Amendment 0002 Scope of Work.pdf

BUILDING 530 – BUILDING REPAIRS

NAS Oceana, Dam Neck Annex, Virginia Beach VA

Amendment 0002

09 JUNE 2026

1) In PART 3, 1.0 PROJECT DESCRIPTION:

Add the following at the end of the section:

1.1 ENVIRONMENTAL & MATERIAL PERFORMANCE MANDATE

The natatorium and the exterior coastal environment (located less than 0.5 miles from the ocean) represent severely corrosive environments. The Design-Builder must select and utilize materials inherently resistant to trichloramine vapor, chloride-laden condensation, coastal salt spray, and continuous high humidity.

The Owner establishes the material baselines and prohibited materials listed herein to ensure a minimum 15-to-20-year operational lifecycle. The Design-Builder’s Designer of Record (DOR) retains full responsibility for the final design, sizing, routing, and system performance, but must adhere strictly to these material baselines. Cost alone shall not be an acceptable justification for a deviation request.

1.2 STRICTLY PROHIBITED MATERIALS AND PRACTICES

The Design-Builder must ensure the following prohibitions are strictly enforced across all HVAC and structural designs associated with the pool environment:

NO internal fibrous glass insulation (duct liner) shall be exposed to the airstream in any natatorium supply, return, or exhaust system.

NO Type 304 or Type 316 Stainless Steel shall be used for structural, load-bearing components (including but not limited to ductwork walls, hangers, suspension cables, and threaded rods) inside the pool envelope due to Stress Corrosion Cracking (SCC) risks.

NO galvanized or uncoated steel grilles, registers, or diffusers shall be used within the pool area.

NO pressure-treated lumber wood framing or uncoated standard steel structural members shall be used within any HVAC duct, air plenum, or seating bench plenum.

2) In PART 3, D30 HVAC, D3040 DISTRIBUTION & OTHER SYSTEMS:

Delete everything after the section entitled, “Pitch and Drainage.”

Add the following after the section entitled, “Pitch and Drainage” (added in Amendment 0001):

Pool Area Supply Air Ductwork For overhead supply air distribution within the natatorium envelope, the Design-Builder must provide and install an engineered, continuous-fabric ductwork system meeting the following criteria:

Fabric Properties: The fabric must be non-permeable, antimicrobial, and specifically engineered for high-humidity natatorium environments.

Suspension & Hardware: The suspension system must be tensioned to prevent sagging.

Suspension tracks must be constructed of anodized extruded aluminum (with a clear anodized architectural finish). Any drop cables or tensioning wires must be fully encapsulated in PVC or heavy-duty epoxy coating. Bare stainless steel cables, bare stainless steel tension springs, or bare metallic snap-clips shall not be used under tensile load within the pool airstream.

Slide hardware and connectors must be heavy-duty polymer, nylon or PVC sliders.

Maintenance Access: The fabric duct system must feature heavy-duty, non-metallic zippers to allow for periodic removal and machine washing.

Pool Area Return Air Ductwork Exposed Runs: All return ductwork exposed within the pool room must be constructed of

Aluminum (Type 3003-H14). The interior airstream surface must be coated with a factory-applied epoxy or phenolic coating.

Concealed Runs: For return ducts hidden in concealed ceiling or wall cavities, double-wall galvanized sheet steel may be utilized, provided the internal liner is solid Aluminum with a factory-applied coating.

Insulation: All return duct insulation must be installed on the exterior of the duct or encapsulated within a double-wall assembly.

Pool Area General Exhaust Ductwork & Equipment Duct Material: Ductwork must meet the exact material standards as the exposed Return Air

Ductwork (Aluminum Type 3003-H14 with factory-applied internal epoxy/phenolic coating).

General Exhaust Fans: Exhaust fan blades, wheels, and housings exposed to the general exhaust airstream must be constructed of Fiberglass Reinforced Plastic (FRP) or Aluminum featuring a heavy-duty, factory-applied phenolic/epoxy coating.

Pool Area Source Capture Exhaust Ductwork & Equipment Below-Grade / In-Slab: All ductwork buried beneath the concrete pool deck or located in underground trenches must be constructed of Schedule 80 PVC, CPVC, or Fiberglass Reinforced Plastic (FRP). Joints must be chemically solvent-welded or thermally bonded.

Vertical Risers: Vertical concealed riser sections traversing walls to the roof must be rigid Aluminum (internally coated with epoxy/phenolic) or FRP. Vertical runs must be externally insulated and must incorporate a low-point condensation collection drain. Fabric ductwork shall not be used for vertical exhaust shafts.

Source Capture Exhaust Fans: Because the source capture system handles highly concentrated, wet chloramine vapors, the exhaust fan(s) serving this system must be constructed of 100% corrosion-resistant Fiberglass Reinforced Plastic (FRP). The fan housing, scroll, impeller wheel, and inlet/outlet cones must be solid FRP. Coated steel, coated aluminum, or stainless steel components in contact with the source capture airstream shall not be permitted.

Source Capture Seating Bench Plenum If the Design-Builder’s DOR incorporates a deck-level seating bench to serve as the source capture exhaust plenum, the following material constraints apply:

Structural Framing: The interior structural framing and bench envelope must be exclusively constructed of Fiberglass (FRP), Extruded PVC, or solid concrete/masonry with a sealed epoxy finish.

Fasteners: Mechanical fasteners must be Type 316 Stainless Steel and must be installed with dielectric polymer isolation (e.g., nylon or neoprene shoulder washers) to prevent galvanic corrosion.

Grilles: Exhaust grilles must be heavy-duty coated aluminum or rigid high-impact PVC.

Exterior Ductwork (Connecting Building to Outdoor PDU) Construction: Exterior ductwork connecting the building envelope to the on-grade Pool

Dehumidification Unit (PDU) must consist of a double-wall aluminum casing (inner liner and outer shell).

Weatherproofing: The insulated duct assembly must be entirely wrapped and encapsulated in a zero-permeability, self-adhering weatherproof cladding.

Geometry: All horizontal exterior duct runs must be fabricated with a pitched top (minimum 1/4-inch per foot slope) to permanently prevent water pooling.

Support: Ductwork must be structurally supported a minimum of 12 inches above finished grade.

Support stands must be Hot-Dip Galvanized (HDG) steel or Type 316 Stainless Steel. Ductwork cladding shall not rest directly on the ground.

Interior Rigid Duct Hangers and Supports For all rigid ductwork (Return, General Exhaust, and Vertical Risers) suspended within the natatorium envelope, the Design-Builder must adhere to the following support requirements:

Hanger Materials: All threaded rods, trapeze hangers, strut channels, and duct straps must be constructed of Fiberglass Reinforced Plastic (FRP), Aluminum (factory-coated with epoxy), or Hot-Dip Galvanized Steel that has been fully encapsulated in a factory-applied heavy-duty PVC or epoxy coating.

Prohibited Materials: Bare electro-galvanized steel, bare carbon steel, and uncoated 304/316 Stainless Steel shall not be used for any overhead load-bearing supports.

Dielectric Isolation: Wherever coated metal hangers or straps come into contact with the aluminum ductwork, dielectric isolation (e.g., neoprene pads or heavy-duty rubber saddles) must be installed to prevent galvanic corrosion and protect the duct's coating from mechanical abrasion.

Material Selection Matrix The following matrix summarizes the mandatory material selections and strict prohibitions for the various HVAC subsystems within the natatorium envelope:

Subsystem / Component Mandatory Baseline Material Strictly Prohibited

Supply Air Ductwork Engineered continuous-fabric (non-permeable, antimicrobial)

Internal fibrous glass liner, bare metallic hardware

Return Air Ductwork Aluminum (Type 3003-H14) with factory epoxy/phenolic coating

Uncoated galvanized steel (exposed runs)

General Exhaust Fans FRP or Aluminum with heavy-duty factory phenolic/epoxy coating

Uncoated steel or standard aluminum

Source Capture Ductwork Schedule 80 PVC, CPVC, or FRP (below-grade); Rigid Aluminum/FRP (risers)

Fabric ductwork for vertical shafts

Source Capture Fans 100% solid Fiberglass Reinforced Plastic (FRP)

Coated steel, coated aluminum, stainless steel

Rigid Duct Hangers FRP, coated Aluminum, or fully PVC/epoxy encapsulated HDG Steel

Bare electro-galvanized, bare carbon steel, uncoated SS

**End of Amendment 0002**