What you will learn What is pressure? The importance of pressure in houses Get to know your pressure gauge Using a digital pressure gauge Pressure gauge tests on houses Pressure gauge troubleshooting
What is Pressure? Residential Pressure Measurement
What is Pressure?
There are two types of pressure that can be measure on a digital gauge.
Measure indoor/outdoor bias pressures caused by: Stack effects & Wind effects To outside -1.0Pa
Bias due to wind and stack Bias pressures under windy conditions
Press [Time Avg], until test pressure varies less than 1Pa. Stabilizes readings Wait for 2X time average period before taking a reading.
Testing in windy weather Use [@ Pressure] key (if available) Increase Time Average to minimize fluctuation Wait at least double the time averaging period before taking a reading Shelter outdoor tube T equal lengths together Move outdoor tube 15 feet from building Cover tube ends with towel
Use a wind dampening kit
What does taking a baseline do? Take a baseline to negate the effects of bias pressure and wind fluctuations.
The measure baseline is automatically subtracted from the displayed readings. 1. Press [Baseline] once. 2. Press [Start] once 3.Wait until number is steady then press [ENTER] once to save. BASE LINE
The measured baseline is subtracted from the pressure reading on Channel PrA. 1. Press [Baseline] once 2. Press [Enter] after about 60 seconds.
Clearing the Baseline feature on both gauges Learn when and how the baseline is cleared from each gauge. Leaving the baseline on, or forgetting that it s off can cause errors during testing.
Pressure gauge Troubleshooting Residential Pressure Measurement
Avoid Problems
Gauge field check Insert a T in the tube and connect it to one reference port. Connect the other reference port as shown. Increase the fan speed and compare Channel A and Channel B. Values should be within 1% of each other. Remove the tubes from the two reference ports and attach to the two input ports. Repeat the test.
Learn to perform a calibration check on a digital gauge. It s a quick and simple way to verify that the gauge is working correctly.
Cross Port Check 1 2 35.2 Pa 35.6 Pa -35.2 Pa -35.6 Pa 3 35.2 Pa 35.6 Pa
Move tubes around and notice the effect A moving tube can generate pressure in the tube. Do not allow tubes to hang in the path of moving air. To outside 8.0Pa
Time averaging can lead to false results if the time averaging period is not taken into account when measurements are being taken. Always wait twice (2X) the time averaging period before taking a reading.
Pinched tubes Pinching or squishing a tube causes the measured pressure to increase
Water in tubes = massive errors Water trapped in tube compresses air in the tube, even with autozero turned ON. Shake out the water to clear the pressure. A single water drop can block air pressure readings.
What can cause problems with measurements?
What happens? Selecting the wrong Flow Range, or wrong device can lead to incorrect results.
Some common problems are frequently seen when taking multi-point tests.
Introduction Residential Duct Leakage Measurement rev-2011-02-21
Image Courtesy of The Energy Conservatory Image Courtesy of Retrotec Inc
Flex duct Flex duct Calibrated Fan Image Courtesy of The Energy Conservatory Flex duct flange Image Courtesy of Retrotec Inc
Image Courtesy of Retrotec Inc A DucTester system includes: DU-220 Fan with 3 flow rings + case 12 Flex-duct DM-2A Digital Manometer + bag Static pressure probe 20 umbilical Quick Guides 12 roll of Grill Mask Image Courtesy of Retrotec Inc
Duct Blaster includes: Duct Blaster fan with 3 flow rings + case DG-700 Digital Pressure and Flow Gauge 12 flex duct Duct Blaster Training video and manual Static pressure probe Sample roll of 8 DuctMask Image Courtesy of The Energy Conservatory
Minneapolis Duct Blaster Image Courtesy of The Energy Conservatory Retrotec DucTester Open Ring 1 (A1) 600-1000 cfm 225-800 cfm Ring 2 (B2) 90-300 cfm Ring 3 (C3 on gauge) 10-125 cfm Low Mid Open 5-25 cfm 25-125 cfm 100-600 cfm Image Courtesy of Retrotec Inc
Residential Duct Leakage Measurement 5 step, Total duct Pressurization test
5 step, Total duct Pressurization test 1. Connect to ducts 2. Prepare ducts and house 3. Connect gauge & fan (pressurization) 4. Measuring 5. No results displayed
Duct testing guides
Step 1: Connect to ducts Image Courtesy of Retrotec Inc Image Courtesy of The Energy Conservatory Image Courtesy of Retrotec Inc Image Courtesy of The Energy Conservatory Image Courtesy of The Energy Conservatory
Images Courtesy of The Energy Conservatory
Step 2: Prepare ducts and house Image Courtesy of Retrotec Inc
25 Pa 90 cfm
Image Courtesy of Retrotec Inc
Fan Pressure Tap Image Courtesy of The Energy Conservatory Electrical Connection
Turn the gauge On Press: ON/ OFF Press: x2 Press: x3 x3 x2 After being set up once, the gauge will return to the previous settings.
Manually adjust fan speed Image Courtesy of The Energy Conservatory Image Courtesy of Retrotec Inc
Open Mid
Minneapolis Duct Blaster Open Ring 1 (A1) 600-1000 CFM 225-800 CFM Ring 2 (B2) 90-300 CFM Ring 3 (C3) 10-125 CFM Retrotec DucTester Open Mid Low 100-600 CFM 25-125 CFM 5-25 CFM
Image courtesy of The Energy Conservatory -25 Pa 90 cfm Image courtesy of Retrotec Inc Image Courtesy of Retrotec Inc
Troubleshooting Not able to reach target pressure Check covers on all registers Tape may be being blown off during pressurization Duct system just too leaky to test accurately Change reference tube location (closer to air handler)
Connect the red and yellow ports. Both channels should have same reading within 1%.
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Pressurization leakage to outdoors Residential Duct Leakage Measurement
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Duct leakage to outdoors setup After completing the total duct leakage test, a duct leakage to the outdoors test can be completed by adding a door fan to the test setup.
Pressurization to outdoors 0 Pa 25 Pa 40 cfm Image Courtesy of Retrotec Inc 25 Pa 25 Pa 40 cfm
Duct leakage to outdoors test The duct leakage to the outdoors test neutralizes air leakage between the duct and interior of the house, by maintaining a zero pressure difference between the two. The leaks measured on the gauge connected to the duct fan is leakage to the outdoors only.
Pressurization to outdoors Single gauge 25Pa 25 Pa 25 Pa 40 cfm 100 cfm 40 cfm Image Courtesy of Retrotec Inc
Leak location Residential Duct Leakage Measurement
Duct Simulator setup Setup the duct simulator with leakage to the house and to the outdoors (with the house simulator tent). Build your own simulator out of a cardboard box with a hole of a known size
Large Building Testing Developed by Retrotec Inc.
Guiness World Record 15,000,000 cubic feet
average 0.62 Year of Year of Air-barrier Number of Floor Enclosure Construction retrofit? Stories Area Area Tested Permeablity ft2 ft2 cfm/ft2 @75Pa 2011-7 96,882 76,084 0.29 2011-7 96,882 76,084 0.39 2011-7 96,882 76,084 0.48 1987 2000 4 - - 0.92 1987 2000 4 - - 0.65 1985 2006 23 - - 0.37 1985 2006 23 - - 0.14 2001-4 - - 3.05 2001-4 - - 0.43 1990 2001 6 - - 0.29 1990 2001 6 - - 0.20 1990 2001 6 - - 0.24 1990 2001 6 - - 0.34 1990 2001 6 - - 0.35 1990 2001 6 - - 0.23 1978-7 - - 1.77 1978 2010 7 - - 0.90 1973-22 - - 0.44 1973 2008 22 - - 0.37
USACE test of 300 buildings 0.17 Year of Year of Air-barrier Number of Floor Enclosure Construction retrofit? Stories Area Area Tested Permeablity ft2 ft2 cfm/ft2 @75Pa 2012-8 2009-1 average 0.17
Acceptable air leakage? For a 4 story building, 120 x 110 x 8 ft, n=0.65 CFM75/ ft 2 USA ASHRAE 90.1 Leaky 0.60 USA Washington State 0.40 cfm/ ft 2 at 75Pa 0.40 UK TS-1Commercial Best Practice 5 m 3 /h/m 2 at 50 Pa 0.36 USA CDA LEED 1.25 in 2 EfLA @ 4 Pa/100 ft 2 0.30 USA ASHRAE 90.1 Average 0.30 USA USACE cfm/ ft 2 at 75Pa 0.25 USA USACE cfm/ ft 2 at 75Pa 0.15 Looser Tighter UK TS-1Commercial Tight 2 m 3 /h/m 2 at 50 Pa 0.14 CDA R-2000 1 in 2 EqLA @10 Pa /100 ft 2 0.13 USA ASHRAE 90.1 Tight 0.10
Real life test: EMAD Antwerp, Belgium Envelope Area = 11,250 m 2 0.601 CFM/ft 2 @ 75Pa 8.22 m 3 /h/m 2
Real life test: BTC South Carolina, USA Envelope A = 136,820ft 2 0.08 CFM/ft 2 @ 75Pa 1.5 m 3 /h/m 2
Real life test: Retrotec Vancouver, Canada Envelope Area = 25,000 ft 2 0.4 CFM/ft 2 @ 75Pa 7.3 m 3 /h/m 2
Face page and graphs for MFT
Estimating how many fans you need
Calculation based on a desired leakage requirement
Calculation using Retrotec s Number of Fan Calculator Spreadsheet
Test Scenarios ( Individual Control with FanTestic) Developed by Retrotec Inc.
FanTestic software
Problem 1 One Zone: Testing a single-zone enclosure requiring multiple fans.
Solution One Zone: Testing a single-zone enclosure requiring multiple fans.
Problem 2 Multiple Zones: Testing multiple zones requiring one fan on each separate zone. (These zones can be adjacent rooms or separated floors)
Solution Multiple Zones: Testing multiple zones requiring one fan on each separate zone. (These zones can be adjacent rooms or separated floors)
Problem 3A Multiple Zones: Testing multiple zones requiring multiple fans on each separate zone. (These zones can be adjacent rooms or separated floors)
Problem 3B Multiple Zones: Testing multiple zones requiring multiple fans on each separate zone. (These zones can be adjacent rooms or separated floors)
Solution Multiple Zones: Testing multiple zones requiring multiple fans on each separate zone. (These zones can be adjacent rooms or separated floors)
Connections that work best (Control cables) Developed by Retrotec Inc.
Large Building Testing Exercises Developed by Retrotec Inc.
Exercise 1 Imbalanced test fan flow caused by individual set points Developed by Retrotec Inc. Click to play video
Control Cable Control Cable Exercise 1 Imbalanced test fan flow caused by individual set points Red tubes attached with T-connecters
Exercise 1 Imbalanced test fan flow caused by individual set points 1. What is the difference between the two Door Fan speeds? (Pick the closest answer) 2%, 10%, 40% X, 80%. 2. What is the total leakage area? (Pick the closest answer) 10 in 2, 50 in 2 X, 100 in 2, 200 in 2. Developed by Retrotec Inc.
Exercise 2 Imbalanced test fan flow Solution : common set point Developed by Retrotec Inc. Click to play video
Control Cable Exercise 2 Imbalanced test fan flow caused by individual set points Only 1 gauge controls the speed of both fans
Exercise 2 Imbalanced test fan flow Solution : common set point 1. What is the total leakage area (EqLA)? (Pick the closest answer) 10 in 2, 20 in 2, 40 in 2 X, 60 in 2. Developed by Retrotec Inc.
Exercise 3 Uneven building test pressures between floors caused by common set point Developed by Retrotec Inc. Click to play video
Exercise 3 Uneven building test pressures between floors caused by common set point Only 1 gauge controls the speed of both fans Developed by Retrotec Inc.
Exercise 3 Uneven building test pressures between floors caused by common set point 1. What is the pressure of the right Simulator Tent? (Pick the closest answer) 10 Pa, 25 Pa, 50 Pa X, 100 Pa. 2. What is the pressure of the left Simulator Tent? (Pick the closest answer) 10 Pa, 25 Pa X, 50 Pa, 100 Pa. Developed by Retrotec Inc.
Exercise 4 Uneven building test pressures between floors Solution: individual set points Developed by Retrotec Inc. Click to play video
Exercise 4 Uneven building test pressures between floors Solution: individual set points Developed by Retrotec Inc.
Exercise 4 Uneven building test pressures between floors Solution: individual set points 1. What is the flow through the left Simulator Tent? (Pick the closest answer) 20 CFM, 120 CFM, 220 CFM, 320 CFM X. 1. What is the flow through the right Simulator Tent? (Pick the closest answer) 20CFM, 120 CFM X, 220 CFM, 320 CFM. Developed by Retrotec Inc.
Exercise 5 Uneven building test pressures between floors Solution: individual set point with manual control Developed by Retrotec Inc. Click to play video
Exercise 5 Uneven building test pressures between floors Solution: individual set point with manual control Developed by Retrotec Inc.
Exercise 5 Uneven building test pressures between floors Solution: individual set point with manual control 1. What is the flow through the left Simulator Tent? (Pick the closest answer) 20 CFM, 120 CFM, 220 CFM, 320 CFM X. 2. What is the flow through the right Simulator Tent? (Pick the closest answer) 20CFM, 120 CFM X, 220 CFM, 320 CFM. Developed by Retrotec Inc.