PART 2
PRODUCTS
2.1
COMPONENTS
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NOTE: Indicate control devices that must be in
enclosures with more stringent requirements than
that covered by NEMA 250 Type 1 and state the
requirements.
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Provide components factory ordered for this project. Rebuilt equipment,
warehoused equipment, or earlier generation equipment shall not be
acceptable. Electrical, electronic, and electropneumatic devices not
located within control panels shall have a NEMA 250 Type 1 enclosure in
accordance with NEMA 250 unless otherwise specified. Actuators and
positive positioners, and transmitters shall operate within temperature
limit ratings of plus 2 to 66 degrees C 35 to 150 degrees F. Panel mounted
instruments shall operate within limit ratings of 2 to 49 degrees C 35 to
120 degrees F and 10 percent to 95 percent relative humidity,
noncondensing. Devices installed outdoors shall operate within limit
ratings of minus 2 to 66 degrees C 35 to 150 degrees F.
2.2
ACTUATORS
Provide pneumatic, electric, or electronic actuators. Actuators shall
function as required within 85 to 110 percent of their power supply rating.
Actuators shall fail to their spring return positions on signal or power
failure unless indicated as timed, power return actuators. Actuators shall
have visible position indicators. Where actuators do not have positive
spring returns for fail-safe operation, provide capacity tanks,
restrictors, check valves, and relays, or reserve power as required to
achieve proper timed positioning for up to 4 minutes after primary power
failure. Actuators shall open or close the devices to which they are
applied within 60 seconds after a full scale signal input change.
Pneumatic actuators shall be rated for 172 kPa (gage) 25 psig operating
pressure except for high pressure cylinder type actuators.
2.2.1
Damper Actuators
Damper actuators shall be rated for at least 125 percent of the motive
power necessary to operate the connected damper. The actuator stroke shall
be limited by an adjustable stop in the direction of the return stroke.
Actuators shall be provided with mounting and connecting hardware.
2.2.2
Valve Actuators
Valve actuators shall be rated for at least 125 percent of the motive power
necessary to operate the valves over their full range of operation against
the total and differential pressures.
2.2.3
Positive Positioners
Positive positioners shall be pneumatic relays with mechanical feedback
mechanisms, adjustable operating ranges, and starting points.
2.3
AUTOMATIC CONTROL VALVES
Provide automatic control valves.
SECTION 15901N
Page 16
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