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Desired Outcome:
Desired Outcome:
Establish an effective thermal and air barrier between CAZ and all other spaces of the building. This will prevent the combustion appliances from being affected by pressure changes in the condition space.
Establish an effective thermal and air barrier between CAZ and all other spaces of the building. This will prevent the combustion appliances from being affected by pressure changes in the condition space.
SWS Detail: 5.0501.1 Isolate CAZ
Author: Matt Turner
Before
Before
CAZ exposed to interior
After
After
CAZ isolated from building envelope
Steps
Steps
- Plan work
Follow work orders to isolate the CAZ.
Use standard stick framing practices to build partitions.
Minimum clearances to combustion appliance in the new space must be maintained (IRC M1306).
3. Complete air barrier
3. Complete air barrier
Use rigid materials and sealants to complete the air barrier on all sides, top and bottom of CAZ.
Finish surfaces only to establish an air barrier.
4. Outside combustion air
4. Outside combustion air
See Combustion Air-Exterior to install or repair properly sized combustion air openings.
5. Complete thermal barrier
5. Complete thermal barrier
Follow instructions in Insulation Sections to install or complete the thermal barrier on all walls ceilings and floors that are adjacent to the conditioned space.
6. Sealed insulated door
6. Sealed insulated door
A properly isolated CAZ will have an insulated door that is air-tight.
The opening must allow for minimum access to equipment located in the new CAZ (IRC M1305.1.1).
Follow instructions in Air Seal Doors and Windows, or Door Install to seal or replace CAZ door when door is on wall between CAZ and building envelope.
7. Seal duct work
7. Seal duct work
Follow instructions in Air Seal Duct section to seal all duct work inside CAZ both supply and return ducts.
8. Insulate all duct
8. Insulate all duct
Follow instructions in Duct Insulation section to ensure all duct inside the CAZ is insulated.
9. Insulate all water lines
9. Insulate all water lines
Follow instructions in DWH Pipe Insulation to insulate all waterlines inside the CAZ to prevent freezing.
10. Zonal pressure testing
10. Zonal pressure testing
Conduct a Zonal Pressure test to determine how isolated the CAZ is. Complete isolation is not required, but the goal is to separate the CAZ as much as possible.
As a best practice a ZPD of 45pa WRT house while house is decompressed to -50 is recommended.
11. Worst Case Draft test
11. Worst Case Draft test
Conduct a Worst Case Draft (WCD) test to verify Category I, II, and III appliances are venting safely before leaving home for the day.
Testing shall be recorded using the Utah WAP Worst Case Draft Test form.
12. Client education
12. Client education
Educate the client on purpose and operation of Isolated CAZ.
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