L.1 Local Area Network, Information Technology, and Communication
L.2 Distribution Duct System (DDS)
L.3 Testing
L.4 Conduit
L.5 Local Area Network
L.6 Telecom
L.7 Supervisory Control and Data Acquisition (SCADA) System
L.8 Paging
L.9 Television

L.1 Local Area Network, Information Technology, and Communication

The following design policies and guidelines should apply to all systems within the communications and information technologies systems discipline. The purpose is to provide uniformity of design based on the established NIH Design Policy and Guidelines.

L.1.1 Design: The design documents should be presented for review at various stages of completion as determined by the Project Officer. The comments returned from the NIH reviewers should be given careful consideration, as these are based on experiences with past designs that have caused problems for research or maintenance personnel. Written responses to these comments should be provided.

L.1.2 Design Analysis Narrative: A separate design analysis narrative should be prepared to explain the intent and reasoning behind the design. This should be presented in the earlier stages of review to ensure that the design is suitable for NIH personnel.

L.1.3 Reference Design and Safety Guidelines for the Electrical Designer: The NIH is a progressive and dynamic biomedical research institution where state-of-the-art medical research is the standard practice. To support state-of-the-art research and medical care, the facilities must also be state of the art. It is the NIH’s intent to build and maintain electrical and communication systems and facilities in accordance with the latest standards.

It has been the NIH experience that the renovation and rehabilitation of existing facilities do not always lend themselves to incorporating the “latest” standards of the industry.

The architect/engineer (A/E) should be alerted to this situation and make an evaluation early in the design stage to determine the implementation feasibility of the latest standards. The A/E should document such findings, provide recommendations, and report them to the Project Officer for a decision on how to proceed.

The A/E design firm should use and comply with, as a minimum, the latest issue of the following design and safety guidelines. In addition, the A/E should use other safety guidelines received from the NIH Project Officer or as required by the program. The reference codes, regulations, and recommended practices include, but are not limited, to the latest version of the following:

• American Hospital Association (AHA), Management and Compliance Series, Electrical Systems for Health Care Facilities
• American National Standards Institute (ANSI)
• AHA, Management and Compliance Series, Fire Warning and Safety Systems
• American Society of Mechanical Engineers (ASME) A17.1: Safety Code for Elevators and Escalators
• Building Officials and Code Administrators, International (BOCA) The BOCA National Building Code
• Electronic Industries Association (EIA)
• International Cable Engineers Association (ICEA)
• International Electrotechnical Commission (IEC)
• Institute of Electrical and Electronics Engineers (IEEE), Color Books
• Lightning Protection Institute, LPI 175 Standard of Practice
• National Electrical Code (NEC), National Fire Protection Association NFPA Standard 70
• National Electrical Manufacturers Association (NEMA) Standards
• National Electrical Safety Code (NESC) IEEE C2
• NFPA, National Fire Codes (NFC)
• NIH Center for Information Technology (CIT) Guidelines
• Institute of Laboratory Animal Resources (ILAR), Guide for the Care and Use of Laboratory Animals
• Telecommunications Industries Association (TIA)
• Uniform Federal Accessibility Standards (UFAS)
• Underwriters Laboratories (UL)

L.1.4 Testing and Operational Requirements: The A/E should incorporate the requirements for testing and operational training and for the startup and checkout of building systems in the project specifications.

The A/E should identify all system tests required and the acceptance criteria. The A/E should reference a specific test code or procedure. If none is available, the A/E should prepare a test procedure to verify proper operations of the systems.

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L.2 Distribution Duct System (DDS)

The NIH has two underground duct and manhole systems; one is for electrical power cables, and one is for communication circuits. The DDS for electrical power has the manholes designed with the letter “E” followed by a number (one to three digits). Where a duct line branches off an existing manhole, the new manhole will have a subletter designation. For example, the existing manhole is E-29, and two new manholes, E-29A and E-29B, are added onto the same branch. The manhole designations for communications manholes will be discussed in General Design Guidelines, Section: Communications, Local Area Network.

The ducts contain only high-voltage feeders, rated 15 kV for use on the NIH nominal 13.8 kV system, and supervisory cables that monitor and control the high-voltage system. The older supervisory cables, which are in the process of being replaced, were multiconductor control cables. The NIH has continued a process of replacing these cables with smaller diameter data links over fiber-optic paths in the existing campus local area network (LAN) cables and over telephone lines.

The area surrounding manholes in grass areas should be regraded to drain away from the manhole cover. Manhole covers should be 13 mm above finish grade. Manholes should be provided with a sump approximately 300 mm x 300 mm x 150 mm deep. Preferably, manholes should be located in grass areas first, sidewalks second, and the street last. Manholes should not be located in parking spaces. Where ducts are sloped from a high to a low manhole, they should be sealed at the high end only to allow condensation to drain. Cables in manholes should be labeled with embossed brass cable tags and brass chains. Manholes should be provided with two manhole covers, one for forced air and materials entry and the other for worker access. The standard manhole frame and cover should be 700 mm in diameter (600 mm inside diameter). Manhole covers should be labeled “ELECTRIC” for power and “TELEPHONE” for communications. The cover should have a small, flat area for labeling with the manhole number by a welded bead. An embossed brass tag with the manhole number should be permanently mounted inside the chimney and legible from outside the manhole with the cover removed.

L.2.1 Elevation Considerations: The DDS consists of multiple duct runs between manholes of 155 mm inside diameter PVC Schedule 40 ducts with a concrete encasement. The encasement has steel reinforcement in a plane just below the lowest row of ducts where the duct run spans disturbed earth, where it enters manholes and buildings (out to 1.8 m), and where it crosses under heavily traveled roadways. The spacing between ducts is 75 mm in all directions. The ducts should be 760 mm minimum clear below grade or top of roadway.

Duct runs should be sloped from the higher manhole entrance to the lower manhole entrance with no intermediate low spots that would pool moisture. If manhole entrance points are on about the same level, then there must be an arch in the duct run so that there is drainage from a high point into both manholes. If a low point is absolutely unavoidable, another manhole should be provided at or near the low point.

L.2.2 Grounding: Each manhole should be equipped with a 3 m long, 20 mm copper-clad steel ground rod through the floor of the manhole, with all metallic components in the manhole such as racks, cable sheaths, ladder, and so on securely grounded to this rod with a #6 AWG green insulated cable.

L.2.3 Maximum Length Between Manholes: The maximum cable length between manholes should be kept to less than 120 m for an essentially straight run and reduced by 15 m for each bend of 0.79 radians and by 30 m for each bend of 1.6 radians. Bends should be made with the largest radius possible. This by no means releases the engineer or the contractor from doing the necessary cable-pulling calculations to ensure that the maximum tension or sidewall pressures are not exceeded.

L.2.4 Spare Capacity: When new duct runs and manholes are installed, additional ducts should be provided for the future. There should be at least two spare ducts included with the required ducts, more if this will round out a duct bank to a symmetrical configuration. Thus, odd numbers of duct, such as 7, 11, or 13, should not be constructed.

L.2.5 Work Space: All communication equipment should be installed in dedicated communication rooms or closets or, if outdoors, in areas protected against physical and water damage. Pipes and ductwork should not be routed through electrical rooms or closets. Pipes or mechanical ducts should not be routed directly above communication equipment. At least one duplex receptacle and 25 percent of the lighting fixtures in communication rooms and closets should be connected to emergency power, if available. Each communication room and closet should have at least two receptacles. A finished
ceiling is not required. Communication rooms and closets should be located central to the loads served.

Where located within buildings that are air-conditioned, such rooms should be airconditioned, if practicable. In other locations, the room should be ventilated to maintain the temperature at not less than 8 °C and not more than 33 °C and the humidity level at noncondensing level. Ventilation should be filtered forced air.

Adequate egress should be provided for the installation and removal of equipment without requiring disconnection of any other equipment except that specifically connected to the piece of equipment to be removed and replaced. Where columns are within the rooms, they should not encroach on the required space around equipment.

Communication closets and rooms should be provided in adequate quantity, size, and location to allow for top and bottom conduit and cable entry and exit from the closet or the room. Space should be provided in communication rooms and closets for future conduit, cable, and equipment.

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L.3 Testing

Acceptance testing should be performed in accordance with NETA and other applicable codes and standards.

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L.4 Conduit

Conduit should be classified by a nominal transition to metric. Conduit should be metallic; PVC or aluminum conduit is not acceptable except as noted below. PVC conduit may be used in underground applications and should be used in concrete duct banks.

Routing of all conduits 25 mm and larger should be clearly shown on the contract drawings. The couplings used on electrical metallic tubing (EMT) should be raintight compression type. Setscrew couplings should not be allowed.

The minimum conduit size should be 21 mm. Surface-mounted conduit in washdown areas should be IMC or rigid galvanized steel (RGS) with threaded couplings. Flexible metal conduit (Greenfield) should be used for lighting fixture connections (whips) and for connections to equipment subject to vibration, noise transmission, or movement. Lighting fixture connections should be made with minimum 1.2 m and maximum 1.8 m lengths of flexible metal conduit in accordance with NEC. Liquid-tight, flexible metal conduit should be used for motor connections and undercabinet lighting. Raceway systems should be provided for all wiring.

L.4.1 Conduits (Within Buildings): The minimum size conduit should be 21 mm except as indicated for flexible conduit. All conduit should be installed parallel with the building features, except for conduit run in or under the slab. Conduit should not be installed in the slab on grade. Fittings for metallic conduits should be compression-type steel or malleable iron. Conduit should not be attached to box covers, except for 15 mm or smaller flexible conduit terminated on a flush-mounted box cover. All conduits should be marked every 15 m indicating its use. All conduits should be supported independent of other systems and equipment and should be supported with approved devices (tie wire is not acceptable). Conduit should not be run exposed on top of roof surfaces.

In addition to the requirements of codes, conduit should be installed as specified below.

RGS conduit with threaded fittings should be used in the following locations:

• Elevator shafts, all exterior areas, and other areas where physical damage is probable.
• Where exposed within 2 400 mm of the finished floor level and a point above 2 400 mm past the vertical-to-horizontal transition.
• Biosafety Level 3 and 4 areas.
• Where exposed in animal research and animal holding facilities.
• Where exposed in parking structures.

PVC schedule 40 nonmetallic conduit should be used in the following locations:

• Below concrete floor slab on grade.
• Within concrete walls or within floors above grade.
• Where elbows are terminated above slab, provide RGS elbows.
• PVC conduit stubbed out of floors should transition to RGS raceway prior to the point where the conduit is exposed.
• RGS conduit may be substituted for PVC schedule 40.
• EMT may be used where allowed by code in all other interior spaces. All fittings used with EMT should be compression type.

Aluminum conduit should be used in magnetic field areas (i.e., MRI, NMR areas).

Steel modular surface metal raceway may be used in offices, laboratories, and similar applications where appropriate and classified as a dry location.

Cable tray may be used where dedicated for communications wiring.

See Conduit Support Detail, Figure L.4.1, below.

Figure L.4.1 Conduit Support Detail

L.4.2 Raceways (Underground): All underground conduit should be PVC or RGS. Conduits should be concrete encased when buried underneath roadways or when used for medium-voltage applications. Minimum size for conduits used for medium voltage should be 129 mm. Generally, conduits serving exterior pole-mounted lighting fixtures should be 53 mm in size. Direct-buried conduit is acceptable for electrical systems rated 600 volts and below. Rigid steel may be direct-buried if coated with asphalt paint or PVC coating.

PVC electrical conduit for underground runs should be a minimum of type EB if concrete encased or schedule 40 if direct-buried. Marking tape indicating “Electrical Cable Buried Below” should be installed in accordance with the latest applicable industry standards. All empty ducts should be provided with 4 mm minimum diameter nylon pull wire for pulling future cables.

All empty ducts should be sealed to prevent water seepage into the handhole or manhole. Ducts should be sloped to prevent water drainage into the building.

Prior to pulling cable into any conduit (whether new or existing), the conduit should be cleaned with a wire brush 16 mm larger than the duct and rodded with a mandrel 8 mm smaller than the duct to test the integrity of the duct.

L.4.3 Manholes and Handholes: Manhole and handhole spacing should be as required by code and by wire-pulling requirements but not more than 150 m apart. The minimum inside dimension of manholes should be 3 700 mm x 2 750 mm x 1 980 mm. The diameter of manhole openings should be 910 mm. Handholes should be a minimum of 610 mm x 610 mm x 610 mm.

Handholes should have steel covers. Covers should be grounded. All cables should be racked on nonmetallic cable racks designed for installation on walls of manholes. Handholes and manholes in streets should meet Maryland Department of Transportation standards.

L.4.4 Surface Metal Raceway: Surface metal raceway should be metallic; plastic is not acceptable. The nominal dimensions of the raceway should be as follows:

Table L.4.4 Raceway Dimensions

Emergency circuits should not be wired with normal power in the same raceway. Power and communications should be in separate channels.

L.4.5 Cable Tray: Galvanized steel is the preferred material to be used in ladder cable tray construction for power cables. Ladder or center-spline cable-tray construction is acceptable for communications cable. However, other materials, such as PVC-coated steel and aluminum, will be considered. Cable trays should consist of factory-manufactured units that bolt together in the field. The minimum cable-tray size for communications cable should be 300 mm x 100 mm nominal. Fabrication in the field, other than the shortening of a single straight section, is prohibited. Ventilated tray bottoms, in lieu of ladder rungs, are not acceptable.

Cable-tray locations should be coordinated with adjacent utilities so that the tray will be accessible for adding or removing cables in the future. Routing should also be adjusted so as not to obstruct access to other utility items that would routinely require access for maintenance or adjustment.

The cable trays should be supported directly from the building structure above wherever possible. The spacing of the support points should be as recommended by the cable-tray manufacturer. Provide minimum #6AWG grounding conductor run continuously in cable tray bonded to each section.

Cable trays should not be allowed through fire-rated walls. Provide a minimum of two 103 mm RGS sleeve with insulated bushing extending a minimum of 150 mm on each side of the fire-rated wall.

L.4.6 Demolition: Where the work requires that wiring be removed from conduit that is not embedded in concrete and if that conduit is not scheduled for re-use on the same project, then the conduit is to be removed.

Exception: Where the work requires that the wiring be removed from an embedded-inconcrete conduit and if that conduit is not scheduled to be re-used, the conduit is to be abandoned in place. Conduit that enters the slab from below is to be cut, after the wires are removed, as close to the slab as practical but with not more than 19 mm protruding. Conduit that enters the slab from above should have the floor material removed so that the conduit can be cut with a cold chisel at least 6 mm below the slab elevation, and then the conduit and enlarged opening should be plugged with nonshrinking grout and the slab surface finished flat and true.

L.4.7 Nameplates: All communication equipment should have nameplates identifying the name of the piece of equipment or the name of the equipment served Nameplates should be laminated, phenolic legend plates with white letters on black surround for normal power and white on red surround for emergency power. Nameplates should have minimum 7 mm high letters for small equipment and disconnects, 13 mm high for medium-size wallmounted equipment, and 50 mm high for freestanding equipment. Nameplates should be attached with stainless steel screws. Where the equipment is remote from its electrical source, under the equipment name in smaller letters the words “FED FROM” followed by the source panel or riser name should be included.

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L.5 Local Area Network

The LAN system commonly refers to data transmission on the NIH campus. Any data, whether for research, system monitoring, or other purpose, travel on the LAN system. Any telephone conversations or voice communication travels on a separate system discussed in General Design Guidelines, Section: Communications, Telecom.

The NIH or the user should install fiber-optic and copper cable under a separate contract. The raceway and other details as described below should be designed into the construction documents. The raceway should be installed in accordance with EIA/TIA standards. Each LAN conduit should have three 25 mm inner ducts installed with pull lines for present and future use. The Interbuilding Closet (IBC) should be 9 m² and is sometimes referred to as
the “Router Room.” The IBC is typically located on the basement or ground floor, away from any electrical rooms.

Four 100 mm conduits should connect the IBC with the first LAN closet(s). Between stacked closets, four 100 mm sleeves should be provided in the floor. The conduits should terminate 150 mm above finished floor and be sealed to prevent flooding of the closet below.

LAN and telephone (voice) closets should have a common wall. The wall should be constructed floor to floor. The 24-hour maintained temperature should be 15 to 25 °C in the IBC and LAN closets. Each closet should have its own thermostat. The relative humidity should be maintained at 30 to 60 percent and be noncondensing. The LAN closet should be 9 m² for up to 900 m² of area served per floor. The minimum wall dimension should be 2.4 m long. Closets should be located such that the maximum run of unshielded twisted pair (UTP) Level 5 EIA/TIA copper conductors are 90 m. Horizontal connections between closets are not required. The closets should be centrally located and stacked floor to floor. The four closet walls should be covered floor to 2.4 m above finished floor (AFF) with 19 mm thick, fire-retardant plywood primed and painted flat white.

The LAN closet should be provided with two 20 A individual emergency circuits. Each circuit should supply a quad receptacle (two duplexes). The receptacles should be quarter-pointed on the long wall 460 mm AFF. Two-lamp fluorescent light fixtures controlled by a switch at the door are required per LAN closet.

A dedicated ground riser (DGR) should be installed continuous through stacked closets. A grounding conductor from the separately derived source serving the receptacles in each closet should be connected to the DGR. This grounding conductor should be installed from the transformer secondary or the panelboard ground bus serving the receptacles if the panelboard contains the neutral-to-ground bonding strap. A ground grid in the IBC should be provided. The DGR should be connected to the IBC ground grid. The IBC ground grid should be connected to the electrical service entrance ground grid in the main electrical room. The ground grid in the IBC should be similar to the electrical service entrance ground grid. See General Design Guidelines, Section: Electrical, Power Quality. If a lightning protection system is provided, it should be tied to the IBC ground grid.

Cable tray should be used in all new installations. Cable tray should be installed in all corridors and elsewhere to form a continuous pathway for LAN cables. Cable tray should be UL-listed as a ground conductor and should be electrically continuous and grounded through approved means. The cable tray should be of the ladder or center spline style.

A 21 mm minimum conduit should be installed from the LAN outlet through the corridor wall to the corridor ceiling space for a single workstation. The conduit installer should provide firestopping after the cables are installed. Conduits in firewalls should be metallic and should penetrate 150 mm beyond the face of the wall. Flexible metal conduit should not be used because the inside surface cuts and chafes the data cable. The maximum conduit fill should be 40 percent of the conduit area for installations requiring the servicing of more than one LAN outlet from a conduit. Where there are questions of conduit size or quantity, contact the NIH Division of Network Systems and Telecommunications Branch. The documents should contain the following required coordination: The general contractor should notify the owner's data wiring subcontractor prior to ceiling installation close-up. The general contractor should schedule telecom/LAN wiring prior to ceiling close-up. The general contractor should allot the required time period to install telecom/LAN wiring. The design documents should state the time period required.

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L.6 Telecom

The construction documents should provide telephone raceway in accordance with EIA/TIA standards. Either the NIH or the user should provide telephone cable and station wiring under a separate contract.

The telephone system including fax data should be installed in accordance with the LAN infrastructure described above.

Telecommunications (telephone and LAN) manholes should be numbered similarly to electric manholes as described in General Design Guidelines, Section: Communications, Distribution Duct System, except using the letter “T” in lieu of “E.”

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L.7 Supervisory Control and Data Acquisition (SCADA) System

The SCADA system is designed for monitoring and controlling the network protectors and switchgears in the NIH system. The SCADA system is required to monitor network protectors, transformers, vaults, control capabilities for remote operations of network protectors, switchgears, motor control centers, and other devices per contract requirements and alarm capabilities for specific SCADA conditions. The system should be designed for vaults or manhole environments with single or multimode fiber primary communications and fiber-optic or copper conductor secondary communications. The SCADA system should monitor as a minimum the following parameters:

• Each phase voltage of each controlled or monitored device (A, B, C phases)
• Each phase current of each controlled or monitored device (A, B, C phases)
• Total power factor of each controlled or monitored device
• Each network protector and transformer temperature
• Each controlled or monitored device status (open/close)
• Each network protector
• Each vault water level
• Number of protector operations
• Time and data stamp of operation events
• Remote changing of protection setpoints

The SCADA system should have, as a minimum, the following control capabilities:

• Remote opening and lockout of any transformer protector on operator command
• Remote opening and lockout of any combination of transformer protectors on operator command
• Remote closing of any single transformer protector on command
• Remote opening and closing per contract requirements and specifications

The SCADA system should have, as a minimum, the following alarm capabilities:

• Remote alarm for any cut in fiber or copper at any location in the SCADA system
• Remote alarm for loss of power to any data concentrator
• Remote alarm for loss of power to any network protector
• Remote alarm for low-voltage condition

L.7.1 SCADA Design Specifications: The SCADA system should utilize a star fiber-optic design for the primary communication channel from the Central Control Room to the data concentrator located in remote substations or vaults. The system should utilize either a star fiber-optic or daisy-chain twisted pair for the secondary communication channel for the data concentrator to the Intelligent Electronic Device(s) (IEDs). The system should consist of the following:

• The control room should be connected to the data concentrators over a fiber-optic network.
• The data concentrators should communicate over a twisted shielded pair to IEDs mounted in a single or in multiple vaults depending on the number of IEDs to ensure that the status of all relays in the system are updated every 4 seconds and that analog information is updated every 10 seconds. If the twisted pair comes out of a vault, the communication wire should be isolated to a maximum of 6 000 V such that the conductor does not become a path for voltage between vaults.
• The system should be designed to also monitor low-voltage switchgear, motor control centers, panelboards, and other distribution equipment within the NIH complex.
• Monitoring and control devices should be designed to meet 0 to 45 °C temp-erature and radio frequency interference.
• The system should be designed and implemented by a single vendor, which accepts system responsibility for its operation.

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L.8 Paging

Paging systems are rarely needed at the NIH; however, where deemed necessary, they should follow these criteria. Paging (public address) systems should be installed in conduit. Paging speakers should be installed in recessed back boxes. The paging system should operate at 70 V. The wiring to speakers should be #18 AWG two-conductor shielded. Paging-speaker sound levels should consider the ambient noise level. Speakers for ceiling mounting in corridors and other finished spaces should have multitap transformers with 1/4, 1/2, 1, 2, and 4 W taps. Speakers for use in machine rooms and other high-noise rooms should be of the horn type with sound outputs at least 3 dB above ambient.

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L.9 Television

Some buildings on campus are wired for cable TV. Conduit should be provided for the installation of the cable by the local cable TV company.