SECTION 15855 - PACKAGED AIR HANDLING EQUIPMENT
PART I - GENERAL
1.01
1.02
RELATED DOCUMENTS:
A.
Drawings and general provisions of Contract, including General and Supplementary
Conditions and Division 01 Specification sections, apply to work of this section.
B.
Division 23 Motors Drives and Electrical Requirements for Mechanical Systems, General
Mechanical Requirements, and General Pipes and Fittings sections apply to work of this
section.
SUMMARY:
A.
Extent of air-handling unit work is indicated on drawings, schedules, and by requirements
of this section.
B.
Types of packaged air-handling units specified in this section include the following:
1.
Rooftop Unit
C.
Refer to other Division 23 sections for vibration control units used in conjunction with air
handling units; not work of this section.
D.
Vibration control units required for air handling units is specified in other Division 23
sections, and is included as work of this section.
E.
Refer to other Division 23 sections for field-applied insulation to air handling units.
F.
Refer to other Division 23 sections for hot and chilled water, and condensate drain piping
required in conjunction with packaged air handling units.
G.
Refer to Division 23 sections for the following work.
1.
Power supply wiring from power source to power connection on unit. Include
starters, disconnects, and required electrical devices, except where specified as
furnished, or factory-installed.
2.
Interlock wiring between electrically-operated equipment units; and between
equipment and field-installed control devices shown on electrical drawings.
a.
H.
Interlock wiring specified as factory-installed is work of this section.
Provide the following electrical work as work of this section, complying with requirements
of Division 26 sections:
1.
Control wiring between field-installed controls, indicating devices, and unit control
panels.
a.
Control wiring specified as work of Division 23 for Automatic Temperature
Controls is work of that section.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 1
1.03
1.04
1.05
QUALITY ASSURANCE:
A.
Manufacturer's Qualifications: Firms regularly engaged in manufacture of packaged
air-handling units with characteristics, sizes, and capacities required, whose products have
been in satisfactory use in similar service for not less than 5 years.
B.
Installer's Qualifications: A firm with at least 3 years of successful installation experience
on projects with metal ductwork systems work similar to that required for project.
SUBMITTALS:
A.
Product Data: Submit manufacturer's technical product data for air handling units
showing dimensions, weights, capacities, ratings, fan performance with operating point
clearly indicated, motor electrical characteristics, gages and finishes of materials, and
installation instructions.
B.
Shop Drawings: Submit assembly-type shop drawings showing unit dimensions, weight
loadings, required clearances, construction details, and field connection details.
C.
Wiring Diagrams: Submit manufacturer's electrical requirements for power supply wiring
to air handling units. Submit manufacturer's ladder-type wiring diagrams for interlock
and control wiring. Clearly differentiate between portions of wiring that are
factory-installed and portions to be field-installed.
D.
Maintenance Data: Submit maintenance instructions, including instructions for
lubrication, filter replacement, motor and drive replacement, and spare parts lists. Include
this data, product data, shop drawings, and wiring diagrams in maintenance manuals; in
accordance with requirements of Division 23 05 93.
REFERENCES:
A.
Codes and Standards:
1.
AMCA Compliance: Test and rate air handling units in accordance with AMCA
standards.
2.
ARI Compliance: Test and rate air handling units in accordance with ARI 430
"Standard for Central-Station Air Handling Units", display certification symbol on
units of certified models.
3.
ASHRAE Compliance: Construct and install refrigerant coils in accordance with
ASHRAE 15 "Safety Code for Mechanical Refrigeration".
4.
NFPA Compliance: Provide air handling unit internal insulation having flame
spread rating not over 25 and smoke developed rating no higher than 50; and
complying with NFPA 90A "Standard for the Installation of Air Conditioning and
Ventilating Systems".
5.
NEC Compliance: Comply with National Electrical Code (NFPA 70) as applicable
to installation and electrical connections of ancillary electrical components of air
handling units.
6.
International Building Code/ International Mechanical Code: Comply with all
sections pertaining to mechanical work.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 2
7.
1.06
Smoke exhaust fan shall meet IBC-2000.
PRODUCT DELIVERY, STORAGE AND HANDLING:
A.
Deliver air-handling units with factory-installed shipping skids and lifting lugs; pack
components in factory-fabricated protective containers.
B.
Handle air-handling units carefully to avoid damage to components, enclosures, and
finish. Do not install damaged components; replace and return damaged components to
air-handling unit manufacturer.
C.
Store air-handling units in clean dry place and protect from weather and construction
traffic. Where necessary to store outside, store above grade and enclosed with waterproof
wrapping.
D.
Comply with Manufacturer's rigging and installation instructions for unloading air
handling units, and moving them to final location.
PART II - PRODUCTS
2.01
ROOF MOUNTED AIR HANDLING UNITS COOLING AND VENTILATING (RTU-1 thru 6):
(with DX cooling and economizer)
A.
Rooftop units shall be in accordance with the following specifications and capacities as
shown on the plans.
B.
Unit performance:
C.
1.
Unit cooling capacities shall be in accordance with and tested to ARI standard
210/240-89 or 360-85, and carry ARI compliance label.
2.
Unit MINIMUM cooling efficiency, including the supply air blower motor shall
be as shown on the plans.
3.
Unit shall be safety certified in accordance with UL Standard UL465, and ANSI
Standard Z21.47. Unit shall be safety certified by an accredited testing laboratory.
Unit nameplate shall carry the label of the certification agency.
4.
Unit to be shipped completely assembled by the manufacturer including all
standard items and optional items. Unit to be 100% run tested by the
manufacturer with a copy of the run test report shipped with the unit.
Unit construction:
1.
Unit is to be completely factory assembled, piped, wired and shipped in one piece,
specifically designed for outdoor rooftop application with a fully weatherproof
cabinet.
2.
Unit is to be designed with dedicated bottom supply / return air style system for
mounting on a roof curb.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 3
D.
3.
Cabinet to be constructed entirely of G90 wt. Galvanized metal with the exterior
constructed of 18 gauge or heavier metal. Roof to be cross broken and sloped to
assure drainage.
4.
Access to compressor(s), controls, filters, blower, and other items needing
periodic checking or maintenance shall be through hinged access doors with a
quarter turn latch (door fastening screws are not acceptable). Air side service
access doors to be fully gasketed with rain break overhangs. Air side doors will
have an internal metal liner to protect the door insulation.
5.
Exterior of unit to be painted with two-part polyurethane paint over a wash primer
and a paint grip type galvanized steel.
6.
Wiring to be color coded and marked with a three digit identification on each end.
7.
The interior air side of the cabinet to be entirely insulated on all exterior panels
with 1" thick, one pound density, neoprene coated, fiberglass insulation.
8.
To guarantee no leakage of conditioned air from the cabinet all of the cabinet
under positive pressure, downstream from the supply air blower, shall have a
separate internal cabinet contained within, and separate from, the exterior cabinet
by an air gap. The internal cabinet shall be guaranteed to hold a static pressure of
up to 12 inches water column.
9.
All openings through the base pan of the unit shall have upturned flanges of at
least 1/2" in height around the opening through the base pan.
10.
Unit to have decals and tags to indicate unit lifting -rigging, service areas and
caution areas.
11.
Provide wiring diagrams with colors and marks which match the color and
markings of the wires. Diagrams to be both point-to-point and Aladder type
diagrams. Laminate and permanently attache the diagrams to the control
compartment door.
12.
Installation and maintenance manuals shall be supplied with each unit, located in
a metal pocket in the control access compartment, as well as in the building O&M
Manual.
Blowers:
1.
2.
3.
E.
Blower(s) to be entirely self contained on a slide deck for service and removal
from the cabinet.
All belt drive blower(s) to have backward inclined airfoil blades. Adjustable Vbelt drive shall be provided with a minimum rating of 140% of the motor
nameplate brake horsepower when the adjustable pulley is at the minimum RPM.
Furnish with high efficiency motor.
Blowers, drives and motors shall be dynamically balanced.
Outside Air:
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 4
F.
1.
Shall be a modulating dry bulb controlled economizer with multi-stage integrated
economizer and compressor operation for maximum benefit. The economizer
shall consist of a motor operated outdoor air damper and return air damper
constructed of extruded aluminum, hollow core, air foil blades with rubber edge
seals and aluminum end seals. The motor shall be furnished and installed by the
rooftop unit manufacturer. Damper blades shall be factory installed and be gear
driven and designed to have no more than 25 CFM of leakage per square foot of
damper area when subjected to 2" WG air pressure differential across the damper.
Damper motor shall be spring return to ensure closing of outdoor air damper
during period of unit shut down or power failure. A pressure relief damper sized
for 100% relief air shall be provided as part of the economizer. Coordinate with
Control Contractor.
2.
During periods of non-economizer operation, the outside air damper shall open to
its minimum position. The damper motor shall be interlocked with the hood
exhaust fan, such that when the exhaust fan is on, the outside air damper shall
open to a more open position. Such that the required make-up air for the hood can
be brought in.
Condensing Section:
1.
G.
H.
Evaporator Coil:
1.
Evaporator coil(s) shall be copper tube with aluminum fins mechanically bonded
to the tubes, galvanized steel end casings, equalizing type vertical tube distributors
with a top suction connection.
2.
Evaporator coils for multi-compressor unit to be circuited with one circuit and
expansion valve per compressor.
3.
Evaporator coils shall be six row copper tube coil with aluminum fins
mechanically bonded to the tubes.
Condenser Coil:
1.
I.
The condensing section shall be equipped with direct drive, vertical discharge
condenser fan(s). The condenser coil shall be sloped at least 30 degrees from
horizontal to protect the coil from damage.
Condenser coil shall be copper tube with aluminum fins mechanically bonded to
the tubes, sized for a minimum of 10 degrees sub-cooling.
Refrigeration System:
1.
Compressor(s) to be of the hermetic scroll type with internal thermal overload
protection and mounted on the compressor manufacturer’s recommended rubber
vibration isolators.
2.
Compressor(s) to be mounted in an isolated compartment to permit operation of
the unit without affecting air flow when the compressor compartment is open.
3.
Compressor(s) to be isolated from the base pan and supply air to avoid any
transmission of noise from the compressor into the building area.
4.
Equip with thermostatic expansion valve(s) type refrigerant flow control.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 5
J.
5.
Equip with automatic re-set low pressure and manual reset high pressure
refrigerant controls.
6.
Unit to be equipped with Schrader type service fittings on both the high side and
low pressure sides of the system.
7.
Equip with refrigerant liquid line driers.
8.
Unit to be fully factory charged with refrigerant R-410A.
9.
Lead circuit(s) shall be provided with hot gas bypass.
10.
All circuits shall be provided with liquid line sight glasses.
11.
Unit shall be equipped with a 5 minute anti-short cycle delay timer for each
compressor.
Filters:
1.
Unit to be furnished with 2" pleated throw away supply air filters.
2.
K.
L.
Unit to be provided with a direct dial reading Magnehelic gauge mounted in the
control compartment.
Temperature Control:
1.
All controls shall be factory wired and tested requiring only field connections to
remote factory furnished controls. Provide complete wiring diagrams.
2.
A remote wall sensor acting through a separate adjustable thermostat sends a
signal to the unit controller. The thermostat shall be located in a control panel in
the Kitchen. The thermostat shall have a sub-base with a fan auto-on switch and a
heat-cool-auto switch. When the kitchen exhaust fan runs the rooftop unit fan
also starts.
3.
The unit shall have a modulating economizer with minimum settings for
ventilation. Provide a override contact point to open the economizer outside air
damper, should it be closed, to provide 1200 cfm when the kitchen hood exhaust
fan runs.
4.
The unit shall have two stage control for the DX cooling and four stage control for
the gas fired heat.
5.
Unit shall be provided with a factory installed low limit controller to prevent
discharge air temperature below 40Ε (adjustable).
Power Options:
1.
Unit shall be provided with a factory installed and wired internal disconnect
switch with fusing. Unit to be provided with all required starters and contactors.
2.
Unit shall be provided with phase and brown-out protection to shut down all
motors in the unit if the phases are more that 10% out of balance on voltage, or
the voltage is more than 10% under design voltage.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 6
3.
M.
N.
Roof Curb:
1.
Roof curb constructed of galvanized steel. Curbs to be fully gasketed between the
curb top and unit bottom with the curb providing full perimeter support, cross
structure support and air seal for the unit. The curb shall be designed for seismic
zone 3.
2.
Unit to be mounted on acoustical style solid bottom roof curb, fully lined with 1"
of neoprene coated, fiberglass insulation and with a wood nailer strip. The curb
shall be adjustable up to 3/4" per foot to allow for a sloped roof.
3.
Install curb on existing sloping roof leveling base. Field ventilating for exact
dimensions.
Approved Manufacturers:
1.
2.
3.
4.
O.
Unit shall be provided with a factory installed and wired 115 volt, 13 amp ground
fault service receptacle.
Carrier
Bryant
Trane
Day & Night
Capacity: Capacity and performance as listed on the drawings.
PART III - EXECUTION
3.01
INSPECTION:
A.
3.02
Examine areas and conditions under which air-handling units are to be installed. Do not
proceed with work until unsatisfactory conditions have been corrected in manner
acceptable to Installer.
INSTALLATION OF AIR-HANDLING UNITS:
A.
General: Install air-handling units where indicated, in accordance with equipment
manufacturer's published installation instructions, and with recognized industry practices,
to ensure that units comply with requirements and serve intended purposes.
B.
Coordination: Coordinate with other work, including ductwork, floor construction, roof
decking, piping, and electrical as necessary to interface installation of air-handling units
with other work.
C.
Access: Provide access space around air handling units and small cabinet fans for service
as indicated, but in no case less than that recommended by manufacturer.
D.
Support: Install floor-mounted air handling units on 4" high reinforced concrete pad, 4"
larger on each side than unit base. Hang or support horizontal small cabinet unit from
structure with spring hangers with seismic bracing.
E.
Mounting: Mount air handling units on vibration isolators, in accordance with
manufacturer's instructions.
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 7
F.
Electrical Wiring: Install electrical devices furnished by manufacturer but not specified to
be factory-mounted. Furnish copy of manufacturer's wiring diagram submittal to
Electrical Installer.
1.
3.03
3.04
Verify that electrical wiring installation is in accordance with manufacturer's
submittal and installation requirements of Division 26 sections. Do not proceed
with equipment start-up until wiring installation is acceptable to equipment
installer.
G.
Piping Connections: Refer to Division 15 HVAC sections. Provide piping, valves,
accessories, gages, supports, and flexible connectors as indicated.
H.
Duct Connections: Refer to Division 15 Air Distribution sections. Provide ductwork,
accessories, and flexible connections as indicated.
I.
Grounding: Provide positive equipment ground for air-handling unit components.
J.
Coil Condensate Drain Trap: Provide coil condensate drain trap of proper size and depth
for each air handling unit coil condensate drain pan.
FIELD QUALITY CONTROL:
A.
Testing: Upon completion of installation of air-handling units, start-up and operate
equipment to demonstrate capability and compliance with requirements. Field correct
malfunctioning units, then retest to demonstrate compliance.
B.
If specified conditions cannot be obtained due to deficiencies in equipment performance
or improper installation or workmanship, the Mechanical Contractor and his
subcontractors shall make any changes necessary to obtain the specified conditions.
EXTRA STOCK:
A.
Provide two complete sets of filters for each air handling unit. Install one set of filters at
completion of air handling system work, and the other set prior to testing, adjusting, and
balancing work. Obtain receipt from Owner that new filters have been installed.
B.
Provide one spare set of belts for each belt-driven air handling unit, obtain receipt from
Owner that belts have been received.
END OF SECTION 15855
Brigham Young University
Maxwell Institute - Benson Bldg Remodel
BYU Project #: D9833 MS #: 08.0160
PACKAGED COOLING ONLY ROOFTOP UNITS
15855 - 8