Specifications

2008 Residential Appendices RA3-7
Appendix RA3 – Residential Field Verification and Diagnostic Test Protocols
2. If the house rough-in duct leakage test was conducted without an air handler installed, inspect the
connection points between the air handler and the supply and return plenums to verify that the connection
points are properly sealed.
3. Inspect all joints to ensure that no cloth backed rubber adhesive duct tape is used.
RA3.1.4.3.4 Duc
t Leakage to Outside from Fan Pressurization of Ducts
The objective of this test is to determine the duct leakage to outside. This measurement is used to verify that
duct systems are entirely located within conditioned space. The procedure is also used to provide an alternate
leakage measurement where it is likely that some of the total duct leakage is to within the conditioned space.
The duct leakage to outside shall be determined by pressurizing the ducts and the conditioned space of the
house to 25 Pa with respect to outside. The following procedure shall be used for the fan pressurization test of
leakage to outside:
1. Seal all the supply and return registers except one return register or the fan access door.
2. Attach the fan flowmeter device to the duct system at the unsealed register or access door.
3. Install a static pressure probe at the supply plenum.
4. Attach a blower door to an external doorway.
5. If any ducts are located in an unconditioned basement, all doors or accesses between the conditioned
space and the basement shall be closed, and at least one operable door or window (if it exists) between
the basement and outside shall be open during the test.
6. If the ducts are located in a conditioned basement, any door between the basement and the remaining
conditioned space shall be open, and any basement doors or windows to outside must be closed during
the test.
7. Adjust the blower door fan to provide plus 25 Pa (0.1 inches of water) pressure in the conditioned space
with respect to outside.
8. Adjust the fan/flowmeter to maintain zero pressure (plus or minus 0.5Pa) between the ducts and the
conditioned space, and adjust the blower door fan to maintain plus 25 Pa (0.1 inches of water) pressure in
the conditioned space with respect to outside. This step may require several iterations.
9. Record the flow through the flowmeter (Q
25
; this is the duct leakage at 25 Pa. To verify ducts in conditioned
space compare this flow to the criterion
10. Where the criterion is a percentage of total flow, divide the leakage flow by the total fan flow determined by
the procedure in Section RA3.1.4.2 and convert to a percentage. If the leakage flow percentage is less
than the criteria from Table RA3.1-2 the system passes.
RA3.1.4.3.5 Leaka
ge Reduction from Fan Pressurization of Ducts
For altered existing duct systems that do not pass the Total Leakage (RA3.1.4.3.1) or Leakage to Outside
(RA3.1.4.3.4) tests, the objective of this test is to show that the original leakage is reduced through duct sealing
as specified in Table RA3.1-2. The following procedure shall be used:
1.
Use the procedure in RA3.1.4.3.1 to measure the leakage before commencing duct sealing.
2. After sealing is complete use the same procedure to measure the leakage after duct sealing.
3. Subtract the sealed leakage from the original leakage and divide the remainder by the original leakage. If
the leakage reduction is 60 percent or greater of the original leakage, the system passes.
4. Complete the Smoke Test specified in RA3.1.4.3.7.
5. Complete the Visual Inspection specified in RA3.1.4.3.8.
RA3.1.4.3.6 Sealing of Al
l Accessible Leaks