Memorial Hermann Best Practices s1

Memorial Hermann Best Practices

July, 2013

SECTION 23 36 00 AIR TERMINAL UNITS

PART 1 - GENERAL

1.01 WORK INCLUDED

A. Comply with the provisions of Section 23 05 00.

B. Furnish labor, materials, tools, equipment, and services for air terminal units.

C. Coordinate work with other Divisions.

D. Although such work is not specifically indicated, furnish and install all supplementary or miscellaneous items, appurtenances and devices incidental to or necessary for a sound, secure and complete installation.

1.02 QUALITY ASSURANCE

A. Acoustical Liner: Meet requirements of NFPA 90A, UL 181, and ASTM C665 as specified.

B. Air Diffusion Council, ADC Standard 1062R2, Air Diffusing Equipment Test Code.

C. Air Moving and Conditioning Association, AMCA Standard 210, Test Code for Air Moving Devices.

D. ASHRAE Standard 70-72, Method of Testing for Rating the Air Flow Performance of Outlets and Inlets.

E. NFPA 90A, Standard for the Installation of Air Conditioning and Ventilating Systems, 1980 edition.

F. SMACNA HVAC Duct Construction Standards, 1st Edition, 1985.

1.03 RELATED WORK

A. Section 23 05 00: Common Work Results for HVAC

B. Section 23 05 23: Valves for HVAC

C. Section 23 05 93: HVAC Systems Test and Balance

D. Section 23 07 00: HVAC Insulation

E. Section 23 09 23: Building Automation and Direct Digital Controls

F. Section 23 20 00: HVAC Piping

G. Section 23 31 13: Sheetmetal Ductwork

1.04 SUBMITTALS

A. Submit product and performance data for review.

B. Submit test reports as specified herein.

C. Submit certificates as specified herein.

1.05 GUARANTEE

A. Manufacturer guarantees resultant noise levels to be within NC rating published by manufacturer.

PART 2 - PRODUCTS

2.01 ACCEPTABLE MANUFACTURERS

A. Titus, MetalAire, Nailor, Kreuger, Price.

2.02 SINGLE DUCT UNITS

A. Single Duct Units: Pressure independent with multi-axis flow ring and heating coil. Boxes shall be constant volume or constant, variable volume as indicated on Drawings.

1. Acoustical liner:

a. Dual Wall: Interior liner of 26 gauge phosphatized steel covering insulation. All cut edges of insulation shall be covered with metal flange. All wire penetrations shall be covered by grommets. High density, glass fiber insulation, 1" thick, 1.9 lb/cu.ft, R-value of 4.2. comply with the requirements of Ul 181 NFPA 90A.

b. Dual Wall : Interior liner of 26 gauge phosphatized steel covering insulation. All cut edges of insulation shall be covered with metal flange. All wire penetrations shall be covered by grommets. High density, glass fiber insulation, 1" thick, 1.9 lb/cu.ft, R-Value of 4.2. Comply with the requirements of UL 181 and NFPA 90A.

2. Casing: Minimum 22 gauge galvanized steel.

3. Provide insulated gasketed access panel on bottom of box for access to integral, internal air valves and heating coil inspection.

4. Leakage: Maximum 1% of nominal capacity at 1" wg. inlet static pressure.

5. Mulitpoint, multiaxis flow ring or cross sensor.

6. Provide integral flow taps and calibration chart on each unit.

7. Factory calibrate sensor and controller for design maximum and minimum CFM.

8. Coils as shown on drawings and specified herein.

9. Factory mount, wire, connect, calibrate, set-up and test DDC controller, pressure transducer, and electronic damper actuator furnished to box manufacturer under Section 23 09 13. Damper actuators integral with box may be furnished by box manufacturer and operation coordinated with DDC controller. Constant volume boxes shall have auto-zone module. All units shall be wired with a discharge air temperature sensor.

10. Control transformer: Provide and factory mount 120v/24v control circuit transformer for each box, sized to handle all box controls. Provide safety devices including toggle disconnect switch and primary and secondary fusing.

B. Fan powered, single duct units: Parallel fan type for intermittent fan operation, pressure independent, with mulit-axis flow ring and heating coil.

1. Acoustical liner:

a. Dual Wall : Interior liner of 26 gauge phosphatized steel covering insulation. All cut edges of insulation shall be covered with metal flange. All wire penetrations shall be covered by grommets. High density, glass fiber insulation, 1" thick, 1.9 lb/cu.ft, R-Value of 4.2. Comply with the requirements of UL 181 and NFPA 90A.

2. Casing: Minimum 22 gauge galvanized steel. Entire bottom panel shall be removable to provide access to fan motor.

3. Leakage: Maximum 1% of nominal capacity at 4" wg. inlet static pressure.

4. Mulitpoint, multiaxis flow ring or cross sensor..

5. Factory calibrate sensor and controller for design maximum and minimum CFM.

6. Motor: Permanently lubricated, three speed direct drive, permanent split capacitor type with thermal overload protection. Motor and fan assembly shall be isolated from casing using rubber isolators.

7. Fan speed control: Provide factory mounted three-speed or SCR control to change fan motor speed. Provide speed adjustment knob outside of control panel. Provide fan disconnect switch.

8. Coils as shown on drawings and specified herein.

9. Factory mount, wire, connect, calibrate, set-up and test DDC controller, pressure transducer, and electronic damper actuator furnished to box manufacturer under Section 23 09 23. Damper actuators integral with box may be furnished by box manufacturer and operation coordinated with DDC controller. All units shall be wired with a discharge air temperature sensor.

11. Pneumatic Actuators: Factory installed and piped.

C. Heating Coils: ARI certified, continuous plate or spiral fin type, leaked test at 300 psi under water.

1. Fins: Aluminum, maximum 8 fins per inch.

2. Tubes: Seamless, copper tubes mechanically expanded into the fin collars; arranged for counter-flow of heating water.

3. Water Velocity: 8 FPS maximum with head loss not greater than indicated on drawings.

D. Electric Heater:

1. Electric heating coils shall be provided of the capacity shown on the drawings.

2. Units with heaters shall be U.L. or ETL listed for zero clearance and shall bear the proper listing mark and label. Each heater shall meet all requirements of the National Electrical Code.

3. Each heater terminal box and frame shall be constructed of minimum 20 gauge corrosion resistant metal. Heating elements shall be constructed of high grade nickel/chromium wire and shall not glow when operating at the rated quantities.

4. Heaters shall be provided with factory supplied and prewired branch circuit fusing as required by NEC and U.L. including control fusing on primary voltage hot line, and heater fusing on all sizes.

5. Main power connections to be supplied integral with each unit by the terminal manufacturer to break all ungrounded conductors. All units shall have door interlocked fused disconnect switch and a control disconnect,.

6. Provide 24 VAC transformer for controls. Factory mount transformer in control enclosure.

7. Electric heating coil shall be removable without disturbing the duct system.

8. Each heater shall be complete with:

a. Primary automatic thermal cutoff and a manual reset thermal secondary safety device. to de-energize the heater in case of overheating.

b. Proportional electronic airflow sensor which shall be totally independent of the duct static pressure and shall adjust the heater capacity according to the available airflow. The heaters shall deliver maximum heating when needed with normal minimum airflow, reduce heating with lower than minimum airflow and stop heating with no airflow.

9. Heaters shall be equipped with full proportional SCR controller to modulate the heater load according to the temperature control signal. The electronic controller shall be compatible with the following input signals:- Variable voltage signal 0-10 VDC, Pulse width modulation AC or DC

2.03 DOUBLE DUCT UNIT – SPECIFIER NOTE – for existing unit replacement only –not for new installations

A. Double duct mixing boxes shall be single pneumatic motor mechanical volume control dual duct mixing boxes by:

B. Each box shall be supplied with a printed tape label showing the box number, design CFM, and minimum inlet static pressure.

C. Boxes shall be fully assembled with air mixing valve, valve operator, and complete individual volume regulating device.

D. Valve operator to be pneumatically controlled by compressed air at 15 psi.

E. Compressed air lines within the unit casing shall be installed and brought to fittings on the exterior to which controls shall be connected.

F. Volume regulators shall control the output volume within plus or minus 5% regardless of pressure variations of 1" to 3" which occur at either or both warm and cold air inlets.

G. Simple screw adjustment of the volume of the unit within its capacity range.

H. Boxes so noted shall be two motor variable constant volume type.

I. All units shall be wired with a discharge air temperature sensor.

2.04 VENTURI VALVE

A. Construction:

1. 16 gauge spun aluminum valve body with continuous welded seam.

2. Aluminum valve body

3. Composite Teflon shaft bearings

4. Spring grade stainless steel spring and PPS slider assembly

5. Supply valves insulated with 3/8" (9.5 mm) flexible closed-cell polyethylene. Flame/smoke rating 25/50. Density is 2 lb/ft3 (32 kg/m3)

6. Pressure independent over a 0.3" -3.0" w.c. (74-747 Pa) drop across valve

7. Volume control accurate to +5% of airflow command signal

8. No additional straight duct runs needed before or after valve

9. Air flow as indicated on the drawings.

B. Controls

1. Each zone shall have a dedicated airflow control system.

2. The airflow control system shall maintain specific airflow (±5% of signal within one second of a change in duct static pressure) regardless of the magnitude of the pressure change, airflow change or quantity of airflow control devices on either the supply air or exhaust/return air manifold (within 0.3” to 3.0" wc).

3. The airflow control system shall use volumetric offset control or room differential pressure monitoring to maintain room pressurization. The system shall maintain proper room pressurization polarity (negative or positive) regardless of any change in room/system conditions, such as rapid changes in duct static pressure.

4. The airflow control system shall maintain specific airflow (±5% of signal) with airflow turndown greater than the values scheduled on plans to ensure accurate pressurization at low airflow and assure maximum energy efficiency.

5. In the event of a power failure, airflow control devices shall fail to the last position and continue to maintain pressure independent flow control within ±5% of signal within one second of a change in duct static pressure.

6. All units shall be wired with a discharge air temperature sensor.

PART 3 - EXECUTION

3.01 INSTALLATION

A. Install all units as indicated and in accordance with manufacturer's recommendations and instructions.

B. Check connections to insure they are tight with all leakage of 1% or less.

C. Provide insulation in accordance with Section 23 07 00.

D. Coordinate control installations with temperature controls vendor.

3.02 CLEANING, TESTING, START-UP, DEMONSTRATION

A. Clean units in accordance with Section 23 05 00, including flushing of connected piping and cleaning of water control valves.

B. Start-up units, check for proper operation as a system with air handling unit, fans, and connected ductwork.

C. Test units in accordance with Section 23 05 00.

D. Prepare units for Test and Balance as required by Section 23 05 93, correct any deficiencies found and retest.

E. Demonstrate operation of units as a complete system to maintenance personnel and instruct them in the operation, adjustment and repair of the system.

END OF SECTION

AIR TERMINAL UNITS

23 36 00 - Page 5