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MQL • GUIDE SPECIFICATIONS
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2.0 Fan decks shall be internally spring isolated (one-inch deflection) with the fan outlet connection to be
made using canvas duct.
3.0 Each unit shall have one fan wheel and housing only.
4.0 Fan wheels shall be designed for continuous operation at the maximum rated fan speed and motor
horsepower. Fan wheels and shafts shall be selected to operate at least 25% below the first critical
speed, and shall be statically and dynamically balanced as an assembly.
5.0 Fan shafts shall be solid steel, turned, ground and polished.
6.0 Fan bearings shall be self-aligning, non-regreasable (permanent) ball bearing type selected for an aver-
age life (L
50
) of 100,000 hours at design operation conditions, per ANSI Code B3.15.
7.0 Fan motor shall be mounted within the fan section casing. Motor shall be NEMA Design B with sizes and
electrical characteristics as shown on the equipment schedule.
8.0 Fan drive shall be designed for a minimum of 1.15 service factor and shall be factory mounted and
aligned. Belt drive package shall be variable-pitch type (constant volume) or fixed-pitch type (variable
volume).
D. Coil Sections:
1.0 All coils shall have aluminum plate fins mechanically bonded to 1/2-in. OD seamless copper tubes by
mechanical expansion. Coils shall be factory leak tested at 450-psig air pressure under water in an illu-
minated test tank. Copper tubes shall be either 0.016” or 0.025” copper tube wall thickness. Coils shall
have G90 galvanized steel or stainless steel casings with copper headers and sweat connections.
2.0 Chilled water coils shall have a working pressure of 300-psig at 200° F. No turbulence-promoting devices
will be permitted inside the tubes. Headers shall have vent connections.
3.0 Direct-expansion coils shall be provided with pressure-type brass distributors with solder-type connec-
tions. Coils shall be designed and tested in accordance with ANSI/ASHRAE 15.
4.0 Hot water coils shall have a working pressure of 300-psig at 200° F. No turbulence-promoting devices
will be permitted inside the tubes. Headers shall have vent connections.
5.0 Steam distributing coils (standard single tube type) shall have a maximum working pressure of 15-psig at
ambient temperatures above 35° F. Tube wall thickness shall be 0.025” as standard.
6.0 Electric heat coils for use in blower coil units shall be open coil type, nichrome wire resistance elements,
insulated by floating ceramic bushings. Thermal cutouts for primary and secondary over-temperature
protection shall be provided to meet UL and NEC requirements. Maximum element watt density shall be
55-watts/sq inch. The manufacturer shall furnish an integral control box. It shall contain primary and sec-
ondary control thermal cutouts, relays, airflow switch, and fused control transformer.
E. Filter Sections:
1.0 Each filter section shall be designed and constructed to house the specific type of filter specified on the
equipment schedule.
2.0 Flat filter sections shall accept 2-in. 30% (MERV-6) pleated filters of standard sizes. Sections shall
include side access slide rails. Flat filter section shall be arranged with minimum depth in direction of
airflow.
3.0 Angle filter section shall accept 2-in. 30% (MERV-6) pleated filters of standard sizes arranged in horizon-
tal V formation. Sections shall include side access slide rails. Angle filter section shall be arranged with
minimum depth in direction of airflow.
F. Damper Sections:
1.0 Mixing boxes, filter mixing boxes and economizers shall have parallel blade, interconnecting dampers.
Damper blades shall have parallel bends for stiffness and shall be mechanically fastened to steel rods
rotating in brass bushings and mounted in rigid galvanized steel frames. Dampers shall be sectionalized
to limit blade width, minimize blade warpage, and ensure tight closure.
2.0 All dampers for mixing boxes and filter mixing boxes shall be rated with a leakage rate not to exceed 5%
of air quantity calculated at 2000 fpm velocity though damper and 4.0-in.wg. pressure difference.
Damper blades shall be gasketed and stainless steel perimeter-sealing strips shall be provided. Damper
linkage shall be provided and installed with all mixing boxes.
G. Access Sections:
1.0 Access sections shall be installed where indicated on the drawings and shall be as specified on the
equipment schedule.
2.0 Access sections shall have removable access panels.
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