Virginia Tech Telecommunications Infrastructure Design Guidelines
View Changes and Revisions to previous Cabling Standards document (1/7/2009)
The Virginia Tech Network Infrastructure & Services (NI&S) Department utilizes applicable codes, standards, and industry guidelines for the design of telecommunications infrastructure. In the initial design phase of a future building, consideration shall be made to provide the space requirements for present telecommunications design needs and more importantly for maximum projected growth.
NI&S requires that full-size blueprints and specifications manuals be submitted for NI&S review. Once the blueprints are finalized, a complete set of full-size printed blueprints is required, plus the Architectural sheets and E-sheets in electronic format (AutoCAD DWG).
This preface outlines the major codes, standards, and guidelines to be followed when planning and installing facilities telecommunications infrastructure (including, but not limited to, telecom/equipment rooms, cabling and pathways). Some of the guidelines herein may vary from industry standards and take precedence over those standards.
The Commonwealth of Virginia ITRM Enterprise Technical Architecture Standard, EA225, specifies that agencies utilize ANSI/TIA/EIA (American National Standards Institute/Telecommunications Industry Association/Electronic Industries Alliance) standards-based designs, with a few exceptions. The latest Enterprise Architecture standard may be downloaded from the VITA website at www.vita.virginia.gov. The latest ANSI/TIA/EIA telecommunications standards may be ordered from IHS Inc. at global.ihs.com.
The major ANSI/TIA/EIA standards adopted by the Commonwealth of Virginia include:
- 568, Commercial Building Telecommunications Cabling Standard
- 569, Commercial Building Standard for Telecommunications Pathways and Spaces
- 606, Administration Standard for Commercial Telecommunications Infrastructure
- J-STD-607, Commercial Building Grounding (Earthing) and Bonding Requirements for Telecommunications
Virginia Tech NI&S also adopts ANSI/TIA/EIA 758, Customer-Owned Outside Plant Telecommunications Infrastructure Standard.
Current releases of the following industry codes, standards and guidelines are additional sources for recommended practices:
- BICSI (Building Industry Consulting Service International) Telecommunications Distribution Methods Manual
- BICSI Outside Plant Design Reference Manual
- BICSI Wireless Design Reference Manual
- DHCD (Virginia Department of Housing and Community Development) Uniform Statewide Building Code that is based upon codes from the International Code Council
- IEEE (Institute of Electrical and Electronics Engineers)
- NEC (National Electrical Code)
- NESC (National Electrical Safety Code)
- OSHA (Occupational Safety and Health Administration)
- SCTE (Society of Cable Telecommunications Engineers) Recommended Practices for Optical Fiber Construction and Testing
- USDA RUS (U.S. Department of Agriculture Rural Utilities Service Telecommunications Program)
These standards and guidelines reflect procedures as described in University Policy #7205 for Information Technology Infrastructure, Architecture and Ongoing Operations.
II. Telecommunications and Equipment Room Guidelines
An Equipment Room (ER) is a special purpose room that provides and maintains a suitable environmentally controlled space for communications and or computing equipment. Equipment Rooms differ from Telecommunications Rooms (TRs) in that an ER is generally considered to serve a building or campus, whereas a TR serves a floor or area of the building.
a. Any or all functions of a TR may be provided by an ER.
b. The ER and TRs shall be dedicated to the telecommunications function and related support facilities. For security purposes, non-NI&S systems shall not be co-located in the ER and TRs. The ER and TRs shall not be shared with electrical installations other than those supporting telecommunications. Equipment not related to the support of the ER or TRs (e.g., piping, HVAC systems, pneumatic tubing) shall not be installed in, pass through, enter, or be stored in the ER or TRs.
c. ER and TR design, including location, should be developed in accordance with the security and disaster avoidance plans of the building.
3. Room Size and Spacing
There shall be a minimum of one TR per floor. Exceptions may be approved by NI&S where conditions warrant. Additional rooms shall be provided when:
a) The floor area to be served exceeds 10,000 sq. ft.; or
b) The horizontal cable distance from the ER/TR to the work area exceeds 90 m (295 ft.).
ER and TR room sizes
ER/TR size shall be determined by NI&S based on the size and program of the building. The minimum ER size is 10' x 15'.
Table of Minimum TR room sizes *
| Serving Area (Sq. Ft.)
|| Room size
|| 10' X 11'
|| 10' X 9'
|| 10' X 7'
* Note: Special purpose rooms, such as laboratories, computer rooms and certain instructional spaces, may have a higher than average density of communications outlets. The size of the ER/TR serving these rooms shall be increased accordingly, as determined by NI&S.
a. Each ER/TR shall be located as close as practical to the center of the area served.
b. ER/TR doors shall open directly onto a hallway to facilitate the movement of large equipment and 24x7 maintenance access.
c. Access through ER/TRs to other areas of the building, including electrical vaults, shall not be permitted.
d. ER/TRs should be located away from sources of electromagnetic interference. Special attention shall be given to electrical power supply transformers, motors, generators, x-ray equipment, and radio/radar transmitters.
e. TRs on multiple floors should be stacked over/under the ER wherever practical and as close as possible to vertical stacks. Depending on building size, there may be multiple TRs per floor. Should this be required, there will need to be multiple TR stacks.
f. ER/TRs shall be located as close as practical to the location where the vertical backbone cable pathways rise throughout the building. This requirement reduces the length and quantity of the associated pathways.
g. The ER shall not be located below grade or below the 100-year flood plain unless preventive measures against water infiltration are employed.
h. ER/TRs shall be positioned such that the risk of water infiltration from in-building systems is minimized. Possible sources of such water infiltration include domestic water supply and drains, fire sprinkler supplies, roof drains, HVAC condensation and drains.
i. ER/TRs shall be positioned away from sources of high quantities of airborne particulates (e.g., dust).
a. A separate supply circuit serving the ER shall be provided and terminated in its own electrical panel in the ER. The electrical panel in the ER shall be sized to meet the projected power requirements of service to the ER and all TRs, and shall be used only to provide power to the ER/TRs.
b. Each TR shall have an electrical panel located in the TR that is fed from the electrical panel in the ER.
c. The electrical panel in the ER shall be connected to an emergency power system (generator).
d. Each ER shall have two 30 amp 208volt circuits terminated on L6-30R at rack location specified by NI&S. One circuit from ER emergency panel and one from building utility power to provide redundancy on network equipment having dual power supplies. Each TR will require one 30 amp 208volt circuit from TR emergency panel (in room) terminated on L6-30R at rack location specified by NI&S.
e. Each equipment rack (ER&TR) will require one 20 amp 120volt receptacle (5-20R) circuit originating from emergency panel in room.
f. Device boxes shall be extended to the top of each equipment rack via flexible conduit. Device boxes shall be mounted to a backplate which shall have accessible screws securing it to the rack location specified by NI&S.
g. In order to provide capacity for growth, in addition to circuits required for equipment racks, all new electrical panels for ER/TRs will also include:
- one 20 amp 120 volt single-pole circuit
- one 20 amp 208 volt double-pole circuit
- one 30 amp 208 volt 3-phase circuit
Each of these circuits will be landed (terminated) on the breaker and extended into individual four inch junction boxes located within 12 inches of the bottom of the panel. These junction boxes shall have blank covers with the panel and breaker information clearly marked.
g. In addition, identified and marked utility duplex outlets shall be placed at 6 foot intervals around the perimeter walls, at a height of 18 inches above the floor. Duplex utility outlets shall be provisioned on normal building power and not tied back to the electrical panel in the ER/TR.
6. Equipment bonding and grounding
a. Grounding systems installed by or for NI&S are for NI&S use only; all other use is strictly prohibited.
b. All stranded grounding conductors shall be insulated and color-coded (green with yellow trace).
c. There shall be at least one grounding conductor, the Telecommunications Bonding Backbone (TBB), for each riser stack. The TBB must be continuous and unbroken from the building central grounding point through each ER/TR in the stack. Minimum grounding conductor size is specified in the table below.
d. Virginia Tech requires that a Terminal Grounding Bar (TGB) be installed in each ER and TR and tied to the TBB. For the TGB, use a Panduit grounding bar, (part number GB2B0312TPI-1), or equal. The TBB shall be tapped in each ER/TR and connected to the TGB in the ER/TR. Minimum grounding conductor size for the connection between the TGB and the TBB is specified in the table below.
e. All grounding conductor terminations shall be compression crimped (no threaded compression lugs).
f. In buildings with more than one TBB, the TBBs shall be bonded together at the top floor and at a minimum of every third floor in between. Minimum grounding conductor size is specified in the table below.
Table of Minimum Grounding Conductor Sizes
| Sizing of the Grounding Conductor
| Length linear m (ft)
|| Size (AWG)
| less than 4 (13)
| 4 - 6 (14-20)
| 6-8 (21-26)
| 8-10 (27-33)
| 10 - 13 (34-41)
| 13 -16 (42 -52)
| 16 - 20 (53 - 66)
| greater than 20 (66)
g. NI&S will provide and ground all equipment racks and building entrance protectors to the TGB using #6 ground conductor.
h. The contractor shall install NI&S-provided labels on grounding conductors every 5-20' as required by the cable path.
i. The contractor shall ground all metal cable trays by connecting them to the central building grounding point per applicable specifications.
7. Environmental Considerations
a. ER/TRs typically require cooling year-round due to the heat generated by telecommunications equipment. The HVAC system shall be capable of maintaining the temperature between 64 degrees F and 78 degrees F in each ER/TR, with relative humidity maintained within the range of 30 to 50%.
b. Each ER/TR shall have its own thermostat controlling the temperature for that room. Thermostat will be hard wired (no battery powered remote thermostats).
c. In some cases, the ER/TR HVAC system(s) should be on the building emergency power system (as determined by NI&S).
d. A positive air pressure shall be maintained with a minimum of one air change per hour, or as required by applicable code.
e. Heat rejection specifications for each ER/TR is determined from the number of telecommunications outlets served by each particular room and the type of equipment used to provision services. Specific heat rejection values for ER and TRs shall be coordinated with NI&S.
f. The preferred location for a Fan Coil Unit (FCU) is above the equipment room entry door to minimize the impact on the usable space within the equipment room.
a. A minimum of one wall shall be covered with 19 mm (3/4 in.) A-C plywood, void free, 2.4 m (8 ft.) high and securely fastened to the wall, capable of supporting attached equipment. Plywood shall be fire-rated (fire retardant) plywood. The location is to be coordinated with NI&S.
b. Lighting shall be a minimum of 500 lux (50 foot candles) measured 1 m (3 ft.) above the finished floor, mounted 2600 mm (8.5 ft.) minimum above finished floor. NI&S requires that at least two lighting fixtures be installed per ER/TR. These lights shall be installed in front and behind the telecommunication equipment rack(s). The location of the lighting fixtures is to be coordinated with NI&S. Lighting shall be controlled by one or more switches located near the entrance door(s) to the room. Dimmer switches shall not be used. At least one light per ER/TR shall be on the building emergency lighting circuit.
c. False ceiling shall not be provided.
d. For ER/TRs, the minimum clear height in the room shall be 2.4 m (8 ft.) without obstructions.
e. The door shall be a minimum of 0.9 m (36 in.) wide and 2 m (80 in.) high, without door sill, hinged to open outward (codes permitting) and fitted with a lock. The doors shall have a lever handle, store room lock, pick guard and shall be keyed to the next available core in the 102 series. The locks for the ER and TRs shall not be on the building master keys. These locks shall be incapable of remaining in an unlocked state when the key is removed. The door shall be equipped with an auto closing device. A door sweep shall be installed at the bottom of the door and shall be consistent with other door sweeps throughout the building. The fire rating of the door shall be consistent with the fire rating of the walls of the room. On outward opening doors, the hinges shall be of the anti-tampering type. These hinges shall be consistent with and match similar mechanisms throughout the building.
f. Floors and walls shall be finished with a static free treatment or sealed to minimize dust; finishes shall be light in color to enhance room lighting.
g. Floor loading capacity of ER/TRs shall be at least 50 lb/sq. ft. The architect/engineer shall verify that concentrations of proposed equipment do not exceed the floor loading limit, which may require increasing the floor loading capacity in some cases.
9. Fire Protection
a. The contractor shall provide fire protection to the room as required by code.
b. Sprinkler heads, if required, shall be provided with wire cages to prevent accidental operation.
10. Pathways and Room Penetrations
a. The size and number of sleeves, conduits and/or cable trays used for backbone and horizontal pathways depends on the requirements of the area served. The size and number of sleeves, conduits and/or cable trays required shall be specified by NI&S.
b. Sleeves or slots shall not be left open except during cable installation and shall be properly firestopped per applicable codes. The interior of all sleeves or slots shall be firestopped in the ER/TR by NI&S after cable installation. Red firestopping material shall be used in all cases.
c. For any multi-story building, A&E shall provide a schematic riser diagram depicting telecommunications infrastructure to include Outside Plant main feed, OSP redundant feed, riser conduits, cable trays and transitions from cable trays to sleeves and a typical station cable conduit and outlet box.
III. Inside Plant Guidelines
The following are requirements for inside cable plant. This includes horizontal wiring, telecommunications outlets, termination equipment, riser and backbone cable, conduit, and cable tray. All cables and conduit must meet all appropriate NEC fire codes. In capital projects and renovations, the electrical contractor installs the cable trays, conduits, fittings and telecommunications outlet boxes. Cable trays and pathways are exclusively for NI&S use; all other use is strictly prohibited.
1. Cable Trays
a. Cable trays provide critical cable management and allow access to horizontal wiring, which is essential for initial installation and future growth. Cable tray systems shall originate in the ER/TR and extend the entire length of the main hallways on that floor. Cable trays shall form part of a continuous cable pathway connected to the serving ER/TR.
b. Cable tray capacity shall be determined by the number of telecommunications outlets that will be served. Larger cable trays should be used in areas that have high-density telecommunications requirements. The dimensions of the cable tray may vary to accommodate the space available as long as the required capacity is maintained. Capacity requirements shall be specified by NI&S. Cable trays shall not be filled greater than the NEC maximum fill for the tray selected.
c. The size of the cable tray may be incrementally decreased the further it extends away from the ER/TR, depending on the specific requirements of the areas being served by that cable tray. This is to be coordinated with NI&S.
d. There must be least 3 inches of clear space above the cable tray for access (6 inches is preferable).
e. All telecommunications cable trays shall have a minimum of 12" clearance from any sort of light fixtures (incandescent, fluorescent or other).
f. No conduits, pipes, wires, threaded rod, grounding hardware or any other obstruction may penetrate the interior area of the tray where the cables are to be routed.
g. All screws, bolts, etc. used to connect the sections of tray must be installed so that they do not obstruct the installation of the cabling.
h. Cable trays are to be installed at the same elevation within the ceiling throughout the building floor.
2. Inside Plant Conduit
a. The electrical contractor will provide clean, dry and debris free conduits, to be used solely by NI&S to provision telecommunications services.
b. Conduits shall either be continuous "home-run" from the telecommunications outlet box to the equipment room, or shall be run from the outlet box and stubbed out within 1 foot of a cable tray that runs continuously to the equipment room. In the case of a renovation where there is no cable tray available, the conduit for the outlet box should be routed to an accessible ceiling area in the corridor.
c. The standard station-cable conduit size is 1-inch diameter minimum. The 1-inch diameter minimum may be increased depending upon the size and number of cables to be installed. Minimum conduit diameter shall be determined by NI&S based on the quantity and size of cable required.
d. The contractor shall install threaded bushings on all conduit ends.
e. The maximum conduit length is 30 m (100 ft.) between pull boxes or pull points, with no more than two 90 degree bends between pull boxes or pull points.
f. All conduit bends shall be sweeps with minimum bend radii as specified in the appropriate standards. There shall be no hard 90 degree bends.
g. The contractor shall provide a pull string (minimum pull strength of 200 pounds) in each conduit. Pull strings must be tied off at both ends of the conduit to prevent loss of the pull string.
h. The standard mounting height for telecommunications outlet boxes is 18" from the finished floor to the top of the outlet box.
i. The standard outlet box shall consist of a nominal 4" x 4" x 2" metal box, with a 4" X 4" drywall ring with mounting holes for a double gang faceplate.
j. If a standard 4" x 4" x 2" metal box is not feasible, NI&S must approve the substitute in order to ensure compatibility with NI&S-supplied hardware, compliance with standards, and life-cycle maintainability. Samples of all non-standard boxes must be provided to NI&S as soon as the manufacturer and part number are determined by the Architect, Electrical Designer or Engineer.
k. There shall be no "back-to-back" outlet box feeds from 1 conduit. Each conduit serves only 1 outlet box.
l. All conduits from a room must be run to the same cable tray or equipment room, i.e., if there is more than one cable tray adjacent to a room, the conduits from a room cannot be "split" between the trays.
3. Station Wiring and Jacks
a. NI&S installs and tests the telecommunication cabling, jacks and faceplates. NI&S also terminates all telecommunication cables and labels each jack individually on the faceplate.
b. It is the responsibility of University Planning, Design and Construction to coordinate with the departments moving into the space(s), and with NI&S, to determine the location and number of telecommunications outlet boxes and station cables required in each space. The university delivers voice and Ethernet service over a converged communications infrastructure that utilizes a single Category 6, or better, four-pair UTP (unshielded twisted pair) cable. The default horizontal station wiring for a single user office space consists of one Category 6 UTP four-pair station cable to each telecommunications outlet box terminated on a 4" x 4" duplex style faceplate. Some single user office spaces may require more than one station cable to each outlet box. Multi-user spaces may also require more than one Category 6 UTP (unshielded twisted pair), four-pair station cable to each telecommunications outlet box terminated on a 4" x 4" duplex style faceplate. Cable placed in plenum return ceilings must be type CMP.
c. Where needed, some combination of fiber, Category 6 and/or coaxial cables may be installed to an individual outlet box.
d. Fiber requires the use of a more spacious outlet box, which should be designed to store a service loop of approximately 1 meter of cable and to minimize stress on the fiber cable and connectors. NI&S must approve the proposed fiber outlet box in order to ensure compatibility with NI&S-supplied hardware, compliance with standards, and life-cycle maintainability. Samples of all fiber outlet boxes must be provided to NI&S as soon as the manufacturer and part number are determined by the Architect, Electrical Designer or Engineer.
e. Each four-pair station cable typically terminates on a Category 6 RJ-45 jack wired in accordance with T568A jack/pin assignments.
f. The cable system, as installed, will be tested by NI&S and must pass relevant performance specifications appropriate to the cable type.
g. On blueprints, the standard symbol for a telecommunications outlet box is a solid triangle, regardless of whether the outlet box is being used for voice, data, or any combination. Any one of these services can be provisioned on one four-pair station cable.
h. Cabling and telecommunications outlet boxes that support devices for wireless access will be part of the cabling design. The electrical contractor will install conduit from the outlet box to within one foot of the cable tray, or to the ER/TR. The Wireless Access Point outlet boxes should be placed in locations designated by CNS during the review process. The outlet boxes should be placed above accessible ceilings where possible. If a ceiling mount is not possible then the outlet boxes should be placed 12" below the ceiling in the locations designated by CNS.
4. Inside Plant Video
a. NI&S installs and tests the video (CATV) cabling, connectors and faceplates. NI&S also terminates all CATV cables and labels each connector individually on the faceplate.
b. All Residence Hall student rooms, lounges and study rooms shall be provided with CATV connections.
c. In academic and administrative buildings, conference rooms, auditoriums and centrally-scheduled classrooms shall be provided with CATV connections.
d. The typical CATV connection consists of a quad-shield RG-6 coax cable that is terminated on a video F-connector.
e. All CATV connection locations shall also be provisioned with a Category 6 station cable.
5. Backbone Cabling
a. NI&S specifies and installs all telecommunications backbone cabling which includes optical fiber, copper and coaxial cable.
b. The size and number of sleeves, conduits and/or cable trays used for backbone pathways depends on the requirements of the areas served. The size and number of sleeves, conduits and/or cable trays required shall be specified by NI&S.
a. All penetrations through fire-rated walls and floors shall be firestopped to restore the fire ratings.
b. Sleeves or slots shall not be left open except during cable installation and shall be properly firestopped per applicable codes. The interior of all sleeves or slots shall be firestopped by NI&S after cable installation.
c. Horizontal penetrations through walls containing cables that are not enclosed in metal conduits, and empty penetrations in walls being reserved for future cables, will be firestopped on both sides of the penetration.
d. Generally, it will be sufficient to firestop a penetration through a fire-rated floor from above only.
e. Red firestopping material will be used in all cases.
7. Consolidation Point Zone Box
a. A consolidation point zone box may be required to serve telecommunication outlets and wireless access in selected rooms, offices, and other spaces.
b. A zone box is comprised of an non-metallic enclosure, a cover or door, and cable entrance/egress points. It accepts telecommunication cables from the closest ER/TR and passes those cables to work area outlet boxes. It shall also be designed to house a wireless access point and/or other devices.
c. Zone boxes shall be located in fully accessible permanent locations such as building soffits, columns and permanent walls, and shall be provided with appropriate access security as agreed to by NI&S, such as key-locking, tool-removable covers, or other suitable means.
d. Appropriate zone boxes shall be flush mounted, or surface mounted if agreed to by NI&S for special cases.
e. Multiple 1-inch cable conduits, the specific number to be determined by NI&S, feed into a zone box from the horizontal cable backbone distribution system (e.g., cable tray) for each work area outlet served. A separate 1-inch conduit shall run from the zone box to each work area outlet box. Conduits shall enter the zone box such that cables can be passed through the box with minimal use of internal space while maintaining minimum cable bend radius, so as to leave maximum room for devices and connectors.
f. New and renovated residence hall rooms require a consolidation point zone box for voice/data/video cables and for wireless access points, or other devices.
g. The contractor shall provide and install NI&S-specified zone boxes. A zone box shall have the following characteristics:
- RF transparent in all directions for internal wireless access point and/or other power over ethernet (POE) electronic devices
- versions for flush and surface mounts, as appropriate
- size shall be specified by NI&S
- aesthetically pleasing to match room decor and paintable, if needed
- easy secure access by door/cover for technicians
- ventilated for wireless access point and other electronic devices
- internal fastening/mounting mechanisms for electronic devices and connectors
- in some cases, power will be required in zone boxes (to be determined by NI&S)
IV. Outside Plant Guidelines
This section defines standards and guidelines for outside cable plant (twisted pair, coax, and fiber) and its associated infrastructure. The cable plant serving new buildings is generally routed from the appropriate campus cable center(s) through steam tunnels, duct systems and/or adjacent buildings. The infrastructure includes cable and pathway components such as ducts, steam tunnels, maintenance holes, and building entrances. When NI&S receives site plans and drawings for a proposed building, NI&S will determine the required outside cable size, optimal routes and duct systems.
The pathway designs will generally follow TIA/EIA 758-A standards.
a. Each building is required to have two diverse building entrances for survivability. Each building entrance must have a separate inside plant pathway to ER/TRs to be specified by NI&S. The location of these building entrances shall be determined in collaboration with NI&S.
b. Each building entrance shall consist of a minimum of two 4 inch conduits and two 2 inch conduits of IMC or rigid steel conduit extended a minimum of 10 feet from the foundation wall or into undisturbed soil. The exact size and number of conduits required depends on the requirements of the building being served and shall be specified by NI&S. These conduits are solely intended for the provisioning of telecommunications services by NI&S. The use of these conduits is managed and documented solely by NI&S.
c. Additional conduit shall be provisioned as required to support other services (e.g., building control systems) that run over non-NI&S cable plant.
d. In all duct systems, the contractor must place a continuous 14 AWG copper wire inside a vacant conduit so that the duct can be "located."
e. All conduit bends will have a radius no less than nine times the internal diameter of the conduit with a minimum radius of 36".
f. No bends will be greater than 90-degrees.
g. No more than two 90-degree bends in a run between pulling points.
h. Conduit runs not to exceed 183 m (600 feet) between pulling points.
i. All underground facilities are to have minimum of 24 inch cover.
j. All excavations shall be reseeded in accordance with Physical Plant specifications.
k. Conduits must enter and exit maintenance holes at the same elevation with no more than 2" penetration into the maintenance hole.
l. The conduits entering a building must have a downward slope away from the building.
m. The contractor shall plug both ends of all conduits to prevent water from seeping into the building.
n. The contractor shall provide a pull string (minimum pull strength of 200 lbs.) in each conduit. Pull strings must be tied off at both ends of the conduit to prevent loss of the pull string.
o. All metallic conduit ends are to be reamed and bushed.
p. All cables in steam tunnels are to be placed at furthest accessible point from steam and/or water lines.
q. Cables in the steam tunnels are to be sleeved with heat resistant material when the route requires them to be in close proximity to heat producing lines or lights.
r. Cables in the steam tunnels are to be mounted to the wall in the least obstructive manner and secured to the wall at a minimum of five foot intervals.
s. Cables are required to be protected in any steam tunnel area, such as junctions, crossings and areas of limited accessibility where cable damage is more likely to occur.
t. Splice cases shall be mounted to steam tunnel walls in the least obstructive manner.
2. Maintenance Holes
a. Inside dimensions of the maintenance hole shall be determined by NI&S, but shall not be less than six feet by eight feet with a clear height of 6' 6".
b. Traffic-bearing construction required for maintenance hole.
c. Maintenance hole must have knockouts on all four sides.
d. Type "C" pulling irons shall be located in the floor of the maintenance hole 6" from each wall and centered in front of each wall.
e. 12" square sump required.
f. Interior walls of the maintenance hole shall be pre-drilled and have 1/2" bolting inserts installed in all inside wall areas 20" on center vertically and 24" on center horizontally for cable racking hardware.
g. Floor of maintenance hole shall be drilled for ground rod (¾ inch).
h. Maintenance hole shall have a 30-inch diameter clear entrance opening.
i. Maintenance hole frame shall have 30-inch diameter clear entrance opening.
j. Cover shall be labeled "COMMUNICATIONS" (Dewey Brothers A3040 or approved equal).
k. When feasible, a floor drain shall be installed in the maintenance hole using a 2" or larger PVC pipe. The drain line shall run to a storm sewer or natural drainage ditch.
3. Building Cable Entrance
a. When outside gel-filled outside cable enters a building and is terminated in an Equipment Room that is located more than 50 feet away from the building entrance, then rigid or IMC conduit is required for the cable between the building entrance and the Equipment Room. In this case, the size and number of inside conduits shall be the same as the size and number of conduits penetrating the building at the building entrance.
b. Conduit runs shall not have more than two 90-degree bends between pulling points.
c. All conduit bends will have a radius no less than nine times the internal diameter of the conduit with a minimum radius of 36".
d. All metallic conduits will be reamed and bushed.
e. If required, pull boxes will be no smaller than 36" x 36" x 8" with clear access to cover.
V. Public Safety & Security
1. Emergency phones (blue light)
a. The foundation for emergency phones shall have the configuration shown in the figure following:
b. Foundation template will be provided to contractor upon request.