Getting in the Zone with Zonal Pressure Diagnostics

Transcription

1 Getting in the Zone with Zonal Pressure Diagnostics NYSCAA/NYSWDA Lake Placid June 2, 2017 Presented by: Al McMahon New York State Weatherization Directors Association

2 On many projects, air sealing is one of the most important measures that we provide! It can also: Be difficult to explain to customers Be confusing to implement Be challenging to value Create conflicts with air quality concerns

3 ZONAL PRESSURE DIAGNOSTICS What is it? (Background, and Where does ZPD fit in the whole process?) Who should do it and when? (Auditor? Crew?) How does this help me?

4 HOUSE AS A SYSTEM HOUSE AS A STRUCTURE

5 System of Systems Air, Water, Heat, Electricity, Waste All in a Shell. Each with a System, interacting with each other, creating a Larger Holistic System.

6 Structure of Structures 6

7 Background Heat Transfer Three ways heat transfers NYSWDA

8 Radiation The transfer of heat from a solid to a fluid or gas. Heat travels from hot to cold. NYSWDA

9 Radiant Barriers 9

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11 Infrared Imaging

12 Weatherization Jobs address the movement of 3 Things!!!! Moisture (Water & Vapor) Heat Air

13 Four Boundaries Defined Water Control Boundary Vapor Control Boundary Thermal Control Boundary Pressure Control Boundary

14 Water Boundary First defense against water intrusion Follows the laws of gravity to direct water away from the structure.

15 Sources of Water Intrusion Roof Leak Window Leaks Poor Grading Foundation Leaks Gutters and Downspouts Failed Sump Pump

16 Vapor Boundary Vapor retarders slow permeability of water vapor They also slow the uncontrolled movement of air which can contain water vapor Vapor retarders can help control moisture in: Basements Ceilings Crawlspaces Floors Slab-on-grade foundations Walls

17 Four Boundaries Defined Water Control Boundary Vapor Control Boundary Thermal Control Boundary Pressure Control Boundary

18 Conduction Heat transfers through a material from the hot side to the cold side DHCR NYSWDA

19 Thermal Boundary Limits heat flow between inside and outside Easy to identify by presence of insulation Missing insulation can have a big impact.

20 Insulation What kind of Insulation exists and how much? The most common insulations encountered are: Fiberglass Batts Blown in Fiberglass Blown in or dense packed cellulose Vermiculite Polyurethane Foam and Rigid Board Air! 20

21 Thermal Boundary and IR camera It will detect thermal patterns It is passive investigation It will show warmer and colder areas

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23 Four Boundaries Defined Water Control Boundary Vapor Control Boundary Thermal Control Boundary Pressure Control Boundary

24 Pressure Boundary Limits air flow between inside and outside.

25 Convection Heat transfer in a fluid or gas. Heat travels from hot to cold. DHCR NYSWDA

26 Defining a Pressure Boundary

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33 Crawl Space

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36 PRESSURE & THERMAL BOUNDARIES Thermal & Air Barriers An uninsulated attic hatch is a gap in the attic s thermal barrier Air Barrier Thermal Barrier 36

37 PRESSURE & THERMAL BOUNDARIES A mechanical chase containing ducts can break the attic s air barrier Air Barrier Thermal Barrier 37

38 PRESSURE & THERMAL BOUNDARIES Moisture Moisture flows with warm air through breaks in the air barrier, causing damage when it condenses on cool surfaces. Air Barrier Thermal Barrier 38

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40 The Bypass (and penetrations)

41 Air Leakage Air Leakage requires: A hole. Pressure difference across that hole. o The bigger the hole or higher the pressure difference, the more airflow. o To reduce airflow, we can reduce the size of the hole or lower the pressure difference. Graphic developed for the US DOE WAP Standardized Curricula

42 Calculated Air Flow p A 1.07 = CFM p = pressure A = area sq. in = 749

43 BUILDING SCIENCE BASICS Direct Leakage occurs at direct openings to the outdoors. Leakage enters or exits the building envelope directly at this location. Indirect Leakage Leakage enters at one location, moves through building cavities, and exits at a different location. Graphic developed for the US DOE WAP Standardized Curricula

44 Hidden Construction Details

45 Dropped Soffits Dropped soffit in kitchen is open to the second-story floor system. Photo courtesy of PA WTC

46 How do we test the location of the Air Barrier?

47 Blower Door

48 Blower door assisted smoke testing

49 Infrared Scanning Infrared combined with a blower door is greater than the sum of it parts. May 25, 2016 NYS Weatherization Directors Association 49

50 ZONAL PRESSURE DIAGNOSTICS (Finally!) Approximately

51 Zonal Pressure Diagnostics Location and effectiveness of the air barrier. Alignment of air barrier and thermal boundary. Approximate amount of square inches of gaps Approximate CFM Saved Photo courtesy of PA Weatherization Training Center (WTC)

52 ZONE PRESSURE DIAGNOSTICS Necessary Equipment Close door and put hand over the opening Photos courtesy of the US Department of Energy

53 Zone Pressure Diagnostics ΔP = -50 Pa Blower Door

54 Close door take reading Double to get % Open to cut in half Zonal Pressure Diagnostics 25Pa 0 50Pa

55 42 Pa. Pressure Pan -50 Pa. 56

56 Zone Pressure Diagnostics Pressure Pan Wall Outlet Thermostat Plug Ducts

57 Basic Zones Conditioned area to conditioned area Conditioned area to unintentionally conditioned area Conditioned area to unconditioned area Conditioned area to outside

58 1850 CFM50 50Pa 37Pa Relative Leakiness Pressure house to attic = 37Pa Pressure attic to exterior must be 13Pa(50Pa 37Pa = 13Pa)

59 Ratio of Pressure to Leakage Zone Pressures Zone-House Zone-Out Relative Size of Leaks Zone-House Zone-Out TO

60 ZONE PRESSURE DIAGNOSTICS 2500 CFM50 Can We Size The Holes? 50Pa 0Pa At 1850 CFM50, house to attic pressure = 37Pa. Bring the blower door back to 50Pa. CFM50 is now 2500 House to attic pressure is now 0Pa.

61 37Pa sq sq CFM50

62 1850 CFM CFM50 50Pa 40Pa 50Pa 0Pa 10Pa Basement door closed 50Pa Basement door open

63 40Pa sq sq CFM50

64 37Pa sq sq CFM50

65 Blower Door and Zonal Number s Series Leakage Calculation (Can t get to Zero) Pre Blower Door:

66 A Case Study House Initial test -50 Pa CFM50

67 Initial test -32 Pa. -50 Pa CFM50

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69 Pa. -50 Pa CFM50

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72 X =

73 Initial test -32 Pa CFM path -50 Pa CFM50

74 Initial test -50 Pa CFM50-25 Pa.

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76 Initial test -50 Pa CFM50-25 Pa.

77 Initial test -50 Pa CFM Pa.

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80 X =

81 Initial test -32 Pa CFM path -50 Pa CFM 2478 CFM 6090 CFM 5200 CFM -25 Pa CFM path

82 1850 CFM50 37Pa Let s put a probe into the cellar to test but lets run another hose to the attic. 50Pa 25Pa

83 ZONE PRESSURE DIAGNOSTICS 2600 CFM50 28Pa 50Pa 0Pa If we open the cellar door to the house the pressure to the basement drops to 0Pa and we put a probe into the attic find the attics 37Pa has dropped to 28Pa. We know there is a connection. We can do this with one manometer!!

84 Image developed for the US DOE WAP National Standardized Curriculum

85 When do you stop Air Sealing?

86 DCalcFree/Tools/ZonePressureDiagnostics.aspx

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91 Who should use Zonal Pressure Diagnostics and when? What are the first steps to make it real and useful to you? You can use a similar process on forced air systems to balance the house at the end of a job.

92 ZONE PRESSURE DIAGNOSTICS Limitations Not great for excessively leaky buildings. ZPD requires being able to change the pressure over the tested surface to determine hole size. Should be used only at certain times. Not great in windy conditions. Time consuming... In the beginning.

93 Balancing Progress and Process Progress Process Process Progress

94 ZONE PRESSURE DIAGNOSTICS Summary 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 but there are simpler useful methods too. The calculations can be time consuming, so use ZPD only calculate when you need to prioritize or verify critical air sealing activities. ZPD requires being able to change the pressure over the tested surface to determine hole size.

95 Have all of your questions been answered? 96

96 Al McMahon x231 Dale Sherman x230 New York State Weatherization Director s Association 97