Description
A radial flow HEPA filter is used to minimize size and increase worker protection during filter change-out. The airflow pattern on the unit directs the contaminated air to the inside of the filter, so that workers are exposed to the “clean” side of the filter during change-out. An optional adapter plate is available to turn a single stage unit into a dual stage HEPA filtration module. A disposable inlet adapter is provided that can remain on the filter during change-out. When a sleeved umbilical cut technique is used to separate the inlet ducting, the contaminated internal of the HEPA filter (first stage filter if configured for dual stage) is never exposed during filter change-out.
The HEPA filter is rated at 250 cfm at 1.3 inches of static pressure clean, and is 99.97% efficient at 0.3 μ as tested on a Q107 penetrometer (in accordance with MIL STD 282) at 100% and 20% of rated flow. Filters are gel seal style and use dimple pleat construction with face guards both upstream and downstream. Differential pressure gages (Minihelic 0 -10” wc) are installed to monitor filter dirt loading on each filter stage.