2.5.2
Smoke Dampers [and Combination Smoke/Fire Dampers]
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NOTE: Use combination smoke/fire dampers only where
required by NFPA and design manuals.
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Smoke dampers and actuator assemblies as required in accordance with NFPA
90A shall meet the Class II leakage requirements of UL 555S. Dampers shall
be factory fabricated, galvanized steel or stainless steel with lubricated
bearings, linkages, and seals to withstand temperatures from minus 29 to
121 degrees C 20 to 250 degrees F. Provide replaceable seals.
[Combination smoke/fire dampers shall have a UL 1.5 hour rating and shall
be equipped with electric/thermal links which close the damper at 74
degrees C 165 degrees F and then automatically reset after normal
temperature is restored by cycling damper actuator.] Equip dampers with
pneumatic or electric actuators which close smoke dampers tightly when
activated. After the smoke has cleared, the dampers shall automatically
reset.
2.6
SENSORS
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NOTE: Use smallest span sufficient to cover the
operating range. Use 0.06 degrees C 0.10 degree F
allowable tolerance sensors where small temperature
changes will have large impact on energy
consumption; e.g., chilled water, where the span is
nominally 4.44 to 6.67 degrees C 8 to 12 degrees F.
The normal 0.28 degree C 0.5 degree F sensor would
have an error of 3 to 6 percent: 0.28 degree C 0.5
degree F divided by 4.44 degree C 8 degrees F
equals .06 or 6 percent.
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NOTE: Indicate outside air sensors mounted on a
north wall if possible; a fan-type air aspirator if
necessary to avoid effects of wind, rain, solar
radiation, and building outside air film; and also
indicate a power source for the aspirator.
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2.6.1
Spans and Ranges
Transmitters shall be calibrated to provide an electric or electronic
output signal of 4 to 20 mA electric or electronic and 21 to 103 kPa 3 to
15 psi output for pneumatics over the indicated span or range.
[a.
Conditioned space temperature, from 10 to 38 degrees C 50 to 100
degrees F.]
[b.
Duct temperature, from 4 to 60 degrees C 40 to 140 degrees F.]
[c.
High temperature hot-water temperature, from 93 to 260 degrees C
200 to 500 degrees F.]
[d.
Chilled water temperature, from minus one to 27 degrees C 30 to
80 degrees F.]
SECTION 15901N
Page 22
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