[2.3.1
Finger Stock
ASTM B 194, Condition HT. The finger stock shall be secured to the door or
frame without using special tools or soldering or adhesives and shall have
a minimum overlap of 50 mm 2 inches.
]2.3.2
Latching Type
Provide lever controller door with roller cam action requiring not more than
90 N 20 pounds of operating force on the handle for both opening and
closing. The door shall be equipped with a three-point latching mechanism
that provides proper compressive force for the RF seal. The mechanism
shall be operable from both sides of the door and shall have
permanently-lubricated ball bearings at points of pivot and rotation. The
door latches and hinges shall be rated for a minimum of 10,000 cycles
without loss of attenuation and without adjustments.
2.3.3
Nonlatching Type
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NOTE: Nonlatching doors may be used for enclosures
having many daily open-close operations; however,
nonlatching doors may not retain as high as
attenuation over the long term compared to doors
having three-point latching mechanisms.
**************************************************************************
Provide door equipped with three heavy-duty ball bearing hinges and a door
pull. Door shall open and close with a force not to exceed 20 N 5 pounds.
2.3.4
Special Door Assemblies
2.3.4.1
Hydraulic or Pneumatic Sealing Mechanism
Shall accomplish the electromagnetic sealing of the opening by use of
pressure to force the door panels against the frame surfaces. The contact
areas of door and frame shall be a peripheral strip not less than 75 mm 3
inches wide, completely around the door, of tinned or highly conductive
noncorrosive surface. After the door is in sealing position, the sealing
mechanism shall accomplish the exertion of pressure in not more than 10
seconds. Actuation shall be possible from both inside and outside of
enclosure. Release mechanism shall actuate in not more than 5 seconds and
shall be provided with a manual override. The mating and sealing of the
door to frame shall be further enhanced by two peripheral rows of beryllium
copper 6 by 25 mm 1/4 by one inch mesh gasket or beryllium copper finger
stock. Removal and replacement of finger stock or gasketing shall be
possible in less than 8 hours without the use of soldering or special
tools. When the door is sealed, the attenuation around the edges shall
meet the requirements of this specification. Provide a threshold of
zinc-plated steel, not less than 10 mm 3/8 inch thick, at each swinging
door. The steel shall be the same alloy as the shielding steel.
2.3.4.2
Sliding Doors
Shall be manually operated from either inside or outside of the shielded
enclosure with a maximum break-away pull of [160 N] [35 pounds][_____] in
the unsealed condition. The door shall center inside of the steel RF
sealing frame designed for the forces involved. The door shall form an RF
seal by the operation of an air valve so that the door shielding, on both
SECTION 13094N
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