1. Testing Fan Filter Units
Monroe A. Britt
Manager, Research & Technology
Clarcor Air Filtration Products
Louisville, KY x

2. Testing Fan Filter Units
Objectives
To develop procedure for testing Fan Filter Units that will be recognized and used by manufacturers, consultants, contractors, and end-users
IEST has formed tentative Working Group to prepare Recommended Practice for publication
First Meeting – Held November 4, 2003, Approx 15 Attendees
Next Meeting – April at ESTECH – Las Vegas

3. Approach to Test Procedure
Develop procedures that can be readily conducted in manufacturers facility or after installation of units in cleanrooms
Instrumentation should be apparatus commonly used is the cleanroom industry
Standardized Reporting Form
Conduct blind “Round Robin” test program between various manufacturers and test labs to verify uniformity of test results

4. Testing Fan Filter Units
Physical Size -- Up to 4 Ft. x 4 Ft. Units
Test Parameters
Air Flow – CFM
Power (watts, amps, PF, volts)
Available External Static Pressure
Sound (pressure and power levels)
Filter Air Velocity Uniformity - FPM
Vibration

5. Air Flow - CFM Efficiency of Media -- HEPA Media, ULPA Media, ePTFE
Media Pack -- Depth of Pack & Pleat Spacing
Pre-Filters
Various Efficiency Levels of Particulate Filters
Gas Phase Filters
Room/Enclosure Pressurization and Exit Losses
Inlet Duct Connections & Duct Work
Height of Plenum above FFU Air Inlet
Current or 60 Hertz
Acoustical Packages
Other Variables

6. Air Flow - CFM Required Air Flow Expressed as Velocity -- FPM
Expressed as Volume -- CFM
CFM = Area x FPM
Area is Active Flow Area of Filter
(Typical 2 x 4 filter Without Center Bar
Contains 7.15 Ft2 of Active Filter Flow Area)
CFM at 90 FPM
90 FPM X 7.15 Ft2 = 640 CFM

7. Fan Filter Unit (FFU) FFU’s Without Constant Flow Control AC Units
ECM Units
FFU’s With Constant Flow Control

8. Air Flow - CFM vs Static Pressure
Test
Plenum
Resistance
(Pre-Filter)
Fan
Housing
Static
Pressure
Tap
Watt Meter
Filter
Flow
Hood
Measure
CFM
Static Pressure
Watts, Amps, PF, Volts
Transition Needed For 4 x 4 FFU

9. Air Flow - CFM vs External Static Pressure
FFU’s w/o Constant Flow Control
HEPA Filter
ULPA Filter
Pressure - Inches W.G.
ULPA Filter
w/Pre-Filter
No Scale
Air Flow - CFM

10. Air Flow vs Watts FFU’s w/o Constant Flow Control
ULPA Filter
w/Pre-Filter
ULPA Filter
Power Consumption – Watts
HEPA Filter
No Scale
Air Flow - CFM

11. Air Flow - CFM vs External Static Pressure
FFU’s with Constant Flow Control
HEPA Filter
ULPA Filter
Pressure - Inches W.G.
ULPA Filter
w/Pre-Filter
No Scale
Rated Air Flow
Air Flow - CFM

12. Air Flow vs Watts FFU’s with Constant Flow Control
ULPA Filter
w/Pre-Filter
ULPA Filter
HEPA Filter
Power Consumption – Watts
No Scale
Air Flow - CFM

13. Air Flow---Power---Static Pressure
Minimum Reporting Data
Complete Description of Fan Unit, Final Filter, and Pre-Filter -- Part Numbers, Construction Codes, etc
Nominal Rated Air Flow
Air Flow - CFM
Watts, Amps, Power Factor, Volts, Hertz
Available External Static Pressure
Dimensions and Active Filter Flow Area

14. Sound Pressure and Power Levels
Background Levels -- Recorded as First Step
Sound Pressure Levels -- To be Measured as Overall dBA, Overall dBL, and as dBL for Octave Bands -- Used to Report Sound Levels and Establish NC Curves for One Fan Filter Unit Installed in Typical Operating Environment
Sound Power Level -- To be Determined as Overall dB and as dB for Octave Bands -- Used by Acoustical Engineers to Predict Sound Pressure Levels in Actual Operating Environments. These Calculations Will Consider Number of FFU’s, Location of FFU’s and Sound Characteristics of Materials, Equipment, and Other Activity in the Individual Cleanroom

15. Sound Pressure Level Test Environment --- 8 x 8 x 8 Soft Wall Room Mic
Acoustical Tiles
3 ft.
Mic
Location
8 Ft.
7 Ft.
Concrete Floor - No Covering

16. Sound Pressure Levels Minimum Reporting Data
Complete Description of Fan Unit, Final Filter, and Pre-Filter -- Part Numbers, Construction Codes, etc
Nominal Rated Air Flow
Background Sound Pressure - dBL & dBA
Background Octave Band Sound Pressure - dB
Overall Sound Pressures -- dBL & dBA
Octave Band Sound Pressures – dB

17. Sound Power Level Test Environment --- 8 x 8 x 8 Soft Wall Room
Acoustical Tiles
3 In.
Plane of Mic
Locations
8 Ft.
7 Ft.
Concrete Floor - No Covering

18. Sound Power Levels
Sub-divide active filter area into equal square areas, maximum of 12” x 12”, minimum of 4 areas/filter
Measure overall sound levels for center points
Average all sound levels measured -- LP
Compute Sound Power Level for FFU -- LW
LW = LP + 10 Log (S1/S0)
LW = Sound Power Level, dB re Watts
LP = Sound Pressure Level, dB re 10-5 N/m2
S1 = Total Area of Measurement Surfaces - m2
S0 = 1.0 m2

19. Sound Power Level Minimum Reporting Data
Complete Description of Fan Unit, Final Filter, and Pre-Filter -- Part Numbers, Construction Codes, etc
Nominal Rated Air Flow
Grid with Measured Values – dB
Average of Measured Values -- dB
Calculated Overall Sound Power -- dB

20. Air Velocity Uniformity
Sub-divide active filter area into equal square areas, maximum of 12” x 12”, minimum of 4 areas/filter
Measure center point velocity for each area at 6 inches downstream of filter or protective grid
Take measurements for minimum of 5 seconds, using apparent average during that period as value for reporting

21. Air Flow Uniformity Minimum Reporting Data
Complete Description of Fan Unit, Final Filter, and Pre-Filter -- Part Numbers, Construction Codes, etc
Nominal Rated Air Flow
Grid with Measured Values – FPM
Standard Deviation of Measured Values

22. Vibration “Site Under Construction” Current Plans
Mount FFU in stiff aluminum frame that
will simulate proper sized ceiling grid
Suspend frame by flexible cables
Measure vibrations at corner of frame
Comments/Input Solicited

23. Future Activity Complete “Working Draft” of Proposed RP
Develop Comprehensive Data Reporting Form
Distribute Draft to First Meeting Members and All Interested Parties
Solicit Comments and Recommendations
IEST Working Group Next Official Meeting
April 25 – 28 , 2004
Riveria -- Las Vegas, NV
WG 036 Meets On April 26 at 8:00 AM