RADIOLOGY ELECTRICAL SYSTEMSPART 1- GENERAL1.1 DESCRIPTIONA. This section specifies the furnishing, installation and connectionof raceway systems and wiring for the radiology equipment.B. Radiology equipment and the high voltage cables will befurnished by the Government.1.2 RELATED WORKA. Section 13091, LEAD RADIATION SHIELDING: Requirements forlead radiation shielding.B. Section 16050, BASIC METHODS AND REQUIREMENTS(ELECTRICAL): General electrical requirements that are common tomore than one section of Division 16.C. Section 16111, CONDUIT SYSTEMS: Conduits, fittings, and boxesfor raceway systems.B. Shop Drawings:1. Sufficient information, clearly presented, shall be included todetermine compliance with the drawings and specifications.2. Show size and location of raceway components, main feederspanels and pullboxes, ductwork and equipment provided by othertrades, and radiology equipment items. Carefully coordinate withmanufacturer’s shop drawings. Shop drawing approval is required bythe radiology equipment manufacturer’s technical representativeprior to fabrication and installation of the raceway and conductorsystem.
C. Certifications: Two weeks prior to final inspection, submit fourcopies of the following to the Resident Engineer:1. Certification that the materials are in accordance with thedrawings and specifications.2. Certification, by the Contractor, that the complete installationhas been properly installed and tested.3. Certification, by the Contractor, that the radiology equipmentmanufacturer’s representative has approved the completeinstallation.1.4 APPLICABLE PUBLICATIONS Publications listed below form a part of this specification to theextent referenced. Publications are referenced in the text by the basicdesignation only.A. National Fire Protection Association (NFPA):70-2005 National Electrical Code (NEC)General1. Factory fabricate, assemble and fit2. Material shall be steel3. Coordinate dimensions of the straight lengths elbows, junctionboxes and other components.4. Hot dipped galvanized steel connections joiner plates on floorand ceiling cable trough.5. Raceway bushings:Cast aluminum.
Install when the radiology equipment is installed.Split ring type bushed nipples for the high voltage cables.Smooth edges of the openings in the raceways for the bushings.6. Provide chase nipples and other components as required.7. Protect cables at their egress from the raceways with fittingsthat are mechanically secure to the raceways8. Provide 45 degrees sweep e1bow at every 90 degrees change indirection elbows shall have partitions.9. Where gasketed openings are required in floor wall or ceilingtroughs split covers shall be provided with fastening devices on bothsides of the cover.2.2 floor TROUGH RACEWAYA. Raceways in the floors shall be watertight in accordance with UL884.B. Sides and bottoms, 2 mm (0.0747 inch) minimum thickness.C. Covers, 6 mm (1/4-inch) thick minimum. Covers shall be bare,carpet-insert, or tile-insert to match the existing floor covering orsurfaceD. Floor-trough covers shall be fully gasketed with screw fasteners.2.3 wall trough racewayA. Flange mounted covers with screw fasteners for flush mountedinstallation.
B. Surface mounted covers with screw fasteners for surfacemounted installations.C. Sides, bottoms, and covers for renovations 2 mm (0.747 inch)minimum thicknessWall duct, nominal 10 mm (3.5 inches) deep by 250 mm (10 inches)wide recessed into wall for control and power cables.2.3 ceiling cable trough Cable trough nominal 10 mm (3.5 inches) deep by 250 mm (10inches) wide with 10 mm (5/8 inches) support rods to permitinspection of cables above dropped ceiling.PART 3 - EXECUTION3.1 SYSTEM INSTALLATIONA. Provide as required by the NEC and NFPA 99 and themanufacturer’s shop drawings the raceways, barriers, conductors,boxes, disconnects, grounds and other equipment for the radiologyequipment and the final connections to the equipment. The radiologyequipment and the high voltage cables will be furnished by theGovernment. The Government will furnish the services of amanufacturers representative to technically supervise theinstallation, connection, adjustment and testing of the equipment.B. Coordinate the raceway systems with the floor, wall, and ceilingstructural supports for the radiology equipment, the locations of theradiology equipment and its auxiliaries, and with the lead shielding inthe walls, floors and ceilings:1. Prior to fabrication of the raceway systems, obtain detailedlayout information from the Resident Engineer for the radiologyequipment and high voltage cables.
2. Install raceways with a minimum of bends in the shortestpractical distance considering equipment and building layout.Individual raceway runs shall not exceed the radiology equipmentmanufacturer’s specified maximum distances.3. Raceways, boxes and devices recessed into or penetratingthrough lead shielded walls, floors and ceilings:a. Line or clad surfaces of the boxes and devices with theequivalent thickness of lead shielding shown for the room, except, theremovable cover.b. Line or clad raceway surfaces with the equivalent thickness oflead shielding shown for the room.c. Overlap the lead shielding on boxes, devices and raceways withthe lead shielding for walls, floors and ceilings by not less than oneinch.d. Arrange the installations so radiation within the rooms will notpenetrate the raceway paths through the lead shielded walls, floorsand ceilings.C. Interconnecting wiring shall be copper, stranded or solid, andhave the type and size as required by the radiology equipmentmanufacturer. However, in no case shall the insulation class be lessthan 600 volts, or the conductor size for low voltage power andgrounding wiring be less than 4 mm² (12 AWG), unless approved bythe Resident Engineer.D. Equipment Grounding Conductors:1. Install an equipment grounding conductor in each raceway. Theconductor shall be copper, sized as shown, and shall have greeninsulation. The conductor size shall at a minimum be equal to the sizeof the largest current-carrying conductor present at that point.
2. Bond all of the equipment grounding conductors in eachenclosure.3. Trough-type raceway sections shall be made electricallycontinuous by short bonding jumpers between adjacent sections.Jumpers shall be exothermically bonded to each raceway section.Jumpers shall be sized per radiology equipment manufacturer’srequirements.4. Provide not less than one 3000mm (ten foot) equipmentgrounding conductor pigtail at each box or junction point where anitem of equipment is connected.5. The grounding conductors shall be continuous back to theelectrical system ground from which the radiology equipment isserved.E. Install protective barriers between the high voltage powercables, the low voltage power conductors and medical systemsconductors where conductors of different types share a commonraceway component.F. Install cables and conductors as required for the radiologyequipment. Provide 3000 mm (ten-foot) pigtails on the wires at all theconnection points to radiology equipment. Wiring shall be tagged andidentified at each end.G. Fit and preserve fill-in pieces of floor covering for the raceways.Install the fill-in pieces after the cables and conductors have beeninstalled in the raceways. H. In existing facilities where it is not feasible to provide radiologyraceways as specified above:1. Install point-to-point conduit and conductor systems for theradiology equipment.
2. Run the raceways for the high voltage cables in the shortestpracticable manner as approved by the Resident Engineer and theequipment manufacturer.3. Line holes in the floors, walls and ceilings for conduitpenetrations with equivalent thickness of lead sleeves curved oroffset, caulked and flanged for adequate shielding so the X-rays willnot penetrate the floors, walls and ceilings.
RACEWAYSInstall all wiring in raceways. Open wiring is prohibited. Racewaysshall be as specified in PG-18-1, Master Specifications. Raceway shallcomply with the definition of the NEC Article 22.214.171.124 CONCEALED AND EXPOSED(a) Exposed conduit is acceptable where finished ceilings are notprovided. Wherever it is impractical to conceal conduits, due toeconomic considerations or the need to accommodate existing fieldconditions, the A/E shall consult with VA to determine acceptablealternatives.(b) Electrical conduits may be installed in concrete walls and floors.(c) Surface metal raceways shall not be installed on the floor. Servicesto equipment in open non-patient care areas shall be served fromunder the slab or through tele/power poles wired from the ceiling.(d) Primary-voltage feeders shall not be exposed on the exterior ofbuildings.2.1.2 UNDERGROUND DUCTS AND CONDUITS(a) Generally, encase underground ducts and conduits in concrete.Direct burial conduit may be used for outdoor lighting and powerbranch circuits.(b) The A/E shall make project-specific recommendations for reducingthe concrete encasement requirement, taking into account theimportance and physical security needs of the conduit(s) involved.
Conduits containing Essential Electrical System wiring andtelecommunications cabling shall not be exempt from the concreteencasement requirement.2.1.3 SPARE CONDUITSWhere electrical capacity is reserved for future use, such as bussedspace in panelboards, motor control centers, switchboards, andswitchgear of all voltage levels, and where under-slab or undergroundconduit is used, the A/E shall provide spare under-slab orunderground conduits to an accessible point. The number and size ofconduits shall be appropriate to the equipment and amount of bussedspace served2.1.4 UNDERFLOOR DUCT SYSTEMS (a) For newconstruction of large office areas, provide underfloor power,telecommunications, and signal systems ducts for the following areas:• Personnel Division• Registrar Division• Fiscal Division• Supply Division• Other - Any large open office spaces where future flexibility isdesirable(b) Provide duplex receptacle and telecommunications outlet fittingson the under floor duct to suit the furniture layout.(c) Space the under floor ducts 5 ft [1.5 M] on centers. In structuralsteel frame buildings, use trench header and utilize the cellular steelas the raceway. Coordinate with the structural engineer to ensure thatthe proper cells are enclosed for raceway use.
2.1.5 RADIOLOGY ROOMS(a) Radiology rooms typically require a manufacturer-specific conduitand wiring trough system. If VA Medical Center has selected amanufacturer, the A/E may base the design on the manufacturer’sshop drawings. If the equipment list is not manufacturer-specific, theA/E shall base the design on a typical radiology system for biddingpurposes.(b) The A/E shall provide the following details on the electrical plansfor the Radiology Room(s):• Power and Signal Plan: A/E shall show complete design for generaluse receptacles, communication, and signal outlets. A/E shall showmain circuit and related equipment servicing the radiologyequipment. A/E shall confirm radiology equipment powerrequirement with radiology shop drawings.• Lighting Plan: A/E shall show complete lighting design. A/E shallcoordinate lighting locations with radiology shop drawings anddrawings from other trades to avoid conflict in field installation.• Radiology Raceway Layout Plans: A/E shall show all surface-mounted and/or recess-mounted raceway systems. A/E shall showwiring tags for all raceway runs. A/E shall coordinate existing fieldconditions, locations, sizes, and quantities of raceways and cablesshown on radiology shop drawings with drawings from other trades toavoid conflict in field installation.• Radiology Wiring Schedule: A/E shall show a schedule for all wiringtags indicating wiring destinations andlocations/sizes/types/quantities of all raceways and wirings.
• A/E shall verify that the proposed radiology equipment installationas shown on radiology shop drawings meets all applicable codes,regulations, and existing building conditions.2.2 GROUNDINGThe grounding system shall be shown complete on the one-linediagram with all components and descriptions from the medium- orlow-voltage service to the low-voltage panels, as applicable for eachproject. The grounding system shall be shown complete on the One-line Diagram for the Normal, Standby, and/or Essential ElectricalSystems, including but not limited to generators, automatic transferswitches, electrical equipment, etc.2.2.1 GROUNDING ELECTRODESGalvanized steel or copper-clad steel electrodes may be used. Allelectrodes are to be of the same material for the entire project.2.2.2 EQUIPMENT GROUNDING CONDUCTORSAll raceways shall contain an equipment grounding conductor.Coordinate with VA Master Specifications and show on the drawings.2.2.3 METAL CURTAIN WALL GROUNDING(a) To help ensure that personnel are not exposed to electrical shock,all exterior metal sheathing of buildings shall be grounded.(b) For buildings with perimeters not exceeding 250 ft [76 M], thesheathing perimeters shall be grounded at diagonally opposite cornersof the building.(c) For buildings with perimeters exceeding 250 ft [76 M], thesheathing perimeters shall be grounded such that the spacingbetween grounding points does not exceed 100 ft [30 M].
(d) A ground point shall consist of a driven ground rod and brazedconnection to the building sheath. A No. 6 AWG bare copperconductor shall be used to connect the sheath to the ground rod.(e) Where a lightning protection system is provided for the building,the sheath shall also be bonded at each down conductor location.2.3 LIGHTNING PROTECTION SYSTEM(a) Lightning protection is mandatory for all Mission Critical buildings.For non-Mission Critical buildings, perform risk analysis per NFPA 780,Annex L, and provide a lightning protection system where NdNc.Submit calculations to VA.(b) Lightning protection systems shall comply with NFPA 780 –Standard for the Installation of Lightning Protection Systems and NFPA70 – National Electrical Code.2.4 MOTOR DISCONNECT SWITCHESProvide all motors with a local disconnect switch (unfused unlessrequired otherwise) located at the motor or a maximum of 5 ft [1.5 M]away, within sight. Clearly indicate this requirement on the ContractDrawings.
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