1 grain of water vapor will pass through 1 square foot of the material when the moisture vapor pressure difference between the colder side and the warmer side of the material is equal to 1 inch of mercury 1 in.
Polyethelene plastic sheeting 01 perms.
Plastic sheets made into tarps are available on a custom basis.
A perm rating of 1 0 for any material is defined as follows.
The one exception to this statement is the labor intensive process of laminating multiple layers more than 6 in a plywood style stacking to get a lower perm rating.
A true 20 mil will weigh in at about 109 msf thats about 5 pounds of plastic per mil.
These membranes have a permeance level that equals between 0 1 perm and 1 perm.
10 mil plastic.
Astm e 1745 currently specifies the maximum permeance rating of a vapor retarder to be 0 1 perms and that it be measured by either e 96 or f 1249 standard test method for water vapor transmission rate through plastic film and sheeting using a modulated infrared sensor.
Asphalt coated kraft paper often attached to one side of fiberglass batts 0 40 us perm 22 si perm.
Construction sheeting poly america s construction sheeting is made from polyethylene which provides for optimum in economy and performance.
Perm is a quantitative value that measures the relative ease with which moisture water vapor will pass through a material.
The best way to identify a true thickness 20 mil vapor barrier is to look at the products weight.
8 mil plastic sheeting.
3 mil plastic sheeting 6 mil plastic sheeting.
1 0 perm or less and greater than 0 1 perm.
In the polyethylene film industry the weight is measured in pounds per 1000 square feet or msf.
For instance 1 mil to 6 mil construction grade polyethylene sheeting in the construction aisle is the lowest grade of polyethylene sheeting available on the market.
As such they are considered as semi impermeable products.
Some examples to consider here are polyethylene film glass sheet metal foil faced insulated sheathing and nonperforated aluminum foil.
Click on the links below to select the thickness for the plastic sheeting roll that will best serve your project or shop by thickness directly sold by the roll in most cases.
Polyethylene plastic sheet 4 or 6 thou 0 10 or 0 15 mm 0 03 us perm 1 7 si perm.
It is made from up to 25 post consumer recycled goods reground resins and the absolute least expensive resins that can be bought from any source in any location across the globe.
Advanced polyethylene vapor retarders that pass the astm e 1745 standard tests 0 3 us perm 17 si perm.
Class ii vapor retarder.