Objectives. How can Pressure effect Building Performance? Weatherization Fundamentals- House as a System with the House of Pressure Part 1

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1 Weatherization Fundamentals- House as a System with the House of Pressure Part 1 Objectives Understand the driving forces that impact moisture, heat and air movement in buildings. Learn some of the ways that interactions can cause performance problems. Understand the concept of Weatherization and the role of diagnostics in verifying that expected results are achieved. How can Pressure effect Building Performance? Health and Safety Durability Comfort Energy Efficiency 1

2 Air Flow Requires All of the Following: Pressure Difference (Driving Force) Hole Air The Bigger the Hole or Pressure Difference the more air flow (Can reduce hole or driving force to reduce air flow) 1 cfm out = 1 cfm in Takes path of least resistance Air Moves from High to Low Pressure Areas Air Moves from High to Low Temperature Areas + Positive - Negative Flow is from + Positive (High) to. - Negative (Low) For every cfm that one Exits cfm. Enters Flow takes path of Least resistance. 2

3 Air Flow Created by Pressure Difference Moves Heat Air (and everything in it) Moisture We can Use Pressure Diagnostics to Determine Which way is Air Moving How Much Air is Moving Two Types of Pressure Diagnostics With house or duct Depressurized or Pressurized by Test Equipment Blower door Duct Blaster Using Existing Equipment in Building Air Handler Exhaust Fans Combustion Appliance 3

4 Pressure Diagnostics with Equipment in Building Air Handler Fan (Dominant Duct Leakage) Door Closure effect on Main body Individual Room Pressures Exhaust Fans (Kitchen,Bath,Dryer, etc.) Combustion Appliance Zone *CAZ Worst Case Draft *WCD Pressure Diagnostics with Blower Door Measure House Pressure Measure Blower Door Fan Pressure Convert Fan Pressure to CFM Airflow Zonal Pressures To Determine Air/Pressure Boundary of building To Determine how much zones are connected Pressure Pan To Help Determine Location of Duct Leakage to the Outdoors Other Tests with Pressure Static Pressure Air Handler Air Flow Duct Leakage 4

5 What Do We Measure? Not total pressure, but pressure differences between one space and another Always one pressure with reference to (WRT) another Units for Measuring Pressure Pascal (Metric Standard) 1 Pascal = weight of 1 Post-it Note. 248 Pascals = 1 w.c (American Standard) 1 water column = pressure required to suck 1 of water up a straw Units for Measuring Air Flow Cubic Feet per Minute (CFM) This is the rate of air flow CFM 50 (standard for blower door) The Blower Door measures the air flow rate in CFM at House pressure of -50 pascals 5

6 How Do We Measure A calibrated gauge that has pressure channels/ports that are used to measure Pressure and Air Flow Magnahelic Gauge Round Gauge with arch-shaped scale Digital Manometer Gives readings on digital screen DG-700 Digital Manometer 6

7 Automated Performance Testing (APT) System Uses computer software to take measurements The House of Pressure Wind Heat Stack Effect, Combustion Fans Exhaust Fans, Duct Leakage, Interior Doors 7

8 Wind Effect Wind Direction Wind creates a positive pressure on the windward side of the building... which creates a negative pressure on the other sides of the house + positive pressure _ negative pressure Stack Effect Warmer air rises and pushes out at the top. Creating a suction that pulls in cooler air at the bottom + positive pressure _ negative pressure Neutral pressure plane 8

9 Stack Effect Positive pressure (relative to outdoors) Neutral Pressure Plane Negative pressure (relative to outdoors) Baseline Pressure Measure Initial Pressure on Building with house in winter mode and no equipment on Subtract this baseline from all the pressure measurements to get adjusted reading Newer Digital Manometers have this function built into gauge Combustion Equipment and Exhaust Fans _ negative pressure _ negative pressure Exhaust Fan Furnace 9

10 Inspect Exhaust Fans Do they work? Are they noisy? Do the occupants use them? Are they vented all the way outdoors? Inspect Exhaust Fans (cont.) Are vent runs as short and straight as possible? Is the proper material used for venting? Inspect Lint traps on dryers Are clothes blocking intake air for dryer? 10

11 Working? 11

12 Measure Exhaust Fan Flow (Home made Flow Box) 1.07 x (square inches) x (square root of Pascals) = cfm 1.07 x (8) x (3) = cfm = 3 4 = 2 4 Exhaust Fan Flow Meter TM (Energy Conservatory) *If Pressure difference more than 8pa move slide gate to next largest open Flow Conversion Chart 12

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14 Duct Leakage Duct leakage can create positive and negative pressures in different areas of the home. The pressures associated with duct leaks can be larger and more important because the driving force is bigger. _ negative pressure + positive pressure All holes are not created equal. Dominant Duct Leakage Setup With Manometer Channel A: is House WRT Outside Channel A Channel B (Turn Air Handler on and off several times) (Notice the immediate pressure change on channel A) Effects of Supply Duct Leakage Zone with Leak Dominant Mainbody Zone with Leak Supply Leak - (Negative) + (Positive) 14

15 Effects of Return Duct Leakage Zone with Leak Dominant Mainbody Zone with Leak Return Leak + (Positive) - (Negative) Dominant Duct Leak Readings 0 Zero NO Leaks / Equal Leaks / House to Leaky - Negative Pressure Dominant Supply Leak + Postive Pressure Dominant Return Leak Negative Pressure: -Can cause Backdrafting and Flame Roll out -Pulls in Unconditioned air, Pollutants and Soil Gases Positive Pressure: -Pushes out Pollutants, Flue Gases, Conditioned Air and Moisture Interior Door Closure Closed doors that prevent supply air from getting back to a return cause positive pressures in those rooms... Meanwhile starving the return for air, causing negative pressures in the zone where the return is located 15

16 Room Pressure Testing This test is used to measure room pressures created by the air handler and to determine if there are any problems associated with the pressures. Room Pressure Testing (Room WRT Main body) Channel B (Use Door Gauge if need to do Pressure Relief) Or connect hose to outdoors to measure Room WRT Outdoors Need to Get Return Air From Behind Closed Doors to Equalize Pressures 16

17 Pressure Relief Needed Rooms are Pressurized Main body is Depressurized to an unsafe condition Pressure Relief Solution Pressure Relief has equalized pressure in rooms Main body is now in a safe condition Fixed Health & Safety, Comfort, Durability problems and increased Energy Efficiency by doing Pressure Relief How Much Sq Relief is needed Open door wide enough to relieve Pressure Use Door Gauge or Tape to measure width of door opening Look up door size on chart & multiply by measured door opening to get sq needed for Pressure Relief 17

18 Door Opening at TOP and SIDE only Source: John Tooley (Pressure Balancing a House) Opening with TOP, SIDE and BOTTOM Source: John Tooley (Pressure Balancing a House) Source: John Tooley (Pressure Balancing a House) 18

19 Source: John Tooley (Pressure Balancing a House) Tamtech.com Zenon (4 x 14) & (4 x 24) R.A.P 8 (8x 8) R.A.P (12 x 12) Recording Room Pressure Readings Bedroom

20 Intentional Depressurization Blowers Doors intentionally Depressurize a home to measure air leakage at 50 Pascals. When we do a Blower Door test we turn off all the heating and cooling equipment, (including gas water heaters), so we do not cause Backdrafting. Backdrafting Spillage of flue gases from combustion equipment into the home. These gases can be harmful and even Deadly, especially Carbon Monoxide which is odorless, colorless, and tasteless. Backdrafting is caused by Depressurization (Negative Pressure) Unintentional Depressurization Depressurization (Negative Pressure) can also be caused by duct leakage, exhaust fans, and even door closure. We want to be able to use or Heating and Cooling equipment without causing Backdrafting. We also want to avoid positive pressures. 20

21 Estimate Tightening effect of work 15 spillage goes up with depressurization 82% 24% 5% From 1075 tests in Mpls Sound Program If you can predict savings from 50% tightening? You can estimate the new depressurization level Then you can add the proposed equipment to the bid as added savings from a furnace or water heater upgrade 21

22 Combustion Appliance Zone (CAZ) Testing This test is done to determine if there is a possibility of a Combustion Appliance backdrafting because of.. Duct Leakage Door Closure Exhaust Fans or Equipment Worst-Case Scenario We use the existing fans (air handler, exhaust fans, clothes dryer, etc) to create the largest possible negative pressure in the area of the appliance. Then we check.. How strong is that negative pressure? Will the appliance draft under that condition? If so, how strong is the chimney draft? 22

23 What is a Safe Reading The greater the Depressurization the more negative our pressure reading will be and the greater the chance of Backdrafting. Worse Bad Good You Are in the CAZ 23

24 You Are NOT in the CAZ House Depressurization Limits (Can Cause Backdrafting) Appliance Chimney Height (ft) Appliance Unlined Chimneys on Exterior Wall Metal Lined, Insulated or Interior Chimneys Gas-Fired 13 or Less -5pa -5pa Furnace, Boiler, pa -6pa 21+ DHW Heater -5pa -7pa OIL-Fired 13 or Less -4pa -4pa Furnace, Boiler, pa -5pa pa -6pa DHW Heater FIREPLACE N/A -3pa -4pa Low-Excess Air N/A -10pa -10pa Fireplace, Wood stove Induced Draft Appliance N/A -15pa -15pa From: CMHC Chimney Safety Users Manual (Reference #4 Appendix A) Note: Under summertime conditions, actual HDL s may be lower than shown above BPI CHART 24

25 WH Fireplace Dryer Supply Return Furnace BR 1 BR 2 BR 3 RE Supply Supply Supply Supply Visually Inspect Combustion Appliance Before Firing Inspect Vent Connector and Chimney NFPA Codes 54 Gas, 31 Oil, 211 Solid Fuels Type of Vent and Chimney, Liners, Connections, Corrosion, Slope, Clearance, and Combustion Air Use inspection mirror to verify clear chimney Check for fuel leaks Calibrated combustible gas detector, Soap bubbles 25

26 Protect Against Combustion Spillage Stacked Tee Venting Upgrades Upgrade systems to meet current NFGC sizing requirements Liners, larger connectors, reconfigure connectors to reduce restrictions and increase capacity Also makes system more resistant to depressurization Connect dhw vent directly to common vent for more rise and 10% capacity increase DRAFT CO TEST Minimum Acceptable Draft in Pascals (for natural draft appliances) Temperature Gas Fired Oil Fired 80 > <

27 BPI CHART e.g. 20/40= = -2.25pa No Return Duct work CAZ -10pa Flue Gases were coming into house because of Depressurization created by the Air Handler Can simulate Backdrafting situation with Blower Door, Some units produce large amounts of CO when Backdrafting TECLOG for Windows Data Logging Software and Graphic Display for Diagnostic Measurements Very useful in seeing effects of pressure We will use this to repeat tests that were done manually earlier TECLOG can be used with the APT or DG

28 TESTING with TECLOG Run Hose to each measured zone Synchronize watch and computer clock Measure Baseline Measure Dominant Duct Leakage Air Handler on and all interior doors open Measure Room Pressures WRT Outdoors Measure Exhaust Fans On Turn 1 by 1 and Mark each as an event TESTING with TECLOG (cont.) Determine Worst Case Interior Door and CAZ Door Setup for EACH combustion zone Repeat with Air Handler Off Reposition Doors WHAT WAS WORST CASE This will be setup for Worst Case Draft Testing TECLOG and Worst Case Draft This can also be performed with Teclog and APT or DG-700. One Channel CAZ WRT OUTSIDE 2 nd Channel VENT WRT CAZ Get CAZ to Worst Case and then fire combustion appliance and record draft reading 28

29 Air Handler Flow Plate Measuring Air Handler Flow Duct Testing 29

30 Manometer Setup for Pressure Pan Pressure Pan Testing Channel A Channel B Channel A: is House WRT Outside Channel B: is Duct WRT House Zonal Testing This test is is used to determine which areas of the House are INSIDE and which areas are OUTSIDE Pressure (Air) Boundary 30