1. Electrical Layout of
Radiology Room
In Guidance of:-
Mrs.Uma Jayshankar
Submitted by:-
Bhakti D.Satam (10-593)
Gayatri M.Surti (10-595)
2. RADIOLOGY ELECTRICAL SYSTEMS
PART 1- GENERAL
1.1 DESCRIPTION
A. This section specifies the furnishing, installation and connection
of raceway systems and wiring for the radiology equipment.
B. Radiology equipment and the high voltage cables will be
furnished by the Government.
1.2 RELATED WORK
A. Section 13091, LEAD RADIATION SHIELDING: Requirements for
lead radiation shielding.
B. Section 16050, BASIC METHODS AND REQUIREMENTS
(ELECTRICAL): General electrical requirements that are common to
more than one section of Division 16.
C. Section 16111, CONDUIT SYSTEMS: Conduits, fittings, and boxes
for raceway systems.
B. Shop Drawings:
1. Sufficient information, clearly presented, shall be included to
determine compliance with the drawings and specifications.
2. Show size and location of raceway components, main feeders
panels and pullboxes, ductwork and equipment provided by other
trades, and radiology equipment items. Carefully coordinate with
manufacturer’s shop drawings. Shop drawing approval is required by
the radiology equipment manufacturer’s technical representative
prior to fabrication and installation of the raceway and conductor
system.
3. C. Certifications: Two weeks prior to final inspection, submit four
copies of the following to the Resident Engineer:
1. Certification that the materials are in accordance with the
drawings and specifications.
2. Certification, by the Contractor, that the complete installation
has been properly installed and tested.
3. Certification, by the Contractor, that the radiology equipment
manufacturer’s representative has approved the complete
installation.
1.4 APPLICABLE PUBLICATIONS
Publications listed below form a part of this specification to the
extent referenced. Publications are referenced in the text by the basic
designation only.
A. National Fire Protection Association (NFPA):
70-2005 National Electrical Code (NEC)
General
1. Factory fabricate, assemble and fit
2. Material shall be steel
3. Coordinate dimensions of the straight lengths elbows, junction
boxes and other components.
4. Hot dipped galvanized steel connections joiner plates on floor
and ceiling cable trough.
5. Raceway bushings:
Cast aluminum.
4. 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 fittings
that are mechanically secure to the raceways
8. Provide 45 degrees sweep e1bow at every 90 degrees change in
direction elbows shall have partitions.
9. Where gasketed openings are required in floor wall or ceiling
troughs split covers shall be provided with fastening devices on both
sides of the cover.
2.2 floor TROUGH RACEWAY
A. Raceways in the floors shall be watertight in accordance with UL
884.
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 or
surface
D. Floor-trough covers shall be fully gasketed with screw fasteners.
2.3 wall trough raceway
A. Flange mounted covers with screw fasteners for flush mounted
installation.
5. B. Surface mounted covers with screw fasteners for surface
mounted installations.
C. Sides, bottoms, and covers for renovations 2 mm (0.747 inch)
minimum thickness
Wall 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 (10
inches) wide with 10 mm (5/8 inches) support rods to permit
inspection of cables above dropped ceiling.
PART 3 - EXECUTION
3.1 SYSTEM INSTALLATION
A. Provide as required by the NEC and NFPA 99 and the
manufacturer’s shop drawings the raceways, barriers, conductors,
boxes, disconnects, grounds and other equipment for the radiology
equipment and the final connections to the equipment. The radiology
equipment and the high voltage cables will be furnished by the
Government. The Government will furnish the services of a
manufacturer's representative to technically supervise the
installation, connection, adjustment and testing of the equipment.
B. Coordinate the raceway systems with the floor, wall, and ceiling
structural supports for the radiology equipment, the locations of the
radiology equipment and its auxiliaries, and with the lead shielding in
the walls, floors and ceilings:
1. Prior to fabrication of the raceway systems, obtain detailed
layout information from the Resident Engineer for the radiology
equipment and high voltage cables.
6. 2. Install raceways with a minimum of bends in the shortest
practical distance considering equipment and building layout.
Individual raceway runs shall not exceed the radiology equipment
manufacturer’s specified maximum distances.
3. Raceways, boxes and devices recessed into or penetrating
through lead shielded walls, floors and ceilings:
a. Line or clad surfaces of the boxes and devices with the
equivalent thickness of lead shielding shown for the room, except, the
removable cover.
b. Line or clad raceway surfaces with the equivalent thickness of
lead shielding shown for the room.
c. Overlap the lead shielding on boxes, devices and raceways with
the lead shielding for walls, floors and ceilings by not less than one
inch.
d. Arrange the installations so radiation within the rooms will not
penetrate the raceway paths through the lead shielded walls, floors
and ceilings.
C. Interconnecting wiring shall be copper, stranded or solid, and
have the type and size as required by the radiology equipment
manufacturer. However, in no case shall the insulation class be less
than 600 volts, or the conductor size for low voltage power and
grounding wiring be less than 4 mm² (12 AWG), unless approved by
the Resident Engineer.
D. Equipment Grounding Conductors:
1. Install an equipment grounding conductor in each raceway. The
conductor shall be copper, sized as shown, and shall have green
insulation. The conductor size shall at a minimum be equal to the size
of the largest current-carrying conductor present at that point.
7. 2. Bond all of the equipment grounding conductors in each
enclosure.
3. Trough-type raceway sections shall be made electrically
continuous by short bonding jumpers between adjacent sections.
Jumpers shall be exothermically bonded to each raceway section.
Jumpers shall be sized per radiology equipment manufacturer’s
requirements.
4. Provide not less than one 3000mm (ten foot) equipment
grounding conductor pigtail at each box or junction point where an
item of equipment is connected.
5. The grounding conductors shall be continuous back to the
electrical system ground from which the radiology equipment is
served.
E. Install protective barriers between the high voltage power
cables, the low voltage power conductors and medical systems
conductors where conductors of different types share a common
raceway component.
F. Install cables and conductors as required for the radiology
equipment. Provide 3000 mm (ten-foot) pigtails on the wires at all the
connection points to radiology equipment. Wiring shall be tagged and
identified 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 been
installed in the raceways.
H. In existing facilities where it is not feasible to provide radiology
raceways as specified above:
1. Install point-to-point conduit and conductor systems for the
radiology equipment.
8. 2. Run the raceways for the high voltage cables in the shortest
practicable manner as approved by the Resident Engineer and the
equipment manufacturer.
3. Line holes in the floors, walls and ceilings for conduit
penetrations with equivalent thickness of lead sleeves curved or
offset, caulked and flanged for adequate shielding so the X-rays will
not penetrate the floors, walls and ceilings.
9. RACEWAYS
Install all wiring in raceways. Open wiring is prohibited. Raceways
shall be as specified in PG-18-1, Master Specifications. Raceway shall
comply with the definition of the NEC Article 100.
2.1.1 CONCEALED AND EXPOSED
(a) Exposed conduit is acceptable where finished ceilings are not
provided. Wherever it is impractical to conceal conduits, due to
economic considerations or the need to accommodate existing field
conditions, the A/E shall consult with VA to determine acceptable
alternatives.
(b) Electrical conduits may be installed in concrete walls and floors.
(c) Surface metal raceways shall not be installed on the floor. Services
to equipment in open non-patient care areas shall be served from
under the slab or through tele/power poles wired from the ceiling.
(d) Primary-voltage feeders shall not be exposed on the exterior of
buildings.
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 power
branch circuits.
(b) The A/E shall make project-specific recommendations for reducing
the concrete encasement requirement, taking into account the
importance and physical security needs of the conduit(s) involved.
10. Conduits containing Essential Electrical System wiring and
telecommunications cabling shall not be exempt from the concrete
encasement requirement.
2.1.3 SPARE CONDUITS
Where electrical capacity is reserved for future use, such as bussed
space in panelboards, motor control centers, switchboards, and
switchgear of all voltage levels, and where under-slab or underground
conduit is used, the A/E shall provide spare under-slab or
underground conduits to an accessible point. The number and size of
conduits shall be appropriate to the equipment and amount of bussed
space served2.1.4 UNDERFLOOR DUCT SYSTEMS (a) For new
construction 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 is
desirable
(b) Provide duplex receptacle and telecommunications outlet fittings
on the under floor duct to suit the furniture layout.
(c) Space the under floor ducts 5 ft [1.5 M] on centers. In structural
steel frame buildings, use trench header and utilize the cellular steel
as the raceway. Coordinate with the structural engineer to ensure that
the proper cells are enclosed for raceway use.
11. 2.1.5 RADIOLOGY ROOMS
(a) Radiology rooms typically require a manufacturer-specific conduit
and wiring trough system. If VA Medical Center has selected a
manufacturer, the A/E may base the design on the manufacturer’s
shop drawings. If the equipment list is not manufacturer-specific, the
A/E shall base the design on a typical radiology system for bidding
purposes.
(b) The A/E shall provide the following details on the electrical plans
for the Radiology Room(s):
• Power and Signal Plan: A/E shall show complete design for general
use receptacles, communication, and signal outlets. A/E shall show
main circuit and related equipment servicing the radiology
equipment. A/E shall confirm radiology equipment power
requirement with radiology shop drawings.
• Lighting Plan: A/E shall show complete lighting design. A/E shall
coordinate lighting locations with radiology shop drawings and
drawings 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 show
wiring tags for all raceway runs. A/E shall coordinate existing field
conditions, locations, sizes, and quantities of raceways and cables
shown on radiology shop drawings with drawings from other trades to
avoid conflict in field installation.
• Radiology Wiring Schedule: A/E shall show a schedule for all wiring
tags indicating wiring destinations and
locations/sizes/types/quantities of all raceways and wirings.
12. • A/E shall verify that the proposed radiology equipment installation
as shown on radiology shop drawings meets all applicable codes,
regulations, and existing building conditions.
2.2 GROUNDING
The grounding system shall be shown complete on the one-line
diagram with all components and descriptions from the medium- or
low-voltage service to the low-voltage panels, as applicable for each
project. The grounding system shall be shown complete on the One-
line Diagram for the Normal, Standby, and/or Essential Electrical
Systems, including but not limited to generators, automatic transfer
switches, electrical equipment, etc.
2.2.1 GROUNDING ELECTRODES
Galvanized steel or copper-clad steel electrodes may be used. All
electrodes are to be of the same material for the entire project.
2.2.2 EQUIPMENT GROUNDING CONDUCTORS
All 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], the
sheathing perimeters shall be grounded at diagonally opposite corners
of the building.
(c) For buildings with perimeters exceeding 250 ft [76 M], the
sheathing perimeters shall be grounded such that the spacing
between grounding points does not exceed 100 ft [30 M].
13. (d) A ground point shall consist of a driven ground rod and brazed
connection to the building sheath. A No. 6 AWG bare copper
conductor 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 NFPA
70 – National Electrical Code.
2.4 MOTOR DISCONNECT SWITCHES
Provide all motors with a local disconnect switch (unfused unless
required otherwise) located at the motor or a maximum of 5 ft [1.5 M]
away, within sight. Clearly indicate this requirement on the Contract
Drawings.
