For total leakage:
(a) Verify that supply and return plenums and all the collars, connectors, transition pieces, duct boots, and return boxes have been installed. If a platform or other building cavity is used to house portions of the air distribution system, it shall contain a duct, be lined with duct board or sheet metal, and all duct connectors and transition parts shall be installed and sealed. The platform, ducts and connectors shall be included in the total leakage test. All joints shall be inspected to ensure that no cloth backed rubber adhesive duct tape is used.
(b) Supply and return leaks may be tested separately, or the supply and return plenums may be connected together using suitable temporary air-tight means to facilitate testing the total system. If the supply and return systems are to be tested separately, the opening to the supply or return plenums shall be sealed to prevent leakage unless used as the point of attachment for the fan flowmeter.
(c) Seal all the supply duct boots and/or return duct boxes except for a location where the fan flowmeter device will be attached.
(d) Attach the fan flowmeter device at the unsealed location..
(e) Insert a static pressure probe at one of the sealed supply duct boots, or return duct boxes, located at a point in the system close to the fan flowmeter.
(f) Adjust the fan flowmeter to produce a positive 25 Pa (0.1 inches water) pressure at the supply plenum with respect to the outside or with respect to the building space with the entry door open to the outside.
(g) Record the airflow through the flowmeter; this is the leakage flow at 25 Pa (0.1 inches water).
(h) If the supply and return ducts are tested separately, repeat items 4 through 6 with the flow meter attached to the unsealed return box and the static pressure probe in the return duct boxes, located at a point in the system close to the fan flowmeter, then add the two leakage rates together to get a total leakage flow.
(i) Divide the leakage flow by the total air handler airflow determined by the procedure in Section RA3.1.4.2 and convert to a percentage. If the leakage flow percentage is less than or equal to the compliance criterion from Table RA3.1-2 the system passes.
After installing the interior finishing wall and verifying that one of the above rough-in tests was completed, the following procedure shall be used:
(a) Remove at least one supply and one return register, and verify that the spaces between the register boot and the interior finishing wall are properly sealed.
(b) 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.
(c) Inspect all joints to ensure that no cloth backed rubber adhesive duct tape is used.
The objective of this test is to determine the amount of duct leakage to outside the air barrier for the conditioned space. This measurement is utilized to verify that duct systems are located entirely within conditioned space. The procedure is also utilized to provide an alternate leakage measurement for situations when it is likely that a portion of the total duct leakage is inside the air barrier for 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 (0.1 inches water) with respect to outside. The following procedure shall be used for the fan pressurization test of leakage to outside:
(a) Seal all the supply registers and return grilles except for one large centrally located return grille or the air handler cabinet access panel.
(b) Attach the fan flowmeter device to the duct system at the unsealed return grille or the air handler cabinet access panel.
(c) Install a static pressure probe at the supply plenum.
(d) Attach a blower door to an external doorway.
(e) 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.
(f) 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.
(g) Adjust the blower door fan to provide positive 25 Pa (0.1 inches of water) pressure in the conditioned space with respect to outside.
(h) Adjust the fan/flowmeter to maintain a zero pressure difference (plus or minus 0.5Pa (.002 inches water)) between the ducts and the conditioned space, and adjust the blower door fan to maintain a positive 25 Pa (0.1 inches of water) pressure in the conditioned space with respect to outside. This step may require several iterations.
(i) Record the flow through the flowmeter; this is the duct leakage flow to outside at 25 Pa (0.1 inches water). If the leakage flow is less than or equal to the applicable compliance criteria in Table RA3.1-2, the system passes.
(j) If required for compliance, divide the leakage flow by the system air handler airflow determined by the procedure in Section RA3.1.4.2, and convert to a percentage. If the leakage flow percentage is less than or equal to the criterion from Table 3.1-2 the system passes.
For altered existing duct systems that are unable to pass either the Fan Pressurization of Ducts test (RA3.1.4.3.1), or the Duct Leakage to Outside test (RA3.1.4.3.4), the objective of this test is to verify that all accessible leaks are sealed. The following procedure shall be used:
(a) Complete the leakage test specified in Section RA3.1.4.3.1 to measure the leakage before commencing duct sealing.
(b) Seal all accessible ducts.
(c) After sealing is complete, again use the procedure in RA3.1.4.3.1 to measure the leakage after duct sealing.
(d) Complete the Smoke Test as specified in RA3.1.4.3.6.
(e) Complete the Visual Inspection as specified in RA3.1.4.3.7.
For altered existing ducts that fail the leakage tests, the objective of the smoke test is to confirm that all accessible leaks have been sealed. The following procedure shall be used:
(a) Inject either theatrical or other non-toxic smoke into a fan pressurization device that is maintaining a duct pressure difference of 25 Pa (0.1 inches water) relative to the duct surroundings, with all grilles and registers in the duct system sealed.
(b) Visually inspect all accessible portions of the duct system during smoke injection.
(c) The system shall pass the test if one of the following conditions is met:
1. No visible smoke exits the accessible portions of the duct system.
2. Smoke only emanates from the furnace cabinet which is gasketed and sealed by the manufacturer and no visible smoke exits from the accessible portions of the duct system.
For altered existing ducts that fail the leakage tests, the objective of this inspection in conjunction with the smoke test (RA3.1.4.3.6) is to confirm that all accessible leaks have been sealed. Visually inspect to verify that the following locations have been sealed:
(a) Connections to plenums and other connections to the forced air unit
(b) Refrigerant line and other penetrations into the forced air unit
(c) Air handler door panel (do not use permanent sealing material, metal tape is acceptable)
(d) Register boots sealed to surrounding material
(e) Connections between lengths of duct, as well as connections to takeoffs, wyes, tees, and splitter boxes.
When ducts are located in conditioned space, additional performance compliance credit is available for low leakage ducts. If duct leakage to outside is equal to or less than 25 cfm when measured in accordance with Section RA3.1.4.3.4, the system passes. The dwelling must also be qualified to receive the credit for verified ducts in conditioned space as verified by visual inspection according to Section RA3.1.4.1.3.
When the Standards specify use of the procedures in Section RA3.1.4.3.8 to determine if space conditioning system ducts are located entirely in directly conditioned space, the duct system location shall be verified by diagnostic testing according to the following criterion: If duct leakage to outside is equal to or less than 25 cfm when measured in accordance with Section RA3.1.4.3.4, the system ducts shall be considered to be located entirely in directly conditioned space. Duct systems that do not meet this criterion shall not be considered to be located entirely in directly conditioned space.
An additional performance compliance credit is available for verified low leakage ducts if a qualified low leakage air-handling unit is installed. The low leakage air-handling unit cabinet (furnace, or heat pump fan and inside coil) shall conform to the qualification requirements given in Reference Joint Appendix JA9, and shall be included in the list of low leakage air handling units published by the Energy Commission. The qualified air handler must be connected to a sealed and tested new duct system to receive the credit.
In order to comply with this credit, the duct system shall be verified to leak less than or equal to the leakage rate specified on the Certificate of Compliance using the methods in Section RA3.1.4.3.1, and the air handler manufacturer make and model number shall be verified to be a model certified to the Energy Commission as qualified for credit as a low leakage air handler.
RA3.1.4.4 Verification of Return Duct Design
Verification shall consist of a visual inspection to confirm that the duct design conforms to the criteria given in Table 150.0-C or Table 150.0-D.
RA3.1.4.5 Verification of Air Filter Device Design
Verification shall consist of a visual inspection to confirm that the air filter devices conform to the requirements given in Section 150.0(m)12.
RA3.1.4.6 Verification of Prescriptive Bypass Duct Requirements for Zonally Controlled Forced Air Systems
When a zonally controlled forced air system is installed, the following shall be verified to determine compliance as required by Standards Section 150.1(c)13:
(a) A visual inspection shall confirm that bypass ducts that deliver conditioned supply air directly to the space conditioning system return duct airflow are not used; or
(b) If the Certificate of Compliance indicates an allowance for use of a bypass duct, the system with the bypass duct shall conform to the specifications given on the Certificate of Compliance.
If the zonally controlled system meets one of these criteria, the system complies. Otherwise the system does not comply