USACE / NAVFAC / AFCESA / NASA UFGS-23 36 00 (August 2008)
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Preparing Activity: NASA Superseding
UFGS-23 36 00.00 40 (July 2007)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 23 36 00
AIR TERMINAL UNITS
08/08
NOTE: This specification covers the requirements for bypass single-duct air
terminal units, dual-duct air terminal units, fan-powered air terminal units,
induction air terminal units, shutoff single-duct air terminal units and integral-diffuser
air terminal units for air handling systems.
Drawings and schedules must portray system dynamics so that equipment functions
as required.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
PART 1 GENERAL
1.1 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[AIR DIFFUSION COUNCIL (ADC)ADC Standards Manual(2002-2007) Flexible Duct Performance and Installation Standards][AIR-CONDITIONING, HEATING AND REFRIGERATION INSTITUTE (AHRI)AHRI 880(1998; Addendum 2002) Standard for Air Terminals][AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS (ASHRAE)ASHRAE 130(2008) Method of Testing for Rating Ducted Air Terminal Units][ASTM INTERNATIONAL (ASTM)ASTM A 653/A 653M(2008) Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip ProcessASTM C 1071(2005e1) Standard Specification for Fibrous Glass Duct Lining Insulation (Thermal and Sound Absorbing Material)ASTM E 84(2008a) Standard Test Method for Surface Burning Characteristics of Building Materials][NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)NEMA 250(2003) Enclosures for Electrical Equipment (1000 Volts Maximum)][NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)NFPA 70(2007; AMD 1 2008) National Electrical Code - 2008 EditionNFPA 90A(2008) Standard for the Installation of Air Conditioning and Ventilating Systems][UNDERWRITERS LABORATORIES (UL)UL 181(2005; Rev thru Oct 2008) Standard for Factory-Made Air Ducts and Air ConnectorsUL 486A-486B(2003; Rev thru Aug 2006) Standard for Wire Connectors]1.2 SUBMITTALS
NOTE: Review Submittal Description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are [for Contractor Quality Control approval.][for information only. When used, a designation following the
"G" designation identifies the office that will review the submittal for the Government.] Submit the following
in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-01 Preconstruction Submittals
Records of Existing Conditions must be submitted in accordance with paragraph entitled, General
Requirements," of this section.
SD-02 Shop Drawings
Detail equipment assemblies and indicate dimensions, required clearances, method of field assembly,
components, and location and size of each field connection.
Bypass Single-Duct Air Terminal Units
Dual-Duct Air Terminal Units
Fan-Powered Air Terminal Units
Induction Air Terminal Units
Shutoff Single-Duct Air Terminal Units
Integral-Diffuser Air Terminal Units
High-Pressure Dual-Duct Mixing Boxes
Low-Pressure Dual-Duct Mixing Boxes
Include a schedule showing unique model designation, room location, model number, size, and
accessories furnished. Include wiring diagrams to show power, signal, and control wiring.
Record Drawings and Spare Parts must be submitted in accordance with paragraph entitled, "General
Requirements," of this section.
SD-03 Product Data
For each type of air terminal units indicated, include rated capacities, furnished specialties,
sound-power ratings, and accessories
Bypass Single-Duct Air Terminal Units
Dual-Duct Air Terminal Units
Fan-Powered Air Terminal Units
Induction Air Terminal Units
Shutoff Single-Duct Air Terminal Units
Integral-Diffuser Air Terminal Units
High-Pressure Dual-Duct Mixing Boxes
Low-Pressure Dual-Duct Mixing Boxes
SD-10 Operation and Maintenance Data
Submit Operation and Maintenance Manuals in accordance with paragraph entitled, "Operation and
Maintenance," of this section.
1.3 GENERAL REQUIREMENTS
NOTE: If Section 23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST
SYSTEMS is not included in the project specification, applicable requirements
therefrom should be inserted and the following paragraph deleted.
Section 23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEMS applies to work specified in this
section.
Materials, Equipment, and Fixture Lists must be submitted for all materials, equipment, and fixtures to be incorporated
in the work. Lists must include manufacturer's style or catalog numbers, specification and drawing reference
numbers, warranty information, and fabrication site information.
Records of Existing Conditions must be submitted consisting of the results of Contractor's survey of work area
conditions and features of existing structures and facilities within and adjacent to the jobsite. Commencement
of work must constitute acceptance of existing conditions.
Record Drawings must be submitted providing current factual information, including deviations and amendments
to the drawings, and concealed and visible changes in the work.
Units must be provided with the configuration, capacity, and static-pressure characteristics indicated.
Where dimensional data are given, these must constitute nominal sizing, which must be adjusted by the manufacturer
when necessary to accommodate acoustic material thickness.
Units identical to the proposed units must have at least 2 years of proven satisfactory field service.
NOTE: Select or delete the following paragraph after checking current "Directory
of Air Diffusion Council (ADC Standards Manual) Certified Products."
Units and spare parts must be certified as having been ADC Standards Manual tested and rated.
1.4 QUALITY ASSURANCE
Indicate drawings size, profiles, and dimensional requirements of air terminal units which are based on the specific
system indicated.
Conform to NFPA 70, Article 100 for electrical components, devices, and accessories: List and label as defined
in NFPA 70, Article 100, by a testing agency acceptable to authorities having jurisdiction, and marked for intended
use.
Air Terminals must be certified under the AHRI 880 Certification Program and must carry the ARI Seal.
Install air terminals units according to NFPA 90A.
1.5 COORDINATION
Coordinate layout and installation of air terminal units and suspension system with other construction that penetrates
ceilings or is supported by them, including light fixtures, HVAC equipment, fire-suppression system, and partition
assemblies.
PART 2 PRODUCTS
2.1 BYPASS SINGLE-DUCT AIR TERMINAL UNITS
2.1.1 Configuration
Provide diverting-damper assembly inside unit casing with control components located inside a protective metal
shroud.
2.1.2 Casing
Provide 0.85 mm 0.034 inch steel casing. Provide 13 mm 1/2 inch thick, coated, fibrous-glass duct casing lining
complying with ASTM C 1071. Secure with adhesive. For the air inlet provide round stub connection for duct attachment.
For the air outlet provide s-slip and drive connections. For access provide removable panels for access to diverter
and other parts requiring service, adjustment, or maintenance; with airtight gasket.
2.1.3 Diverter Assembly
Provide [galvanized-steel gate, with polyethylene linear bearings] [aluminum blade, with nylon-fitted pivot points]
[_____] diverter assembly.
2.1.4 Multi-Outlet Attenuator Section
Provide [two][ three][ four][ _____][ 150 mm 6 inch][200 mm 8 inch ][250 mm 10 inch][ _____] diameter collars;
each with locking butterfly balancing damper.
2.1.5 Hot-Water Heating Coil
Provide a copper tube heating coil, mechanically expanded into aluminum-plate fins. Heating coil must pass leak
test underwater to1380 kPa 200 psig.
2.1.6 Electric Heating Coil
Provide a factory installed and wired slip-in-type, open-coil design with integral control box. Include the following features:
Primary and secondary over temperature protection
Nickel chrome 80/20 heating elements
Airflow switch
Non-interlocking disconnect switch
Fuses (for coils more than 48 A)
Mercury contactors
Pneumatic-electric switches and relays.
Magnetic contactor for each step of control (for three-phase coils)
2.1.7 Electric Controls
Provide a 24 V damper actuator that is powered closed, powered open with microswitch to energize heating control
circuit.
Provide a wall-mounting electric type thermostat with temperature display in Fahrenheit and Celsius, and with
space temperature set point.
Provide a changeover thermostat of duct-mounting, electric type that reverses action of controls when duct temperature
rises 21 degrees C 70 degrees F.
2.1.8 Electronic Controls
Provide a 24 V damper actuator that is powered closed, powered open
2.1.9 Pneumatic Controls
2.1.9.1 Pneumatic Damper Operator
Provide a [ 55 to 90 kPa8 to 13 psig][ 21 to 90 kPa3 to 13 psig] spring range.
2.1.9.2 Velocity Controllers
Provide a factory calibrated and field adjustable controller to minimum and maximum air volumes. Controllers
must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet
static-pressure variations up to wg 1000 Pa 4 inch when tested in accordance with ASHRAE 130. Controller must
have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet and air outlet.
2.1.10 Thermostat
Provide a wall-mounting electronic type thermostat with integral control of room temperature. Thermostat must
be time-proportional with reheat-coil control feature, and displays a temperature set-point display in Fahrenheit
and Celsius. The auxiliary switch must energize heating control circuit Changeover thermistor must have a reverse
action feature.
2.2 DUAL-DUCT AIR TERMINAL UNITS
2.2.1 Configuration
Provide two volume dampers inside unit casing with mixing attenuator section and control components located inside
a protective metal shroud.
2.2.2 Casing
Provide [ 0.85 mm steel0.034 inch][ 0.80 mm aluminum0.032 inch] casing. The casing must include an integral
mixing baffle to efficiently mix the hot and cold airstream.
2.2.2.1 Casing Lining
Provide 0.85 mm steel 0.034 inch casing. Provide 13 mm 1/2 inch thick, coated, fibrous-glass duct casing lining
complying with ASTM C 1071. Secure with adhesive. [Cover liner with nonporous foil.][Cover liner with nonporous
foil and perforated metal.]
Attach a 19 mm 3/4 inch thick adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must
be coated with NFPA 90A approved seal.
For the air inlet provide round stub connection for duct attachment. For the air outlet provide s-slip and drive
connections. For access provide removable panels for access to diverter and other parts requiring service, adjustment,
or maintenance; with airtight gasket.
2.2.3 Volume Damper
Provide a galvanized steel volume damper with peripheral gasket and self-lubricating bearings.
Perform a Maximum Damper Leakage Test in conformance to AHRI 880, for 3 percent of nominal airflow at [ 750 Pa
3 inch wg] [ 1500 Pa6 inch wg] inlet static pressure.
Select either Damper Position, Hot Deck: normally [open] [closed] or Damper Position, Cold Deck: normally [closed]
[open].
2.2.4 Attenuator Section
Provide [ 0.85 mm steel0.034 inch] [ 0.8 mm0.03 inch aluminum] sheet metal.
Provide 13 mm1/2 inch thick, coated, fibrous-glass duct casing lining complying with ASTM C 1071. Secure with
adhesive. [Cover liner with nonporous foil.][Cover liner with nonporous foil and perforated metal.]
Attach a 19 mm3/4 inch thick adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must be
coated with NFPA 90A approved seal.
2.2.5 Multi-Outlet Attenuator Section
Provide [two] [three] [four] [_____] [ 150 mm6 inch] 200 mm[8 inch] [ 250 mm10 inch] [_____] diameter collars;
each with locking butterfly balancing damper.
2.2.6 Pneumatic Controls
2.2.6.1 Pneumatic Damper Operator
Provide a [ 55 to 90 kPa8 to 13 psig] [ 21 to 90 kPa3 to 13 psig] spring range.
2.2.6.2 Velocity Controllers
Provide a factory calibrated and field adjustable controller to minimum and maximum air volumes. Controllers
must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet
static-pressure variations up to 1000 Pa 4 inch wg when tested in accordance with ASHRAE 130. Controller must
have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet and air outlet.
2.2.6.3 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware.
2.2.7 Electronic Controls
2.2.7.1 Damper Actuator
Provide a 24 V, powered closed, [spring return open] [powered open] damper actuator.
2.2.7.2 Velocity Control
Provide a factory calibrated controller to minimum and maximum air volumes, field adjustable at thermostat.
Controller must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating
for inlet static-pressure variations up to 1000 Pa 4 inch wg, when tested in accordance with ASHRAE 130. Controller
must have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet and air outlet.
2.2.7.3 Thermostat
Provide a wall-mounting electronic type thermostat with integral control of room temperature. Thermostat must
be time-proportional with reheat-coil control feature, and displays a temperature set-point display in Fahrenheit
and Celsius.
2.2.8 DDC Controls
NOTE: Select first paragraph and subparagraphs below when control components
are packaged with the equipment.
2.2.8.1 Damper Actuators
Provide a 24 V, powered closed, [spring return open] [powered open] damper actuator.
2.2.8.2 Velocity Sensors
Provide a multipoint array with velocity sensors in cold-deck and hot-deck air inlet and air outlet.
2.2.8.3 Terminal Unit Controller
Provide a pressure independent, [variable-air] [constant] volume controller with electronic airflow transducers
factory calibrated to minimum and maximum air volumes. Include the following features:
Proportional, plus integral control of room temperature
Time-proportional reheat-coil control
Occupied and unoccupied operating mode
Remote reset of airflow or temperature set points
Adjusting and monitoring with portable terminal
2.2.8.4 Room Sensor
Provide a wall mounting room sensor, with temperature set-point adjustment and access for connection of portable
operator terminal.
2.2.9 Control Sequence
Modulate cold-air damper to maintain room temperature. Modulate warm-air damper to maintain constant airflow.
2.3 FAN-POWERED AIR TERMINAL UNITS
2.3.1 Configuration
Provide volume-damper assembly and fan in [series] [parallel] arrangement inside unit casing with control components
inside a protective metal shroud.
2.3.2 Casing
Provide [ 0.85 mm steel0.034 inch] [ 0.80 mm aluminum0.032 inch] casing. The casing must include an integral
mixing baffle to efficiently mix the hot and cold airstream.
2.3.2.1 Casing Lining
Provide [ 13 mm1/2 inch] [ 19 mm3/4 inch] [ 25 mm1 inch] thick with 1.5 density, coated, fibrous-glass duct casing
lining complying with ASTM C 1071. Secure with adhesive. [Cover liner with nonporous foil.][Cover liner with
nonporous foil and perforated metal.]
Attach a 19 mm 3/4 inch thick adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must be
coated with NFPA 90A approved seal.
For the air inlet provide round stub connection for duct attachment. For the air outlet provide s-slip and drive
connections. For access provide removable panels for access to diverter and other parts requiring service, adjustment,
or maintenance; with airtight gasket and quarter-turn gaskets.
2.3.3 Volume Damper
Provide a galvanized steel volume damper with peripheral gasket and self-lubricating bearings.
Perform a Maximum Damper Leakage Test in conformance to AHRI 880, for [2] [3] percent of nominal airflow at [
750 Pa3 inch wg] [ 1500Pa6 inch wg] inlet static pressure, when tested in accordance with ASHRAE 130.
Select damper position: Normally [open] [closed].
2.3.4 Fan Section
Provide a galvanized-steel plenum, with direct-drive, forward-curved fan with air filter and backdraft damper.
2.3.4.1 Lining
Provide [ 13 mm1/2 inch] [ 19 mm3/4 inch] [ 25 mm1 inch] thick, coated, fibrous-glass duct liner complying with
ASTM C 1071; secured with adhesive. [Cover liner with nonporous foil.] [Cover liner with nonporous foil and perforated
metal.]
2.3.4.2 Motor
Comply with requirements in Section 26 60 13.00 40 LOW-VOLTAGE MOTORS for [Multi-speed] [_____] motors. Motor
must include a speed control feature that is adjustable Infinitely with pneumatic-electric and electronic controls.
Fan-Motor Assembly must contain rubber isolators.
2.3.4.3 Air Filter
[ 50 mm2 inch] [ 25 mm1 inch] thick, [fiberglass throwaway] [polyurethane].
2.3.5 Attenuator Section
Provide [ 0.85 mm steel0.034 inch] [ 0.8 mm0.03 inch aluminum] sheet metal. Provide 1/2 inch 13 mm thick, coated,
fibrous-glass duct casing lining complying with ASTM C 1071. Secure with adhesive. [Cover liner with nonporous
foil.][Cover liner with nonporous foil and perforated metal.]
Attach a 19 mm 3/4 inch thick adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must be
coated with NFPA 90A approved seal.
NOTE: If heating coil is required, retain one of two paragraphs and associated
subparagraphs below.
2.3.6 Hot-Water Heating Coil
Provide a copper tube, mechanically expanded into aluminum-plate fins; leak tested underwater to 200 psig 1380
kPa; and factory installed.
2.3.7 Electric Heating Coil
Provide a slip-in-type, open-coil design with integral control box factory wired and installed. Include the
following features:
Primary and secondary over-temperature protection
Nickel chrome 80/20 heating elements
Fan interlock contacts
Non-interlocking disconnect switch
Fuses (for coils more than 48 A)
Mercury contactors
Pneumatic-electric switches and relay
Magnetic contactor for each step of control (for three-phase coils)
2.3.8 Factory-Mounted and -Wired Controls
Mount electrical components in control box with removable cover. Incorporate single-point electrical connection
to power source.
Factory mounted control transformer for control voltage on electric and electronic control units with terminal
strip in control box for field wiring of thermostat and power source.
Fan and controls to terminal strip, and terminal lugs must match quantities, sizes, and materials of branch-circuit
conductors for wiring terminations. Enclose terminal lugs in terminal box that is sized according to NFPA 70
.
Factory-mount a fused type disconnect switch.
2.3.9 Control Panel Enclosure
Conform to NEMA 250, Type 1, with access panel sealed from airflow and mounted on side of unit.
2.3.10 Electric Controls
Provide a 24V damper actuator with wall-mounting electric thermostat and appropriate mounting hardware.
2.3.11 Pneumatic Controls
2.3.11.1 Pneumatic Damper Operator
Provide a [ 55 to 90 kPa8 to 13 psig] [ 21 to 90 kPa3 to 13 psig] spring range.
2.3.11.2 Velocity Controller
Provide a factory calibrated and field adjustable controller to minimum and maximum air volumes. Controllers
must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet
static-pressure variations up to 1000 Pa 4 inch wg, when tested in accordance with ASHRAE 130. Controller must
have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet.
2.3.11.3 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware.
2.3.12 Electronic Controls
Provide a bidirectional damper operator and microprocessor-based controller with integral airflow transducer
and room sensor must be compatible with temperature controls and must have the following features:
Proportional, plus integral control of room temperature
Time-proportional reheat-coil control
Occupied and unoccupied operating mode
Remote reset of airflow or temperature set points
Adjusting and monitoring with portable terminal
Communication with temperature-control system
2.4 INDUCTION AIR TERMINAL UNITS
2.4.1 Configuration
Provide a volume-damper assembly inside unit casing with mechanical induction damper mounted on casing and control
components located inside a protective metal shroud.
2.4.2 Casing
Provide [ 0.85 mm steel0.034 inch] [ 0.80 mm aluminum0.032 inch] casing. The casing must include an integral mixing
baffle to efficiently mix the hot and cold airstream.
2.4.2.1 Casing Lining
Provide [ 13 mm1/2 inch] [ 19 mm3/4 inch] [ 25 mm1 inch] thick, coated, fibrous-glass duct casing lining complying
with ASTM C 1071. Secure with adhesive.
For the air inlet provide round stub connection for duct attachment. For the air outlet provide s-slip and drive
connections [size matching inlet size]. For access provide removable panels for access to diverter and other
parts requiring service, adjustment, or maintenance; with airtight gasket.
2.4.3 Volume Damper
Provide a galvanized steel volume damper with peripheral gasket and self-lubricating bearing.
Perform a Maximum Damper Leakage Test in conformance to AHRI 880, for [2] [3] percent of nominal airflow at [
750 Pa3 inch wg] [ 1500 Pa6 inch wg] inlet static pressure, when tested in accordance with ASHRAE 130.
Select Damper Position, normally [open] [closed].
2.4.4 Induction Damper
Provide galvanized-steel, multi-blade assembly with self-lubricating bearings.
NOTE: If heating coil is required, retain one of two paragraphs and associated
subparagraphs below.
2.4.5 Hot-Water Heating Coil
Provide a copper tube, mechanically expanded into aluminum-plate fins; leak tested underwater to 1380 kPa 200
psig; and factory installed.
2.4.6 Electric Heating Coil
Provide a slip-in-type, open-coil design with integral control box factory wired and installed. Include the
following features:
Primary and secondary over-temperature protection
Nickel chrome 80/20 heating elements
Airflow switch
Non-interlocking disconnect switch
Fuses (for coils more than 48 A)
Mercury contactors
Pneumatic-electric switches and relays
Magnetic contactor for each step of control (for three-phase coils)
2.4.7 Pneumatic Controls
2.4.7.1 Damper Operator
Provide a pneumatic, 35 to 70 kPa 5 to 10 psig spring range damper operator.
2.4.7.2 Velocity Controller
Provide a factory calibrated and field adjustable to minimum and maximum air volumes; must maintain constant
airflow dictated by thermostat within 5 percent of set point while compensating for inlet static-pressure variations
up to 1000 Pa 4 inch wg, when tested in accordance with ASHRAE 130. Controller must have a multipoint velocity
sensor at air inlet.
2.4.7.3 Induction Damper Operator
Provide a pneumatic, spring range induction damper operator matching reset range of controller.
2.4.7.4 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware.
2.4.8 Electronic Controls
2.4.8.1 Damper Actuator
Provide a pneumatic, 35 to 70 kPa 5 to 10 psig spring range damper operator.
2.4.8.2 Velocity Controller
Provide a factory calibrated and field adjustable to minimum and maximum air volumes; must maintain constant
airflow dictated by thermostat within 5 percent of set point while compensating for inlet static-pressure variations
up to 1000 Pa 4 inch wg when tested in accordance with ASHRAE 130, and must have a multipoint velocity sensor
at air inlet.
2.4.8.3 Induction Damper Operator
Provide a pneumatic, spring range induction damper operator matching reset range of controller.
2.4.8.4 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware with the following features:
Proportional, plus integral control of room temperature
Time-proportional reheat-coil control
Temperature set-point display in Fahrenheit and Celsius
2.5 SHUTOFF SINGLE-DUCT AIR TERMINAL UNITS
2.5.1 Configuration
Provide a volume-damper assembly inside unit casing with control components located inside a protective metal
shroud.
2.5.2 Casing
Provide [ 0.85 mm steel0.034 inch] [ 0.80 mm0.032 inch aluminum] casing. The casing must include an integral
mixing baffle to efficiently mix the hot and cold airstream.
2.5.2.1 Casing Lining
Provide [ 13 mm1/2 inch] [ 19 mm3/4 inch] [ 25 mm1 inch] thick, coated, fibrous-glass duct casing lining complying
with ASTM C 1071. Secure with adhesive. [Cover liner with nonporous foil.][Cover liner with nonporous foil and
perforated metal.]
Attach a 19 mm thick 3/4 inch adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must be
coated with NFPA 90A approved seal.
For the air inlet provide round stub connection for duct attachment. For the air outlet provide s-slip and drive
connections. For access provide removable panels for access to diverter and other parts requiring service, adjustment,
or maintenance; with airtight gasket.
NOTE: Retain one of first two paragraphs and associated subparagraphs below;
retain first for units with mechanical volume regulators.
2.5.3 Regulator Assembly
Provide [extruded-aluminum] [galvanized-steel] components with key damper blades onto shaft with nylon-fitted
pivot points located inside unit casing.
2.5.3.1 Automatic Flow-Control Assembly
Match combined spring rates for each volume-regulator size with machined dashpot for stable operation. Provide
factory-calibrated and field-adjustable assembly with shaft extension for connection to externally mounted control
actuator.
NOTE: Retain first paragraph below for units with system-air-powered volume
regulators.
2.5.4 Regulator Assembly
Provide system-air-powered bellows section incorporating polypropylene bellows for volume regulation and thermostatic
control. Bellows must operate at temperatures from 18 to plus 60 deg C 0 to 140 deg F minus. Bellows must be
impervious to moisture and fungus, and must be suitable for 2500 Pa10 inch wg static pressure, when tested in
accordance with ASHRAE 130, and must be factory tested for leaks.
2.5.5 Volume Damper
Provide a galvanized steel volume damper with peripheral gasket and self-lubricating bearings.
Perform a Maximum Damper Leakage Test in conformance to AHRI 880, for [2] [3] percent of nominal airflow at [
750 Pa3 inch wg] [ 1500 Pa6 inch wg] inlet static pressure, when tested in accordance with ASHRAE 130.
Select Damper Position, normally [open] [closed].
2.5.6 Attenuator Section
Provide [ 0.85 mm steel0.034 inch] [ 0.8 mm0.03 inch aluminum] sheet metal.
Provide 13 mm 1/2 inch thick, coated, fibrous-glass duct casing lining complying with ASTM C 1071. Secure with
adhesive. [Cover liner with nonporous foil.][Cover liner with nonporous foil and perforated metal.]
Attach a 19 mm 3/4 inch thick adhesive of polyurethane foam insulation complying with UL 181 erosion requirements,
and having a maximum flame-spread index of 25, and a maximum smoke-developed index of 50, for both insulation
and adhesive, when tested according to ASTM E 84. Any cut edges of fiberglass exposed to the airstream must
be coated with NFPA 90A approved seal.
2.5.7 Multi-Outlet Attenuator Section
Provide [two] [three] [four] [_____] [ 150 mm6 inch] [ 200 mm8 inch] [ 250 mm10 inch] [_____] diameter collars;
each with locking butterfly balancing damper.
NOTE: If heating coil is required, retain one of two paragraphs and associated
subparagraphs below.
2.5.8 Hot-Water Heating Coil
Provide a copper tube, mechanically expanded into aluminum-plate fins; leak tested underwater to 200 psig 1380
kPa; and factory installed.
2.5.9 Electric Heating Coil
Provide a slip-in-type, open-coil design with integral control box factory wired and installed. Include the
following features:
Primary and secondary over-temperature protection
Nickel chrome 80/20 heating elements
Airflow switch
Non-interlocking disconnect switch
Fuses (for coils more than 48 A)
Mercury contactors
Pneumatic-electric switches and relays
Magnetic contactor for each step of control (for three-phase coils)
NOTE: Retain one of five paragraphs and associated subparagraphs below.
2.5.10 Electric Controls
2.5.10.1 Damper Actuator
Provide a 24 V, powered closed, [spring return open] [powered open] damper actuator.
2.5.10.2 Thermostat
Provide a wall-mounting electronic type thermostat with clock display, temperature display in Fahrenheit and
Celsius, and space temperature set point.
2.5.11 Pneumatic Controls
2.5.11.1 Pneumatic Damper Operator
Provide a 55 to 90 kPa[8 to 13 psig] [ 21 to 90 kPa3 to 13 psig] spring range.
2.5.11.2 Velocity Controllers
Provide a factory calibrated and field adjustable controller to minimum and maximum air volumes. Controllers
must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet
static-pressure variations up to 1000 Pa 4 inch wg, when tested in accordance with ASHRAE 130. Controller must
have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet and air outlet.
2.5.11.3 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware.
2.5.12 Electronic Controls
Bidirectional damper operator and microprocessor-based thermostat with integral airflow transducer and room sensor
must be compatible with temperature controls specified.
2.5.12.1 Damper Actuator
Provide a 24 V, powered closed, [spring return open] [powered open] damper actuator.
2.5.12.2 Velocity Controller
Provide a factory calibrated controller to minimum and maximum air volumes, field adjustable at thermostat.
Controller must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating
for inlet static-pressure variations up to 1000 Pa 4 inch wg, when tested in accordance with ASHRAE 130. Controller
must have a multipoint velocity sensor. Locate velocity sensors in cold-deck air inlet and air outlet.
2.5.12.3 Thermostat
Provide a wall-mounting electronic type thermostat with integral control of room temperature. Thermostat must
be time-proportional with reheat-coil control feature, and displays a temperature set-point display in Fahrenheit
and Celsius.
NOTE: Select first paragraph and subparagraphs below when control components
are packaged with the equipment.
2.5.13 DDC Controls
Bidirectional damper operators and microprocessor-based controller and room sensor must be compatible with temperature
controls specified.
2.5.13.1 Damper Actuators
Provide a 24 V, powered closed, [spring return open] [powered open] damper actuator.
2.5.13.2 Terminal Unit Controller
Provide a pressure independent, [variable-air] [constant] volume controller with electronic airflow transducers
factory calibrated to minimum and maximum air volumes. Include the following features:
Proportional, plus integral control of room temperature
Time-proportional reheat-coil control
Occupied and unoccupied operating mode
Remote reset of airflow or temperature set points
Adjusting and monitoring with portable terminal
2.5.13.3 Room Sensor
Provide a wall mounting room sensor, with temperature set-point adjustment and access for connection of portable
operator terminal.
2.5.14 Control Sequence
Make suitable for operation with duct pressures between60 and 750 Pa 0.25 and 3.0 inch wg inlet static pressure.
Provide a factory-mounted and -piped, 5-micron filter; velocity-resetting, adjustable, high-limit control, with
amplifying relay. Provide a system-powered, wall-mounting thermostat.
2.6 INTEGRAL-DIFFUSER AIR TERMINAL UNITS
2.6.1 Configuration
Provide a volume-damper assembly inside unit casing with [integral] [attached] [linear-slot] [square-ceiling]
[louver-face] [perforated] diffuser.
2.6.2 Casing
Provide [ 0.85 mm0.034 inch steel] [ 0.80 mm0.032 inch aluminum] casing. The casing must include an integral
mixing baffle to efficiently mix the hot and cold airstream.
2.6.2.1 Casing Lining
Provide 0.85 mm 0.034 inch steel casing. Provide 13 mm 1/2 inch thick, coated, fibrous-glass duct casing lining
complying with ASTM C 1071. Secure with adhesive. For the air inlet provide round stub connection for duct attachment.
2.6.3 Volume Damper
Provide galvanized steel with peripheral gasket and self-lubricating bearings.
Damper Position: Normally [open] [closed].
2.6.4 Diffuser
Provide a galvanized-steel insulated plenum with extruded-aluminum or sheet-steel diffuser, having fixed or variable
geometry designed to operate from 100 percent to minimum airflow, manual adjustment of airflow direction, and
white baked-enamel finish.
NOTE: Retain one of three paragraphs and associated subparagraphs below.
2.6.5 Electric Controls
2.6.5.1 Damper Actuator
Provide a 24 V, powered closed, [spring return open] [powered open].
2.6.5.2 Thermostat
Provide a wall-mounting electronic type thermostat with clock display, temperature display in Fahrenheit and
Celsius, and space temperature set point.
2.6.6 Pneumatic Controls
Damper operator [, velocity controller,] and thermostat must be compatible
with temperature controls specified.
2.6.6.1 Pneumatic Damper Operator
Provide a [ 55 to 90 kPa8 to 13 psig] [ 21 to 90 kPa3 to 13 psig] spring range.
2.6.6.2 Velocity Controller
Provide a factory calibrated and field adjustable velocity controller to minimum and maximum air volumes. Controller
must maintain constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet
static-pressure variations up to 1000 Pa 4 inch wg when tested in accordance with ASHRAE 130. Controller must
have a multipoint velocity sensor at air inlet.
2.6.6.3 Thermostat
Provide a wall-mounting pneumatic type thermostat with appropriate mounting hardware.
2.6.7 Electronic Controls
Bidirectional damper operator and microprocessor-based thermostat with integral airflow transducer and room sensor
must be compatible with temperature controls specified.
2.6.7.1 Damper Actuator
Provide a 24 V, powered closed, [spring return open] [powered open].
2.6.7.2 Velocity Controller
Provide a factory calibrated and field adjustable to minimum and maximum air volumes. Controller must maintain
constant airflow dictated by thermostat within 5 percent of set point while compensating for inlet static-pressure
variations up to 1000 Pa 4 inch wg when tested in accordance with ASHRAE 130. Controller must have a multipoint
velocity sensor at air inlet.
2.6.7.3 Thermostatt
Provide a wall-mounting electronic type thermostat with integral control of room temperature. Thermostat must
be time-proportional with reheat-coil control feature, and displays a temperature set-point display in Fahrenheit
and Celsius.
NOTE: Retain paragraph and subparagraphs below for units with system-powered
controls.
2.6.8 Control Sequence
Make suitable for operation with duct pressures between 60 and 750 Pa 0.25 and 3.0inch wg inlet static pressure.
Provide factory-mounted and -piped, 5-micron filter; velocity-resetting, adjustable, high-limit control; and
amplifying relay with a system-powered, wall-mounting thermostat.
2.7 HIGH-PRESSURE DUAL-DUCT MIXING BOXES
Provide mechanical constant-volume control type units with a mechanical controller that is operated by the entering
mixed-airstream and maintains a constant airflow through the unit.
[Units must be factory preset to deliver air volumes indicated.]
2.7.1 Construction
Unit must be factory assembled, complete with casing, air mixing valve assembly, single air mixing valve operator,
and mechanical constant-volume control, ready for field mounting and connection to control.
Casing exterior must be not less than 0.040 inch 1 millimeter thick aluminum, or 20 gage mill-galvanized steel
with not less than 380 grams per square meter 1.25 ounces of zinc per square foot of two-sided surface, conforming
to ASTM A 653/A 653M.
Casing interior must be acoustically baffled and lined with fibrous glass thick enough to attain required sound
power level performance and preclude condensation on any exterior surface, but in no case less than 25 millimeter
1 inch. Air side of fibrous glass must be chloroprene-impregnated and manufactured to resist delamination or
surface erosion at air velocities to 20 meter per second 4,000 feet per minute. Liner edges exposed to airstream
must be protected by metal turnovers. Liner and fibrous-glass baffle material must conform to NFPA 90A.
Inlet valves and connecting linkage must be constructed for modulation by a single operator. Hot inlet valve
must be normally open, and the cold inlet valve must be normally closed. Hot and cold inlet ports must be field
reversible.
[Mechanical constant-volume control must be externally adjustable and must have a cubic meter per second feet-per-minute
graduated capacity scale, which also indicates minimum/maximum range of the unit.]
[Mechanical constant-volume control must be externally adjustable. A calibration chart must be provided with
each unit indicating capacity per revolution of mechanical constant-volume device. Each unit must be labeled
with minimum/maximum volume range to facilitate field adjustment.]
Components subject to friction must have oil-impregnated bronze bearings, graphite-impregnated or lubricant-impregnated
nylon bearings; and lubricant-impregnated elastomers, corrosion-resistant steel, and similar materials.
Casing must be fitted with rigid, airtight access panels, easily removable and of ample size to give free access
to interior parts. Closure must be achieved by spring-retained, quarter-turn, slotted-cam captive devices, or
similar operating fasteners.
Calking compounds must be chloroprene, polyurethane polysulfides, or silicone elastomers. Gaskets must be chloroprene,
polyurethane, or vinyl.
2.7.2 Casing Leakage
Casing joints must be sealed to prevent leakage of more than 2 percent of rated capacity with all connections
sealed and with an internal static pressure of 250 pascal 1 inch wg.
2.7.3 Inlet Valve Leakage
Leakage in fully closed valve position must not exceed 2 percent of unit rated capacity against inlet pressure
of 2000 pascal 8 inches wg.
2.7.4 Mixed-Air Temperature Requirements
A thermometer traverse of all unit outlets must show variation of not more than 5 percent of the difference,
at the time, between the temperatures of equal quantities of cold and warm airstreams entering the unit.
2.7.5 Volume Control Requirements
Mechanical constant-volume control must maintain design volume within plus or minus 5 percent, regardless of
the modulation position of inlet valves or the fluctuation of inlet or outlet pressure, within limits of indicated
minimum pressure.
2.7.6 Sound Level Requirements
NOTE: Select the first of the two paragraphs pertaining to airborne noise only
when acceptable NC levels or space attenuation requirements are not a part of
the specification.
Select the second of the two paragraphs pertaining to airborne noise as well
as casing radiated noise when acceptable NC levels or space attenuation requirements
are not a part of the specification.
Rewrite if ceiling construction sound transmission loss is different from that
specified. NC 40 must be specified as a limiting factor when no criteria are
specified.
[When determining equipment sound-power level performance and when no space-attenuation criteria are given, 18
dB space attenuation must be assumed in all octave bands. Manufacturer must design and incorporate sound correction
factors for equipment.]
[Unit must meet the airborne and radiated sound-power level (PWL) requirements scheduled, to attain the specified
NC levels. An 18 dB space attenuation must be assumed in all octave bands with consideration given to downstream
duct construction and configuration in determining airborne NC levels.]
The following ceiling sound-transmission loss (TL) characteristics, based on 25 millimeter 1 inch acoustic lay-in
panels and T-bar suspension, must be assumed in computing resultant space radiated NC levels:
OCTAVE BAND 2ND 3RD 4TH 5TH 6TH 7TH
PWL-TL -2 -4 -9 -10 -13 -15
[NC40 must be the limiting factor.]
2.7.7 Control Requirements
Operating-control power source must be dry, compressed air of instrument quality at 100 kilopascal 15 pounds
per square inch, gage, unless otherwise approved.
Air mixing valve operator must be provided by the automatic temperature control manufacturer and installed by
the unit manufacturer, unless field installation for specific construction is approved. Operator must be controlled
by a direct-acting thermostat.
Pneumatic control tubing must be copper and must be brought to the exterior of the casing for connection to automatic
temperature control system.
2.8 LOW-PRESSURE DUAL-DUCT MIXING BOXES
NOTE: Drawings and schedules must portray system dynamics so that equipment
functions as required.
Units must be manual-damper volume control type. A calibration chart must be provided with each unit. Each
unit must be labeled with capacity minimum/maximum range to facilitate field adjustment.
Volume control damper must be externally adjustable over an inlet pressure range of 12 to 250 pascal 0.05 to
1 inch wg.
Components subject to friction must have oil-impregnated bronze bearings, graphite-impregnated nylon bearings,
and lubricant-impregnated elastomers, corrosion-resistant steel, and similar materials.
Casing must be fitted with rigid, airtight access panels, easily removable, and of ample size to give free access
to interior parts. Closure must be achieved by spring-retained, quarter-turn, slotted-cam captive devices or
similar operating fasteners.
Calking compounds must be chloroprene, polyurethane polysulfides, or silicone elastomers. Gaskets must be chloroprene,
polyurethane, or vinyl.
2.8.1 Casing Leakage
Casing joints must be sealed to prevent leakage of more than 2 percent of rated capacity, with all connections
sealed and with an internal static pressure of 250 pascal 1 inch wg.
2.8.2 Inlet Valve Leakage
Leakage in fully closed valve position must not exceed 2 percent of unit rated capacity against inlet pressure
of 250 pascal 1 inch wg.
2.8.3 Mixed-Air Temperature Requirements
A thermometer traverse of all unit outlets must show variation of not more than 5 percent of the difference,
at the time, between the temperatures of equal quantities of cold and warm airstreams entering the unit.
2.8.4 Sound Level Requirements
NOTE: When no acceptable noise criteria level is specified, NC 40 must be specified
as the limiting factor.
When determining equipment sound power level performance when no space-attenuation criteria are given, 18 dB
space attenuation must be assumed in all octave bands. Manufacturer must design and incorporate sound correction
factors for equipment.
2.8.5 Control Requirements
Operating-control power source must be dry, compressed air of instrument quality at 100 kilopascal 15 psig, unless
otherwise approved.
Air mixing valve operator must be provided by the automatic temperature control manufacturer and installed by
the unit manufacturer, unless field installation for specific construction is approved. Operator must be controlled
by a direct-acting thermostat.
Pneumatic control tubing must be copper and must be brought to the exterior of the casing for connection to automatic
temperature control system.
2.9 SOURCE QUALITY CONTROL
2.9.1 Identification
Label each air terminal unit with plan number, nominal airflow, maximum and minimum factory-set airflows, coil
type, and ARI certification seal.
2.9.2 Verification of Performance
Rate air terminal units according to AHRI 880.
PART 3 EXECUTION
3.1 INSTALLATION
Install air terminal units level and plumb. Maintain sufficient clearance for normal service and maintenance.
3.2 CONNECTIONS
Coordinate piping installations and specialty arrangements with schematics on Drawings and with requirements
specified in piping systems. If Drawings are explicit enough, these requirements may be reduced or omitted.
Install piping adjacent to air terminal units to allow service and maintenance.
3.2.1 Hot-Water Piping
Connect heating coils to supply with shutoff valve, strainer, control valve, and union or flange; and to return
with balancing valve and union or flange.
Connect ducts to air terminal units.
Ground units with electric heating coils.
Tighten electrical connectors and terminals according to manufacturer's published torque-tightening values.
If manufacturer's torque values are not indicated, use those specified in UL 486A-486B.
3.3 OPERATION AND MAINTENANCE
Contractor shall submit [6] [_____] copies of the Operation and Maintenance Manuals 30 calendar days prior to
testing the following items. Data must be updated and resubmitted for final approval no later than 30 calendar
days prior to contract completion.
3.4 FIELD QUALITY CONTROL
NOTE: Retain first paragraph below to require a factory-authorized service
representative to perform, or assist Contractor with, field inspections, tests,
and adjustments. Retain one of two options to suit Project; delete both to
require only an inspection before field testing.
Engage a factory-authorized service representative to inspect[, test, and adjust] field-assembled components
and equipment installation, including connections[, and to assist in field testing]. Report results in writing.
Perform the following field tests and inspections and prepare test reports.
After installing air terminal units and after electrical circuitry has been energized, test for compliance with
requirements.
NOTE: Retain first paragraph below for air terminal units with hot-water coils.
3.4.1 Leak Test
After installation, fill water coils and test for leaks. Repair leaks and retest until no leaks exist.
3.4.2 Operational Test
After electrical circuitry has been energized, start units to confirm proper motor rotation and unit operation.
Test and adjust controls and safeties. Replace damaged and malfunctioning controls and equipment.
Remove and replace malfunctioning units and retest as specified above.
3.5 STARTUP SERVICE
NOTE: Delete this Article if factory-authorized service representative is not
required.
Engage a factory-authorized service representative to perform startup service.
Complete installation and startup checks according to manufacturer's written instructions and do the following:
Verify that inlet duct connections are as recommended by air terminal unit manufacturer to achieve proper
performance.
Verify that controls and control enclosure are accessible.
Verify that control connections are complete.
Verify that nameplate and identification tag are visible.
Verify that controls respond to inputs as specified.
3.6 DEMONSTRATION
Engage a factory-authorized service representative to train Owner's maintenance personnel to adjust, operate,
and maintain air terminal units.