Facility Maintenance & Repair

All new mechanical equipment including chiller, cooling towers, and pumps were powered by variable speed drives to ensure maximum system efficiency.  In order to make the entire chilled water plant more efficient, a 522-ton plate and frame heat exchanger was salvaged from the site and reinstalled along with new variable frequency drives on the cooling tower, pumps, and chiller.  Furthermore, all existing chilled and condenser water piping inside the plant was completely removed and replaced with schedule 40 14”, 12”, 10”, & 8” welded steel pipe.  All the new indoor and outdoor mechanical piping was insulated with mineral fiber insulation that included a separate PVC protective jacket for areas exposed to damage in the mechanical room.

Additional mechanical work included the installation of 8” future chilled water supply and return site piping throughout the basement and service tunnels of the entire campus.  Work also included the installation of a new Reverse Osmosis water treatment system to supply soft (mineral free) filtered water to the existing penthouse AHU humidifiers.  A new 60 MIL TPO roofing system for the pharmacy area where the cooling towers were located was also installed as part of this project’s scope of work.  SCS also replaced the existing chilled water plant DDC control system with a new Chiller Plant Optimization (CPO) equipped HVAC DDC system from Johnson Controls, Inc.  The CPO system consisted of the installing 8 venturi flow meters and four motorized control valves along with all new sensors and controllers for every piece of equipment in the plant.  The new JCI HVAC DDC with CPO allowed for accurate control, energy metering, and energy optimization of the chilled water plant all while being interfaced with the existing NIAGRA building management system (BMS).

The electrical scope of work included new electrical feeders, electrical service, circuit breakers, panel boards, motor control centers to support the new plant.  Structural work included the design and construction of three new cooling tower structural steel frames to support the three 400-ton BAC cooling towers.  Additional structural work included the installation of cast in place concrete pads for all new and reutilized equipment including chiller, heat exchanger, pumps, and side steam filtration unit.

On this design-bid-build, firm fixed price construction contract, Sergent Construction Services acted as general contractor as well as self-performed 80% of the following trades: demolition, cistern installation, equipment rigging, structural steel, HVAC, mechanical piping, plumbing, carpentry, and cast in place concrete.

In order to provide a redundant emergency power source for mission control, the two UPS’s were tied to line power through two static transfer switches.  This allowed the system to operate on both utility and E-power while providing redundant UPS power if the primary UPS wasn’t functioning.  New electrical switch gear consisted of three 800A Distribution Boards, one 400A Distribution Board, one 30 KVA transformer, rack-in 800A electronic breakers, and two 1200A Switchgears.  Entirely new electrical feeders and branch circuits were provided throughout the facility to feed all new and affected existing electrical systems.

The installation of the new critical power electrical equipment increased cooling loads on the affected buildings.  In order to handle the increased cooling loads, the entire HVAC system in Bldg. 4848 where the electrical panelboard and UPSs are housed was completely removed and replaced.  The new HVAC system consisted of 10-ton and 25-ton packaged heat pumps with economizers placed on CIP reinforced concrete equipment pads adjacent to Bldg. 4848.  The entire ductwork system in the building was removed and replaced with new.  The packaged heat pumps were equipped with on-board HVAC DDC controls to allow for integration of the units into the campus wide HVAC DDC/BAS.  The electrical feeders for these units were routed from the new electrical switchgear installed in Bldg. 4848. Additional HVAC system installation included the installation of three mini split systems ranging in size from 3 to 4 tons in Rm 1002 of Bldg. 4800 where a new PDU and existing telecommunication equipment was located.

Site work included the installation of 13 free standing structural steel frames to support the new emergency power electrical feeders for mission controls above grade.  The new feeders included eight 4” RGS Conduits with #600 mcm & 1/0 ground conductors and three 1” RGS conduits with three #6 AWG and #10 AWG ground Conductors).  Additional work included the installation of contractor designed structural steel brackets and framework to support the new electrical feeders from the exterior of the Mission Control facility.

The project scope of work also included the integration of all new electrical gear into the existing Utility Monitoring and Control system (BAS).  Additionally, all electrical distribution boards were equipped with energy meters which were integrated into the base wide energy management system for monitoring by NASA’s facilities department.  Architectural renovations included the installation of new doors and frontal opening in Bldg. 4848 to allow for proper egress.  Furthermore, the entire fire alarm in Bldg. 4848 was removed and replaced with a new system that is properly tied into the base wide Fire Alarm & MNS system.

Finally, additional quality assurance requirements included the factory start-up for all installed electrical switchgear, PDU’s, Panelboard, and UPS’s.  The quality of the electrical system installation was further verified by a third-party InterNational Electrical Testing Association (NETA) accredited inspection firm.  Furthermore, the entire new electrical system was put through a 24-hour load bank functional performance test to verify system functionality and battery performance.

On this design-bid-build construction contract, Sergent Construction (SC) acted as general contractor overseeing construction as well as self-performed the following trades: demolition, HVAC, equipment rigging, carpentry, electrical, and mechanical piping.  In total, SC self-performed 75% of this project’s work.

Additional work included the removal and replacement of the existing built-up bitumen roofing system with a new Single Ply 60 Mil PVC roofing system.  The new roofing system included the installation of 5” of insulation overtop of ½” gypsum cover board in order to meet the project’s LEED derived thermal and light reflectance performance specifications.

Site work for this project included the installation of underground electrical, underground chilled water line, concrete slab on grade, and site fencing for the new chilled water plant which was located separate from the school building.  Construction, repair, and alteration of plumbing systems including the installation of new equipment drains and roof drains.

The electrical scope of this project consisted of electrical rehabilitations including 2 new main panels to feed the various newly installed HVAC equipment.  Additional work included the removal and reinstallation of approximately 1,000 light fixtures throughout the interior and exterior of the school.  Along with the installation of lights a new theatrical lighting control system was installed along with new theatrical lights.  Throughout the project’s life cycle SCS’s electrical team was requested to troubleshoot and repair many electrical devices and circuits that were in disrepair in addition to our original contracted work.

On this design-bid-build construction contract, Sergent Construction acted as general contractor overseeing construction as well as self-performed the following trades: electrical, temporary electrical, temporary cooling demolition, finish HVAC, equipment rigging, structural steel installation, and site work.  In total, SCS self-performed 60% of this project’s work.

Additional work included the installation of 97 new single coil VAV’s on five floors of the main hospital with services provided to admin areas, patient rooms, CLC, laboratories, and surgery suites.  New supply ductwork was installed throughout the renovated floors to allow the existing dual duct system to be converted to a supply and return ductwork system.  Additional work included the installation of heating hot water piping system to supply heat to the new VAV’s.  The heating hot water system was supplied with heated water through the installation of a steam to hot water heat exchanger system.  This included a skid mount parallel heat exchangers, parallel pumps, and HVAC DDC.

Work also included the removal and replacement of ceilings, installation of new lights, partition walls, drywall, paint, roofing patch and repair, core drilling, fire caulking, and large-scale abatement of asbestos-containing materials (ACM) pipe insulation and duct mastic.  Additional work included the installation of new DDC controls for all installed equipment including AHUs, pumps, heat exchangers, VAVs, and glycol systems.  All new equipment was equipped with VFDs drives to ensure that all equipment would operate at max efficiency given the building loads.  Lastly, new fire alarm devices, FACPs, and plumbing were installed to support the new VAVs and AHUs.  In all, over 60,000 SF of hospital floor space was renovated.

For this design-bid-build contract, SCS acted as the general contractor as well as self-performed the following trades; demolition, mechanical piping, ductwork, electrical, and equipment installation.  In total, SCS self-performed 90% of the project’s scope of work.

In addition to the installation of a 150 Ton Air Cooled Chiller and associated chilled water pumps, piping, hydronic accessories, and structural steel platforms, a new heating hot water system was also installed in the laboratory and SPD to service the 40 new VAVs.  New supply and return ductwork systems were also installed in the mechanical rooms, laboratories, admin spaces, and SPD.  Lastly, new ceilings, lighting, paint, drywall partitions were provided for the laboratory and SPD.  This project also included the installation of new roofing systems in the renovated areas.  In addition, extensive abatement of asbestos-containing materials (ACM) was done for ACM materials found in the pipe insulation and duct mastic in the laboratory and SPD areas.

For this design-bid-build contract, SCS acted as the general contractor as well as self-performed the following trades; demolition, mechanical piping, ductwork, electrical, and equipment installation.  In total, SCS self-performed 85% of the project’s scope of work.

In order to tie together all the new and replaced equipment, all the existing chilled and condenser water piping between these pieces of equipment was removed and replaced with schedule 40, 8” welded black iron pipe.  All the new indoor and outdoor mechanical piping was insulated with mineral fiber insulation that included a separate PVC protective jacket and aluminum jacket for outdoor insulation.  The pumps were insulated with custom fabricated insulated pump boxes which allowed for easy access for future maintenance and replacement.

Work on this project also included a complete upgrade to the existing chilled water plant’s HVAC DDC system which included the installation of 4 venturi flow meters, nine 8” motorized control valves, and new sensors and controllers necessary to operate the new equipment.  The new control system allowed for accurate control and energy metering of the chilled water plant during operation via flow meters and temperature sensors.  The control system was also tied into the facilities existing building management system.  The electrical scope of work on this project included new electrical feeders, circuit breakers, panel boards, and motor control centers to allow for the installation of the upsized replacement mechanical equipment and new mechanical equipment.

On this design-bid-build construction contract, Sergent Construction (SC) acted as general contractor and self-performed the following trades: demolition, equipment rigging, HVAC, mechanical piping, carpentry, and concrete.  In total, SC self-performed over 80% of this project’s work.

To ensure efficient operation, an entirely new HVAC DDC system was installed to control both the AHUs and exhaust fans.  The HVAC DDC system consisted of new HVAC Sequence of Operations for the AHUs and exhaust fans with controls provided via BACNET controllers tied back to the facilities BACNET BAS front end.  The new HVAC DDC system included new energy meters for both the electrical and natural gas systems feeding the AHUs.  All HVAC DDC, motor starters, and electrical disconnects were contained in NEMA 4X stainless steel enclosures to ensure system longevity and weather resistance.  New duct smoke detectors were provided for each AHU and tied back into the building’s fire alarm system.  Additional work included the installation of new domestic water lines, drain lines, heated hot water supply/return, and mechanical insulation to service the new AHUs.

All existing building utilities that were in the way of construction including electrical, lighting, fire protection, and fire alarm were reworked and/or relocated to allow for system installation.  New electrical home runs and circuit protections was provided for all installed equipment.  The new and existing electrical systems all underwent an arc flash and power/short-circuit coordination study.  Once the expected short-circuit currents are known, a protection coordination study is performed to determine the optimum characteristics, ratings, and settings of the power system protective devices.

On this design-bid-build construction contract, Sergent Construction (SC) acted as general contractor overseeing construction as well as self-performed the following relevant trades: electrical, demolition, HVAC, equipment rigging, mechanical piping, and ductwork R&R.  In total, SCS self-performed 85% of this project’s work.

Work also included the expansion of the heating hot water loop in the hospital to accommodate the installation of two new domestic water heat exchangers to provide hot water for two patient wings at the hospital.  Additionally, the facility BMS and HVAC DDC were tied into the new boilers and heat exchangers to allow for proper control and monitoring by the VA Medical Center’s facilities department.

On this firm fixed price design-bid-build construction contract Sergent Construction Services acted as the general contractor and in addition self-performed the demolition, HVAC, mechanical, and plumbing.  In total, SCS self-performed 90% of this task order’s scope of work and this contract’s scope of work.

Site work also included the removal and replacement of the station’s above ground fueling system.  The existing 500-gallon gasoline Con-Vault fuel tank was replaced with a new 1,000-gallon Con-Vault fuel tank.  The existing fuel system piping was also removed and replaced with stainless steel piping.  In addition, new filter vessels were added to the fuel system in conjunction with the removal and replacement of the fuel systems hose reels and dispensers.

The HVAC work also included the complete removal and replace of all supply, return, and exhaust ductwork, installation of new condensers and air handlers, exhaust fans, and the installation of zero clearance grease ductwork for the kitchen hoods.  Additional work on this project included paint and flooring throughout the 8,000SF facility, new drywall ceilings, drywall finishing, complete bathroom demolition and rehabilitation with the installation of new vanities, shower stalls, plumbing, and plumbing fixtures in the facility’s 9 restrooms.

On this design-bid-build construction project, Sergent Construction Services acted as the general contractor and self-performed 75% of the work including demolition and HVAC installation as well as all work related to the fuel system, plumbing, electrical, and carpentry efforts.

Due to the critical nature of AHU 52 and lack of redundancy SCS provided 20,000 CFM temporary AHU from our fleet of temporary AHUs in order to allow for this AHU to be replaced while leaving the hospital fully operational.

On this design-bid-build construction contract, Sergent Construction (SC) acted as general contractor overseeing construction as well as self-performed the following relevant trades: demolition, HVAC, electrical, and plumbing.  In total, SCS self-performed 80% of this contract’s scope of work.

Work performed in each area is outlined below:

Housing Units (RPFN): Replace water damaged roof insulation as necessary in all 24 housing units.  Reseal roof penetrations in 24 units.  Replace flashing at wall and roof joints in all 24 units.  Replace water damaged drywall and paint in all 24 housing units.  Remove and replace wood laminate flooring in all 24 housing units including VCT at the entryways.  Repair two 10”x10” wood columns that were both water and termite damaged.  Replace missing exterior wall panels and siding to match original.  Reseal all exterior windows and door frames on the outside perimeter of all housing units.  Clean, lubricate, and refurbish ground floor storage access doors including frames and hardware.  Remove cork flooring found throughout the housing facilities and replace with VCT.  Replace accordion storm shutters and Plexiglas in several units.  Remove and replace portions of the HVAC ducts and registers in all 24 housing units that were damaged due to moisture.  Replace T1-11 wood siding in ground floor storage areas and leave areas clean and unfinished.

RPFN Buildings 104, 110, & 113:  SC performed a noninvasive roof inspection and found the standing seam roofs ridge cap gasket system wasn’t completely installed per the original roof plan.  USCG gave SC a follow-on and separate contract to remove and re-install existing roof as necessary to ensure a weather tight seal.

WPB Building: Replace damaged overhead garage door including channels and hardware.  Replace damaged and missing flashing that connects flat roof to wall.  Caulk and seal all upstairs windows and horizontal seams between 1st and 2nd floors.  Replace 3 downspouts and gutter system on the east and north walls.

Engineering Building: Replace damaged overhead garage door, including channels and hardware.  Repair two double door frame connections to the building.  Repair additional overhead frame connections to wall.

Swimming Pool: Replace 5’ tall decorative fencing and access gate.

Station Building: Repair hurricane shutters and replace gutter downspout.

UPH Building: Replace water damaged drywall and paint throughout building.  Seal gaps in roof flashing.  Seal all hurricane shutters and replace ceiling in one carport.

On this design-bid-build construction contract, Sergent Construction (SC) acted as general contractor as well as self-performed the following trades: demolition, carpentry, structural repairs, insulation, roof repairs, drywall, paint, and shutter replacement.  Additional self-performed work included siding replacement, sealing of doors and windows, flashing repairs, wood siding, overhead doors, gutters, door repairs, and fencing.  In total, SCS self-performed 90% of this project’s scope of work.

With regards to the structural columns, Sergent Construction had discovered damages to two structural columns and base plates.  These two columns provided for a safe and stabilized use of a three story USCG housing unit.  As a result of SC’s discovery, the USCG included a requirement for a design-build engineering effort for the replacement of these two columns.  This additional effort called for the design, removal, and replacement of these two structural columns, base plates, and spread footing.  The complete design and engineering for this effort was completed by SC’s in-house design team in conjunction with SC’s on-site supervisory staff who provided the necessary in-field data necessary to quickly complete the design.  While the design was under consideration, the Sergent Construction team quickly developed an extensive temporary shoring system along the exterior of the housing units.   This temporary shoring, column, base plate, and footing design allowed for the complete removal and replacement of the two rotten 10”x10” columns while still allowing for continued and occupied use of the facility.

On this design-build construction contract, Sergent Construction (SC) acted as general contractor as well as self-performed the following trades: HVAC work, structural member removal and replacement, installation and removal of temporary shoring for the protection of existing structures, and repair of the standing seam metal roof’s weather tight gasket system.  In total, SCS self-performed 85% of this task order’s scope of work.

Interior renovations included: demolition, in some cases complete gutting of the buildings, structural modifications, new electrical distribution systems, lighting systems, mechanical systems including, plumbing, compressed air, and HVAC systems which incorporated chillers, boilers, air handling units, VAV’s and an EMCS control system.  The new floor plan configurations required the installation of framing and gypsum board partitions, new frames/doors and hardware, and interior finishes.

On this design-build construction contract, Sergent Construction (SC) acted as general contractor as well as self-performed the following trades: HVAC work, interior and exterior mechanical and structural, electrical, earthwork, and plumbing.  In total, SCS self-performed 85% of this task order’s scope of work.

Since the entire building was occupied during construction, Sergent Construction Services’ personnel provided temporary barriers, negative ventilation, and a closely coordinated schedule to work around the customers operational schedule.

On this design-bid-build construction contract, Sergent Construction Services acted as general contractor as well as self-performed the following trades: installation of plumbing, plumbing fixtures, installation of new HVAC system, installation of DDC Controls, FA system modifications, structural framing, and the installation of electrical systems and lighting.  In all, SCS self-performed 75% of this project’s scope of work.