Draft SPECIFICATION - MV Powerhouse.pdf

DRAFT

National Aeronautics and Space Administration

NASA Shared Services Center (NSSC) Building 1111, Jerry Hlass Road Stennis Space Center, MS 39529

SPECIFICATION

MEDIUM VOLTAGE (MV) POWERHOUSE

1.0 GENERAL DESCRIPTION

The Medium Voltage (MV) Powerhouse shall be a factory-built, single-piece, NEMA 3R rated enclosure designed to house MV and LV electrical distribution equipment. The structure shall be capable of transport with all internal equipment installed and shall be suitable for general-purpose, non-hazardous industrial applications.

2.0 ENCLOSURE CONFIGURATION

• Construction: NEMA 3R, interlocking pre-galvanized steel wall and roof panels

• Base: Structural steel grid base engineered for lifting, transport, and floor loading

• Dimensions (nominal):

– Length: 38 ft

– Width: 15 ft

– Ceiling Height: 10 ft 6 in

• Configuration: Single-piece factory-assembled unit

• Environmental Design:

– Roof load: 20 psf

– Snow load: 20 psf

– Wind load: 130 mph, Exposure C

– Seismic Category: C

– Interior lighting level: 30 foot-candles at 3 ft elevation

• Insulation Values:

– Walls: R-13

– Roof: R-19

– Floor: R-12

– Personnel doors: R-6.8

3.0 HVAC SYSTEM

• Two (2) Bard 4-ton wall-mounted HVAC units, 480V, 3-phase

• Cooling Redundancy: None

• Temperature Set Points:

– Interior: 65°F minimum / 80°F maximum

– Exterior design range: 0°F to 100°F

• Features: High/low pressure protection, low ambient control, alarm relay, thermostat, anti-cycle protection

• Lead-lag controller with alarms for power loss, refrigerant lockout, high/low temp, smoke/fire, filter replacement, humidity/temperature monitoring, and Modbus TCP/IP communication

• HVAC disconnects and filtered supply/return

• Coated coils and economizers included

• No ductwork included unless required during engineering review

4.0 STRUCTURAL CONSTRUCTION

• Structural steel members: W16x26, C10x15.3, 3×3×3/16 rectangular tube steel frames

• Lift lugs: Six (6) SL-30FL heavy-duty lift lugs

• Floor system:

– 1/4 in steel plate flooring

– 4-inch spray polyurethane foam insulation (fire-resistant)

• Wall & roof assemblies:

– 16-gauge G90 galvanized steel interlocking panels (walls, roof, ceiling)

– Interior walls: 16-gauge galvanized panel system

– Insulation: R-13 fiberglass in walls, R-19 urethane ductboard in ceiling

• Exterior & equipment doors:

– Wind-rated CECO doors (3070 and 6080)

– Panic hardware, drip shields, closures, crash chain, stainless hinges

– Equipment access doors with full gasketing, padlocking hardware, and reinforced design

• Exterior canopies: 4 ft × 3 ft and 7 ft × 3 ft galvanized assemblies (ship loose)

5.0 FINISH SYSTEMS

• Exterior: ANSI-70 polyurethane system, min. 3.0 mils DFT

• Interior: White polyurethane or factory pre-painted galvannealed panels

• Floor coating: High-solids epoxy, minimum 4 mils with non-skid aggregate

• Base exterior and underside coated per corrosion and protective coating specifications

• Touch-up paint provided

6.0 ELECTRICAL SYSTEMS

6.1 General

• All equipment UL listed

• Wiring installed per NEC voltage separation criteria

6.2 Conduit & Cabling

• Interior: EMT conduit, minimum 3/4 in

• Exterior: Rigid galvanized steel conduit, minimum 3/4 in

• Wiring: THHN/THWN copper conductors, #12 AWG minimum

• HVAC controls: #18 AWG thermostat wiring

6.3 Lighting & Power Distribution

• Interior lighting: Fourteen (14) 4-ft LED fixtures (4000 lumens each)

• Exterior wallpacks: Two (2) LED wall-mount fixtures with photocell

• Emergency lighting: Two (2) combination exit/emergency units

• Receptacles:

– Interior 120V duplex

– Exterior GFCI

– Combination switch/receptacle stations

• Distribution Equipment: – Eaton 125VDC distribution panel

– 45 kVA transformer (480V–208Y/120V)

– 480/277V, 600A AC panelboard

– DC PowerCab system with 100 AH battery string

6.4 MV Cable Systems

• 5 kV EPR/PVC shielded cables (#350 MCM) in specified linear footage

• Stress cone termination kits

• Cable trays (18-in and 24-in widths) with straight sections, 90-degree elbows, and full support system

7.0 GROUNDING SYSTEM

• Full perimeter copper grounding bar loop (2 in × 1/4 in)

• Ground pads (stainless steel) and lugs (#4/0)

• Ground drops:

– Major equipment: 4/0 bare copper

– Small equipment: appropriately sized copper ≤ #6

8.0 CUSTOMER-SUPPLIED EQUIPMENT (INSTALLED BY CONTRACTOR)

• 5 kV switchgear (multiple vertical sections)

• 5 kV MCCs (multiple vertical sections)

• Breaker lift truck

• Mechanical bus splicing (booted style, up to 4 bars)

• Control wiring re-terminations (up to 12 per splice)

• Floor fastening by bolting or welding as required

• Heater circuits and control-power circuits routed to panelboards

9.0 CONTROL WIRING

• Up to 150 points for panel-to-panel control wiring (14 AWG THHN)

• Customer must supply complete wiring lists with source/destination terminals, labels, and cable types

• Additional wiring engineering will be billed separately

10.0 ACCESSORIES

• Door signage (“Danger High Voltage”)

• Gutter system with hangers, end caps, downspouts

• Removable floor cutouts with gaskets

• No platforms or stairs provided

• Fire extinguisher (4A:60B:C) included

11.0 DOCUMENTATION & SERVICES

• Structural calculations (PE-sealed)

• HVAC calculations

• Center-of-gravity documentation

• Foundation load chart

• UL compliance certification

• In-house material handling and inspection

• Two days of customer FAT participation

• Electronic drawing sets (structural & electrical) for approval, construction, and as-built conditions

• Project management services

12.0 SHIPPING

• Approx. shipping dimensions:

– 38 ft 6 in L

– 15 ft 6 in W

– 13 ft 2.5 in H

• Weight:

– Empty: 42,996 lb

– Equipment installed: 23,305 lb

– Total: 66,301 lb

• Items such as HVAC units, canopies, and select accessories may ship loose

• All customer-provided equipment must be labeled with required reference numbers

13.0 NOTES

• All lifting shall use provided lift lugs

• During transport, support at lift or pier locations only

• If HVAC units operate with independent thermostats (non-lead-lag), temperature settings shall be staggered by 5–10 degrees

• Spreader bars, rigging, and lifting gear not included unless otherwise specified