NORTH NEVADA EVENTS CENTER
November 17, 2010
MECHANICAL DESIGN NARRATIVE
The existing North portion of the TRW building is being considered for use as an exposition hall. The
space originally had sections for office functions with the larger portion being utilized for electronic
manufacturing. Area considered is approximately 64,000 square feet; 46,700 square feet of the area
will be dedicated to the actual exposition area.
This narrative will be referring to various documents, included in the submittal. The architectural
drawings will indicate the existing/demo plans, and the new proposed area plan. Also included are
PDF documents dated 1981, indicating existing HVAC and plumbing plans. These are assumed to be
fairly accurate with only minor changes that may have been occurred since originally constructed.
New schematic plans currently dated are included to help visualize scope of the two design
considerations. Also included is information for the major equipment described in the narrative and
associated documents.
The renovation will require modifications to the existing spaces, and the following mechanical design
criteria will provide information needed for developing the requested budgets. Two separate HVAC
design approaches are to be considered and evaluated for costs. Plumbing modifications will be
required due to the increased occupancy loads and code requirements. The existing kitchen has had
all equipment and fixtures removed except for one hood. No work is anticipated in this area at this
time.
The first design consideration will be to utilize the existing air handler systems and most of the
ductwork. The second system design would remove existing ductwork and abandon the associated
air handlers and replace with new packaged rooftop units.
Fire and smoke venting, if required by the Fire Department, will differ depending on the design
consideration. The utilization of the existing HVAC system will have two options to consider one
nd
utilizing roof vents, and the 2 will be mechanical exhaust, while the new HVAC system utilizing
package RTU units will utilize only mechanical exhaust. In either case a method for introducing make
up air will need to be considered (through doors, or other new openings). The costs associated with
the smoke vent/exhaust shall be an add alternate.
UTILIZATION OF EXISTING HVAC SYSTEMS
Intent: Reuse existing air handler systems for heating and ventilation only. Cooling for the
main Exposition area to be provided by adding new evaporative coolers on roof. The original
design appears to have the been designed to accommodate economization using roof top
exhaust fans to relieve building pressure and will be reused in the air handler economizer
mode and for the evaporative cooling mode.
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MECHANICAL NARRATIVE
The existing 30-year-old air handler systems serving the proposed area for renovation consist
of three constant volume air handlers (AHU-1, 2, 3), one multi-zone air handler (AHU-4) and
one VAV air handler (AHU-5). These air handlers are configured for chilled water and
hydronic heating. The units have been checked by owners and have found that all units can
be operated, but condition of all components has not been determined. The system chiller is
not functional, but the boiler is operational.
The existing air handlers, noted above, will be used for heating and ventilation only, and will
need to be reconditioned. The cooling coil and heating coils, along with associated piping and
controls for each air handler will be removed. New heating coils are to be installed in each of
the air handlers. The heating coil piping will require new control valve. New blower shaft
bearings are to be installed. AHU -5 will need to have the inlet guide vanes locked open or
removed. The interior of the air handlers will need to be thoroughly cleaned and checked for
air leaks and resealed. Each of the AHU blower motors will need to be tested for proper
continuity, rpm, amps and bearing noise. New sheaves and belts will be installed on each
unit. The filter racks in each unit will be inspected and resealed to insure air stream is
properly filtered.
The existing exhaust fans will remain and be utilized. Only duct that extends down from
ceiling space to floor from exhaust fans will be removed. All fans will need to be checked for
proper operation, and have new belts installed.
There are two heating circulation pumps in the lower mechanical room. One has been
removed; the second has had a new motor installed. Provide new replacement heating pump
(P-1a)
Ductwork modifications will be as described – please refer to the accompanying 1981
mechanical drawings, and proposed HVAC drawings M-1 and M-2.
On 1981 sheets M-1 and M-2, the duct work associated with AHU -1, 2, and 3 will require the
removal of all of the duct branch drops to diffusers, and the opening patched. A new round
duct drop will be installed in the bottom of the duct at the previous diffuser take-offs. This
diffuser replacement will typically be 2 for 1, with the new diffuser type being a round end of
duct adjustable diffuser mounted at 14” AFF. Typical diffuser will have 16” round neck with
balance damper at diffuser.
Again referring to 1981 sheet M-1, the duct work associated with AHU-5 will have all VAV
boxes and connections to slot diffusers removed, except where duct serves existing offices,
and bathrooms at existing entry. The supply duct will be separated at the transition in supply
duct from 36 x 24 to 30 x 20. The 30 x 20 duct, VAV boxes, and diffusers will require some
modification to accommodate the new entry vestibule, and will be connected to a new
package VAV roof top unit. The remaining duct from AHU-5 serving the event area will be
modified similar to AHU 1, 2, 3 ductwork as noted above, but will require some new branch
duct to feed the new diffusers.
The existing hydronic baseboard on the East exposures will remain except for where the
entry is renovated. In the vestibule, new hydronic fan powered cabinet heaters will be utilized,
and fed from the baseboard heating piping.
New gas piping will need to be installed from the meter location to the new packaged RTU.
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NORTH NEVADA EVENTS CENTER
MECHANICAL NARRATIVE
The duct work from AHU-4 supplying the old kitchen and support areas will remain as is. This
will provide ventilation and heating only at this point. A new DX coil and remote condenser
can be added in the future to this air handler if the area is finished out such that it requires
mechanical cooling.
Provide a line item cost to clean existing duct that will be reused. Inspect duct when work
begins and report to owner conditions found.
10 evaporative coolers supplying approximately 19,000 CFM each will provide cooing in the
main expo area. Each location will require a new roof opening, and curb installed. The curb
will have to be flashed back in to existing roofing (or into new roofing if installed). Each unit
will require motorized damper in the supply duct. A fill and drain kit shall be included and
piped below the roof. The make-up water supply will be from a new tap in the existing cold
water service near the central bathrooms. This single new connection will be provided with a
backflow preventer and will serve all the new coolers. The drain lines(s) will be piped to the
janitor rooms and discharged to janitor sinks. (Drain flow rate regulated by pipe size).
The existing exhaust fan system (scheduled for approximately 79,000 CFM) will be utilized in
the evaporative cooling mode. (A new 6500-CFM fan will be added). Additional barometric
relief will be required and installed to keep building from over pressurizing. 4 new relief
openings will be provided with back draft dampers. These will need to accommodate an
additional 100,000 CFM of air.
Additional bathroom exhaust ductwork will be needed, and fans will need to be replaced
(1981 plans EF-8 and EF-11) with larger fans to accommodate new bathroom fixtures.
The HVAC systems shall be retrofitted using new Set Point DDC controls, and will be able to
communicate with main UCCS campus facilities. See 2010 plan sheet M-1 for basic control
sequences.
The smoke vent requirement per IBC 910, 2009 allows for automatically operated smoke
vents in a fully sprinklered building. These could be an approved combination vent/skylight
vent. These must be placed evenly throughout the ceiling space and may be difficult to do
and coordinate with the existing mechanical duct and equipment. The requirement will be for
a minimum of 467 square feet of venting. (3’ x 6’ units would require approximately 26
placements, etc; and coordinating with existing duct and other ceiling systems could be
difficult and may not end up with much symmetry).
The alternate is to provide mechanical smoke exhaust. The exhaust requirement will be a
minimum of 140,100 CFM. The existing exhaust fans on the roof (79,000-CFM) will not meet
this requirement alone. (These fans are probably not listed for smoke exhaust, and will need
to be discussed with the fire department to verify if they can be used). Additional exhaust fans
would need to be installed to provide an additional 61,100-CFM. The code mandates a
maximum of 30,000 CFM per fan. Adding one additional 6500 CFM building exhaust fan and
two dedicated 27,000-CFM exhaust fans is recommended. The existing fans and the new
6500 CFM fan will be used for HVAC economizer operation, and would have to be overridden
by the Fire Control Panel to operate in conjunction with the 2 new dedicated smoke exhaust
fans.
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MECHANICAL NARRATIVE
NEW HVAC SYSTEMS FOR EXPO AREA
Intent: Provide new packaged rooftop units to serve the main Exposition area and separate
units for the existing offices, and bathrooms near the existing entry, and in the future, possibly
add a dedicated unit for the kitchen and support areas.
Refer to existing mechanical drawings dated 1981, demo all supply ductwork associated with
AHU-1, 2 and 3 beginning at the penetration from the mechanical room. These air handlers
along with AHU-5 will be abandoned in place. Remove all supply ducts from AHU-5 to the
transition (36 x 24 to 30 x 20). Remaining duct will be reused. .Ductwork from AHU-4 to
kitchen area will remain.
Referring to proposed HVAC plans M-3 and M-4, six new 50-ton packaged gas/DX rooftop
units with power exhaust will be installed for the main Exposition area. The unit’s discharge
will be a single supply drop with minimal ductwork, and a separate return back to the unit. A
smaller 10 ton VAV packaged roof top will be installed and connected to existing 30 x 20 duct
serving the main entry and offices. VAV boxes and diffusers will require some modification to
accommodate the new entry vestibule. The existing hydronic baseboard on the East
exposures will be replaced with electric baseboard except for where the entry is renovated. In
the vestibule, new electric fan powered cabinet heaters will be utilized.
Each RTU location will require a new roof opening, and a factory curb installed. The curb will
have to be flashed back in to existing roofing (or into new roofing if installed). The new 50 ton
units weigh approximately 6,500 lb each, requiring a structural review, units may require
reoriented to accommodate the structural limitations.
Bathroom exhaust fans will need to be replaced (1981 plans EF-8 and EF-11) with larger fans
for additional bathroom fixtures being added.
New gas piping will need to be installed from the meter location to the new rooftops at 7
locations.
All new systems will have new Set Point DDC controls, and will be able to communicate with
main UCCS campus facilities. See 2010 plan sheet M-2 for basic sequence of control.
The smoke vent requirement per IBC 910, 2009 allows for mechanical smoke exhaust. The
exhaust requirement will be a minimum of 140,100 CFM. The new RTU units have a powered
exhaust that will be used for the smoke exhaust. Each RTU will have a capacity of
approximately 18-19,000 CFM and when combined with the existing exhaust fans, (resheaved to about 2500 CFM each). The existing fans would not be used for any other
purpose except smoke exhaust and would operate when the Fire Control signals RTU’s to
change to smoke exhaust mode. (These fans are probably not listed for smoke exhaust, and
will need to be discussed with the fire department to verify if they can be used).
Standard skylights could easily be coordinated with this mechanical system and added if
budget allows.
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MECHANICAL NARRATIVE
Plumbing System Modifications
The existing acid waste drainage indicated on 1981 plans will be abandoned and grouted
closed at floor drain locations.
Bathrooms will be modified to accommodate the occupancy requirements. This will include
additional fixtures at the two main bathroom groups. For the North (central location) the
existing water closets are wall hung back outlet and for the intent of this budget, assume new
fixtures can be connected to existing waste line in plumbing chase. In the other main
bathroom to the south the slab will need to be cut and new waste lines added to
accommodate the additional fixtures, specifically for 2 new lavs and 5 new water closets
where there is not a possibility of connection to existing plumbing chase. This would be true
foe the new unisex bathroom adjacent to the main bathroom area. Water for new flush valves
will require new supply from main.
The existing domestic hot water was supplied from a central water heater in the mechanical
room. The water heater is not functional and has been abandoned. New water heaters are to
be installed to serve each bathroom group. At each location, abandon existing mixing valve
and pipe cold water to new electric water heater. Resupply existing fixtures and new fixtures
from new water heaters. At each location, provide a small recirc pump to minim Mize the wait
time and water use. The bathroom group at the main entry will also need to have the hot
water supplied from a new electric water heater. Insure that all janitor closets remain
connected to revised water supply.
All existing flush valves for urinals and water closets need to be checked for proper operation,
and have new repair kits installed where needed. Faucets needing repair will be replaced.
Fire Protection System
The building is currently fully sprinkled protecting spaces with lay-in ceilings. These ceilings
will be removed. The sprinkler system will require modification to provide coverage for the
open exposed ceiling. Variations will be needed to accommodate the ductwork indicated in
the two HVAC design considerations described above. The entire system will require new
Hydraulic calculations. Refer to above narrative for discussion regarding smoke exhaust
systems.
The installation shall conform to the 2009 International Mechanical Code, International Plumbing
Code, NFPA, National Electrical Codes and all Colorado Springs code requirements.
The budget shall include permit fees and drawings necessary for permits.