Advanced Blower Door Techniques. North Carolina Energy Star Conference Friday November 16, 2007

Transcription

1 Advanced Blower Door Techniques North Carolina Energy Star Conference Friday November 16,

2 Is that unconditioned attic connected to the conditioned basement? Is that nasty crawl space inside or outside the house? Is that air blasting through the register a leak to the outside or a disconnected duct in the basement? Learn how to perform the pressure measurements, and more importantly, how to interpret them and understand the implications for air sealing or indoor air quality. 2

3 Objectives Learn to use your blower door more effectively and to improve your air sealing work Find out how to use pressure diagnostics to locate thermal bypasses and building connections Discover multiple ways of determining air sealing potential, from using basic charts to using computer software and handheld calculators 3

4 Use Your Blower Door to do more Where the air barrier (PRESSURE BOUNDARY) is so we can determine where to air seal If the Pressure Boundary and insulation (THERMAL BOUNDARY) line up Are zones with poor air quality such as Garages connected to the indoors Is warm moist air getting into the cold Attic 4

5 Zone Testing Pressure Diagnostics = Zone Testing What are Zones? Spaces that might be better connected to Inside or Outside 5

6 ZONE TYPES can you tell what determines type? Primary Zones Attic Basement Garage Crawlspace Attached Porch Secondary Zones Cantilevers Floor Cavity b/w Floors Soffits Porch Ceiling Interior Wall 6

7 Primary Zones Zone Types Are zones that have an opening in one of the surfaces House to Zone or Zone to Outside This is an advantage for testing Secondary Zones Do not have an access in either surface Only Direct Pressure measurements can be taken 7

8 Levels of Zone Testing Level 1 Direct Pressure Measurement (Review) Level 2 Charts and Graphs (Walk away able to do this ) Level 3 ZPD Calculators (Will do some examples) 8

9 Level 1 Pressure Only Is the zone more indoors or more outdoors? Do Pressure and Thermal Boundaries line up? 9

10 The Pressure Boundary and Thermal Boundary must be together and continuous. 10

11 If the boundaries are misaligned or If there are holes,voids or gaps this will make the building difficult to heat and cool. 11

12 Outside Zones and Inside Zones Measured with Reference to House We want Zones Outside the House (Unheated Areas) to be closer to 50 We want Zones Inside the House (Heated Areas) be closer to 0 12

13 Examples of Outside & Inside Zones Attics Outside Zones (Unheated) Garage Porches Crawlspace Basement Inside Zones (Heated) Interior Walls Floors Between Stories Crawlspace Basement 13

14 WRT With Reference To Zone WRT House = 40PA Zone WRT Outside = PA Zone WRT House = 15PA Zone WRT Outside = PA Zone WRT House = 25PA Zone WRT Outside PA 14

15 Let s Do Some Level 1! 15

16 Kneewall Attic Unsealed/Uninsulated 16

17 Interconnection Depressurize house to 50 Pa Measure pressure to one zone Open a door to the other zone, readjust blower door to read 50 again If the zones are connected, the pressure in the first zone will change, If not, it won t 17

18 Pressures and Leakage Attic Zonal Reading of 25pa Means hole between Attic and House is Same size as Hole Between Attic and Outdoors 18

19 Pressures and Leakage Attic Zonal Reading of 48pa Means hole between Attic and House is 1/8 th size of Hole Between Attic and Outdoors 19

20 Ratios of Pressures to Leakage Zone Pressures Relative Size of Leaks Zone-House Zone-Out Zone-House Zone-Out ½ / ¼ / /

21 Level 2 Charts and Graphs Zone with an opening Can calculate square inches leakage of both barriers Can calculate the leakage through the zone (available CFM50 reduction) Total Path Leakage 21

22 Total Path Leakage The CFM50 that describes how much air will go through the two barriers Always less than the tightest barrier Identifies potential for reduction in house CFM50 22

23 Add a Hole Depressurize house to 50 Pa, measure housezone and zone-out Make a hole in one of the barriers Adjust fan to keep 50 Pa, measure pressures Use Chart or software to get CFM50 of either barrier 23

24 Open a Door (Flow Method) Depressurize house to 50 Pa, measure house CFM50, house-zone and/or zone-out Open a door with highest pressure difference across it (tightest air barrier) Measure new house CFM50 Verify house-zone is near 0 and or zone-out 50 24

25 New Charts for In-Field Garage Chart You can always open a DOOR H/G or G/O (makes this easier) Attic Chart You can only open the hatch that is there (a bit more tricky) 25

26 Let s Do Some Level 2! 26

27 Give the Charts a Try! (Hand them out!) Attached garages Quick Easy Important Attics Sometimes Quick and Easy Also Important 27

28 Level 3 Software More Detailed calculations using Software or Handheld Calculator Test Can be automated with laptop computer and equipment 28

29 Remeasure When You Think You re Done Outside zones (attic, garage) should be much closer to 50 than when you started Inside zones (interior walls, chases, ducts) should be much closer to zero than when you started Zones that haven t changed much in the right direction are opportunities for further improvement 29

30 Limitations/Cautions Don t attribute much meaning to measurements between 47 & 50 Small errors in measuring may generate large errors in the result Don t assume attic is OK because pressure is 48 Can seal zone-exterior (attic vents) to get numbers into a better range Read small pressure 30

31 Limitations/Cautions Re-check unusual measurements If a number is unbelievable, don t believe it! Disconnected, misplaced or pinched hoses Unknown fans Mis-read gauges Its best to be able to get 50 Pascal before and after adding a hole Zone Connections can give exaggerated numbers in doing advanced on several zones, especially kneewalls 31

32 Improving Accuracy Take Baseline Measurements Measure pressures directly; don t subtract Try to measure the smallest pressure difference carefully Do it again For add-a-hole, try to add the hole to the barrier with the largest pressure difference 32

33 The End 33

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36 Are the zones where they are supposed to be?? If not we need to seal holes between inside and outside. By sealing the holes we stop Air Leakage by making a PRESSURE BOUNDARY Pressure Boundary (Air Block between Inside and Outside) 36

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39 Kitchen Soffit and Base Cabinet were open to attic 39

40 Soffit Open to Attic 40

41 Kneewall Attic Heated Area Insulated/Air Sealed 41

42 Kneewall Attic Unheated Area Insulated/Air Sealed 42

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45 Unsheathed Kneewall where addition attic meets 2nd story Addition attic is open to Floor System between 1 st and 2 nd Floors (Can Look all the way through to Porch) 45

46 Porch is Open to Upstairs and Downstairs Exterior Walls Porch is open to Floor System between 1 st and 2 nd Floors (Can Look all the way through to Attic above single story) 46

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48 Test Key Areas Attics, Side attics, Porch roofs Garages,Basements, Crawlspaces Chases (plumb, elec, duct, chimney) Plumbing Access, Duct Location, Soffits Keep It Simple Record basic pressure measurements Explain bad pressure readings (ex 10 attic) Should take very little time (Bdoor is all ready up) 48

49 Kneewall Attic Unsealed/Uninsulated 49

50 50

51 Kneewall Attic Air Sealed/Uninsulated 51

52 Kneewall Attic Air Sealed/Insulated 52

53 Snow melting because of bypasses in attic kneewall 53

54 Interconnection Depressurize house to 50 Pa Measure pressure to one zone Open a door to the other zone, readjust blower door to read 50 again If the zones are connected, the pressure in the first zone will change, If not, it won t 54

55 Ratios of Pressures to Leakage Zone Pressures Relative Size of Leaks Zone-House Zone-Out Zone-House Zone-Out ½ / ¼ / /

56 Attic Zone Leakage paths and Surfaces Roof Bypasses Gable Ceiling Soffit

57 ATTICS In Mild to Southern Climates (e.g. No Ice Damns) Direct Pressure is sufficient. Look at venting to help guide you. 48PA WRT House and not a lot of venting = good, but if 48 and lot of venting still should check 15PA = there are some major holes that need to be dealt with 57

58 Attached Garage Zone Ceiling Exterior Garage Walls Garage Wall to House 58

59 Garage Advanced Zonal Pressure Diagnostics are recommended Open Door Method (Manual or with TI-86) Hybrid Method (with ZPD Utility, PC, PDA,TI-86) Ideal to get below 20sq inches of Leakage between Garage and House 59

60 Basic Procedure Measure pressure between the house and a zone, with the house depressurized to 50 Pa Can close attic vents to get better numbers Make sure to take baseline pressures Is this zone in or out? A little or a lot? Quantify the leakage Add a hole Open a door Estimate venting 60

61 Add a Hole Depressurize house to 50 Pa, measure housezone and zone-out Make a hole in one of the barriers Adjust fan to keep 50 Pa, measure pressures Use chart or software (TI-86) WX Ware) to get CFM50 of either barrier 61

62 Take initial direct pressure Reading Follow up to Line 1 and over to left to find target Pressure 62

63 Open hole to zone enough to reach target pressure while keeping Blower Door at 50PA Measure Size of Hole made in Square Inches 63

64 Available CFM Reduction Take initial direct pressure Reading Follow up to Line 2 and over to right Sq size of Hole times Multiplier = available CFM50 Reduction 64

65 Open a Door Depressurize house to 50 Pa, measure house CFM50, house-zone and/or zone-out Open a door with highest pressure difference across it (tightest air barrier) Measure new house CFM50 Verify house-zone is near 0 and or zone-out 50 65

66 1 1 Saturn Resource Management 66

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68 Estimate Roof Venting With house at 50 Pa, measure house-zone and zone-out Estimate net free area of roof venting by visual inspection Use chart or software to get house-zone CFM50 Usually the least accurate method, because difficult to estimate net free area 68

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70 Add a Hole, Low-Tech Version With house at 50, measure house-zone Open a hole (attic hatch) just big enough to cut the house-zone pressure in half Keep house at 50 The hole you added is roughly equal to the existing leakage 70

71 Remeasure When You Think You re Done Outside zones (attic, garage) should be much closer to 50 than when you started Inside zones (interior walls, chases, ducts) should be much closer to zero than when you started Zones that haven t changed much in the right direction are opportunities for further improvement 71

72 Limitations/Cautions Don t attribute much meaning to measurements between 47 & 50 Small errors in measuring may generate large errors in the result Don t assume attic is OK because pressure is 48 Can seal zone-exterior (attic vents) to get numbers into a better range Read small pressure 72

73 Limitations/Cautions Re-check unusual measurements If a number is unbelievable, don t believe it! Disconnected, misplaced or pinched hoses Unknown fans Mis-read gauges Its best to be able to get 50 Pascal before and after adding a hole Zone Connections can give exaggerated numbers in doing advanced on several zones, especially kneewalls 73

74 Improving Accuracy Measure pressures directly; don t subtract Try to measure the smallest pressure difference carefully Do it again For add-a-hole, try to add the hole to the barrier with the largest pressure difference 74

75 New Zone Pressure Diagnostics Study Completed by Center for Energy and Environment, Michael Blasnik & Assoc. and the Energy Conservatory To test out how accurate the current tests are and when to use them Actually ended up creating a Hybrid method by combining Add a hole and Flow Method. To crosscheck and increase repeatability 75

76 When to Do Advanced Zonal Pressure Diagnostic Testing Important to access amount of leakage for IAQ issues (How much Leakage between Garage, or Moldy crawlspace and house) Durability Issues (How much leakage of moist house air leaking into attic of cold climate house) 76

77 New Zone Diagnostics Previously had programmed new hybrid method into a spreadsheet, and has now develop into a stand alone windows program, and currently developing for palm by The Energy Conservatory Rick Karg has added this to the TI-86 Calculator (Ziptest Pro2) 77

78 ZPD Utility for PC Available at Select Products link then click on Software Scroll to bottom of page to download installation file 78

79 ZPD Study Available at Energy Center of Wisconsin website To get directly to download page visit 79

80 Reference Articles Home Energy Magazine May/June 2002 Zone Pressure Diagnostics Home Energy Magazine Sept/Oct 1994 User Friendly Pressure Diagnostics BOTH OF THESE ARE AVAILABLE AT 80

81 TECTITE & ZPD Utility The ZPD Utility can be used with a handheld manometer or by using TECTITE. I use a form to collect data from TECTITE Then am able quickly input data into ZPD Utility TECTITE zone pressure info can be collected at same time as multi-point blower door test. 81

82 Summary of Work Flow (1) Find Primary Zones and Thermal Boundaries Infrared scan before Blower Door Initial Blower Door Reading Use Infrared Camera with Blower Door to locate air leakage paths 82

83 Summary of Work Flow (2) Direct ZPD for all Primary Zones Can use Pressure Ratio Chart to determine relative leakiness by estimating Net Free Area of Hole through one surface Direct Measurement on suspicious areas Cantilevers, Soffits, Chases, Floor Cavities, Porches Check for Interconnections between zones 83

84 Summary of Work Flow (3) Advanced ZPD for all Attached Garages and Crawlspaces with moisture/mold issues. Advanced ZPD for Attics in cold climate areas, especially for tight houses with high moisture Use Visual Clues and Smoke Puffer from inside zone to help locate leaks in Pressure Boundary 84

85 Summary of Work Flow (4) Where is Pressure Boundary, Is the Zone Inside or Outside Does it line up with Thermal Boundary Where should the Zone be and how will it be accomplished (Strategies for Air Sealing and Insulating) Explain recommendations to client (Mechanical, Air sealing, and Insulation) (e.g. leaving enclosed porch outside and insulating wall between the house and the porch) 85

86 Summary of Work Flow (5) Do Intermediate Blower Door Test Did Zone Pressures move toward right direction Exterior Zone closer to 50PA WRT House Interior Zone closer to 0PA WRT House Pressure Pans in outside zone less than 1.0PA 86

87 Summary of Work Flow (6) Advanced ZPD to Measure remaining leakage to primary zones that were measured during the assessment Final Infrared Scan Take Final Blower Door Reading 87