Objectives. Home Performance Diagnostics with the House of Pressure (Part 1) How can Pressure effect Building Performance?

Transcription

1 Home Performance Diagnostics with the House of Pressure (Part 1) Objectives Learn the basic rules of air flow and differences Begin to be able to recognize building problems related to airflow and differences 2008 Have a better understanding of the correct way to measure building s and flows How can Pressure effect Building Performance? Health and Safety Durability Comfort Energy Efficiency 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 + Positive - Negative Air Moves from High to Low Pressure Areas Air Moves from High to Low Temperature Areas Flow is from + Positive (High) to. - Negative (Low) For every cfm that one Exits cfm. Enters Flow takes path of Least resistance. 1

2 Air Flow Created by Pressure Difference We can Use Pressure Diagnostics to Determine Moves Heat Air (and everything in it) Moisture Which way is Air Moving How Much Air is Moving By Measuring Pressure Difference 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 Pressure Diagnostics with Equipment in Building Air Handler Fan (Dominant Duct Leakage) Door Closure effect on Main body Individual Room Pressures Exhaust Fans (Kitch,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 (Total and Individual Register) Duct Leakage with Duct Blaster 2

3 What Do We Measure? Not total, but differences between one space and another Always one 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 = 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 How Do We Measure A calibrated gauge that has channels/ports that are used to measure Pressure and Air Flow CFM 50 (standard for blower door) The Blower Door measures the air flow rate in CFM at House of -50 pascals Magnahelic Gauge Round Gauge with arch-shaped scale Digital Manometer Gives readings on digital screen DG-700 Digital Manometer 3

4 Automated Performance Testing (APT) System The House of Pressure Uses computer software to take measurements Wind Effect Wind Wind Direction Heat Stack Effect, Combustion Fans Exhaust Fans, Duct Leakage, Interior Doors Wind creates a positive on the windward side of the building... which creates a negative on the other sides of the house + positive _ negative Stack Effect Warmer air rises and pushes out at the top. Creating a suction that pulls in cooler air at the bottom + positive _ negative Neutral plane 4

5 Stack Effect Negative (relative to outdoors) Positive (relative to outdoors) Neutral Pressure Plane Baseline Pressure Measure Initial Pressure on Building with house in winter mode and no equipment on Subtract this baseline from all the measurements to get adjusted reading Newer Digital Manometers have this function built into gauge Combustion Equipment and Exhaust Fans Inspect Exhaust Fans Do they work? _ negative Furnace _ negative Exhaust Fan 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? 5

6 Working? 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 6

7 Duct Leakage Duct leakage can create positive and negative s in different areas of the home. The s associated with duct leaks can be larger and more important because the driving force is bigger. _ negative + positive All holes are not created equal. Dominant Duct Leakage Setup With Manometer Effects of Duct Leakage (Dominant Supply Leak) Channel A: is House WRT Outside Channel A Channel B (Turn Air Handler on and off several times) (Notice the immediate change on channel A) Dominant Mainbody Zone with Leak Supply Leak - (Negative) + (Positive) 7

8 Effects of Duct Leakage (Dominant Return Leak) 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) Dominant Mainbody Zone with Leak Return Leak + (Positive) - (Negative) (-Negative Pressure) Can cause backdrafting (-12.5) Can cause Flame Roll out Interior Door Closure Room Pressure Testing Closed doors that prevent supply air from getting back to a return cause positive s in those rooms... meanwhile starving the return for air, causing negative s in the zone where the return is located This test is used to measure room s created by the air handler and to determine if there are any problems associated with the s. Room Pressure Testing (Room WRT Main body) Channel B Need to Get Return Air From Behind Closed Doors (to Equalize Pressures) 0000 A B Hose to Room WRT WRT Open to House (main body) Or connect hose to outdoors to measure Room WRT Outdoors (Use Door Gauge if need to do Pressure Relief) 8

9 Pressure Relief Needed Pressure Relief Solution Pressure Relief has equalized in rooms Rooms are Pressurized Main body is Depressurized to an unsafe condition 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 Door Opening at TOP and SIDE only 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 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) 9

10 Tamtech.com Zenon (4 x 14) & (4 x 24) Source: John Tooley (Pressure Balancing a House) R.A.P 8 (8x 8) R.A.P (12 x 12) Recording Room Pressure Readings Intentional Depressurization Bedroom 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 s. 10

11 Depressurization Chart Estimate Tightening effect of work 15 Natural Florida Retrofit spillage goes up with depressurization 24% 82% 5% If you can predict savings from 50% tightening You can estimate the new depressurization level From 1075 tests in Mpls Sound Program Then you can add the proposed equipment to the bid as added savings from a furnace or water heater upgrade 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 11

12 Worst-Case Scenario We use the existing fans (air handler, exhaust fans, clothes dryer, etc) to create the largest possible negative in the area of the appliance. Then we check.. How strong is that negative? Will the appliance draft under that condition? If so, how strong is the chimney draft? What is a Safe Reading The greater the Depressurization the more negative our reading will be and the greater the chance of Backdrafting. Worse Bad Good COMBUSTION APPLIANCE ZONE TESTING (CAZ With Reference To Outside ) Channel A (CAZ With Reference To Outside ) Channel A 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 pa DHW Heater -5pa OIL-Fired 13 or Less -4pa -4pa Furnace, Boiler, pa -5pa pa -6pa DHW Heater FIREPLACE N/A -3pa -4pa Low-Excess Air Fireplace, Wood stove N/A -10pa -10pa 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 List each CAZ location and appliances in each Dryer WH Fireplace Combustion Appliance Zone TEST Steps 1 Setup Manometer and Pressure hoses to measure CAZ (WRT) Outdoors Location 1 Pre Pos t Location 2 Pre Pos t Location 3 Pre Pos t 2 All interior doors open, Measure Baseline Pressure 3 Turn on all Exhaust Fans *except whole house fans Supply Return Furnace 4 Close all interior doors * except doors to rooms with exhaust fans 5 6 Is Blower Door being used to simulate fireplace at 300 cfm? (use Ring B ) If Door from CAZ to House Open it (Record CAZ WRT outside ) Y N Y N Y N Y N Y N Y N BR 1 BR 2 BR 3 RE Supply Close Door from CAZ to House (Record CAZ WRT outside ) Turn on Furnace Blower (Record CAZ WRT outside ) *check position of interior doors for worst case with smoke puffer If Door from CAZ to House Open it (Record CAZ WRT outside ) Supply Supply Supply Recreate Worst Case Conditions for each CAZ (Complete this and following steps on each Heating Inspection form) Perform Worst Case Draft and Combustion Tests for each appliance under this worst case condition *There should be no spillage after 30 seconds and Draft should be established after 5 minutes *Monitor ambient CO in CAZ while doing these tests if CAZ 5pa or worse, if ambient CO gets above 20ppm discontinue testing 12

13 Visually Inspect Combustion Appliance Before Firing Inspect Vent Connector and Chimney NF 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 Protect Against Combustion Spillage Venting Upgrades Stacked Tee 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 > < WORST-CASE DRAFT TESTING Channel A (CAZ WRT Outside) CAZ Depressurization Channel B (Vent Pipe WRT CAZ) Worst Case Draft Open to Zone with Combustion Appliance Green Hose to Outside A B B WRT WRT Use this setup when you are in the Combustion Appliance Zone Hose to Vent Pipe Open to (CAZ) Static Pressure Probe 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 13

14 TECLOG for Windows Data Logging Software and Graphic Display for Diagnostic Measurements Very useful in seeing effects of We will use this to repeat tests that were done manually earlier TECLOG can be used with the APT or DG- 700 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 14

15 Duct Blaster Manometer Setup for Pressure Pan Pressure Pan Testing Zonal Testing Channel A Channel B This test is is used to determine which areas of the House are INSIDE and which areas are OUTSIDE Pressure (Air) Boundary Channel A: is House WRT Outside Channel B: is Duct WRT House 15