Testing Fan Filter Units Monroe A. Britt Manager, Research & Technology Clarcor Air Filtration Products Louisville, KY 502 969 2304 x1260 -- mbritt@clcair.com

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

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

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

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 -- 50 or 60 Hertz Acoustical Packages Other Variables

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

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

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

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

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

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

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

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

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

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

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

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

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 10 -12 Watts LP = Sound Pressure Level, dB re 10-5 N/m2 S1 = Total Area of Measurement Surfaces - m2 S0 = 1.0 m2

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

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

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

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

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