Learn about the variety of tools and test instruments that apply in RESNET standards 310 (pending) and 380. We'll cover the proper procedures as well as pros and cons of various devices.

1. Overviewof DiagnosticTesting
EquipmentUsedin RESNETstandards
Bill Spohn
President, Owner,TruTechTools, LTD
2020 RESNET Building
Performance Conference
Scottsdale, AZ
February 26, 2020

2. BillSpohn
 Bacharach, Inc.
 Testo, Inc.
 TruTechTools, LTD
 BS & MS ME
 Professional Engineer
 Standards committees
 Consultant, trainer
 Podcaster:
 Building HVAC Science
 RESTalk
2019
The Team that makes possible what I do!

4. Our topic
 Tools and test instruments that apply in RESNET standards 310
(pending) and 380
 NOTE:

Use RESNET website as you source for info on the standards
 https://www.resnet.us/about/standards/resnet-ansi/
 Overview of 380 changes in 2019 version:
 www.bit.ly/380-2019-info

5. Which
standards?
 Standard 310. (proposed) is the standard for grading the
installation of HVAC systems with 5 steps
 www.bit.ly/310-DRAFT
 Standard 380 is the Standard forTesting Airtightness of
Envelopes, Ducts Systems; andAirflow in MechanicalVentilation
Systems
 2016: www.bit.ly/380-2016
 2019: www.bit.ly/380-2019

6. Applicability of
the standards
 ENERGY STAR National Program Requirements Rev 10 is available
for use now and will be required for ENERGY STAR Certified
Homes permitted on or after Oct. 1, 2020.
 It integrates the new ANSI/ACCA/RESNET Standard 310, as an
option, once completed.

7. What is
standard 310?
 Evaluation of installation quality of Unitary HVAC systems.
 Comprised of five tasks –
 a design review
 a total duct leakage test
 a Blower Fan volumetric airflow test
 a Blower Fan watt draw test
 a non-invasive evaluation of refrigerant charge
 The five tasks are designed to be completed in sequence and upon
completion of each task, the results are evaluated for compliance
with specified thresholds.

8. Where does
standard 310
apply?
 Unitary HVAC Systems
 Air conditioners and heat pumps up to 65 kBTUh (5.4Tons)
 Furnaces up to 125 kBTUh
 Detached one- and two-family Dwellings,Townhouses, as well as
in Dwelling Units and Sleeping Units that have their own HVAC
system separate from other units
 It is intended for use by home energy raters, energy auditors, code
officials, or HVAC contractors.

9. Standard 310 Stop or Go Approach

10. 310:
Section 4:
Evaluate the
design
 Lots of detail collection
 Manual J and S are employed
 Rating of data collected against the standard’s requirements.

11. 310:
Section 5:
Total Duct
Leakage
 Measure in accordance with RESNET Standard 380
 Coming up!
 Rating

12. 310:
Section 6:
BlowerCFM
 6.4 Pressure Matching Method
 6.5 TrueFlow Grid
 6.6 Flow hood
 6.7 Static PressureTables
 Or
 On Board Diagnostic system output
 Sec. 8.6 of ASTM E-1554-13
 Appendix A ASHRAE 152-2004
 CEC RA3.3 (2016 Reference Appendices)

13. 6.4 Pressure
matching
 In place of door, on an extension, at central return
 Match the NSOP

14. TrueFlow® Plate (Pitot Array) or Flow Grid
 How it works
 Like multiple Pitot Tubes yielding an
average velocity sampled over large
area
 Benefits
 Fast to set up, adjustable
 Central return or in filter slot
 Very close to “run conditions” (NSOP)
 Limitations
 Needs specific digital manometer
 If >1 central return, need one
simultaneously in each return
 Applications
 System airflow
Cost ~$895 + precision manometer

15. The
TrueFlow®
Air Handler
Flow Meter
Passive intercept flow
measurement
• Obstructions within 6” upstream or 2”
downstream that block air flow may
reduce accuracy
• If there is an obstruction and using a
spacer, place spacer is directly in front of
the obstruction
• If installed downstream of a 90 degree
bend and using a spacer orient it so
spacer is on the inside corner of the bend.

16. The Energy ConservatoryTrueFlow® Air Handler Flow Meter
TrueFlow® Air Handler Flow Meter is a registered trademark of The Energy Conservatory

17. 6.6 Flow hood
 Accuracy +/-3 % + 7 CFM
 Range must suit your system air flow range
 Place over each Return Grill and sum
 Measure for 10 seconds
 Correct for back pressure

18. Capture Devices in general
 Flow hoods
 Typically Pitot array
 Benefits
 Fast to set up and use
 Captures all the air, if hood skirt is right
 Snapshots
 Multifunction meters
 3 ranges : 500, 1250 & 2500 CFM
 Limitations
 Accuracy is mass dependent/corrected
 Back pressure compensation
 Flow straighteners
$1500 - $2200 - $3200

19. Testo 420
 Great price point: ~$2162
 Lightweight
 BlueTooth to app
 Swirl reducing grid built in to skirt
 Temperature, Humidity & Barometric readings *
 Detachable precision manometer
 * used internally for corrections

20. ACIN Powered Flow Hood
Flow Finder MK2
• Internal fan and sensor
compensates for back pressure
• Up to 500 CFM supply or return
• High accuracy
• Single piece
• Light weight (5 lbs)
COST = $2950

21. 6.7Static
Pressure
Tables
 OEM “Fan Curves”

22. Static Pressure Tip
 How it works
 Static or balloon pressure of air is delivered to
a pressure sensor
 Benefits
 Easy to use, cost effective
 Limitations
 Air Density correction considerations
 Does not directly equate to airflow
 Applications
 In duct measurement
Price $ 20 each, usually need 2 plus a decent manometer
Connect hose here->
Static
Static

23. Total External Static Pressure
 Manufacturer profiles each heat exchanger or evaporator coil
 By measuring across system components (coil or HX)
 CFM
 Pressure drop
 Creates a table of CFM at ESP for various configurations
 The industry standard for TESP in equipment design is ½”wc,
ranges from 0.3-1.0” H2O are possible
 ECM motors produce odd results

27. RESOURCES
 Free guide to testing TESP
 www.bit.ly/TTT-ESP
 20 Minute video lesson
 www.bit.ly/ESP-VIDEO
 Look for Energy Star Videos on ”How to”
 www.bit.ly/380videos

28. CFMGrade

29. Section 7
BlowerWatt
Draw
 +/- 2% or +/- 10W
 7.4 Plug inWatt Meter
 7.5 Clamp on power meter
 7.6 Analog Utility meter
 7.7 Digital Utility meter
 OR
On board Diagnostic System

30. Plug in watt
meter

31. Clamp on
power meter

32. Section 8
SystemCharge
 8.4 Non Invasive system test
 Thermometer (+/- 1.8 deg F)
 OA DB
 Humidity probe (+/- 1.8 % +3%)
 RAWB & DB
 Pipe clamp probe (+/- 2.3 deg F)
 Liquid LineTemp
 8.5 Weigh the charge

33. Standard 380
Standard for Testing:
Airtightness of Building
Enclosures
Airtightness of Heating &
Cooling Air Distribution
Systems
Airflow of Mechanical
Ventilation Systems
Blower door test:
Airflow calculated from
manometer pressure
Duct leakage test:
Airflow calculated
from manometer
pressure
Here’s where it gets
complicated……

34. “Which
equipment is
RESNET
approved?”
 The airflow (at outlet terminal) is permitted to be
measured using a Powered Flow Hood (Section
5.2.1) or using a Bag Inflation Device (Section 5.2.2).
 Standard 380 sets the specifications for the
equipment used to perform the tests covered by that
standard.
 As long as the testing equipment meets the technical
specifications for the type of equipment specified for
the test, the equipment can be used to perform the
test.
 RESNET does not endorse or approve specific
pieces of equipment.”

35.  ‘testing volumetric airflow”: CFM
 3 choices of where you can measure
 What is being assumed here…….?

36. Ventilation System Measurements
At an air INLET TERMINAL
by the book (Standard 380)
 Powered flow hood
 Retrotec Acin FlowFinder®
 Duct tester adapted to be a powered flow hood
 FlowBlaster® <- now out of production
 Air Flow resistance device
 TEC Exhaust Fan Flow Meter
 Use only if there is ONE BRANCH
 Only when box pressure is between 1-8 Pa
 Passive Flow hood
 Tolerance of +/-5% or +/-5 CFM
 Only when back pressure is < 8 Pa

37. Ventilation System Measurements
At an air OUTLET TERMINAL
by the book (Standard 380)
 Powered flow hood
 Acin FlowFinder® Retrotec
 FlowBlaster® <- now out of production
 Bag inflation device: must make your own
 Airtight perimeter seal
 Plastic bag of known volume
 Frame to hold the bag open
 Shutter that controls airflow into the bag
 The thickness of the bag shall be selected such that three or more
measurements of a single outlet terminal produce results that are within
20% of each other.
 Volume of the bag chosen so bag fills within 3 to 20 seconds.

38. The PVCD
 The polymeric
volumetric capture
device
 AKA The garbage bag
 Works by timing how
long it takes to fill a
known volume with air
 Use a “pressure spike”
inside bag to indicate
full

39. Garbage Bag Flow
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
375
400
425
450
475
1
1.5
2
2.5
3
3.5
4
5
6
7
8
8.5
9
Seconds to fill bag
CFM
33 gallon
55 gallon

40. Bag Inflation Device: Truly capturing it.

41. AirProbe (Averaging FlowStation)
 How it works
 Similar to an averaging Pitot Tube
 Benefits
 Easy to use, cost effective
 Limitations
 MUST be exact size of duct
 Denser air has more mass, thus more pressure at a given velocity
 “Lower velocity” limits only with precise manometer with calculation
 1” diameter hole to drill and plug
 Must use specific equation, not a Pitot Tube
 Reading changes with orientation to up stream elbows
 Other look-a-likes available, use each with extreme care
 Applications
 In duct measurement
Price <$100 plus manometer $200, about $300 total

42. CFM = 800
Area = 1 sq ft
Vel = 800 FPM
dP = (Vel / Kv) 2
dP = 0.102 IWC
Or: www.bit.ly/Kele-Calc

44. www.redcalc.com/red-calc-free/

45. Dwyer MAFS
A different
product!
 Air velocity calculation
 1096.2 x Cp x SQRT (Pv/D)
 Pv = pressure in IWC
 D = Air Density in Lbs/Ft3
 Cp depends on MAFS length
 D = 1.325 x Pb /T
 Pb = Barometric pressure in IN HG
 T = AbsoluteTemp in Kelvin
 Kelvin = F + 460
 Location in straight run
 10 to 15 DD upstream and 5 DD downstream
 8” duct means 6.6 to 10 feet UP and 3.3 feet down
MAFS
PAFS
Use only with a reference

46. Powered Flow Hood
Flow Finder MK2
• Internal fan and sensor
compensates for back pressure
• Up to 500 CFM supply or return
• High accuracy
• Single piece
• Light weight (5 lbs)
COST = $2950

47. Manometers matter
 Oftentimes pressure is used as the core measurement
in airflow
 Know the range and necessary accuracy of your
measurement
 Low cost manometers may give you 100% error if used
in the wrong application
 Just because you see a stable number does not mean
the reading is accurate.
 If pressure is off by 10%, calculated flow is off by 5%

48. Exhaust Fan Flow Meter
,’,’,’,’ ,l
,,’’,’,’,’,
DG-700
InputInput
T
DM32
RefInput
T
Ch A Input - monitoring the pressure
Ch B Ref – Calculating the results
Channel A Must be
between 1 – 8 Pa
Tubes “T” together

49. Exhaust Flow measurement
experiment with Kele
AirProbes
courtesy of
Steve Rogers

50. Flex duct was around a cylinder to insure it had a bend radius equal to the
duct diameter like the manufacturer specifies. The segmented adjustable
elbow was set to 90 degrees.

52. 1-888-224-3437 INFO@TRUTECHTOOLS.COM
WWW.TRUTECHTOOLS.COM
SPECIAL OFFER for RESNET CONFERENCE ATTENDEES
ONLY!
Use coupon code:
testo20resnet20
For 20% off your order on any testo products
May not be combined with any other coupon, offer or promo.
Expires 3-31-20

53. fin