SOW_Replace_HVAC_Buxton_Ranger_Station.pdf

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OUTER BANKS GROUP

WRIGHT BROTHERS NATIONAL MEMORIAL

FORT RALEIGH NATIONAL HISTORIC SITE

CAPE HATTERANS NATIONAL SEASHORE

STATEMENT OF WORK:

Replace HVAC System at Buxton Ranger Station

NATIONAL PARK SERVICE

Region II

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TABLE OF CONTENTS

TABLE OF CONTENTS

1.0 BACKGROUND/ EXISTING CONDITIONS ..………………….…………………………………3

2.0 OBJECTIVES .……………………………………………………………………………………….6

3.0 PLACE OF PERFORMANCE

4.0 TASKS/SPECIFICATIONS …………………………………...…………………………………….6

5.0 SUBMITTALS ………….…………………...……………………………………………….……….8

6.0 DELIVERARY

7.0 OTHER UNIQUE REQUIREMENTS…...…………………………………………...…………..…9

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1.0 BACKGROUND AND EXISTING CONDITIONS

The Buxton Ranger Station is a historic building located on Lighthouse Rd in Buxton, NC and provides office space for Outer Banks Group personnel. The building includes two structures side by side connected by a portico between the two structures. The main entrance is at the rear of the building. The two structures are two story similar in size and have separate HVAC system for the downstairs and upstairs (See basic floorplans below). There is no existing HVAC plan for the building. The building as a whole is referred to as the Buxton Ranger Station. To differentiate between the two sides of the building, the right side when looking at the floor plan is referred to as the Ranger or VRP side, while the left side is referred to as the Resource

Management side. For the purposes of this project, these naming conventions will be used. The

HVAC systems and controls at the Ranger Station are at the end of their life cycle and are consistently performing poorly.

The heat pumps are located outside the building and provide refrigerant lines into the building to the air handler units for each side. Dates of manufacture for exterior and interior units show

2004 and 2006. One exterior heat pump unit was replaced in 2021. The Resource Management side has an HVAC closet located on the ground floor near the entrance at the rear of the building containing two air handlers. Ducting from one air handler is installed in a chaseway along the ceiling of the first floor toward the front of the building. Supply vents include rectangular, square, and round louvers of various sizes. Another Air handler supplies air through a chase extending upward through the second floor into the attic space where ducting runs above the ceiling to supply louvers installed in the ceilings. On the Ranger side the two air handlers are located in a second story closet located near the front of the building. One air handler supplies ducting into the attic space above, providing supply vents through the ceilings in each room. The other air handler is situated upside down, providing air down to a chaseway in the ceiling of the first floor to various rooms. The upstairs HVAC closet ceiling and floor have been cut to allow ducting to pass through. The floor tile appears to be 12 inch vinyl tile atop plywood. Severla floor tiles are broken, but generally appear to be intact and undamaged. Manufacture dates of the units are 2006. The flooring and adhesive do not appear to be asbestos containing materials.

The floor does appear to be slight deflection in the floor likely from inadequate floor joist support and weight of the 2 HVAC units. The HVAC systems have been modified in the past to add ductwork to reach several offices. The Utility room with Telecommunications equipment is without HVAC. Some sections of ductwork may have tears or separations in the insulation as indicated by ceiling damage and rust on supply registers. The porches on the easter side of the building were enclosed and converted to office space and are labeled as the “District Resource

Management Office” and “Visitor Use Office” in Figure 1 below. The attic insulated duct sheet metal and round duct is undersized and improperly fitted to supply registers. The ceiling in one room outside the mechanical space on the VRP side is sagging slightly from condensate and/or improper bracing and installation. Attic insulation is insufficient for space and climate. The

4 | P a g e building is historic and some interior finishes are plaster, while some are wood, drywall, or other material.

The NPS completed load calculations for HVAC unit sizing and duct sizing, including cubic feet per minute (CFM) into each room. The calculations followed Air Conditioning Contractors of

America (ACCA) Manual J, using 95 degrees outside air temp, and 70 degrees inside air temp and 55% inside relative humidity for calculations. Calculations are provided and attached to this scope of work. The figures below show the basic layout of the rooms within the structure. The number in parenthesis indicates the number of personnel in each room for purposes of heat load calculations. The Park has to scale floor plans of the building showing the room sizes, walls, and windows. These drawings are attached at the end of this scope of work and are available electronically for use on this project. However, some features such as insulation, HVAC register size, and duct size are not shown.

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Figure 1: Basic Floorplan for first story. Right side (north side) referred to as “Ranger or

VRP side” Left side (south side) referred to as “Resource Management side”. The number in parentheses are the number of personnel in each room for purposes of Heat Load calculations.

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Figure 2: Basic Floorplan for second story. Right side (north side) referred to as “Ranger or VRP side”; Left side (south side) referred to as “Resource Management side” The number in parentheses are the number of personnel in each room for purposes of Heat

Load calculations.

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2.0 OBJECTIVE

Replace HVAC systems including heat pumps, air handlers, and ducting at the Buxton

Ranger Station according to International Building Code, American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) and ACCA standards, and Sheet

Metal Air Conditional Contractors National Association (SMACNA) standards.

3.0 PLACE OF PERFORMANCE

The address for the Buxton Ranger Station is 46500 Lighthouse Road in Buxton, NC 27920.

4.0 TASKS/SPECIFICATIONS

4.1 Task 1 Demolition

4.1.1 Recover Refrigerant from existing HVAC units.

4.1.2 Carefully disconnect the one newly installed outdoor heat pump unit and deliver it to the Buxton Maintenance Facility on Loggerhead Lane approximately 1 mile from the Buxton Ranger Station.

4.1.3 Demolish the remaining 3 outdoor heat pump units, 4 indoor air handler units, including the existing line sets. Do not damage adjacent flooring.

Demo the HVAC ducting in the attic space. Do not abandon in place any portion of the HVAC Ducting which is slated for removal. Demolish existing thermostats, louvers, grills/return grills, registers, and exterior electrical disconnects.

4.1.4 Demo existing insulation in the attic space. Do not abandon attic insulation, straps, fasteners, staples, etc. associated with the attic insulation.

4.1.5 The main trunk line for HVAC ducting on the downstairs shall remain in place. Close off and seal the existing ductwork at the District

Management Office, and Visitor Use Office

4.1.6 On the downstairs areas Ranger Side, in the room marked “Evidence

Room”, carefully remove the double closet doors, closet shelving, the wall separating small closet space from the copier room, and ceiling of the closet space. Temporarily remove the doors of the closet to the VRP copier room. See the disposition of the VRP copier room double doors below.

4.1.7 On the downstairs North (VRP) side, in the hallway between the Ranger office and restroom, carefully temporarily remove the ceiling light outside the restroom door. Store the light for reinstallation. Demo the dropped section of drywall ceiling to expose the ceiling joist space above.

4.1.8 Carefully remove existing flooring and subflooring in the upstairs HVAC closet, approximately 48 sf. Patch and seal the supply duct for the

8 | P a g e downstairs main trunkline. Repair existing floor joists and provide new

¾” plywood floor and floor covering.

4.1.9 Demo existing outdoor wooden stands.

4.1.10 Carpentry and wood framing materials and demo work necessary to remove the existing systems is included.

4.2 Task 2: Provide two new split systems for the Left/South (Resource Management)

Side.

4.2.1 Build a new Outdoor HVAC stand in same location as the existing. New stands shall consisted of pressure treated 4x4 posts, 2x4 joists, 2x6 board platform floor with no walls, approximately 30 inches above ground level.

Provide approximately 36” clear space in between the two units. Provide approximately 6” – 8” clear space around the outside of the footprint of the new units.

4.2.2 Install the new outdoor compressor units on the new stands.

4.2.3 Provide new subpanel / disconnect with new breakers at outside units.

Provide new liquid tight flexible conduit and wiring to new units. Provide new NEMA 4X type 316 stainless steel boxes. Provide 4x6 wood posts adjacent to the platform on which to mount the subpanel.

4.2.4 Provide new indoor air handler units in the existing downstairs HVAC closet. Provide new copper line set with UV protected insulation sized according to manufacturer instructions. Connect to existing duct in the

HVAC Closet with new insulated sheet metal transitions sized for the new unit. Provide new return duct to meet the size of the new return filter grill opening. Filters shall be located at the return registers. New indoor air

9 | P a g e handlers shall match the serial number series for the outdoor heat pump unit.

4.2.5 Provide each system with Ductbox, condensate drain traps, shut off Safe-T

Switch.

4.2.6 New HVAC Units shall meet or exceed a 15 SEER rating.

4.2.7 New outdoor units shall have anti-corrosion technology made for coastal environments.

4.2.8 For downstairs Resource Management, provide a 3 ton split system. For upstairs, provide a 2.5 ton split system.

4.2.9 Patch the existing Duct opening in 3 locations: District Resource Manager

Office, Resource Management RM (copier room), and Hallway. Install new drywall to cover the old opening. Paint the drywall with a white primer and 2 coats of interior water based latex with low or no VOCs less than 50 g/L VOC. Finish color will be yellow and blue to match existing;

shade and sheen selected by the NPS to match the adjacent wall.

4.2.10 Provide duct dampeners to adjust airflow to each room. The duct dampener shall be within reach and immediately behind the grill.

4.2.11 Provide new supply duct openings and prefabricated insulated aluminum duct grills. Duct openings and grills in each room shall deliver the proper

CFM and throw to sweep the entire room.

4.2.12 Resize the downstairs return opening to 24”x20”. Opening and new filter grill shall fit within the wainscotting, below the chair rail and above the base molding. Provide 12 new filters for the return grill.

4.2.13 Provide new digital thermostat on the first floor adjacent to the closet door by the stair case. Patch the drywall at the old thermostat with new drywall to cover the old opening. Paint the drywall with a white primer and 2 coats of interior water based latex with low or no VOCs less than 50 g/L VOC.

Finish color will be yellow and blue to match existing; shade and sheen selected by the NPS to match the adjacent wall.

4.2.14 Provide new lay in batt attic insulation to R-30. Do not cover soffit vents at the eaves.

4.2.15 Provide supports for new bent sheet metal duct in the attic space.

Supports shall be sufficient to raise new main trunk line above new R-30 attic insulation.

4.2.16 Provide new sheet metal duct wrapped with R-8 insulation, sealed per

ACCA and SMACNA standards.

4.2.17 Provide insulated round flexible duct from new main metal duct to each supply grille. Maximum length of any round flexible duct shall be 8 ft including the bends.

4.2.18 Provide 10 inch diameter flex duct and grilles on the two end rooms (east and west ends), and 6 inch flex duct and grilles for the interior rooms, including the restroom.

4.2.19 Resize the two upstairs return openings to 16”x20” and 10”x20”. New openings and new filter grills shall fit within the wainscotting, below the chair rail and above the base molding. Provide 12 new filters for each return grill.

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4.2.20 Provide new digital thermostat on the second floor in the same location as the existing.

4.3 Task 3: Provide two new split systems for the Right/North (Visitor Resource

Protection) Side.

4.3.1 Build a new Outdoor HVAC stand in same location as the existing. New stands shall consisted of pressure treated 4x4 posts, 2x4 joists, 2x6 board platform floor with no walls, approximately 30 inches above ground level.

Provide approximately 36” clear space in between the two units. Provide approximately 6” – 8” clear space around the outside of the footprint of the new units.

4.3.2 Install the new outdoor compressor units on the new stands.

4.3.3 Provide new subpanel / disconnect with new breakers at outside units.

Provide new liquid tight flexible conduit and wiring to new units. Provide new NEMA 4X type 316 stainless steel boxes. Provide 4x6 wood posts adjacent to the platform on which to mount the subpanel.

4.3.4 Repair the floor and ceiling of the upstairs mechanical closet. Provide new ¾”plywood floor, with appropriate joists and fasteners meeting

Residential Building Code. Paint new plywood floor with 1 coat of white primer and 3 coats of interior water based latex with low or no VOCs less than 50 g/L VOC. Finish color will be light blue; shade and sheen selected by the NPS.

4.3.5 Provide a new indoor air handler unit serving the upstairs in the existing upstairs HVAC closet. New indoor air handle shall match the serial number series for the outdoor heat pump unit.

4.3.6 Provide the new indoor air handler serving the downstairs in the existing closet adjacent to the Evidence Room.

4.3.7 Provide each system with new pedestals, condensate drain traps, shut off

Safe-T Switch, and spring vibration isolators.

4.3.8 Provide each system with Ductbox, condensate drain traps, shut off Safe-T

Switch.

4.3.9 New HVAC Units shall meet or exceed a 15 SEER rating.

4.3.10 New outdoor units shall have anti-corrosion technology made for coastal environments.

4.3.11 For downstairs Visitor and Resource Protection, provide a 3 ton split system. For upstairs, provide a 2.5 ton split system.

4.3.12 Provide duct dampeners to adjust airflow to each room. The duct dampener shall be within reach and immediately behind the grill.

4.3.13 Provide new supply duct openings and prefabricated insulated aluminum duct grills. Duct openings and grills in each room shall deliver the proper

CFM and throw to sweep the entire room.

4.3.14 Provide one additional duct opening and grill in the downstairs room labeled “Ranger Office (6)”.

4.3.15 Provide an additional new duct opening and insulated metal duct from the existing duct trunkline to the bathroom. Provide a new HVAC supply grille into the restroom.

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4.3.16 Provide new drywall ceiling outside the restroom at the same ceiling height as the removed ceiling. Paint the new drywall ceiling with 1 coat of white primer and 2 coats of interior water based latex with low or no

VOCs less than 50 g/L VOC. Finish color will be white; shade and sheen selected by the NPS.

4.3.17 At the closet between the Evidence Room and the VRP Copier Room, provide a new 2x4 stud wall with 5/8” thick, 1 hr fire rated sheetrock drywall on each side. New wall shall be connected to the ceiling joists above and interior wall of the evidence room in place of the existing

Evidence room closet doors. The doors in the hallway for this new HVAC closet are historic and shall be carefully removed and handled and delivered to the Museum Resource Building at Fort Raleigh National

Historic Site Manteo, NC 27954. Contact the Contracting Officer’s

Representative to coordinate delivery of the door. Provide a new removable doorway. New doorway material shall be ½” plywood, painted on all 6 sides. Paint shall include 1 coat primer and 6 coats of interior water based latex with low or no VOCs less than 50 g/L VOC. Finish color will be white; shade and sheen selected by the NPS. Provide return grill sized to fit 25 x20x1 filter. Grill to be installed in the new removable doorway. Provide new frame/interior trim and stop around inside of new doorway. Provide five inch long black brass handles at four locations on the new removable doorway. Provide threshold track and trimwork to securely hold removable doorway in place. Provide two ceiling and two floor bolts to secure removable doorway in place.

4.3.18 In the ceiling of the new downstairs VRP HVAC closet, provide sheet metal transition ducting from the new air handler into a new opening of the main HVAC trunkline.

4.3.19 Provide new digital thermostat on the first floor in same location as the existing.

4.3.20 Provide new lay in batt attic insulation to R-30. Do not cover soffit vents at the eaves.

4.3.21 Provide supports for new bent sheet metal duct in the attic space.

Supports shall be sufficient to raise new main trunk line above new R-30 attic insulation.

4.3.22 Provide new sheet metal duct wrapped with R-8 insulation, sealed per

ACCA and SMACNA standards.

4.3.23 Provide insulated round flexible duct from new main metal duct to each supply grille. Maximum length of any round flexible duct shall be 8 ft including the bends.

4.3.24 Provide 10 inch diameter flex duct and grilles on the two end rooms (east and west ends), and 6 inch flex duct and grilles for the interior rooms, including the restroom.

4.4 Task 4: Provide Start-up, testing, and balancing for newly installed systems.

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4.4.1 Provide a date and time for the Start-up of these new units. Coordinate with the Contracting Officer Representative (COR) to invite the Subject

Matter Experts (SME) to the start up.

4.4.2 Complete first testing and balance one day after start-up. Coordinate and

Schedule the testing and balancing with the COR and SME.

4.4.2.1 The system shall be balanced when each room measures +/- 1 degree Fahrenheit to the set point.

4.5 Task 5: Provide Operations and Maintenance Manuals specifically for the exact type, brand, and model numbers of the new HVAC Units installed.

5.0 SUBMITTALS

5.1 Product Data. Provide initial operating conditions for the items below, including

BTU//tons, air flow in cfm per room, and dimensions for equipment and ducting.

5.1.1 Outdoor heat pump units

5.1.2 Indoor air handler units

5.1.3 Duct material and insulation

5.1.4 Digital Thermostats

6.0 DELIVERY AND STORAGE AND HANDLING

6.1 Deliver materials to the project site in original containers with seals unbroken and labeled with manufacturer's name, product brand name and type, date of manufacture, approval or listing agency markings, and directions for storing and mixing with other components.

6.2 Delivery of materials to the park will be brought in when needed. Items stored outside will be done at the Contractor’s own risk. Use and storage of a work trailer can be coordinated with the COR.

6.2.1 Store and handle materials according to the manufacturer’s recommendations.

7.0 OTHER UNIQUE REQUIREMENTS:

7.1 The units shall be stored and handled according to the manufacturer's recommendations.

7.2 Remove, cut, alter, replace, patch and repair existing work as necessary to install new

AC units. Existing work to be altered or extended and that is found to be defective in any way, shall be reported to the COR before it is disturbed. Materials and

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8.0 BUILDING SKETCHES:

8.1 The Figures below provide a layout of the floorplans of the first and second floor, along with an overlay of the HVAC system ductwork installed in the first floor ceiling and the second floor attic space. The below figures are for orientation purposes only and not meant to define the tasks for the scope of work or to be scaled and sized for new work.

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Figure 3: 1994 drawing of First Floor Plan.

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Figure 4: 1994 Drawing of Second Floor Plan.

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Figure 5: HVAC Layout sketch, Not to Scale

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Figure 6: Upstairs HVAC Layout sketch, Not to Scale Buxton Ranger Station