General
Provide and install Anemostat dual duct air terminals, Model DU, where shown on drawings or schedule, that comply with the indicated size, capacity, and performance ratings. The air terminals shall be single unit construction, factory constructed and assembled. The terminals shall have been tested and performance determined in accordance with industry standards AHRI 880 and ASHRAE 130.

Acoustical Performance
The air terminal radiated and discharge sound levels shall not exceed the power levels as scheduled, at the differential static pressure (dPs) shown.

Leakage, Damper & Casing
The damper leakage shall not exceed 2% of the maximum rated capacity of the inlet at 4" Differential Static Pressure. The air terminal casing leakage shall not exceed 1/2% of the maximum rated capacity of the casing at 1/2" static pressure in the casing.

Acoustic Lining
The air terminal shall be internally lined with a minimum of 1/2" thick, dual density thermal-acoustical glass fiber insulation. The insulation shall conform to the requirements of NFPA 90A and UL 181. The insulation shall be surface treated to prevent erosion and fibers entering the air stream. (Option 1) The air terminal shall be internally lined with (1/2")(1") thick foil-faced insulation, with an aluminum laminate facing. The aluminum laminate shall face the air stream to prevent erosion and airborne fibers. The edges of the insulation shall be sealed with aluminum tape, and the insulation shall meet NFPA 90A, UL181, ASTM C665, and shall be approved for use by the California Office of Statewide Health, Planning and Development (OSHPD).

(Option 2) The air terminal shall be internally lined with Anemostat Fiber-Lok Insulating system, consisting of minimum 1" thick, 4 1/4 lb/ft3 thermal-acoustical fiber board insulation, with an aluminum laminate facing. The aluminum laminate shall face the air stream to prevent erosion and airborne fibers. Any exposed edges of the insulation shall be captured in zinc-coated steel channels, and the insulation shall meet NFPA 90A, UL181, ASTM C665, and shall be approved for use by the California Office of Statewide Health, Planning and Development (OSHPD).

Construction
Inlets/Casing
The air terminal casing and primary air inlets shall be constructed of minimum 22 gauge zinc-coated sheet steel. (Option 1) The casing shall include steel control enclosures, housing all primary flow controls, including actuators, controllers, relays, etc.

Damper
The primary air dampers shall consist of a single elliptical blade composite, that requires nominal 60 degree rotation from fully opened to fully closed positions. The steel damper blade shall be mechanically attached to the shaft with either threaded fasteners, or welded. Rivets are not acceptable. The shaft shall be a continuous, singular axle across the full inlet diameter, and extending through the terminal casing. The damper shall have a tear resistant neoprene lip seal around its perimeter to form a tight air seal for full shut-off. Seals other than neoprene are not approved. The damper shafts shall rotate in self lubricating bearings. Damper position shall be indicated on the end of the shaft on the outside of the casing. The primary damper fail positions for pneumatic applications (normally open / normally closed) shall be easily re-configured in the field.

Pneumatic Air Flow Sensors
The primary air shall be measured by a multi-point, cross type flow sensor of the automatic averaging type, located in each primary air inlet for Inlet (I) sensing control strategies, and shall accurately sense primary air flow within +/-5% for any inlet condition of equal sized duct. For Inlet-Total (I-T) sensing control strategies, a multi-point total flow sensor, located in the discharge of the terminal, shall measure the combined hot and cold air flow rates, and only one inlet sensor shall be required.
 
Hot Water Heating Coils
Hot water coils, 1 or 2 row as required, shall be factory mounted at the discharge of the air terminal. Hot water coils shall be ventable and drainable. Coil construction shall include a 20 gauge zinc-coated sheet steel frame, with aluminum corrugated fins at 10- fins/inch. Tubing shall be 1/2" O.D. copper, minimum .017" wall thickness, mechanically expanded in the aluminum fins.

Electric Heating Coils
Electric heating coils shall be of the size and capacity as shown on the drawings or as scheduled. Electric duct heaters shall be of the open coil design, and shall be listed by UL or ETL for zero clearance and shall meet the requirements of the National Electric Code.

The electric heater frame and control panel shall be minimum 20 gauge, zinc-coated sheet steel. Heating elements shall be of high grade nickel, rated at 35 watts per square inch of wire surface. Elements shall be held in place with floating ceramic bushing, which are held in place by minimum 20 gauge galvanized steel brackets.

Each electric heater shall be furnished with two over-temperature safety devices, serviceable and replaceable in the control enclosure without removing the heater from the duct. The primary safety device shall be a disc-type automatic reset that will shut off the heater during over temperature, and automatically reset the heater when duct temperatures are within limits. The second safety device shall be a heat limiter in the power lines that opens the circuit and de-energizes the elements if the primary safety device fails. Each heater shall be furnished with a specific wiring diagram. Each heater shall include an air proving switch, PE switch or contactor  per step, overcurrent protection as required by N.E.C. or U.L., and a door interlocking disconnect switch. All power lines shall be broken when the hinged heater door is opened.

PNEUMATIC CONTROL SYSTEM
The air terminal pneumatic controls shall be suitable for a 20 psi control system. The controls shall be pressure independent, and shall be capable of maintaining air flow set point within +/-5% of the design air volume regardless of changes in system static pressure. An identification label, control diagram, and inlet sensor flow chart shall be attached to each terminal. The sequence of operation is based on Anemostat Control Package DP- _________. The pneumatic velocity controllers shall be furnished and mounted by the terminal manufacturer, and the maximum & minimum primary air flow shall be set at the factory. The controller shall be Anemostat (Model 23/24) (Model 31 and shall maintain a constant reset span independent of the primary air flow rate). Balancing taps, separate from the sensor or controller taps, shall be provided for field adjustment of set points. The controls shall reset flow, as dictated by the space thermostat (furnished by the TC). Controller air consumption for each controller shall not exceed (Model 23, 24 - .009 scfm @ 20 psi) (Model 31 - .017 scfm @ 20 psi). CFM limiters are not acceptable. The air flow sensors shall amplify the velocity pressure signals and provide closed loop feedback of actual flow to the velocity controllers. The pneumatic actuators shall be furnished and mounted by the unit manufacturer to move the primary damper in response to the demand of the pressure independent velocity controllers. The actuator shall be capable of positioning the damper from full open to full closed, and to any modulated mid-position. The use of mechanical stops to position the dampers for flow control is not acceptable. The dampers shall fail in an (open) (closed) position should the control air drop to 0 psi.

ELECTRONIC ANALOG CONTROL SYSTEM
The air terminal analog controls shall be pressure independent, and shall be capable of maintaining air flow set point within +/-5% of the design air volume regardless of changes in system static pressure. An identification label, control diagram, and inlet sensor flow chart shall be attached to each terminal. The sequence of operation is based on Anemostat Control Package DA-__________. A transformer shall be furnished and mounted by the unit manufacturer to step down the primary line voltage as required. All controls shall be mounted within a steel enclosure. The electric actuator and controller shall be combined as a single component. The electric actuator shall be designed for permanent stall utilizing a magnetic clutch. The actuator shall develop a minimum 45 inch-pounds torque. The controller shall maintain a constant reset span regardless of maximum and minimum flow settings, and shall reset the flow linearly with respect to room temperature changes. The wall thermostat, factory set for design primary air flows, shall be furnished by the terminal unit manufacturer for installation by the temperature control contractor. Primary air flow adjustments shall be made at the wall thermostat utilizing a digital voltmeter. Air flow sensors shall provide closed loop feedback of actual flow to the velocity controller.

DIRECT DIGITAL CONTROL SYSTEM
The air terminal DDC controls, including the controller(s), air flow transducers, actuators, and 24vac transformer, shall be provided by the ATC contractor to the terminal manufacturer for factory mounting. It shall be the responsibility of the DDC control supplier to forward specific wiring diagrams to the factory. The terminal manufacturer shall provide the pneumatic primary inlet flow 
sensors.