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Zone Pressure Diagnostics

Zone Pressure Diagnostics. WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY. WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010. Learning Objectives. Zone Pressure diagnostics. By attending this session, participants will:

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Zone Pressure Diagnostics

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  1. Zone Pressure Diagnostics WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – August 2010

  2. Learning Objectives Zone Pressure diagnostics By attending this session, participants will: • Gain an understanding of the powers and limitations of Zone Pressure Diagnostics (ZPD). • Learn when it is best to use zone pressure diagnostics. • Practice using ZPD charts.

  3. Necessary Equipment Zone Pressure diagnostics Photos courtesy of the US Department of Energy

  4. Determine relative leakiness. The higher the pressure the smaller the hole. Prioritize air sealing activities. Quickly determine which are the leakiest surfaces. Evaluate completed air sealing measures. Know if your crew does good work. Practical Applications Zone Pressure diagnostics

  5. Relative Leakiness Zone Pressure diagnostics 1850 CFM50 Pressure houseto attic = 37Pa Pressure attic toexterior must be 13Pa(50Pa – 37Pa = 13Pa) Q: What doesthis tell us? 50Pa 37Pa ? Pa

  6. Zone Pressures Relative Size of Leaks Ratio of Pressure to Leakage Zone Pressure diagnostics TO TO

  7. Probing Cavities Zone Pressure diagnostics Let’s put a probe into the cellar. What does25Pa mean? What if we stick a probe into the first floor ceiling cavity and read 41Pa? 50Pa 37Pa 25Pa 41Pa

  8. Changing Pressures Zone Pressure diagnostics If we open the cellar door to the house and put a probe into the attic we might find the attic 37Pa has dropped to25Pa. The pressure between the house and basement will now be zero. WHY? 50Pa 25Pa 0Pa

  9. Can We Size The Holes? Zone Pressure diagnostics Pressure is gradually reduced by each layer of wall or ceiling between inside and outside. Collecting CFM50 and pressure across each configuration lets us calculate hole size in each surface. 50Pa 25Pa 0Pa

  10. Here is what we know Zone Pressure diagnostics 1850 CFM50 2200 CFM50 50Pa 25Pa 50Pa 50Pa 25Pa 0Pa Basement door closed Basement door open

  11. Open A Door – Zone To Main Body Zone Pressure diagnostics 25Pa 1850 2200 350 350 2.76 966 97 sq” 350 2.76 966 97 sq” 616 CFM50 350 1.76

  12. What Do The Results Mean? Zone Pressure diagnostics H/Z 350 x 2.76 = 966 CFM50 = 96.6 sq” of hole in the floor Z/O 350 x 2.76 = 966 CFM50 = 96.6 sq” hole in basement walls T/P 350 x 1.76 = 616 CFM50 is attributable to the path 50Pa 50Pa

  13. Open A Door – Zone To Outside Zone Pressure diagnostics

  14. No Door on the Zone? Zone Pressure diagnostics At 1850 CFM50, house to attic pressure = 37Pa. Open attic hatch enough to create at least 6Pachange. Bring the blower door back to 50Pa. CFM50 is now 2500 House to attic pressure is now 20Pa. 50Pa 20Pa

  15. Flow Method: Hole – Zone To House #1 Zone Pressure diagnostics

  16. Flow Method: Hole – Zone To House #2 Zone Pressure diagnostics 1850 37Pa 2500 20Pa 650 1.36 884

  17. Flow Method: Hole – Zone To Outside Zone Pressure diagnostics

  18. What Did We Learn Overall? Zone Pressure diagnostics Of 1850 CFM50: Through attic: ≈ 900 Through basement ≈ 600 Walls (remainder) ≈ 350 50Pa

  19. Checking Air Sealing Zone Pressure diagnostics How about a garage? Any space that will accept a probe can be checked for pressure. ZPD requires being able to change the pressure over the surface to determine hole size. 48Pa 50Pa 2Pa

  20. Limitations Zone Pressure diagnostics • Not great for excessively leaky buildings. • ZPD requires being able to change the pressure over the tested surface to determine hole size. • Not great in windy conditions. • Time consuming.

  21. Practice!

  22. Open A Door – Zone To Main Body Zone Pressure diagnostics 40Pa 2050 2550 500 500 500 500

  23. Open A Door – Zone To Main Body Zone Pressure diagnostics 40Pa 2050 2550 500 0.63 500 31.5 sq” 315 500 1.54 77 sq” 770 500 270 CFM50 0.54

  24. Flow Method: Hole – Zone To House Zone Pressure diagnostics 1200 45Pa 1850 18Pa 650

  25. Flow Method: Hole – Zone To House Zone Pressure diagnostics 1200 45Pa 1850 18Pa 650 0.43 280

  26. Summary Zone Pressure diagnostics • ZPD can help you determine the relative leakiness of a home, prioritize air sealing activities, and evaluate completed air sealing measures. • ZPD requires a computer or charts to do the calculations. • The calculations can be time consuming, so use ZPD only when needed to prioritize or verify critical air sealing activities. • ZPD does not work well in extremely leaky homes or when it’s very windy. • ZPD requires being able to change the pressure over the tested surface to determine hole size.

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