DESIGN AND CONSTRUCTION STANDARDS
GENERAL DESIGN GUIDELINES 2.06
2.06 MECHANICAL
GENERAL
It is expected that the mechanical design professional will conform to accepted good engineering design
practices. For this reason, most of the items covered in the mechanical guidelines pertain to those items,
which may be unique to the University of South Alabama, its mechanical systems or preference or
requirements mandated by the University. Any item not specifically outlined or commented upon in these
guidelines is left to the judgment of the engineering design professional to use current accepted good
engineering practice. The construction documents are subject to review and comment by the University
Facilities Department at any time during the course of design or construction of the project.
SPECIFIC EXISTING UNIVERSITY CONDITIONS
Central Utilities consists of the equipment in our 2 Central Energy Plants which provide heating and cooling
throughout campus via a closed loop Medium Temperature Hot Water System and a closed loop Chilled
Water System. All campus chillers use R134A coolant only.
Central Energy Plant 1, housed in our main Central Utilities Building, has 5 chillers and 2 boilers. Central
Energy Plant 2, housed near the Medical College and controlled remotely from the main Central Utilities
Building, has 2 chillers and no boilers. The attached equipment list shows details of this equipment and
other for each plant.
MAIN CENTRAL PLANT EQUIPMENT LIST - CHILLERS
CHILLER #1
CHILLER #2
CHILLER #3
CHILLER #4
CHILLER #5
BRAND
SERIAL #
CARRIER
CARRIER
CARRIER
YORK
YORK
35390
35391
67438
HTT5G1-GCBS
HTT4G1-GCBS
COOLING TONS
1016
1016
1525
1040
1040
DRIVE
HERMETIC
HERMETIC
HERMETIC
OUT DRIVE
OUT DRIVE
The main central utilities plant also includes 6 cooling tower cells and 6 cooling tower pumps. There are 2
Cleaver Brooks 700 Ton boilers, one operates year round. There are 3 hot water pumps for hot water and 5
chilled water pumps that send water thru the campus HVAC water distribution system.
MAIN CENTRAL PLANT EQUIPMENT LIST - BOILERS
CENTRAL PLANT #2 EQUIPMENT LIST
CHILLER #1
CHILLER #2
BRAND
SERIAL #
YORK
YORK
YKMAXE
YKMAXE
COOLING TONS
1200
1200
DRIVE
OUT DRIVE
OUT DRIVE
Central plant #2 plant also includes 4 cooling tower cells and 2 cooling tower pumps. There are 3 secondary
chilled water pumps and 2 primary water pumps that send water thru the campus HVAC water distribution
system.
Central Utilities monitors our on campus natural gas lines. In the event of repair or maintenance, a qualified
contractor must perform the work. The Central Utilities Staff is aware of the location of gas valves and can
shut them off in the event of an emergency situation. Central Utilities also monitors our on campus water
lines, is aware of the location of valves and can shut them off in the event of an emergency situation.
HVAC DESIGN
The typical HVAC design is a variable air volume air-handling unit driven by a variable speed drive serving
variable air volume terminal units. These terminal units will typically have a hot water coil. In general most all
of the terminal units will have a hot water coil because the minimum fresh air requirement will sometimes get
the space too cold and reheat will have to be employed. All terminal units serving external zones shall have
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DESIGN AND CONSTRUCTION STANDARDS
GENERAL DESIGN GUIDELINES 2.06
fan-powered parallel type units, while interior zones may have VAV terminal units that may have a hot water
coil. (Currently discuss terminal unit types with Engineering Services prior to Schematic Design). Typically
corner offices with two exposures will have a dedicated terminal unit and all other terminal units serving
areas with similar exposures and loads shall serve a maximum of four offices. Dedicated unit(s) shall serve
conference and meeting rooms.
DESIGN CONDITIONS
In general, heat to 72F and cool to 74F. Typical summer design conditions at the main campus are 93.9
degrees F dry bulb / 74.8 degrees F wet bulb (2005 -ASHRAE 0.4% design condition or Latest Edition).
Typical winter design conditions are 18.8 degrees F dry bulb (2005 ASHRAE 0.4% design condition or
Latest Edition). The Designer shall consider a winter design condition of 0 degrees F dry bulb for freeze
protection of the building. The Designer shall also consider a summer design condition of 105 degrees F dry
bulb for protection of equipment and for a maximum of 82 degrees F in any animal area. The Designer shall
consider a humidity design condition of 133.2 grains of moisture per pound of dry air (2005 ASHRAE 0.4%
design condition or Latest Edition) Humidity is not typically actively controlled in the majority of buildings.
Consult the program and the building occupants for specific conditions related to humidity. Clearly show
expected humidity conditions on the drawing schedule page.
Provide negative pressure at labs.
AIR HANDLING UNITS
All AHU’s shall be double wall units. AHU layout and coil type shall be designated with maintenance access
in mind. Airflow across cooling coils shall be less than 500 feet per minute. Generally a hot water preheat
coil shall be used.
Shut off valves shall be above the coil pull so building will not have to be drained to work on unit.
DUCT LINER
In general, the use of duct liner is not permitted. Duct liner is generally only allowed in terminal units boxes,
downstream of terminal units for approximately five feet for acoustic purposes and for use in sound elbows
in the return air stream. When duct liner is used, it must comply with the technical specifications found
elsewhere in this document.
HUMIDIFICATION
The addition of humidity to the air stream is only done to certain buildings where tight control of humidity is
required, such as certain research areas and libraries. The Designer should document required space
conditions and tolerances with the user group to see if control of humidity is warranted. It is typical to use
direct injection steam as the means for humidification. The chemicals used for water treatment at the Central
Steam Plant are FDA approved. Documentation and research materials can be supplied to the Engineer on
the use of this steam for direct contact humidification. The Engineer shall review these documents as
appropriate and select the best method.
FIRE PROTECTION
MAWSS water main pressure will typically range from 80 psig to 120 psig. A fire flow test shall be done for
each building. In general all University buildings will be served by a wet pipe sprinkler system unless the
specific program requires an alternate.
PLUMBING
Typically PVC piping is not allowed inside or outside. Back flow preventers manufactured by Watts are
required on each building entrance. Typically two half sized units are used. The particular site will determine
the model and placement of the back flow preventer.
Static and Dynamic flow tests should be taken to determine if booster pumps are required at each project.
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DESIGN AND CONSTRUCTION STANDARDS
GENERAL DESIGN GUIDELINES 2.06
PIPING
The University has specific requirements for all types of piping, including hot water, and chilled water piping.
Refer to specific specification sections found elsewhere in this document. Generally “victaulic” and
“ProPress” fittings are not allowed. Victaulic fittings are allowed on fire protection systems and in certain
circumstances where a small amount of pipe movement is required.
BOILERS
The campus is presented with 180 degree water from the main Central Utilities Plant. This is the preferred
method of heating if possible. Boilers for stand-alone buildings are to provide redundant capability to the
greatest degree possible. In buildings where animals are housed, 100 percent redundant capability for all
animal areas is required.
CHILLERS
Two separate chiller plants serve the majority of campus. This is the preferred method of cooling. In these
plants, the design intent is for peak load requirements to be met when the largest unit is not in operation.
Chillers for stand-alone buildings are to provide redundant capability to the greatest degree possible. In
buildings where animals are housed, 100 percent redundant capability for all animal areas is required.
Generally water cooled chillers are preferred over air cooled chillers and DX type of systems. USA has
specific requirements for centrifugal chillers as found in the specification section found elsewhere in this
document. Scroll type chillers are preferred in their applicable size ranges. Currently, the gap between the
scroll machines and the centrifugal machines is filled with screw machines manufactured by Carrier, Trane
or York. Due to noise considerations, screw type chillers shall be used only with the pre approval of the
University Facilities department. Sometimes the use of reciprocating chillers manufactured by Carrier or
York is more appropriate.
COOLING TOWERS
The preference for cooling towers is as follows and considers longevity and service.
1. Permanent towers as manufactured by Tower Engineering.
2. Fiberglass towers.
3. Galvanized towers with either fiberglass or stainless steel cold-water basin.
The specific tower to be used depends on the project type and site location. The Designer shall carefully
consider the location of the cooling tower and take into account trees in the area, effect of plume and any
drift and be at least 50 feet away from any outside air intake. The Designer shall consider cleaning
provisions for cooling towers. The Designer shall discuss the use of sand filters for condenser water systems
with Campus Services Engineering Services.
CONTROLS
Distributed DDC controls are used throughout the campus. The currently approved Vendor is Siemens. ALC
Controls (Manufacturer: Automated Logic) and Johnson Controls are to be used only in certain building
where they have a presence. Every coil shall have a discharge temperature sensor (including terminal
units). See control specification section for graphics and other specific requirements
METERS
All campus-based utilities (electricity, domestic water and hot and chilled water, and natural gas) shall be
metered and in most cases tied into the DDC control system for monitoring and utilization. When feasible
irrigation meters and meters for cooling tower makeup water shall be installed separately to avoid sewer
charges. This requirement is building specific. Check with the Facilities Department for applicability.
Each building's electrical use is monitored by Snyder electrical software.
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DESIGN AND CONSTRUCTION STANDARDS
GENERAL DESIGN GUIDELINES 2.06
SUBSTITUTIONS
The Design Consultant shall never use the phrase “or equal” without prior approval. Each piece of
equipment or item shall have 3 manufacturers with equal products.
DOCUMENT CONTENT
In general, all mechanical sections of the construction documents shall contain technical specifications,
equipment schedules, flow diagrams, riser diagrams, plans, large scale mechanical room partial plans,
sections and details. Underground utilities shall include plans upon a topographic background and profile
drawings of the utility routing. Utility routing shall include dimensioned fitting locations and elevations. All
HVAC design equipment schedules, HVAC controls input/output summaries, HVAC/BAS control diagrams,
and equipment sequences of control shall be located on the mechanical drawings.
The Engineer shall make sure that all abbreviations used on the design drawings are defined on a legend
page. All mechanical room plans shall clearly show access requirements needed for such things as coils
pulls, access around electrical devices, etc. This partial plans shall be drawn at a scale of not less than
¼”=1’-0”. The Engineer shall include an air flow schematic diagram that indicates air handling units, exhaust
fans, etc. with air flow rates. This drawing shall show how air is distributed on a floor by floor basis.
Typically the USA Facilities department will review available documents at the schematic design stage,
design development stage, 60% stage and 90% stage. A meeting is typically held during schematic design
and/or design development to discuss general methods of heating and cooling and air distribution
BUILDING CONSIDERATIONS
The use of hard type ceiling is discouraged. Lay in ceilings are much preferred to allow access to above
ceiling components. If the use of hard type ceilings is unavoidable, with University project manager preapproval, the Design Associate shall locate adequately sized access panels on the drawings.
Mechanical rooms shall be laid out so as to have adequate access for maintenance. All mechanical rooms
must have adequate lighting, electrical outlets, a hose faucet, fire extinguisher and shall have painted walls.
The Designers shall provide electrical outlets, wash down faucet s and lighting near all cooling towers. Care
must be taken to provide a walking path for operation and maintenance of equipment. The Engineer shall
design so as to eliminate head knockers and trip hazards such as drain piping.
The Engineer shall locate enough hub drains to eliminate piping running across the floor. All mechanical
rooms and spaces shall be designed to be waterproof by the use of curbs, drains and waterproofing
materials as required. Water shall flow to and out of the drains and not pond on the floor. Flood testing shall
be required to demonstrate effectiveness of waterproofing.
Wall mounted fire extinguishers shall be provided for every mechanical room. In general floor drains shall
be provided for mechanical rooms, laboratories, rest rooms, under emergency showers and in general
locations to accommodate release of water from fire protection systems. The designers shall discuss floor
drain locations with USA Facilities during the design phase.
Doors to mechanical rooms larger than 200 square feet shall have an opening of 6 feet. For buildings
100,000 square feet or larger, penthouse mechanical rooms shall be served by an elevator. The elevator
cab is to be large enough to facilitate the removal of the largest part of the equipment in the mechanical
room. For penthouse mechanical rooms that are not served by an elevator, a rail and hoist are to be
provided to facilitate the removal of equipment through a floor hatch or opening.
The Design consultant should consider how equipment is brought into and taken out of the building and
provide adequate egress for equipment without dismantling the equipment or taking apart portions of the
building.
In mechanical rooms, at all penetrations in floor, provide a sleeve to 2" A.F.F., to reduce liquids from
dripping to the floors below.
Owner will provide labeling for above ceiling valves to contractor to install on suspended ceiling system.
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DESIGN AND CONSTRUCTION STANDARDS
GENERAL DESIGN GUIDELINES 2.06
ASHRAE 15
The Engineer shall be responsible for bringing any mechanical room (new or existing) up to the ASHRAE 15
Code, Latest Edition (Safety Code for Mechanical Refrigeration) if appropriate.
INSTALLATION TESTS
Test the following systems and have the Contractor create certificates documenting the test.
C.
A.
Soil, waste, vent and rainwater systems.
B.
Domestic cold and hot water.
Fire protection systems – Generally test these systems with a hydrostatic test. For systems
in certain occupied buildings such as data centers or libraries, do a preliminary test with air. Do
not exceed 20 psig for the preliminary air pressure test.
D.
Natural gas systems.
E.
Compressed air systems.
F.
Heating hot water systems.
G.
Chilled water systems.
I.
Air tests shall only be used for preliminary tests on fire protection piping in certain
occupied buildings, natural gas systems and compressed air systems. For other systems
Contractors must do a hydrostatic test. Any exceptions must be approved by the
Engineer and the Owner
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