© Copyright CalCERTS, Inc. 2019
Code Cycle: 2016 & 2019 Standards
Reference: CalCERTS QII Handbook, Section 3
Tyvek has many products, some of which can be used as an air barrier meeting house wrap ASTM E2178. However, to qualify as an air barrier the individual material will need to meet the requirements of ASTM E2178, ASTM E283, ASTM E779 or an equivalent approved method. Doubling up a material does not mean a non-certified product now meets the air barrier requirements. Tyvek is not specifically listed, but they have house wrap products that meet the air barrier requirements. Take a look at the attachments for a list of approved air barrier materials. Also, see the link below for the CalCERTS QII Handbook.
Continuous Air Barrier
A combination of interconnected materials and assemblies joined and sealed together to provide a continuous barrier to air leakage through the building envelope. The air barrier separates conditioned from unconditioned space, or adjoining conditioned spaces of different occupancies or uses. An air barrier is required in all thermal envelope assemblies to limit air movement between unconditioned/outside spaces and conditioned/inside spaces and must meet some very technical test requirements.
If unsure of the materials, the completed building can be tested to demonstrate that the air leakage rate of the building envelope does not exceed 0.40 cfm/ft2 at a pressure differential of 0.3 in w.g. (1.57 psf) (2.0 L/s.m2 at 75 pa) in accordance with ASTM E779 or an equivalent approved method.
Note: This allows non-tested materials to be used as long as the house passes a blower door test with a special target of 0.40 cfm75 for every square foot of conditioned floor area. Example: a 2100 square foot home would have a target of 840 cfm at 75 Pa.
Individual materials and assemblies of materials that can demonstrate compliance with the air barrier testing requirements must be installed according to the manufacturer`s instructions and a HERS Rater shall verify the integrity of the installation.
Below are example materials meeting the air permeance testing performance levels above. Manufacturers of these and other product types must provide a specification or product data sheet showing compliance to the ASTM testing requirements to be considered as an air barrier.
- Fiberglass and cellulose insulation do not create an effective air barrier.
- Spray foam, when installed to the proper thickness can act as an effective air barrier.
- Rigid foam installed to the proper thickness and sealed per manufacturer’s recommendations can act as an effective air barrier.
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