© Copyright CalCERTS, Inc. 2019
Code Cycle: 2019 Standards Only!
Reference: 2019 CalCERTS New Construction Manual – Chapter 3
Form: Incorporated into CF3R-ENV-20
Impact: New HERS Test (Blower Door)
Notes: This test is an alternative to the new requirement of balanced IAQ ventilation in Multifamily dwelling units.
Target: 0.3 cfm50/sq. ft. of envelope surface area.
Section 150.0(o)1Eii states that a blower door test is required for multifamily attached dwelling units when a continuously operating supply only or exhaust only system is used. Balanced ventilation systems do not require a blower door test.
Multifamily attached dwelling units shall have mechanical ventilation airflow provided at rates in accordance with Equation 150.0-B [ASHRAE 62.2 section 4.1.1], and comply with one of the following subsections i or ii below. When subsection ii below is utilized for compliance, all dwelling units in the multifamily building shall use the same ventilation system type.
i. A balanced ventilation system shall provide the required dwelling-unit ventilation airflow,
ii. Continuously operating supply ventilation systems, or continuously operating exhaust ventilation systems shall be allowed to be used to provide the required dwelling unit ventilation airflow if the dwelling-unit envelope leakage is less than or equal to 0.3 cubic feet per minute at 50 Pa (0.2 inch water) per ft2 of dwelling unit envelope surface area as confirmed by field verification and diagnostic testing in accordance with the procedures specified in Reference Residential Appendix RA3.8.
Section 150.0(o)1cii2 states that for single family, the blower door test is only required when the IAQ calculation uses less than 2 ACH50.
If the dwelling unit envelope leakage is less than 2 ACH50 is confirmed by field verification and diagnostic testing, Q50 shall be calculated according to Equation 150.0-D below, using the value for dwelling unit envelope leakage less than 2 ACH50 verified by the procedures specified in Reference Residential Appendix RA3.8.
Q50 = Vdu x Verified ACH50 / 60 min (Equation 150.0-D)
Q50 = leakage rate at 50 Pa
Vdu = dwelling unit conditioned volume, ft3
ACH50 = air changes per hour at 50 Pa (0.2-inch water
If they install balanced IAQ ventilation:
- No blower door test is required.
- Balanced ventilation will be confirmed as part of the IAQ verification.
If they install exhaust or supply only IAQ ventilation:
- Must determine target CFM50 (enclosure surface area x 0.3) Be sure to measure all exterior wall, floor, and ceiling surface areas, as well as all adjoining dwelling unit walls.
- Measured CFM50 must be less than or equal to the target.
- Test IAQ ventilation as usual.