05_Mechanical Narrative.pdf
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- Solicitation number
- 36C25526R0125
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This is a mechanical design specification document for a Centralized Emergency Power System construction project at Robert J. Dole VAMC in Wichita, Kansas (VA Project No. 589A7-21-132). The project involves constructing a new extreme impact-rated generator building to house three Emergency Diesel Generators (EDGs) and electrical switchgear with capacity to support the existing campus and future expansions totaling 150,000 square feet. Medium voltage power will be distributed to existing campus selector switches via underground concrete-encased ductbank. The project is designed in accordance with VA Design Guide for Hospitals, VA Physical Security and Resiliency Design Manual (June 1, 2025), VA HVAC Design Manual (September 1, 2025), and NFPA 110 standards.
The mechanical systems include: three large roof-mounted extreme impact-rated gravity intake hoods and 13 wall louvers for combustion and ventilation air; two exhaust fans maintaining VA-required minimum 4 air-changes per hour; a roof-mounted AHU with steam heating and DX cooling coil maintaining 80°F summer and 45°F minimum winter temperatures; a heat-pump split system for the switchgear room (45-80°F); and steam unit heaters for the fire riser room (minimum 40°F). Sound attenuators are included throughout intake and exhaust systems. Fuel storage consists of two 40,000-gallon double-wall fiberglass underground tanks at 5 feet below grade with interstitial leak monitoring, sized to operate generators for 133% of 96 hours minimum. A 500-gallon double-wall day tank and pump skid will be provided with the pump skid located in an interior pit to manage suction lift requirements. Steam and condensate lines will be supplied via new shallow concrete trench connecting to existing steam vault. Controls integrate generator operation with louver dampers, exhaust fans, and HVAC systems through thermostat and BAS interlock; modulating exhaust dampers allow heat recovery during winter operation.
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DEPARTMENT OF VETERANS AFFAIRS VA PROJECT NO. 589A7-21-132
ROBERT J. DOLE VAMC CENTRALIZED EMERGENCY POWER SYSTEM
WICHITA, KANSAS 100% CONSTRUCTION DOCUMENTS: 03/18/2026
MILLER-REMICK LLC 5-1 CHERRY HILL, NEW JERSEY
CHAPTER 5
MECHANICAL
1. GENERAL
This project shall construct a new Centralized Emergency Power System, sized and configured to satisfy the emergency power demand for the existing campus and future campus expansions totaling 150,000 square feet. The Centralized Emergency Power System shall consist of a new extreme impact rated generator building that has the capacity to back up the main electric utility services entering the campus. Medium voltage power shall be distributed to the existing campus selector switches via a new underground concrete-encased ductbank system.
1. SCOPE OF WORK
A. Systems to be altered:
1) This is a new building with new utilities (steam and condensate) installed to the building.
B. The new Generator Building will be designed in accordance with, but not limited to the following Applicable Codes and Standards:
• VA Design Guide for Hospitals
• VA Physical Security and Resiliency Design Manual (PSRDM), June 1, 2025 Revision
• VA HVAC Design Manual, September 1, 2025
• Latest applicable version of NFPA 110, Standard for Emergency and Standby Power Systems
2. DESIGN APPROACH
A. A new generator building will be constructed to house the three new Emergency Diesel Generators (EDG) and new electrical switchgear. The building will be provided with an air conditioning system to maintain the building temperature within the generator and switchgear equipment temperature requirements. During the initial generator startup all (3) will start until one reaches 100% load capacity then at least one generator will drop off, this sequence will only last 5-10 seconds. Thus, the makeup air system will only be designed to provide air for
(2) two generators. The building will have extreme impact rated exhaust louvers and ductwork connected to the each of the engine generator radiators. Due to the large quantity of air for the
(2) two operating generators (3) Large roof mounted extreme impact rated resistant gravity intake hoods and a total of 13 wall louvers are required to provide the necessary combustion and ventilation air. The roof hoods will be centered in each structural bay and close to the plan south side of the building. The extreme impact rated intake louvers will be located high on the plan as follows: (9) along the south wall and (2) each on the east and west walls. The RTU and
(2) exhaust fans which will maintain the VA required minimum of 4 air-changes. The exhaust
DEPARTMENT OF VETERANS AFFAIRS VA PROJECT NO. 589A7-21-132
MILLER-REMICK LLC 5-2 CHERRY HILL, NEW JERSEY
fans will be located along the plan north side of the roof at the required 25 feet from any intake.
This arrangement will allow the air to swap across the generator, which is the preferred arrangement by the manufacturers. Dampers on the generator radiator exhaust plenum will allow for a portion of the hot exhaust air to be returned back into the generator building. This will help warm the building during winter season. The dampers will be controlled by a separate thermostat to prevent the space from overheating. The purpose of the exhaust fan system will be provided to meet the required VA required minimum ventilation when mechanical cooling is not required, and when the generators are not running. A roof-mounted AHU with a steam heating coil and a DX cooling coil will be provided. The RTU will maintain the summer space temperature of 80 degrees F and minimum of 45 degrees F, Per the VA HVAC Design manual these are not required to operate when the generators are running. The Switchgear Room will be provided with a heat-pump split cooling/heating system consisting of a wall mounted cassette and a condensing unit which will be installed on the top of the switchgear room. The heat-pump split system will be controlled by a space thermostat. Steam Unit heaters will be provided inside the Fire Riser room to the space above the VA required minimum of 40 degrees F. The unit heater will be controlled by a space thermostat for the unit heater in the Fire Riser room. Due to the sound levels produced by the generators, sound attenuators will be included in the generator radiator exhaust plenums and in all points of intake air (roof hoods and wall louvers).
B. Steam for the RTU & Unit Heater. Due to the location of the natural gas utilities the VA directed the A/E to provide steam to the new generator building. A new shallow concrete trench for a new HPS and pumped-condensate lines. The new trench and piping will connect into an existing steam vault. The routing of the trench takes into the account minimizing the impact to the parking areas during construction.
C. Fuel Oil – Per PSRDM and NFPA requirements, the fuel oil storage capacity is be sized to run the generators for a 133% of minimum of 96 hours. These requirements cover an emergency backup generator system, the generators for this project will be a backup system to the emergency generators. The VA shall confirm that these requirements apply to this project. The above calculations determined that a total storage capacity 80,000-gallon underground storage tanks is required to allow for the generator operation. The Wichita VA requested that the tanks be fiberglass and that the piping from the tanks into the building be in an accessible trench.
Basis of Design will be (2) 40,000 double-wall fiberglass tanks mounted underground at a depth of 5 feet below grade. The tanks will have leak monitoring in the interstitial space. (Refer to Appendix C). The piping from the tanks to the building will be located inside a precast-shallow concrete trench. A new 500-gallon double wall fuel oil day tank and pump skid will be provided. New pipe trenches inside the building will be included. The trenches will slope to a drain and be piped through an oil/water separator. The Wichita VA decided not to include any type of plumbing within the building. Thus, an oil-water separator will NOT be required. All fuel oil piping (both exterior and (interior not in a trench) will have secondary containment and leak detection. The fuel oil pump calculations showed that the suction lift exceeded the 15 in Hg limit, to mitigate this the pump skid and filtration skid will be located within a pit inside the building to keep the elevation of the pumps as close to the tanks as possible.
D. Controls – The Emergency Generator shall be interlocked with the louver dampers. When the generator is energized, the power to the dampers are turned off and they spring open. End switches on the dampers provide status of the position of the dampers. If the dampers fail to open an alarm shall be sent to the BAS. When the generator is running the exhaust fan is commanded to run. When the space temperature rises above 80 degrees F, the HVAC air
DEPARTMENT OF VETERANS AFFAIRS VA PROJECT NO. 589A7-21-132
MILLER-REMICK LLC 5-3 CHERRY HILL, NEW JERSEY
conditioning system is commanded to start. Per the current VA HVAC Design manual, the space is only ventilated when the generator is running. Dampers on the generator radiator exhaust plenum will allow for a portion of the hot exhaust air to be returned back into the generator building. The dampers that control how much air is exhausted to the outdoors will be modulating type with spring open type. This will help warm the building during winter season.
The dampers will be controlled by a separate thermostat to prevent the space from overheating.
The air conditioning systems will be off when the generator(s) running. The switchgear room will be kept between 45 and 80 degrees F. The unit heater in the fire riser room will keep the space temperature above 50 degrees F, the unit heater will be controlled by a thermostat in the space
E. Fire Protection – Refer to the FIRE SUPPRESSION SYSTEM DESIGN APPROACH in Section 3.
DEPARTMENT OF VETERANS AFFAIRS VA PROJECT NO. 589A7-21-132
MILLER-REMICK LLC 5-4 CHERRY HILL, NEW JERSEY
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MECHANICAL
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