Blower Door and Building Diagnostics Funding Funding for this class was provided by the Alaska Housing Finance Corporation (AHFC). 1 Wisdom and Associates, Inc. 2 Amenities Refreshments Bathrooms Cell Phones Break schedule 3 Disclaimer The information and materials provided by the Alaska Housing Finance Corporation are not comprehensive and do not necessarily constitute an endorsement or approval, but are intended to provide a starting point for research and information. AHFC does not endorse or sell any products. All photos and videos are property of Wisdom and Associates, Inc. unless otherwise noted. 4 Resources • AHFC - Research Information Center • Alaska Residential Building Manual www.ahfc.us • Cold Climate Housing Research Center www.cchrc.org • One stop shop for AK Energy Efficiency information www.akenergyefficiency.org About the Instructor 6 Participant Introductions • Name • Reason for participation • Your expectations Scope of Course • Blower door testing and techniques • Building airflow standard • Diagnostic pressure testing Covered In This Course • Conducting a blower door test • Interpreting results • Air tightness • Pressure imbalances in the home • Building Airflow Standard • Pressure diagnostics • Basic duct testing Definitions • ACH - Air Changer per Hour: the number of times per hour that the entire volume of air in a house is exchanged in one hour at a particular pressure. Generally expressed at neutral pressure and at 50 Pascals of pressure Definitions • CFM - Cubic Feet per Minute: the number of cubic feet per minute flowing through a house. • Correlation Coefficient - how well individual pressure and flow readings fit to an average curve. This number measures the accuracy of a blower door test. Definitions • ELA - Effective Leakage Area: The area, in square inches, of a hole which leaks the same amount as a house at 4 Pascals pressure difference • EqLA - Equivalent Leakage Area: The area, in square inches, of a hole which leaks the same amount as a house at a 10 Pascal pressure difference Definitions • House Volume: The volume of air inside the thermal envelope of a house. • Infiltration: Uncontrolled air leakage into a building • “n”: The slope of a leakage curve. An indicator of the size of holes in a house. A number less than .6 indicates large holes, a number greater than .7 indicates smaller holes. Definitions • Negative Pressure: Less than atmospheric pressure inside the house. Negative pressure occurs when the pressure inside the house is less than the pressure outside. Negative pressure promotes air infiltration. • Pascal - Pa: A metric unit of pressure. 50 Pascals equals 0.2 inches of water column Definitions • Positive Pressure: Greater than atmospheric pressure inside the house. Positive pressure occurs when the pressure inside outside the house is more less than pressure outside. Positive pressure promotes air exfiltration. What is a Blower Door? What is a Blower Door? • Diagnostic tool used to measure air tightness – Locate air leakage sites – Document air tightness – Estimate natural air infiltration – Document effectiveness of air sealing – Measure duct leakage What is a Blower Door? • Powerful calibrated fan temporarily sealed in an exterior doorway • Pulls air into or out of a building • Creates air pressure differential between inside and outside – Pressure forces air through gaps and cracks in the building envelope What is a Blower Door Test? • Single or series of fan flow measurements from 15 to 60 Pascals – One Pa (Pascal) = .004 Inches Water Column • Test conducted at high pressure to reduce interference from wind, stack effect • “One Point” (50 Pa) test used for quick airtightness assessment Tectite What is a Blower Door Test? • Can estimate leakage between house and attached structural components – Garage, attic, crawlspace • Can estimate outside air leakage into ductwork • Assists use of chemical smoke, infrared camera Equipment Calibration • Equipment must be factory calibrated – Fans and gauges • Energy Conservatory – 2 yrs for gauges, 4 for fans • Retrotec – 5 yrs for gauges and fans • Self check between calibrations recommended Safety Considerations • Blower door is powerful, potentially dangerous • Keep people and pets away • Plug in tightly • Do not use ungrounded or adapter plugs • Do not use if wet • Unplug if making fan adjustments • Do not reverse while blades are turning • Do not leave on for long periods (overheat) Safety Considerations • For long term operations (blower door directed air sealing) use a flow ring to increase velocity – Do not leave on low speed • Fan may automatically shut down if too hot • Turn off combustion appliances for the test! – Flame roll out, CO – Includes attaches spaces (duplex etc.) Safety Considerations • Fires and wood stove completely out – Close damper – Clean out ashes! • Leave the house like you found it – Thermostats – Pilot lights • Put your car keys on the appliance you shut off! Manometer Gauges Two Primary Providers • Energy Conservatory • RetroTec Energy Conservatory DG-700 • 2 Independent Channels that can be read simultaneously • 4 time averaging functions • Automatically calculates flow readings for Minneapolis products Energy Conservatory DG-700 • Can measure and record pressure baselines • 50 and 25 Pascal leakage measurement at any building pressure • Can conduct an automated test with TECTITE Energy Conservatory DG-700 • Can maintain 50, 25, and 0 Pascal pressure without a computer (Cruise Mode) Retrotec DM-2 • Two independent pressure channels • Continuous time averaging • Measures and removes baseline pressures • Enter volume and area for air change and leakage ratios Retrotec DM-2 • Can directly control fan speed • 50 Pascal cruise control w/ flow, ACH and leakage measurements • 3 fan splitter available for simultaneous control of 3 fans at once Setting Up the Building Setting up the Building • Perform inspection of the home and adjacent spaces • Pollutants may be drawn into the living space by the fan – Mold – Vermiculite – Asbestos etc. Setting up the Building • Close all adjustable openings – Windows – Exterior doors – Attic access hatch – Crawlspace hatch (only if unconditioned) – Crawlspace vents – Passive ventilation vents Setting up the Building • Open interior doors – Treat house as a single unit • Conditioned basements and crawlspaces opened Setting up the Building • Turn off combustion appliances – Turn off switch – Unplug – Set to “pilot” • If combustion appliances turn on during a depressurization test, it is possible for flames to be sucked out of the combustion air inlet (flame rollout). This is a fire hazard and can possibly result in high CO levels. Setting up the Building • Turn off combustion appliances in adjacent units of multi-family housing • Wood stoves and fire places completely out – Close damper – Clean out ashes • Turn off exhaust fans – Clothes dryer, exhaust fan, range hood Video: Setting up the house Conducting a Depressurization Test Depressurization Test • Two common test procedures – One point test – Multi point test • One point test - singe measurement at -50 Pa – Quick and simple way to measure air tightness – TECTITE not required (although useful) Depressurization Test • Multi point test – Measures over a range of pressures (60Pa to 15Pa) • Required for AHFC energy ratings • Minimum 5 to 8 different target pressures • Averages out errors, increases accuracy • Estimates leakage area of building Depressurization Test • Turn on fan for initial inspection • Increasing fan speed increases pressure differential • Frame may pop out of door if not installed properly! • At -30Pa walk through to look for doors/window popping open, ashes Can’t Reach 50 Factors • Unable to depressurize building to -50Pa, remove flow restrictions and try again • Still can’t reach -50Pa, no adjustment for DG-700 users • Manual gauges: – Take one point test at highest possible building pressure – Manually use Table 2 to estimate air flow Can’t Reach 50 Factors Can’t Reach 50 Factors • Can’t Reach 50 Factor formula: Can’t Reach 50 Factors - Errors • The actual exponent of the leaks being measured differing from the assumed exponent (N) of 0.65. • The assumed exponent value of 0.65 is based on the average observed exponent for a large sample of residential Blower Door tests Can’t Reach 50 Factors - Errors CRF 50 Example • With the fan running full speed, you are able to achieve a building pressure of 44 Pascals with a measured fan flow of 6,000 cfm. • The corresponding CRF Factor for a building pressure of 44 Pascals is 1.09. The estimated flow needed to achieve the target pressure of 50 Pascals is 6,000 x 1.09 = 6,540 cfm. CRF Exercise • With the fan running full speed, you are able to achieve a building pressure of 28 Pascals with a measured fan flow of 5,600 cfm. • What is the CRF Factor? • What is the estimated CFM50? CRF Exercise • The corresponding CRF Factor for a building pressure of 28 Pascals is 1.46. • The estimated flow needed to achieve the target pressure of 50 Pascals is 5,600 x 1.46 = 8,176 cfm. Can’t Reach 50 Factors • The TECTITE program automatically applies the CRF Factors to One-Point Test data. Can’t Reach 50 Factors • Multi-Point test • Subtract rings until target pressure is reached • Still can’t reach? Start at highest achievable pressure and work down Testing in Windy Weather • Strong, gusty winds cause fluctuations in pressure • Watch gauges and use “Time Average” function • Use multiple outdoor reference hoses • During a multi point test, errors are averaged out • If it is