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Chapter 6: Maintaining Your Filtered Enclosure
Purpose
After installing the new HEPA filter, the HEPA filter should be
leak checked. This test is performed to determine the integrity of
the HEPA filter, the filter housing, and the filter mounting frames.
Leak testing is to be done by a qualified technician with calibrated
equipment. Remove the top perforated exhaust cover by using a
Phillips screwdriver to unfasten the (2) screws used to secure (2)
clips. See Figure 6-1. The filter passes the leak test at .01% or
better. Reference Leak Testing and Photometer scanning from the
Institute of Environmental Services (IES-RP-CC001.3)
Apparatus
1. An aerosol photometer ATI model 2D, 2E, 2G or
equivalent. Air Techniques Hamilton Associates inc. 11403
Cron Ridge Dr. Owings Mills, MD 21117
2. One aerosol generator of the Laskin nozzle(s) type. An
aerosol of mineral oil or suitable liquid shall be created by
flowing air through it. The compressed air supplied to the
generator should be adjusted to a pressure of 10± 1 psig. during
operation. Air Techniques Inc. Model TDA-4A or equal. One
nozzle at 10 psig is (67.5 cfm x 100ug/l)/(Vol. of air), For the
2' at 90 fpm or 130 cfm, one nozzle @10 psig is 13,500/130
cfm = 52 ug/l. For the 3' at 90 fpm or 200 cfm, one nozzle @
10 psig is 34 ug/l. For the 4' at 90 fpm or 265 cfm, one nozzle
at 10 psig is 26 ug/l.
3. Mineral oil (Catalog #1491400).
4. Sampling Nozzle, Rectangular 1/2" x 3-1/4", Air Techniques,
Inc.
Procedure
For the ATI 2G Photometer
1. Turn on the photometer and allow it to operate for a minimum
of 5 minutes. Leave the valve in the “CLEAR” setting.
2. Press the “ENTER” keypad. Press the “REF” keypad.
The display will display “P1” for approximately 1 second,
and then display a numerical value.
3. The display will display “P1” for approximately 1 second, and
then display a numerical value.
HEPA