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Electrical Engineering

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F A C I L I T I E S S T A N D A R D S F O R T H E P U B L I C B U I L D I N G S S E R V I C E

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6.0 TABLE OF CONTENTS

6.1 General Approach

6.2 Codes and Standards183 Electrical Design Standards

6.3 Commissioning

6.4 Placing Electrical Systems and Communications Systems in Buildings

6.5 General Design Criteria

6.6 Electrical Load Analysis188 Standards for Sizing Equipment and Systems

6.7 Utility Coordination and Site Considerations

6.8 Site Distribution

6.9 Primary Distribution193 Transformers

6.10 Secondary Distribution194 Secondary Distribution Systems

6.11 Wiring Devices197 Placement of Receptacles

6.12 Emergency Power Systems199 Batteries199 Generator Systems

6.13 Uninterruptible Power Systems

6.14 Computer Center Power Distribution

6.15 Lighting204 Interior Lighting204 General Lighting Fixture Criteria208 Lighting Criteria for Building Spaces208 Lobbies, Atria, Tunnels and Public Corridors208 Mechanical and Electrical Spaces208 Dining Areas and Serveries209 Lighting Controls210 Exterior Lighting

6.16 Raceway System for Communications212 Communications Raceways

6.17 Layout of Main Electrical Rooms

6.18 Alterations in Existing Buildings and Historic Structures215 Placing Electrical and Communications

Systems in Renovated Buildings216 Building Service216 Secondary Power Distribution216 Computer Center Power216 Lighting218 Communications Distribution

Harry S. Truman Presidential Library and Museum Addition and RenovationArchitect: Gould EvansGSA Project Manager: Ann Marie Sweet-AbshirePhoto: Mike Sinclair

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E L E C T R I C A L E N G I N E E R I N G

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It is GSA’s goal to build facilities equipped with the latestadvances in office technology and communication. Thisintent should be extended to include the future evolutionof automated office and telecommunications equipmentas well. Making this concept a reality requires acomprehensive design for engineering systems that goesbeyond the requirements of the immediate buildingprogram. It also requires a higher level of integrationbetween architecture and engineering systems than onewould usually expect in an office building.

The trend toward intelligent buildings is gaining momen-tum in the Federal sector. The Government recognizesthat communications needs and technology are growingat an increasingly rapid pace. Work stations are becomingmore powerful, requiring faster and easier access to moreinformation. GSA must install the wiring and interfaces tosupport these requirements. It should be noted that thedesign of all communications systems is the responsibilityof GSA’s Federal Technology Service (FTS).

A computer-based building automation system (BAS) thatmonitors and automatically controls lighting, heating,ventilating and air conditioning is critical to the efficientoperation of the modern Federal office building. GSAencourages integration of building automation systemsgenerally. Exceptions are the fire alarm and securitysystems, which shall function as stand-alone systems witha monitoring only interface to the BAS.

6.1 General Approach

Electrical and communications systems in GSA buildingsprovide the infrastructure for an efficient workenvironment for the occupants. These systems mustsupport the many types of equipment used in a modernoffice setting in a reliable fashion.

There are three characteristics that distinguish GSAbuildings: long life span, changing occupancy needs, andthe use of a life cycle cost approach to account for totalproject cost.

GSA owns and operates its buildings much longer thanthe private sector. Consequently, a higher level ofdurability is required for all systems, as is the ability toreplace equipment during the life of the building.

During the life span of a typical Federal building, manyminor and major alterations are necessary as the missionsof Government agencies change. The flexibility to adjustto alterations easily must be designed into the buildingsystems from the outset. Electrical and communicationssystems should provide ample capacity for increased loadconcentrations in the future and allow modifications to bemade in one area without causing major disruptions inother areas of the facility.


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Architects and engineers should always make environ-mentally responsible choices regarding new buildingmaterials and the disposal of discarded products.Recycled material use needs to be maximized to thefullest extent practical within the project requirements.Architects and engineers should consider integratingrenewable energy technologies such as photovoltaics andother solar applications, geothermal heat and wind intobuilding systems.

Security is an important consideration in electricalengineering systems design. Refer to Chapter 8: SecurityDesign for detailed criteria related to this matter.

Consult Chapter 4.1: Installation Standards of the FineArts Program Desk Guide for additional information.

Submission Requirements. Every project will haveunique characteristics and requirements for submissionand review. These shall be developed by the GSA ProjectManager. The general submission requirements for each phase of project development are described inAppendix A.

Atrium, Sandra Day O’Connor U.S. Courthouse, Phoenix, AZ


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Ronald Reagan Building, Washington, D.C.

6.2 Codes and Standards

Model codes and standards adopted by GSA arediscussed in Chapter 1: General Requirements, Codesand Standards, Building Codes. All electrical andcommunications systems must meet or exceed therequirements of the National Electric Code (NEC).

Electrical Design StandardsThe standards listed below are intended as guidelinesfor design only. They are mandatory only wherereferenced as such in the text of the chapter. The list isnot meant to restrict engineers from using additionalguides or standards as desired.

Electronic Industries Alliance / TelecommunicationsIndustry Association (EIA/TIA) Standards:

• EIA/TIA Standard 568: Commercial BuildingTelecommunications Wiring Standard (and related bulletins)

• EIA/TIA Standard 569: Commercial Building Standard For Telecommunications Pathways And Spaces (and related bulletins)

• EIA/TIA Standard 606: Administration Standard ForThe Commercial Telecommunications Infrastructure (and related bulletins)

• EIA/TIA Standard 607: Commercial Building Grounding (Earthing) And Bonding Requirements For Telecommunications (and related bulletins)

Oakland Federal Building, Oakland, CA.


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6.3 Commissioning

The design team’s electrical engineer shall identify and coordinate commissioning practices with theConstruction Manager, Project Manager, and (if con-tracted separately) the Commissioning Authority, for theproject’s programmed performance goals. As appropriate,coordinate with other disciplines to fully enable requiredtesting and certifications. Incorporate into constructionspecifications those testing and certification requirementsthat involve construction contractors. Examples ofpossible programmed performance goals, include:

• Emergency Power Equipment Modes of Operation. • Clean Power/Grounding Characteristics.• Functionality of Building-wide Communication Systems. • Lighting Levels.• Lighting Control Functions.• Effectiveness of Building Automation System Interface.• Functionality of Applied Innovative Technologies.


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Horizontal Distribution of Power and Communications.In new construction the building shall have raised accessflooring. In buildings with access flooring, power circuitsshould be provided via conduit, modular wire distribu-tion boxes and modular wire cable sets to flush floorreceptacles. Communication cables can be laid exposeddirectly on the slab and grouped together in rows 3600mm (12 feet) on center.

Power, data and telephone cables shall be groupedtogether in pathways that are separated into channels for each system. Independent channels are required in horizontal pathways for normal power, emergencypower, mechanical, fire alarm, security, television andcommunications. The communications channel includesvoice and data. Major zones within the facility shouldhave horizontal distribution capacity for all sevencategories described above. Horizontal pathways servingindividual work stations must have at least three channelsfor power, voice and data. EIA/TIA Standard 569:Commercial Building Standard For TelecommunicationsPathways And Spaces (and related bulletins) providesdetailed requirements for communications pathways,including requirements for underfloor ducts, access floor,conduit, cable trays and wireways, ceiling pathways andperimeter pathways. Provide at least 650 mm2 (1 squareinch) of horizontal capacity for power and communi-cations to office areas for every 10 m2 (100 square feet) of occupied area.

6.4 Placing Electrical Systemsand Communications Systemsin Buildings

In order to achieve system flexibility and thorough integra-tion between building architecture and engineering systems,a concept for the power and telecommunications infra-structure that supports the distribution of electrical andcommunications systems must be established during thearchitectural schematic design. The locations of verticalbackbone pathways, horizontal pathways, closets, equip-ment rooms and utility entrance facilities for electricaland communications distribution equipment must beestablished before the architectural concept is finalized.

Electrical Closets . The spacing of electrical andcommunications closets in buildings is described inChapter 3: Architectural and Interior Design, BuildingPlanning, Placement of Core Elements and Distances.

Communications Closets. Communications closets shall meet the requirements of EIA/TIA Standard 569:Commercial Building Standard For TelecommunicationsPathways And Spaces (and related bulletins). The locationand size of communications closets are discussed inChapter 3: Architectural and Interior Design.

Planning Grid, Floor Grid and Ceiling Grid. A commonplanning grid is to be used in all GSA buildings. Electricaland communications elements in floors and ceilingsincluding lights, power, telephone and data are givenprecise locations within the planning grid. Therelationship of this grid to wall placement, ceiling gridsand location of mechanical and electrical elements isdescribed in detail in Chapter 3: Architectural and InteriorDesign, Building Planning, Planning Grid.

U.S. Courthouse, Kansas City, KS


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The placement of outlets in walls or in the partitions ofsystems furniture should be avoided because of thedifficulty it creates for future reconfiguration of the officespace. This is true for both closed office and open planconcepts. Light switches likewise should be located oncolumns and the walls of fixed core elements, to themaximum extent possible.

Flat conductors, poke-through and/or power poles shallnot be used in new construction.

These criteria apply to all occupiable area or net usablespace in a GSA building but not to public spaces orsupport spaces, which can be considered fixed elementsand are not subject to frequent changes.

Vertical Distribution. Risers for normal power,emergency power and communications should becombined with other core elements to form compactgroups and maximize usable floor space. The number andsize of risers will depend on the systems chosen, butfuture flexibility should be an important criterion in thevertical layout as well. Electrical and communicationclosets shall be vertically stacked. Electrical closets shallhave two capped 4-inch spare sleeves through thestructural floor for future flexibility. Communicationsclosets shall also have two capped spare sleeves in eachcloset. Vertical risers for normal power, emergency power,and communications should be aligned throughout thebuilding to minimize conduit bends and additionalcabling. Be aware of the requirements to locate fire alarmvertical risers remotely.


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Lightning Protection. Lightning protection shall beprovided in accordance with NFPA 780. The systemshould be carefully designed to ensure that static dis-charges are provided with an adequate path to ground.Surge arresters on the main electrical service should also be considered.

Cathodic Protection. The need for corrosion protectionfor conduits and for all other underground piping andburied metals on the project must be evaluated throughsoil resistivity and pH testing. Testing for soils resistivity is part of the Geotechnical Report. Cathodic protectionshall be provided for all metal underground storage tanks.See Appendix A: Submission Requirements. Cathodicprotection should be designed by a qualified specialist.

Artwork. Museum standards for lighting works of artrange from 5 to 10 foot-candles for extremely lightsensitive materials such as paper and textiles, to 20 to 40foot-candles for moderately sensitive materials such as oil paintings and wood.

Please consult Chapter 4.1, Installation Standards, of theFine Arts Program Desk Guide for additional information.

6.5 General Design Criteria

Energy Conservation. The largest factor in the energyconsumption of a building is lighting. The overallefficiency of the lighting system depends both on theindividual components and on the interaction ofcomponents in a system. A good controls strategy thateliminates lighting in unoccupied spaces and reduces itwhere daylighting is available can contribute significantlyto energy conservation. The best way to institute suchcontrols is through a Building Automation System (BAS).See section on Lighting, Lighting Controls in this chapterfor further discussion. Designers should check with localpower companies and include technologies that qualifyfor rebates. The Office of Chief Architect assigns anenergy goal for each GSA new construction and buildingmodernization.

Visual Impact. Options regarding the location andselection of electrical work that will have a visual impacton the interior and exterior of the building should beclosely coordinated with the architectural design. Thisincludes colors and finishes of lights, outlets and switches.

Equipment Grounding Conductor. All low voltage power distribution systems should be supplemented witha separate, insulated equipment grounding conductor.Grounding for communication systems must follow therequirements in the EIA/TIA Standard 607: CommercialBuilding Grounding (Earthing) And Bonding RequirementsFor Telecommunications (and related bulletins).


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Standards for Sizing Equipment and Systems To ensure maximum flexibility for future systems changes,the electrical system must be sized as follows: panelboardsfor branch circuits must be sized with 50 percent spareampacity, panelboards serving lighting only with 25percent space switchboard ampacity, distribution panels with 35 percent spare ampacity and main switchgear with25 percent spare ampacity. Spare overcurrent devices shallbe provided as well as bus extension for installation offuture protective devices.

Table 6-1Minimum Connected Receptacle Load

Minimum connected receptacle loadType of occupiable area Load per square meter Load per square foot

Normal systems

Office/Workstation 14 VA 1.3 VA

Non-workstation areas such as public and storage 10 VA 1 VA

Core and Public areas 5 VA 0.5 VA

Electronic systems

Office/Workstation 13 VA 1.2 VA

Computer rooms 700 VA 65 VA

NOTE: Normal and electronic equipment systems are as shown on Figure 6-2

6.6 Electrical Load Analysis

In establishing electrical loads for Federal buildings it isimportant to look beyond the immediate requirementsstated in the project program. Future moves and changeshave the effect of redistributing electrical loads. Theminimum connected receptacle loads indicated in Table 6-1 combined with other building loads multipliedby appropriate demand factors, and with spare capacityadded, shall be used for obtaining the overall electricalload of the building. If the load requirements stated in theprogram are higher, the program requirements must, ofcourse, be satisfied.


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In the case of large buildings or buildings with largefootprints, it may be necessary to have more than oneservice. In large office buildings and in campus situations,it may also be necessary to distribute medium voltagepower. If available, medium voltage, up to 15KV, shouldbe used for primary power distribution to substations.

Communications Service Coordination. The Architect/Engineer shall coordinate with the client agency todetermine the enclosure and pathway requirements fortelecom systems. The Scope of Services varies with eachproject; it includes as a minimum design of the infra-structure (pathway and enclosure) and may include fulldesign and specification of the telecom system.

6.7 Utility Coordination and Site Considerations

Power Company Coordination. See Chapter 2: SitePlanning and Landscape Design, Site Utilities, UtilitiesServices.

These data must be established prior to initial systemdesign. Electrical load estimates must be prepared inconjunction with utility company discussions to establishthe capacity of the new electrical services.

The service entrance location for commercial electricalpower should be determined concurrently with the devel-opment of conceptual design. Space planning documentsand standards for equipment furnished by utilitycompanies should be incorporated into the conceptdesign. Locations for transformers, vaults, meters andother utility items must be coordinated with thearchitectural design to avoid detracting from thebuilding’s appearance.

Site Considerations. The routing of site utilities andlocation of manholes should be determined early in thedesign process.

It is desirable to have the utility company furnish power atthe main utilization voltage, i.e., 480/277V or 208/120V(for small buildings). GSA prefers that the utility companyown and maintain the transformers.

The Federal Triangle, Washington, D.C.


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Where it is necessary to run communication cablesalongside power cables, two separate systems must beprovided with separate manhole compartments. The same holds true for normal and emergency power cables.Ductbanks should be spaced at least 300 mm (1 foot)apart. Site entrance facilities including ductbanks andmanholes must comply with requirements stated inFederal Information Processing Standard 175: FederalBuilding Standard for Telecommunication Pathways andSpaces (see also EIA/TIA [Electronic IndustrialAssociation/Telecommunication Industry Association]Standard 568-A and related bulletins)

Electrical and communication ducts should be kept clearof all other underground utilities, especially hightemperature water or steam.

Duct Sizes. Ducts should be sized as required for thenumber and size of cables. Inner ducts must be providedinside communication ducts wherever fiber optic cableswill be used. A sufficient number of spare ducts should beincluded for planned future expansion; in addition, aminimum of 25 percent spare ducts must be provided forunknown future expansion.

Manholes. Manholes should be spaced no farther than150 m (500 feet) apart for straight runs. The distancebetween the service entrance and the first manhole shouldnot exceed 30 m (100 feet). Double manholes should beused where electric power and communication linesfollow the same route. Separate manholes should beprovided for low and medium voltage systems. Manholes

6.8 Site Distribution

Exterior distribution systems must be either direct buriedconduit or concrete encased conduit systems. Cableselection should be based on all aspects of cable operationand the installation environment, including corrosion,ambient heat, rodent attack, pulling tensions, andpotential mechanical abuse and seismic activity.

Direct Buried Conduit. Direct buried PVC, coatedintermediate metallic conduit (IMC) or rigid galvanizedsteel (RGS) is appropriate for the distribution of branchcircuits. Direct buried cable should not be used.

Concrete-Encased Ductbank. Concrete-encasedductbanks should be used where many circuits follow thesame route, for runs under permanent hard pavementsand where service reliability is paramount, such as serviceentrances.

Duct line routes should be selected to balance maximumflexibility with minimum cost and to avoid foundations of other buildings and other structures. Ducts should beprovided with a cover of at least 600 mm (24 inches).Ductbanks under railroads should be reinforced. Ductsshould slope 4 percent toward manholes. Changes indirection should be by sweeps with a radius of 7.5 m (25 feet) or more. Stub-ups into electrical equipment maybe installed with manufactured elbows. Duct line routesshould be selected to balance maximum flexibility withminimum cost and to avoid foundations of other buildingsand other structures.


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should have clear interior dimensions of no less than 1800mm (6 feet) in depth, 1800 mm (6 feet) in length, and1800 mm (6 feet) in width with an access opening at thetop of not less than 750 mm (30 inches) in diameter.Manholes must have a minimum wall space of 1800 mm(6 feet) on all sides where splices are to be racked.

Stubs. Minimum of two spare stubs should be provided(to maintain a square or rectangular ductbank) so that themanhole wall will not need to be disturbed when a futureextension is made. Stubs for communications manholesmust be coordinated with GSA Federal TechnologyService.

Smaller manholes may be used for low voltage feeders(600V and below), branch circuits or communicationscircuits. They should be not less than 1200 mm (4 feet) indepth, 1200 mm (4 feet) in length, and 1200 mm (4 feet)in width with a standard manhole cover and sump of thesame type provided for manholes. Generally, at least fourracks should be installed. Where more than two splicesoccur (600V feeders only), a 6 feet by 6 feet by 6 feetmanhole may be more appropriate.

6.9 Primary Distribution

The selection of a primary distribution system, i.e., radial,loop, primary selective, secondary selective, network, etc.,should be evaluated on a case by case basis, with consider-ation given first to safety, then to cost and reliability.Generally, radial or loop systems are preferred.

The primary distribution system design should be basedon the estimated demand load plus 25 percent sparecapacity.

See Chapter 7: Fire Protection Engineering for additionalrequirements.

Medium Voltage Switchgear. When required, mediumvoltage service switchgear may be provided with either air,vacuum or SF6 circuit breakers or fused air interrupterswitches. Provide voltmeter, ammeter and watt-hourmeter with demand register. Meters should be pulse-typefor connection to the BAS. Providing a power monitoringand management system is an acceptable option.

Conductors. Conductors should be insulated with crosslinked polyethylene (XLP) or ethylene propylene rubber(EPR). 133 percent insulation should be provided.Conductor size should not exceed 240 mm2 (500 Kcmil).

Spot Network Transformers. In cases where reliability isan absolutely critical concern - the IRS office thatprocesses refund checks, for example - networktransformers should be considered. In large cities, whereload densities are very high, utility companies may chooseto supply power through network transformers. If so,these systems should be utility owned and maintained.


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Double-ended Substations. If reliability is critical andspot networks cannot be provided by the utility, double-ended substations should be used. Transformers may beequipped with fans to increase the rated capacity. Thesum of the estimated demand load of both ends of thesubstation must not exceed the rating of either trans-former, and it must not exceed the fan cooling rating. Alldouble-ended substations should be equipped with twosecondary main breakers and one tie breaker set up foropen transition automatic transfer.

TransformersSubstation transformers must be dry-type with epoxyresin cast coils or silica oil filled type. Liquid filledtransformers may be used outdoors. Substations shouldbe located at least 30 m (100 feet) from communicationsframe equipment to avoid radio frequency interference.Provide lightning arrestors on the primary side of alltransformers. Consider surge suppression on thesecondary and/or downstream busses.

Transformers located in underground vaults must not bepositioned directly adjacent to or beneath an exit way.

Where silica oil filled transformers are used, the designmust comply with all spillage containment and electricalcode requirements.

6.10 Secondary Distribution

Main Switchboards. 208V and/or 480V serviceswitchboards as well as substation secondary switchboardsshould be provided with a single main service disconnectdevice. This main device should be molded case, insulatedcase, power air circuit breaker or fusible switch (whereappropriate) individually mounted, draw-out type (asapplicable). Insulated case and power air circuit breakersshould be electrically operated.

The meter section should contain a voltmeter, ammeterand watt-hour meter with demand register. Meters shouldbe pulse type for connection to the BAS. Providing apower monitoring and management system is anacceptable option.

Feeder devices of switchboards 2,000 AMPS and largershould be molded case, insulated case, power air circuitbreakers or fusible switches where appropriate,individually mounted, draw-out type as applicable andelectrically operated. Feeder devices of switchboardsbelow 2,000 AMPS may be group-mounted, molded casecircuit breakers or fusible switches.

Switchboards should be front and rear accessible. Insmaller switchboards, front access only is acceptable ifspace is limited.

Grounding. All grounding systems must be carefullycoordinated, especially in regard to: NEC groundingelectrode systems; lightning protection; communicationsgrounding; and computer room signal reference guide.Power distribution system grounding must be in accor-dance with the National Electrical Code. Also referencegeneral design criteria (this chapter) for equipmentgrounding conductor. Grounding for communications


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systems must follow the requirements in EIA/TIAStandard 607: Commercial Building Grounding (Earthing)And Bonding Requirements For Telecommunications (andrelated bulletins).

Ground Sources. The ground source for the electricalpower system must have a maximum resistance to groundof 5 ohms, except in small buildings i.e. less than 5000 m2

(50,000 square feet) that have only minimal communi-cations systems. Grounding systems for these buildingsmay have a resistance up to 10 ohms. The groundingdesign must be based on a soils resistivity test and groundresistivity calculations. Below-grade connections shouldbe exothermically welded.

A wall-mounted, 6 mm by 50 mm (0.25-inch by 2-inch)copper ground bus should be provided in each electricalroom. The ground bus should be located in the rear accessaisle of the room and should extend at least 1 m (3 feet).It should be interconnected with the ground electrode andground bus in the switchgear or switchboard.

Isolated Grounding Panels. Provide separate panels forcomputer loads to separate from general electrical loads inlieu of an IG system which is more complex and prone tomis-wiring.

Submetering. Electric power meters must be provided onthe services to all spaces planned to be outleased, to allcomputer rooms and to the parking garage, if any.

Power Factor Correction. If the utility rate structure has apower factor penalty, non-PCB centralized automaticpower factor capacitors should be connected at the mainelectrical service on the load side of the utility metering.Power factor capacitors should be designed toautomatically correct a lagging power factor to a valuethat will avoid penalty charges. Switching circuits should

be specifically designed to prevent electrical noise fromentering the electrical power distribution system.

Motor Control Centers. Grouped motor controls shouldbe used where more than six starters are required in anequipment room. Motor control center constructionshould be NEMA Class I, Type B with magnetic (or solidstate if appropriate) starters and either circuit breakers orfuses. Minimum starter size should be size 1 in motorcontrol centers. Each starter should have three overloadrelays. Control circuit voltage should be 120V connectedahead of each starter via control transformer as required.

Reduced voltage starters may be used for larger motors toreduce starting KVA.

In the design of motor control centers on emergencypower, time delay relays should be considered to reducestarting KVA on the generator.

Elevator Power. Elevators should be powered from ashunt trip circuit breaker located in the elevator machinerooms. Electrical design standards in elevator standardANSI/ASME A17.1 must be followed.

Secondary Distribution SystemsSecondary electrical power distribution systems in Federalbuildings are classified as normal, emergency anduninterruptible. Normal power serves the general powerand lighting loads in the building. Emergency power isdistributed to life safety and critical loads. Uninterruptiblepower is required for critical loads, which cannot beinterrupted.

In typical GSA office buildings it is recommended that208/120V normal power be subdivided to isolate the officeelectronic equipment load. Figure 6-2 shows a typicalpower distribution scheme.


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NORMAL SERVICE GENERATOR

ATS

EMERGENCY SYSTEMNORMAL SYSTEM

ISOLATIONTRANSFORMER

UPS

PDU

CRITICALTECHNICAL

SYSTEM

EMERGENCYSYSTEM

ELECTRONICEQUIPMENT

SYSTEM

NORMALSYSTEM

NORMAL SYSTEM

Figure 6.2 Typical Power Distribution Scheme


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Bus Duct. Where plug-in bus duct is used, it should havean integral ground bus, sized at 50 percent of the phasebus to serve as the equipment grounding conductor.

Conductors. Aluminum or copper conductors areacceptable for motor windings, transformer windings,switchgear bussing, switchboard bussing and bus duct,where the conductor is purchased as part of theequipment. Aluminum conductors shall not be used forprimary feeders, branch feeding or branch circuits.

Power Distribution Panels. In general, circuit breakertype panels will be the standard of construction forfederal buildings. With the exception of lighting andreceptacle panel boards, fusible switches may beconsidered if specific design considerations warrant theirapplication, such as in electrical coordination of electricalover-current devices.

Lighting and Receptacle Panelboards. Lighting andreceptacle panelboards shall be circuit breaker type.Provide minimum 30 poles for 100 amps panelboards andminimum 42 poles for 225 amp panelboards.

Lighting panelboards shall have minimum of three 20-amp 1-pole spare circuit breakers.

Receptacle panelboards should have minimum of six 20-amp 1-pole spare circuit breakers. For initial planningpurposes, the number of receptacle circuits may beestimated by assuming 19 m2 (200 square feet) per circuit.

All panelboards must be located in closets. Incircumstances where horizontal runs would becomeexcessive and another riser is not warranted, shallowclosets, at least 600 mm (24inches) deep, may be used foradditional panelboards.

Panelboards Serving Electronic Equipment. Electronicequipment panelboards serving personal computers,computer terminals or dedicated work stations shouldhave an isolated ground bus. The service to the electronicpanelboard should be supplied from an isolationtransformer. Consideration shall be given to providingequipment with 200 percent neutrals. For initial planningpurposes, the number of receptacle circuits may beestimated by assuming 19 m2 (200 square feet) percircuit.

Feeders and branch circuits serving electronic load panelsshould be provided with isolated ground conductors.


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Number of Receptacles. For initial planning purposes,assume that office space uses systems furniture with adensity of two work stations for every 9 m2 (100 squarefeet). Electrical systems should be designed to allow twoduplex outlets for electronic equipment power and twoduplex outlets for normal power per work station.

Conference Rooms. Conference rooms shall be served inthe same fashion as general office space.

Maintenance Shops. Maintenance shops require plugmoldstrips above work benches with outlets 450 mm (18inches) on center.

Electrical and Communications Closets. Electrical closetsrequire one emergency power receptacle that is identifiedas Emergency Power at the receptacle. The communi-cations closet will contain power and grounding for thepassive and active devices used for the telecommuni-cations system, including at least two dedicated 20A, 120Volt duplex electrical outlets on emergency power, andadditional convenience outlets at 1.8m (6 foot) intervalsaround the walls and direct connection to the mainbuilding grounding system. If uninterruptible power isrequired in communications closets, it will be furnished aspart of the communications system.

Main Mechanical and Electrical Rooms. Mainmechanical and electrical equipment rooms shall eachhave one emergency power receptacle that is identified as Emergency Power at the receptacle.

Exterior Mechanical Equipment. Provide one receptacleadjacent to mechanical equipment exterior to thebuilding.

Toilet Rooms. Each toilet room shall have at least one GFIreceptacle at the vanity or sink.

6.11 Wiring Devices

In GSA buildings, general wiring devices must bespecification grade. Emergency receptacles must be red.Isolated grounding receptacles must be orange. Specialpurpose receptacles must be brown. The color of standardreceptacles and switches should be coordinated with thearchitectural color scheme; for example, white, not ivory,devices should be used if walls are white or light gray.

Building standard receptacle must be duplex, specificationgrade NEMA 5-20R. Special purpose receptacles shouldbe provided as required. Device plates should be plastic,colored to match the receptacles.

Placement of ReceptaclesCorridors. Receptacles in corridors shall be located 15 m(50 feet) on center and 7.5 m (25 feet) from corridorends.

Office Space. Receptacles for housekeeping shall be placedin exterior walls and walls around permanent cores orcorridors. Except for these, placement of receptacles inwalls should be avoided to the maximum extent possible.See Chapter 3: Architectural and Interior Design, BuildingPlanning, Planning Module, Floor-to-Floor Heights andVertical Building Zoning, and Space Planning, Office Space,Utility Placement.

Raised Access Floor. All wiring beneath a raised accessfloor shall be routed in metal rigid or flexible conduit to underfloor distribution boxes. One distribution box per bay is recommended (see section Placing ElectricalSystems in Buildings, Horizontal Distribution of Power andCommunications). Flush-mounted access floor serviceboxes should be attached to the underfloor distributionboxes by means of a plug-in modular wiring system tofacilitate easy relocation.


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When installed at high altitudes or in higher-than-ratedambient temperatures, the unit must be derated inaccordance with manufacturers’ recommendations.Operation of starting batteries and battery chargers mustalso be considered in sizing calculations. In humidlocations heaters can reduce moisture collection in thegenerator windings. Silencers are required for allgenerators. Acoustical treatment of the generator roomshall be provided if necessary.

Generators should be located at least 30 m (100 feet) fromcommunications frame equipment to avoid radiofrequency interference. See Chapter 3: Architectural andInterior Design, Space Planning, Building Support Spaces,Mechanical and Electrical Rooms, Emergency GeneratorRooms for additional generator room requirements.

Radiators should be unit-mounted if possible. Ifventilation is restricted in indoor applications, remoteinstallation is acceptable. Heat recovery and load sheddingshould not be considered.

Capacity. The engine generator should be sized toapproximately 110 percent of design load; ideally it shouldrun at 50 percent to 80 percent of its rated capacity afterthe effect of the inrush current declines. When sizing thegenerator, consider the inrush current of the motors thatare automatically started simultaneously. The initialvoltage drop on generator output due to starting currentsof loads must not exceed 15 percent.

6.12 Emergency Power Systems

All facilities must have an emergency power system for life safety as required by code. It must be designed inaccordance with NFPA 110, Emergency and Standby PowerSystems. See Chapter 7: Fire Protection Engineering foradditional requirements.

BatteriesSelf contained battery units may be used for individuallight fixtures in buildings where an emergency generatoris not required for other systems.

Fire alarm and security systems must be provided withtheir own battery back-up.

Generator SystemsThe system should consist of a central engine generatorand a separate distribution system with automatic transferswitch(es), distribution panels, and 480/277V lightingpanel (if applicable) with dry-type transformers feeding208/120V panels as required.

Service Conditions. If the unit is to be installed outdoors,it should be provided with a suitable enclosure and haveprovisions to ensure reliable starting in cold weather.Starting aids such as jacket-water heaters can be specifiedto improve reliable starting capability in cold weather.


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Emergency Power Loads. Emergency power should beprovided for the following functions:

• Egress and exit lighting.• Fire alarm system.• Generator auxiliaries.• Smoke control systems (if required by code)1.• Fire pump.• Lighting2.• Telephone switch.• Security systems.• Mechanical control systems.• Building Automation System (BAS).• Elevators (one per bank)1.• Sump pumps.• Sewage ejector pumps.• Exhaust fans removing toxic, explosive or flammable

fumes.• Uninterruptible power systems serving computer rooms1.• Air conditioning systems for computer and UPS rooms1.• Exhaust fan in UPS battery rooms.• Power and lighting for Fire Control Center and Security

Control Center.• Lighting for main electrical room, electrical closets, and

communications closets.• Air conditioning systems for communications closets.• Emergency power receptacles.• Horizontal sliding doors.• Other associated equipment designated by code.

Notes:1 Evaluate on a case by case basis.2 As noted in the Section: Lighting Criteria for Building Spaces

of this chapter.

Distribution System. The distribution system should bedesigned so that emergency and auxiliary power sourcescannot backfeed energy into the de-energized normalvoltage systems under normal, emergency or failureconditions.

Generator Derangement Alarms. Generator derangementalarms must be provided in the generator room. Allmalfunctions should be transmitted to the BAS. Inbuildings without BAS, a generator alarm annunciatorshould be located within the Fire Command Center.

Automatic Transfer Switches. Automatic transferswitches serving motor loads should be dual motor-operated (adjustable time delay neutral position) or havein-phase monitor (transfer when normal and emergencyvoltages are in phase) to reduce possible motor damagecaused by out-of-phase transfer. They may also have pre-transfer contacts to signal time delay relays in theemergency motor control centers.

In order to reduce possible nuisance tripping of groundfault relays, automatic transfer switches serving 3-phase,4-wire loads should have 4-pole contacts with anoverlapping neutral.

Automatic transfer switches should include a bypassisolation switch that allows manual bypass of the normalor emergency source to insure continued power toemergency circuits in the event of a switch failure orrequired maintenance.

Load Bank. Generally, generators should be run with theactual load connected. In selected applications wherecritical loads cannot tolerate a momentary outage, loadbanks may be considered.

Paralleling. For computer centers and other criticalfacilities, generator paralleling should be considered.

Fuel Distribution System. See Chapter 5: MechanicalEngineering, Heating Systems, Boilers and Heat Exchangers,for information on fuel oil piping and underground fueloil tanks.


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Emergency Electrical Power Source Requirements. Whenthe UPS is running on emergency power, the current torecharge the UPS batteries should be limited. This limitedbattery charging load should be added when sizing theemergency generator.

If the UPS system is backed up by a generator to providefor continuous operation, then the generator must alsoprovide power to all necessary auxiliary equipment, i.e.,the lighting, ventilation, and air conditioning supplyingthe UPS and serving the critical technical area.

System Status and Control Panel. The UPS shouldinclude all instruments and controls for proper systemoperation. The system status panel should have anappropriate audio/visual alarm to alert operators ofpotential problems. It should include the followingmonitoring and alarm functions: system on, systembypassed, system fault, out of phase utility fault, closedgenerator circuit breaker. It should have an audible alarmand alarm silencer button. Since UPS equipment roomsare usually unattended, an additional remote system statuspanel must be provided in the space served by the UPS.The alarms should also be transmitted to the BAS.

UPS and Battery Room Requirements. Provide emer-gency lighting in both spaces. Provide a telephone in oradjacent to the UPS room. Battery room design mustaccommodate: proper ventilation; hydrogen detection,spill containment; working clearances. See Chapter 3:Architectural and Interior Design, Space Planning, Spacesfor Uninterruptible Power Systems (UPS) and Batteriesfor additional requirements for UPS and battery room.See NEC and Chapter 7: Fire Protection Engineering foradditional requirements.

6.13 Uninterruptible Power Systems

In some facilities computer room back-up systems may be designed by the tenant agency. If this is the case, shellspace and utility rough-ins should be provided. In facil-ities where uninterruptible power supply (UPS) systemsare to be provided as part of the building construction,they should be designed as described in this section. AllUPS systems are considered to be above standard for GSA space. Tenant agencies with UPS requirements areadvised that a maintenance contract is recommended.

Requirements for UPS systems must be evaluated on acase by case basis. If UPS is required, it may or may notrequire generator back-up. When generator back-up isunnecessary, sufficient battery capacity should beprovided to allow for an orderly shut-down.

Electrical Service Size. A UPS system should be sizedwith 25 percent spare capacity.

Critical Technical Loads. The nature, size, and locationsof critical loads to be supplied by the UPS will be pro-vided in the program. The UPS system should servecritical loads only. Non-critical loads should be served by separate distribution systems supplied from either thenormal or electronic distribution system. Section SiteDistribution, Secondary Distribution, Secondary Distribu-tion Systems Figure 6-2 of this chapter shows the integra-tion of UPS into the building power distribution system.


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6.14 Computer Center Power Distribution

In some GSA buildings the power distribution system forcomputer centers will be designed by the tenant agency.In that case utility rough-in should be provided under theconstruction contract. If distribution is to be providedunder the building contract, it should be designed accord-ing to the criteria in this section.

Power Distribution Units (PDU’s). PDU’s with internalor remote isolation transformers and output panelboardsshould be provided in all computer centers.

Non-linear Loads. Non-linear loads generate harmoniccurrents that are reflected into the neutral service con-ductors. Engineers should exercise caution when design-ing circuits and selecting equipment to serve non-linearloads, such as automated data processing equipment incomputer centers. It is recommended to size neutrals attwice the size of the phase conductor. PDU’s with internalor remote isolation transformers should also be deratedfor non-linear loads. The transformer rating must take theincreased neutral size into account.

Computer Center Grounding. To prevent electrical noisefrom affecting computer system operation, a low-frequency power system grounding and a high-frequencysignal reference grounding system should be provided.The design of the computer room grounding systemshould be discussed with the computer center staff.

Low Frequency Power System Grounding. The primaryconcern is to provide a safe, low-frequency, single pointgrounding system which complies with Article 250 of the

National Electrical Code. The single point ground must be established to ground the isolation transformer or itsassociated main service distribution panel.

A grounding conductor should be run from the PDUisolation transformer to the nearest effective earthgrounding electrode as defined in the NEC. All circuitsserving Automated Data Processing (ADP) equipmentfrom a PDU should have grounding conductors equal insize to the phase conductors.

High Frequency Power System Grounding. In additionto the low frequency power system grounding, a highfrequency signal reference grounding system for radiofrequency noise is required (with the two systems bondedtogether at one point). A grid made up of 600 mm (2foot) squares will provide an effective signal referencegrounding system. The raised floor grid may be used if ithas mechanically bolted stringers. Alternatively a grid canbe constructed by laying a 600 mm mesh (2-foot squares)of braided copper strap or 1.3 mm (16 gauge, 0.051 inch)by 50 mm (2-inch) copper strip directly on the structuralfloor below the raised access floor. Data processingequipment should be connected to the reference grid bythe most direct route with a braided copper strap.

Common Mode Noise Reduction. The reduction ofcommon mode noise is particularly important for theproper operation of computer-based, distributedmicroprocessor-based systems, i.e., building automationsystems, electronic security systems, card access controlsystems, and local area networks.

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• Provide isolation transformers, electronic power distri-bution panelboards or power conditioners to servecritical electronics equipment loads.

• Provide isolated grounding service on dedicatedcircuits to critical data terminating or communicatingequipment.

• Replace metallic data and signal conductors with fiberoptic cables where practical.

The following guidelines should be considered to reducecommon mode noise:

• Avoid running unshielded metallic signal or data linesparallel to power feeders.

• Where metallic signal or data lines must be routed innoise prone environments, use shielded cables orinstall wiring in ferrous metal conduit or enclosed cabletrays.

• Locate metallic signal or data lines and equipment at asafe distance from arc- producing equipment such asline voltage regulators, transformers, battery chargers,motors, generators, and switching devices.


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Light Sources. Generally, interior lighting should befluorescent. Downlights should be compact fluorescent;high bay lighting should be high intensity discharge(HID) type. HID can also be an appropriate source forindirect lighting of high spaces. However, it should not beused in spaces where instantaneous control is important,such as conference rooms, auditoria or courtrooms.

Dimming can be accomplished with incandescent,fluorescent or HID fixtures, although HID and fluorescentdimmers should not be used where harmonics constitutea problem. Incandescent lighting should be usedsparingly. It is appropriate where special architecturaleffects are desired.

General Lighting Fixture CriteriaLighting Fixture Features. Lighting fixtures andassociated fittings should always be of standardcommercial design. Custom-designed fixtures should beavoided. They may only be used with express approvalfrom GSA in cases where available standard units cannotfulfill the required function.

Offices and other areas using personal computers or otherVDT systems should use indirect or deep-cell parabolicceiling fixtures. If acrylic lenses or diffusers are used, theyshould be non-combustible.

Baseline Building Fixture. The fixture to be used forbaseline cost comparisons for office space is a 600 mm (2-foot) by 1200 mm (4-foot) 3 lamp fixture utilizing T-8or CFL lamps and electronic ballasts, deep cell parabolicdiffuser, and white enamel reflector.

The number of fixture types and lamp types in thebuilding must be minimized.

6.15 Lighting

Lighting should be designed to enhance both the overallbuilding architecture as well as the effect of individualspaces within the building.

Interior LightingConsideration should be given to the options offered bydirect lighting, indirect lighting, downlighting, uplightingand lighting from wall- or floor-mounted fixtures.

Illumination Levels. For lighting levels for interior spacessee the values indicated in Table 6-3. For those areas notlisted in the table, the IES Lighting Handbook may be usedas a guide.

In office areas with system furniture, assume thatundercabinet task lighting is used and provide generalillumination of about 300 Lux (30 footcandles) on thework surface. Ceiling lighting branch circuit capacity,however, should be sufficient to provide levels in Table 6-3for occupancy changes.

Energy Efficient Design. Lighting design must complywith ASHRAE/IES 90.1 as modified by Table 6-4. Powerallowances for normal system receptacles include tasklighting as shown in Table 6-1. Lighting calculationsshould show the effect of both general and task lightingassuming that task lighting where it is used has compactfluorescent tubes.

Accessibility for Servicing. Careful consideration must betaken in the design of lighting systems regarding servicingof the fixtures and replacement of tubes or bulbs. Thisissue needs to be discussed with building operation staffto determine the dimensional limits of servicingequipment.


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Table 6-3Interior Illumination Levels (Average)Area Nominal Illumination Level in

Lumens/Square Meter (lux)

Office SpaceNormal work station space, open or closed offices1 500ADP Areas 500Conference Rooms 300Training Rooms 500Internal Corridors 200Auditoria 150-200Public AreasEntrance Lobbies, Atria 200Elevator Lobbies, Public Corridors 200Ped. Tunnels and Bridges 200Stairwells 200

Support SpacesToilets 200Staff Locker Rooms 200Storage Rooms, Janitors’ Closets 200Electrical Rooms, Generator Rooms 200Mechanical Rooms 200Communications Rooms 200Maintenance Shops 200Loading Docks 200Trash Rooms 200

Specialty AreasDining Areas 150-200Kitchens 500Outleased Space 500Physical Fitness Space 500Child Care Centers 500Structured Parking, General Space 50Structured Parking, Intersections 100Structured Parking, Entrances 500

1 Level assumes a combination of task and ceiling lighting where systems furniture is used. (This may include a combination ofdirect/indirect fixtures at the ceiling for ambient lighting.)

NOTE: To determine footcandles (fc), divide lux amount by 11.



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Table 6-4System Performance Unit Lighting Power AllowanceCommon Activity Areas

UPD UPDArea/Activity W/m2 Wft2 Note

Auditoriums 15.0 1.4 cCorridor 8.6 0.8 aClassroom/Lecture Hall 19.4 1.8Elect/Mech Equipment Room

General 7.5 0.7 aControl Rooms 16.1 1.5 a

Food ServiceFast Food/Cafeteria 8.6 0.8Leisure Dining 15.0 1.4 bBar/Lounge 14.0 1.3 bKitchen 15.0 1.4

Recreation/Lounge 5.4 0.5Stairs

Active Traffic 6.5 0.6Emergency Exit 4.3 0.4

Toilet & Washroom 5.4 0.5Garage

Auto & Pedestrian Circulation 2.7 0.25Parking Area 2.1 0.2

Laboratories 23.7 2.2Library

Audio Visual 11.8 1.1Stack Area 16.1 1.5Card File & Cataloging 8.6 0.8Reading Area 10.7 1.0

Lobby (General)Reception & Waiting 5.9 0.55Elevator Lobbies 4.3 0.4

Atrium (Multi-Story)First 3 Floors 4.3 0.4Each Additional Floor 1.6 0.15

Locker Room & Shower 6.5 0.6



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UPD UPDArea/Activity W/m2 Wft2 Note

OfficeEnclosed offices of less than 900 ft2 and all open plan officeswithout partitions or with partitions lower than 4.5 ft.below ceiling

Reading, Typing and Filing 14.0 1.3 dDrafting 23.6 2.2 dAccounting 19.4 1.8 d

Open plan offices, 900ft2 or larger, with medium partitions 3.5 to 4.5 ft. below ceiling

Reading, Typing and Filing 16.1 1.5 aDrafting 28.0 2.6 aAccounting 22.6 2.1 a

Open plan offices, 900ft2 or larger, with large partitions higher than 3.5 ft. below ceiling

Reading, Typing and Filing 18.3 1.7 aDrafting 32.3 3.0 aAccounting 25.8 2.4 a

Common Activity AreasConference/Meeting Room 14.0 1.3 cComputer/Office Equipment 22.6 2.1Filing, Inactive 10.7 1.0Mail Room 19.4 1.8

Shop (Non-Industrial)Machinery 26.9 2.5Electrical/Electronic 26.9 2.5Painting 17.2 1.6Carpentry 24.7 2.3Welding 12.9 1.2

Storage and WarehouseInactive Storage 2.1 0.2Active Storage, Bulky 3.2 0.3Active Storage, Fine 9.7 0.9Material Handling 10.7 1.0

Unlisted Spaces 2.1 0.2

Notes:a Area factor of 1.0 shall be used for these spaces.b Base UPD includes lighting required for clean-up purpose.c A 1.5 adjustment factor is applicable for multi-function spaces.d Minimum of 90% of all work stations shall be enclosed with partitions of the height prescribed.



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Fixture Ballasts. Ballasts should have a sound rating of “A” for 430 MA lamps, “B” for 800 MA lamps and “C”for 1500 MA lamps. Electronic ballasts should be usedwherever possible.

Exit Signs. Exit signs shall be of the LED type, have anEnergyStar rating, and meet the requirements of NFPA 101.

Lighting Criteria for Building SpacesOffice Lighting. Office lighting is generally fluorescentlighting. A lighting layout with a fairly even level ofgeneral illumination is desirable. Modular (plug-in)wiring for fluorescent lighting fixtures should be used foroffice areas to facilitate changes. In open office areas withsystems furniture partitions, the coefficient of utilizationmust be reduced to account for the light obstruction andabsorption of the partitions.

Design for glare, contrast, visual comfort and colorrendering and correction must be in compliance withrecommendations contained in the IlluminatingEngineering Society of North America (IES) LightingHandbook.

Task lighting will be used in situations, such as areas ofsystems furniture, where the general lighting level wouldbe insufficient for the specific functions required.

ADP Areas. Generally, ADP areas should have the samelighting as offices. If the area contains special workstations for computer graphics, dimmable fluorescentlighting may be required. If a large ADP area is segregatedinto areas of high and low personnel activity, switchingdesign should provide for separate control of lights inhigh- and low-activity areas of the space.

Conference Rooms and Training Rooms. These spacesshould have a combination of fluorescent and dimmableincandescent lighting.

Lobbies, Atria, Tunnels and Public CorridorsSpecial lighting design concepts are encouraged in thesespaces. The lighting design should be an integral part ofthe architecture. Wall fixtures or combination wall andceiling fixtures may be considered in corridors andtunnels to help break the monotony of a long, plain space.As stated previously, careful consideration must be takenin the design of lighting systems regarding servicing offixtures and replacement of lamps.

Mechanical and Electrical SpacesLighting in equipment rooms or closets needs to beprovided by industrial-type fluorescent fixtures. Careshould be taken to locate light fixtures so that lighting isnot obstructed by tall or suspended pieces of equipment.

Dining Areas and ServeriesAmple daylight is the illumination of choice in diningareas, assisted by fluorescent fixtures. Limited compactfluorescent lighting for accents is acceptable if comparablearchitectural effect to incandescent lighting can beachieved.

Character-Defining Spaces in Historic Structures.Spaces that contribute to the character of a historic struc-ture, as identified the HBPP, should be lighted in a man-ner that enhances their historic and architectural character.Maintenance and rehabilitation of historic lightingfixtures should be considered, and may be required in theHBPP. Care should be taken to avoid placing fixtures,switches, conduit, or other electrical facilities throughcharacter-defining architectural elements.

Structured Parking. Fixtures for parking areas may befluorescent strip fixtures with wire guards or diffusers.Care must be taken in locating fixtures to maintain therequired vehicle clearance. Enclosed fluorescent or HIDfixtures should be considered for above-grade parkingstructures.



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High Bay Lighting. Lighting in shop, supply, or ware-house areas with ceilings above 4900 mm (16 feet) shouldbe color-improved high-pressure sodium. In areas wherecolor rendition is known to be of particular importance,metal halide should be used.

Supplemental Emergency Lighting. Partial emergencypowered lighting must also be provided in main mech-anical, electrical and communications equipment rooms;UPS, battery and ADP rooms; security control centers;fire command centers; the room where the BuildingAutomation System is located; adjacent to exits; and stair-wells. Where CCTV cameras are used for security systems,emergency lighting should be provided at the task area.

Lighting ControlsAll lighting must be provided with manual, automatic, orprogrammable microprocessor lighting controls. Theapplication of these controls and the controlled zones willdepend on a number of space factors: frequency of use,available daylighting, normal and extended work hoursand the use of open or closed office plans. All of thesefactors must be considered when establishing zones, zonecontrols and appropriate lighting control.

Lighting Configuration Benefits. An appropriate lightingconfiguration can benefit the Government; it reducesoperating costs by permitting limited operation afterworking hours, takes advantage of natural light during thedaytime working hours and facilitates the subdivision ofspaces.

Enclosed Space Lighting Controls. Enclosed spacelighting controls may include switches, occupancy sensors,daylight sensors, light level sensors or micro-processors.The lights can be zoned by space or multiple spaces. Ifmicroprocessor controls are used to turn off the lights, alocal means of override should be provided in every officeto continue operations when required.

The following design guidance is provided for enclosedareas:

• Photoelectric sensors that reduce lighting levels inresponse to daylighting are recommended for smallclosed spaces with glazing.

• Occupancy sensors should be considered for smallclosed spaces without glazing.

• Microprocessor control, programmable controller orcentral computer control are recommended for multipleclosed spaces or large zones.

• Touchtone telephone or manual override controlsshould be provided if microprocessor, programmablecontroller or central computer control is provided.

Open Space Lighting Controls. Open space lightingcontrols may include switches, light level sensors forspaces adjacent to glazing and microprocessor controls for zones within the space. If microprocessor controls areused to turn off the lights, a local means of overrideshould be provided to continue operations when required.

Large open space should be subdivided into zones ofapproximately 100 m2 (1,000 square feet) or one bay. Thefollowing guidelines are provided for open plan spaces:

• Controls should be located on core area walls, onpermanent corridor walls or on columns

• Remote control schemes and reductions from aprogrammable controller, microprocessor, and/orcentral computer should be considered.

Occupancy Sensor Lighting Controls. Infrared,ultrasonic, or passive dual sensors should be consideredfor small, enclosed office spaces, corridors (if adequatelighting is provided by emergency system) and toilet areas.Each occupancy sensor should control no more than oneenclosed space/area. Each occupancy sensor should bemarked by a label identifying the panel and circuit

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number. Occupancy sensors should not be used in openoffice areas or spaces housing heat producing equipment.

Ambient Light Sensor Controls. Photoelectric sensorsshould be considered for fixtures adjacent to glazed areasand for parking structures.

Exterior LightingExterior luminaires must comply with local zoning laws.Lighting levels for exterior spaces should be the valuesindicated by the IES Lighting Handbook. Flood lightingshould only be provided if specified in the building pro-gram. Exterior lighting of a historic structure should bedesigned to blend with and support the new architecturalcharacteristics that contribute to the structure’s character.

Parking and Roadway Lighting. Parking and roadwaylighting should be an HID source and should not exceed a10 to 1 maximum to minimum ratio and a 4 to 1 averageto minimum ratio.

Parking lots should be designed with high-efficiency, pole-mounted luminaires. High- pressure sodium lamps arepreferred but consideration should be given to existingsite illumination and the local environment. Emergencypower is not required for parking lot lighting.

Entrances. Lighting fixtures should be provided at allentrances and exits of major buildings. These exteriorlighting fixtures shall be connected to the emergencylighting circuit.

Loading Docks. Exterior door lighting should be providedat loading docks. Fixtures for illumination of the interiorof trailers should be provided at each truck position.

Controls. Exterior lighting circuits should be controlledby photocell and a time clock controller to include bothall-night and part-night lighting circuits.


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commercial switch of the type designated by FTS. Theroom should be shielded from radio and noise inter-ferences. (See Chapter 3: Architectural and Interior Design,Space Planning, Mechanical and Electrical Rooms foradditional information on frame room requirements.)

Communications Closets. Communications closets shall meet the requirements of EIA/TIA Standard 607:Commercial Building Grounding (Earthing) And BondingRequirements For Telecommunications (and relatedbulletins). See Chapter 3: Architectural and Interior Design,Communications Closets for additional information oncommunications closets. Communications and electri-cal closets should be located adjacent to each other.Communications closets must be stacked vertically.Communications closets should be sized to accommo-date telephone terminal boards and broadband andnarrowband data communications equipment, includingcross-connects, lightwave terminal cabinets, andequipment racks with patch panels and concentrators.Telecommunications closets will contain the mechanicalterminations for that portion of the horizontal wiringsystem and portion of the backbone wiring system for thebuilding area served by the closet. It may also contain themain or intermediate cross-connect for the backbonewiring system. The telecommunications closet may alsoprovide the demarcation point or interbuilding entrancefacility. Closets will have the capability for continuousHVAC service, and be equipped with fire protection perChapter 7: Fire Protection Engineering.

6.16 Raceway System for Communications

Communications systems for all GSA buildings will meetthe requirements of EIA/TIA Standard 569: CommercialBuilding Standard For Telecommunications Pathways AndSpaces (and related bulletins). Communications systemsfor all GSA buildings will be designed by FTS andinstalled by FTS or the tenant. Only the raceway system ispart of the building design and construction. It consists ofmanholes, ductbanks, entrance rooms and vaults,communications equipment room(s), closets, and thesleeves, ducts, conduits, raceways and outlets thatcomprise the horizontal pathways, backbone pathwaysand workstation outlets of the technology infrastructure.

Bonding for communication system must comply with EIA/TIA Standard 607: Commercial BuildingGrounding (Earthing) And Bonding Requirements ForTelecommunications (and related bulletins).

Since FTS will manage the design of the communicationssystems, all criteria for routing and types of racewaysmust be obtained from FTS.

Communications Equipment or Frame Room. Acommunications equipment or frame room should beprovided in every building. It must be sized to accommo-date voice and data distribution and transmissionequipment and support equipment with adequateequipment access clearances. FTS will provide detailedinformation on the communications equipment. A 5 ohm(maximum) signal ground and an emergency powerreceptacle should be provided in the room. The electricalservice should be sized to accommodate the largest


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Communications RacewaysRaised Access Floor. The standard option for deliveringcommunications services in Federal buildings is by layingthe cable in a tray for main runs and then branchingdirectly on the floor slab below the raised access flooringsystem.

Above Ceiling Delivery. Communications distribution inceilings should be avoided and only used where no otheralternative exists. Where necessary, communicationscabling above ceilings must be run in cable tray and/orconduit.

Administration of Communications Infrastructure.Long-term use of the communications infrastructurerequires administration of the systems including placingidentification on all elements, keeping records anddrawings on all elements, and task order information onwork performed on all infrastructure elements. Theadministration system must maintain information onhorizontal and backbone pathways, equipment rooms andcloset spaces, cables, termination hardware, terminationpositions, splices, grounding system and bondingconductors. The information should be compatible withother building management and facility maintenancesystems employed at the site.

6.17 Layout of Main Electrical Rooms

Separate electrical rooms may be provided for mediumvoltage and low voltage switchgear assemblies.

Vertical Clearances. Main electrical equipment roomsgenerally should have a clear height to the underside ofthe structure for compliance with requirements of theNEC. Where maintenance or equipment replacementrequires the lifting of heavy parts, hoists should beinstalled.

Horizontal Clearances. Electrical equipment roomsshould be planned with clear circulation aisles andadequate access to all equipment. Layout should be neat,and the equipment rooms should be easy to clean.Horizontal clearances should comply with requirementsset forth by the NEC.

Lighting. Lighting in equipment rooms should be laid outso as not to interfere with equipment. Switched emergencylighting must be provided in main electrical rooms.

Housekeeping Pads. Housekeeping pads should be at least75 mm (3 inches) larger than the mounted equipment onall sides.

Posted Instructions. Posted operating instructions arerequired for manually operated electrical systems. Theyshould consist of simplified instructions and diagrams of equipment, controls and operation of the systems,including selector switches, main-tie-main transfers,ATS by-pass, UPS by-pass, etc.

Instructions should be framed and posted adjacent to themajor equipment of the system.


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6.18 Alterations in Existing Buildings and Historic Structures

The goal of GSA’s alteration projects is to approximate as well as possible the facilities standards described in this book for new projects. Renovation designs mustsatisfy the immediate occupancy needs but should alsoanticipate additional future changes. Remodeling shouldmake building systems more flexible.

Alteration projects can occur at three basic scales: refur-bishing of an area within a building, such as a floor or asuite; major renovation of an entire structure; and up-grade/restoration of historic structures.

In the first instance, the aim should be to satisfy the newrequirements within the parameters and constraints ofthe existing systems. The smaller the area in comparisonto the overall building, the less changes to existing systemsshould be attempted.

In the second case, the engineer has the opportunity todesign major upgrades into the electrical and communi-cations systems. The electrical and communications ser-vices can come close to systems that would be designedfor a new building, within the obvious limits of availablephysical space and structural capacity.

Where a historic structure is to be altered, specialdocuments will be provided by GSA to help guide thedesign of the alterations. The most important of these isthe Building Preservation Plan (BPP) which identifieszones of architectural importance, specific character-defining elements that should be preserved, and


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Placing Electrical and Communications Systems in Renovated BuildingsEven more than in new construction, the optimalplacement of engineering systems in the building struc-ture is a crucial element in the success of the alteration.Vertical and horizontal distribution of utilities must beintegrated into the architectural concept from the outset.

Chapter 3: Architectural and Interior Design, Alterations in Existing Buildings and Historic Structures, PlacingMechanical and Electrical Systems in Renovated Buildingsdescribes some of the strategies available for placement of power, lighting and communications systems.

Vertical Distribution. If new risers are required, theyshould preferably be located in or adjacent to existingclosets. Where there is lack of space, communicationsrisers and electrical risers can perhaps be combined.

Horizontal Distribution. Raised access flooring is highlyrecommended for large modernization projects. Most ofthe criteria established for raised flooring earlier in thischapter would apply, except that module sizes may have tobe varied to fit existing conditions.

In buildings where raised access flooring is not feasible,horizontal electrical and communications distributionmay be located in the ceiling. Fortunately, many olderbuildings have high floor-to-floor heights, which permitan expansion of the existing ceiling space. Vertical zoningof this space between various engineering systems iscritical. The zoning should be established according to theprinciples described earlier in this chapter or according toexisting ceiling zones.

standards to be employed. See Chapter 1: GeneralRequirements, Applicability of the Facilities Standards,Types of Facilities, Historic Buildings.

The electrical systems in historic buildings often differgreatly from today’s design and construction standards,and frequently these systems need to be upgradedsubstantially or completely rebuilt or replaced. The endresult should be a building whose lighting and otherelectrical facilities support its modern use while retainingits historic and architectural character. Historic lightfixtures, hardware and other period features should beretained and any supplementation shall be inconspicuousto avoid detracting from existing historic buildingornamental spaces.

The end user requirements are an important part of theprogramming information for alteration projects. Closeinteraction between designers and users is essential duringthe programming and conceptual design phase to meetthe users’ needs without excessive construction costs. Thegeneral policies and standards that an administratorwould give designers are usually not specific enough.

Alteration design requires ingenuity and imagination. It isinherently unsuited to rigid sets of rules. Each case isunique. The paragraphs that follow in this section shouldbe viewed as guidelines and helpful hints to be used whenappropriate and disregarded when not.

See Chapter 3: Architectural and Interior Design,Alterations in Existing Buildings and Historic Structures.



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In buildings with decorative or inaccessible ceilings,electrical raceways for power and communications linescan be located along walls, or be incorporated into thedesign of a molding or a special chase between windowsills and floor. Raceways should have some additionalspace for future changes to the electrical andcommunications systems.

In buildings with fairly close spacing of columns ormasonry walls, it may be possible to locate all receptacles,phone and data outlets in furred wall space. The furringshould be treated as an architectural feature in historicbuildings. If bay sizes are too large for this solution,systems furniture with built-in electrical service is analternative. Power poles are also an option as long as theyare integrated into the architectural design. Poke-throughand flat cable should be avoided.

Building ServiceIf new switchgear is provided, consider sizing it accordingto the loads provided in the section Electrical LoadAnalysis, Table 6-1, of this chapter even if less than theentire building is being remodeled at the time.

Secondary Power DistributionNew panelboards should be added as required with ample spare capacity. See section Electrical Load Analysis,Standards for Sizing Equipment and Systems in thischapter. In both large and small remodeling projects,panelboards serving electronic loads should be servedfrom an isolation transformer and sized withconsideration given to harmonic currents.

Computer Center PowerNon-linear computer loads should be isolated fromnormal power. Ensure that the size of the supplytransformer for non-linear loads is rated and protected onthe basis of input and output current. Provide circuitbreakers with true RMS overload protection on the supplyand load sides of the transformer and increase the size ofthe neutral to twice the size of the phase conductor.

LightingGeneral Renovations. For small remodeling projects,existing lighting systems should be matched foruniformity and ease of maintenance. In total buildingmodernizations, the guidelines established in the sectionLighting of this chapter should be followed.

In structures with ornamental or inaccessible ceilings,indirect lighting offers many possibilities. Fixtures may be located in wall coves or at the top of low columns or partitions.

Historic Structures. In historic buildings, the quality ofthe fixtures and the quality of the light are integral to the architectural integrity of the building. The characterof many old buildings has been compromised by poorlighting designs. Designers are encouraged to seekimaginative solutions to achieve required light outputwhile preserving the essential visual characteristics ofhistoric lighting, such as variable light levels, highlightingof architectural features, light source color, reflectedpatterns, and the surface reflectivity of historic materials.

Many historic buildings have beautiful plaster ceilings that do not permit use of lay-in fixtures. Indirect lightingfrom coves, combined with task lighting, can be a goodalternative. Wall sconces are another alternative, particu-larly in corridors. In public spaces, chandeliers or otherdecorative fixtures may need to be restored or duplicated.

Metzenbaum Courthouse, Cleveland, OH



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These fixtures may be retro-fitted with compactfluorescent lamps, reflectors, and other light sources toincrease light output and energy efficiency. Use of halidelamps as the sole light source in historic fixtures isdiscouraged because of differential color shifting thatoccurs as lamps age.

Reproduction historic lights for significant spaces such ascourtrooms may be fitted with multiple light sources andseparate switches to allow for multiple light levels. Selectlamps providing color rendition as close as possible tothat of original lighting. In historically significant spacesrequiring increased light levels, apply the following orderof preference:

1. Retrofit historic lights with energy efficientballasts/lamps

2. Add discretely designed supplementary lighting,preferably reflected light, to avoid competing withperiod lighting.

In historically significant spaces, supplementing of ceiling-mounted lights with wall mounted sconces, indirect lightsmounted on furniture, or freestanding lamps is preferableto installing additional ceiling mounted fixtures.

The light source is another important concern. Typically,the existing source is incandescent. Where feasible, thelight fixture should be changed to a fluorescent source,with color rendition as close as possible to that of theincandescent light.



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Communications DistributionCommunications systems are specified by the clientagency, and they will, therefore, furnish raceway systemscriteria for alteration projects.

Telephone. Generally, older buildings have telephoneclosets and wiring. For small alterations, the telephonesystem should probably just be extended to meet newrequirements. For major building modernizations, a new distribution system for phone and data should beinstalled, as described in the section Raceway System for Communications of this chapter.

Data. Data wiring is generally non-existent in olderbuildings. A cable tray or raceway system should beincluded in even the smallest projects to facilitatecomputer networking.

In total building renovations, vertical and horizontal dataand telephone distribution should be provided. If there isno existing underfloor system, consider a cable tray loopin the ceiling of the permanent circulation corridors.

Date post:	22-Jan-2017
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