical test thickness is 1 mil (1 thousandths of an inch thick). Some vapor permeability measurements are given as cc/m2.d, but in the case of water vapor, one cubic centimeter (cc) is equal to one gram. Vapor permeability is a measure of the affinity of the vapor to the substance and thus the vapors ability to diffuse through the substance. This is different from air or oxygen permeability which is dependent on the porosity of a substance.
Synonyms and Related Terms
Dampfdurchlässigkeit (Deut.); perméabilité à la vapeur (Fr.); water vapor permeability
Authority
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976