C-3 and C-4
Crank Lock HEPA Filter Housing
Bulletin PB1604-0107
Important Features
• Choice of frame construction materials
• Stainless steel filter locking mechanism for
strength, durability and long-term integrity
• Access for up to four filters and prefilters wide
per door for quick filter changeout
• Double pin hinges enable the doors to make
level contact with the door gasket for a uni-
formly tight seal
General
C-3 and C-4 Side Access HEPA/ULPA Filter Housings
are designed for use with nominal 12 inch deep
HEPA/ULPA filters. They are factory-assembled
flanged units suitable for gel sealed or gasket sealed
HEPA filters. Both the prefilters and the primary
HEPA/ULPA filters are serviceable through the same
gasketed side access door.
Versatility
C-3 and C-4 housings may be used with Alpha 95 fil-
ters (95% DOP efficiency) and with Alpha Cell and
Alpha 2000 filters (99.97% and 99.99% DOP efficien-
cy). Standard housings accept nominal 12 inch deep
filters and 16” and 18” carbon adsorbers in a variety
of face sizes. They can be arranged from one filter
high and one filter wide to four filters high and eight fil-
ters wide. If large housings are not practical to rig into
place, smaller units may be stacked in the field.
Options
• Choce of frame construction materials
• Insulation
• Lifting lugs
• Transitions
• Static pressure ports
• DOP test ports
• High temperature modifications
• Weathercap
• Magnahelic gauges (mounted)
• PrefilterTrack
Construction
Housings are 24 inches deep in the direction of air
flow, (26 inches deep if it has a 4” prefilter section.)
and are constructed in your choce of frame materials.
Flanges are furnished for duct connections on the air
entering and air leaving sides. All joints are intermit-
tently welded and finished to remove all burrs and
sharp edges. The joints are then sealed with silicone
enabling the housing to withstand an internal pressure
of +/- 3.0 in. w.g.
The filter locking mechanism for the fluid gel seal-
model housing is a 300 Series stainless steel hand-
operated arm that moves the filter s gel-filled channel
on to the internal housing knife edge sealing flange.
The same mechanism also pulls the filter away from
the sealing flange when changing filters. The filter
locking mechanism for gasket seal-model housing is a
300 Series stainless steel and brass device. The
mechanism presses the gasketed filter against the
housing s sealing surface by means of a mechanical
bolt and thrust assembly that is manually operated
using a standard 3/4 inch socket or wrench.
Standard 2 inch or 4 inch prefilter tracks will accom-
modate pleated panel filters with efficiency ranges up
to 50% per the ASHRAE Standard 52.2 dust spot test
methods. Access doors have 0.5 in. thick closed cell
neoprene gaskets around the inside perimeter.
Double pin door hinges which pivot, allow the door to
make level contact with the gasket when closed.
Stainless steel wing nuts secure the doors.
Flanders Filters - Foremost in Air Filtration
Toll Free: 1-800-637-2803
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