WebThe test method for determining the water vapor permeance of any building material is ASTM E96. This test measures diffusion using two possible means — the dry cup method, also known as Method A or the desiccant method, and the wet cup method, also referred to as Method B or the water method. WebFeb 18, 2024 · Boston Building Emissions Performance Standard

Building Materials Property Table - Energy

WebAir barrier materials (ie. self-adhered sheet air barriers, liquid applied membranes, medium density sprayed polyurethane foam, mechanically fastened commercial building wraps and boardstock air barriers) are defined by their air permeance … WebSep 25, 2024 · An array of materials can be used as a WRB, but they are all not equal. When evaluating the potential effectiveness of a WRB, durability and the balance of holdout and permeability are critical factors. Plastic building wraps Plastic, nonwoven building wraps have been the most popular WRB for the last 40 years. editing asp files

Protecting the Building Envelope from Water Damage

WebThis is permeability—the relationship between permeance (number of holes) and the material’s thickness. A general rule of thumb: As the thickness doubles, the permeability is cut in half. So, a 2-in.-thick cardboard box would allow half as many balls to make it all the way out of the holes, as compared to a 1-in.-thick cardboard box. WebFeb 1, 2013 · Permeance is measured in units of perms and is used to describe thinner materials (e.g., jacketing products) that are used in the field in the exact thickness at which the material is tested. A similar … WebClass I covers materials most frequently referred to as vapor barriers. These vapor retarders have a permeance level of 0.1 perm or less and are considered impermeable. Examples include polyethylene film, glass, … editing as punctuation in film