What is permeability?
–dictionary.com Permeability is… “The property or state of being permeable.” (Thanks dictionary.com) You’ve probably heard of a perm — permeability is weather or not hair can be permed, or, permanently changed. Although hair can not actually be changed ‘permanently’ (the effects will wear off eventually and isn’t visibly permanent.
Permeability, rated in ng, is a measure of the transference of grains of water through a material at a standard vapor pressure and temperature. The Canadian National Building Code gives a Code Approved Vapour Barrier rating to materials with a permeability rating of less than 60 ng while the Alberta Building Code requires a permeability less than 45 ng. Enviro Foam meets the requirements of the Alberta Building Code as a Vapour Barrier.
Imagine a sponge. Some sponges have big holes, some are more tightly structured, each absorbs liquid to a point of saturation. Magnetic shielding material is similar. Depending upon its structure, magnetic shielding material absorbs magnetic interference to a point of saturation. As magnetic interference increases, so too should the permeability of the material.
