Understanding Blower Door Testing and Interpreting Results

Transcription

1 This webinar is being recorded and will be available at: Understanding Blower Door Testing and Interpreting Results Introduction Presented by: Mike Turns, Senior Program Manager Performance Systems Development (PSD) Principle Investigator, Pennsylvania Energy Code Field Study/Penn Energy Codes Program 1

2 Continuing Education PA L&I CEUs for code officials for this webinar ($20 admin fee): After the webinar, go to: Answer all poll questions Enter the code to be given later in the webinar Groups watching the webinar from the same computer must send a signin list including the name, and signature of each attendee. These individuals must also take and pass the post-webinar quiz. 4 Overview 1. Air leakage basics 2. Blower door setup and operation 3. Interpreting the results 4. Who owns one of these things (is not afraid to use it)? 5 2

3 What is your profession? POLL 1 Are there multiple people watching from your computer? If so, how many? POLL 2 7 3

4 AIR LEAKAGE BASICS 8 Building Air Flow 4

5 Air Leakage or Is It Ventilation? Air that enters or leaves the building through various openings in the envelope Air Leakage Random and uncontrolled volumes of air Derived from random sources Moving randomly through building components 5

6 Ventilation Controlled amount of air Derived from clean, dry sources Moving as designed through building zones Contributing to efficient performance of building systems Contributing to the health and comfort of the occupants Physics of Air Flow Air Flow is dependent on 3 variables: A volume of air A hole A pressure difference existing across the hole 6

7 Stack Effect Infiltration occurs low in the structure Exfiltration occurs higher in the structure Magnitude determined by height of structure Magnitude determined by inside to outside temperature difference Colder outdoor temperature increases stack effect Flue Effect (Exhaust Effect) One cubic foot of air infiltration for each cubic foot of air exhausted by chimneys, ventilators, and exhaust appliances 7

8 Combined Flue and Stack Effect Wind Effect Wind pressure creates a positive pressure on the windward side of the building (air infiltration) Wind pressure creates a negative pressure on the leeward side of the building (air exfiltration) 8

9 Typical Air Leakage Flows Establishing a Pressure Difference across the Air/Thermal Boundary Provides Method for Diagnostics: - Quantifying total volume of leakage - Quantifying air flow interactions between house and attached zones (attic, garages, crawl spaces, cellars) - Visually identifying leakage sites (diagnostic smoke, cob webs, dust disturbances) - Increasing the contrast of infrared imaging for identification of air leakage sources 9

10 How Can We Measure Air Leakage Rates? Blower Doors: Used to measure air leakage by creating a pressure within the building and measuring the air flow required to create that pressure The Code and Air Sealing Verification IECC Air Sealing and Insulation Building envelope air tightness and insulation installation shall be demonstrated by: Blower door test, or Visual inspection 10

11 Count ACH50 4/27/2016 Envelope Tightness (ACH50) ACH All Climates Count 70 Number > Percent > 7.0 7% Average 4.3 Max 8.9 Min ACH50 BLOWER DOOR BASICS 23 11

12 Building Air Leakage Testing Blower door creates negative pressure Measure house pressure + air flow out Standard test pressure = 50 pascals High air 50 pascals = large air leakage Low air 50 pascals = small air leakage Building Air Leakage Testing 1. Depressurize building to negative 50 pascals 2. Measure how much air (cfm) required to maintain 50 pascals 25 12

13 Leakage Testing Equipment Fan and Rings Digital Gauge Door and Frame The Gauge Digital Manometer 27 13

14 BLOWER DOOR SETUP AND OPERATION 28 Preparing the House IECC (paraphrased) Exterior windows and doors closed Dampers closed Interior doors open HVAC systems off HVAC registers and grilles open (normal operating condition) Nothing temporarily sealed during the test, except wholehouse ventilation openings (seal them up) 29 14

15 Blower Door Setup Install the frame and canvas cover Two tubes from the manometer One to the outside (to measure the pressure) One to the fan (to measure the air flow) Plug in the fan and give some juice 30 Performing the Test Increase the fan speed until you hit 50 Pa Read the CFM 31 15

16 WHO OWNS ONE OF THESE THINGS? And Is Not Afraid to Use It 32 Training and Credentials Certified HERS Raters Certified BPI Building Analysts and Envelope Professionals Duct and Envelope Testing (DET) Verification Technicians 33 16

17 INTERPRETING TEST RESULTS 34 Testing Option Building Envelope Leakage Limits IECC Max leakage: 7.0 ACH50 How do we arrive at this number and what does it mean? 17

18 Units of Measurement Flow cubic feet per minute (CFM) or Flow compared to volume air changes per hour (ACH) 50 Pascal CFM50 is the primary output of a blower door test CFM50 Provides a reasonable standard by which the industry can measure and evaluate air flow rates. CFM50 = Cubic Feet per Minute at 50 Pascals of pressure (i.e. At what rate does air enter the house under testing conditions?) 18

19 Converting CFM50 to ACH50 Converting to ACH50 levels the playing field in terms of different house sizes (mostly) It s easier for a big house to reach 7 ACH50 than a small one, all else being equal, but that s another story ACH50 = Air Changes per Hour of airflow at 50 pascals of pressure (i.e. under testing conditions) ACH50 = CFM50 cubic feet minute x 60 minutes House Volume (AC) cubic feet hour 38 CFM50 to ACH50 Conversion Example Inputs: Blower door test result: 1897 CFM50 Volume of conditioned space: 26,470 cubic feet Conversion: ACH50 = CFM50 x 60 Volume ACH50 = 1897 x 60 26,470 ACH50 =

20 Infiltration in Harrisburg (1897 CFM50) Average CFM High CFM Stack Infiltration Wind Infiltration Total Infiltration Infiltration in Harrisburg (1897 CFM50) 41 20

21 Infiltration in Harrisburg (1897 CFM50) 42 A code official receives documentation of a blower door test that lists a CFM50 of 2,345 and a volume of conditioned space of 18,239 cubic feet. Does this meet the 2009 IECC maximum leakage rate under the blower door test option? POLL 3 - QUIZ 43 21

22 Quiz Answer ACH50 = CFM50 x 60 Volume ACH50 = 2,345 x 60 18,239 ACH50 = 7.7 Does not meet code (7.0 max) 44 Other Cool Units ACH natural: Average air leakage rate under natural conditions For a 2-story building in PA with normal wind exposure: 7 ACH50 = 0.47 ACH natural Equivalent leakage area The size of the opening if all the cracks and holes were put together in one location 2,000 ft 2 rectangular house 7 ACH50 = 196 in 2 = 14x14 in hole Like cracking a 3-ft wide window 5.4 inches 45 22

23 DOCUMENTATION 46 Documentation Blower Door Testing Recommended data: ACH50 CFM50 Conditioned volume Pass/fail Name/signature 23

24 Editable Air Leakage Verification Form Download sample blower door and duct leakage testing forms at: 48 SUMMARY 49 24

25 Summary Build tight, ventilate right Blower door tests help quantify air leakage and diagnose problems Trained professionals exist Optional blower door test per 2009 IECC: 7 ACH50 Be aware of CFM50 to ACH50 conversion Use sample documentation form Don t forget to ventilate 50 Next Month s Webinar Understanding Duct Leakage Testing and Interpreting Results May 24, 2016 Noon to 1:00 pm PennEnergyCodes.com/events 51 25

26 Continuing Education Hours You will receive a follow-up in about an hour Follow the link and enter: BDACH50 Or, do it now: OTHER OPPORTUNITIES 53 26

27 Energy Code Consultation What it includes: Plan review/software analysis Air barrier and insulation inspection Blower door test Duct leakage test Recommendations Builders/Code Officials/Raters Contact Brandon at: 54 Sign up for the Energy Code Challenge You have already earned 50 points in the Energy Code Challenge (link will be also sent in follow-up ) Sign up and enter BDACH50 to receive 50 points 27

28 Code Compliance/Education Tablet Tool E-CODE Assistant app Tool: Tablet-based, interactive inspection checklist Intended audience: Energy code inspectors, project managers, Raters Get started at 56 Penn Energy Codes Website 28

29 Training and Technical Assistance Training events: May 10 PENNBOC Region V Enola, PA More webinars sign up now Custom training/technical assistance Contact Brandon Cornell: bcornell@psdconsulting.com to apply 58 29