Page 3 - BPS-PIAD-Technical-Bulletin

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Selecting your PIAD Model Number

Please see Page 4 for all available options
Step 1 - Determine the Overall Dimensions of your Protected Devices
Measure the overall height and width of all protected devices, being sure to
include all mounting bezels or trim.
Step 2 - Determine your PIAD Window Dimensions & Hinge Location
Add 1” to overall Height & Depth of your Device(s), to provide adequate mounting
frame clearance, and then determine which side of the PIAD you prefer to hinge.
Step 3 - Determine your PIAD Size Range
We use two letters to specify the Hinged Side and Adjacent Sides Size Ranges.
Step 4 - Determine your PIAD NEMA Rating
We offer NEMA 12, 4 or 4X Ratings to meet your installation site conditions.
Step 5 - Determine your PIAD Depth
Measure the distance your device(s) will project or protrude from the surface
of your enclosure to determine how much internal clearance is required.
Step 6 - Select a preferred material for your PIAD Frame and Door
304 or 316 Stainless Steel may be selected for any application, but Carbon
Steel is not suitable for NEMA 4X ratings.
PIAD Mounting Clearances
Step 7 - Select a preferred window material for your PIAD
Safety Glass or Lexan are suitable for any application, but we advise against As illustrated above, it’s critical to add 1” to the bezel or trim height
selecting wire reinforced glass, unless required by the authority having jurisdiction. and width dimensions of your protected device(s) to ensure your

Step 8 - Select a preferred finish for your PIAD Frame and Door PIAD will fit easily around them and establish a window size.
Black or Custom Color Powder Coatings are available for any Material, but As illustrated below, it’s also essential to add 10” to your bezel
brush finishes are only offered for Stainless Steel Materials. or trim dimensions to ensure you’ll have adequate clearance
around the perimeter of your PIAD. This will ensure it does not
Step 9 - Select a preferred Door Latch Style and Operator for your PIAD interfere with mounting other devices adjacent to your PIAD.
Powder Coated Die Cast Zinc Latches are suitable for NEMA 12, 4 and 4X
Ratings, and Stainless Steel Latches are available for highly corrosive areas.

PIAD Latch Operator Options

The vice action compression latches utilized on Best Purging Systems model PIAD provide
a positive seal for the door gasket to meet NEMA 12, 4 or 4X standards. The compression
latches are available in three different styles, as described below:
Hand Operated Latch - A black polyester powder coated
die cast zinc or electro-polished 316 stainless steel knob
allows easy operation of the compression latch with a
thumb and forefinger. This latch is recommended when
general or unregulated access to the PIAD is required
and the enclosed equipment is not protected by Type X
pressurization.
IMPORTANT NOTE: If utilized on Type X pressurized
enclosures, an electrical interlock rated for the area is
required to deenergize power to all non rated equipment
to comply with section 5.5.2 of the NFPA 496-2017 edition.
Key Operated Latch - This latch requires a special key
to operate. One key is supplied with each PIAD and
additional keys are available upon request. This latch is
recommended when authorized or regulated access to Ventilation Requirements
the PIAD is required and/or when the enclosed equipment
is protected by pressurization.
When your PIAD is utilized on purged or pressurized enclosures,
IMPORTANT NOTE: When utilized with a Type X it is critical to satisfy NFPA Section 5.2.6 requirements regarding
pressurized enclosure, the key operated latch complies protection of compartments adjacent to the protected enclosure.
with section 5.5.2 of the NFPA 496-2017 edition,
eliminating the need for electrical interlock switches. We provide complementary technical assistance in this situation
by helping you determine if the device(s) your PIAD is protecting
Tool Operated Latch - This latch requires a customer will adequately ventilate the sealed area created by the PIAD.
supplied 5/32" hex head tool to operate. This latch is If your devices do not provide adequate ventilation, we can
recommended when authorized or regulated access to recommend methods to 1) properly ventilate the sealed area
the PIAD is required and/or when the enclosed equipment within the PIAD (which NFPA 496 defines as an adjacent
is protected by purging or pressurization. compartment); or 2) purge and/or pressurize the area created
IMPORTANT NOTE: When utilized with a Type X by the PIAD, either separately or in series with your protected
enclosure, depending on the surrounding Area’s Classification.
pressurized enclosure, the tool operated latch complies
with section 5.5.2 of the NFPA 496-2017 edition, Please contact our Sales Associates and Technical Consultants
eliminating the need for electrical interlock switches. for more information, guidance and recommendations.

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