Firefighter'sGuide To · Cable vaults are normally found below-gradeeither as an ... withmanual remote shutdown. Inmanyinstallations, the standby ... (AST) or Underground Fuel Storage

Firefighter's Guide To

Telephone Central Offices

Produced by AT&T CRE National Standards - Fire Protection

and AT&T Global Network Operations

March 25, 2009

Restricted for use by authorized local fire service personnel.

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AT&T FIREFIGHTER'S GUIDE TO TELEPHONE CENTRAL OFFICES

For Fire Service Personnel

1.0 GENERAL

1.1 Telephone central office equipment buildings, or "central offices", areuniquerelative to all othertypes of buildings firefighters may encounter. Thispamphlet, inconjunction with site visitsby fire units, is intended to familiarize first-responder firefighters with the unique features of central office buildings. During the fire fighter'sorientation we will inform you of particular safety aspects,provide informationtoenhance the effectiveness of fire fighting efforts and provide guidance to assist inassurance of continued telecommunications operations of the central office.

1.2 The first unique aspect of fighting a central office fire revolves around the overallpurpose of the building. A central office exists to house the switching equipment thatprovides telecommunications service to the community, region and nation. A smallcentral office will normally have few or no personnel present and various densities ofcommunications equipment in one room or multiple floors. Larger central offices mayhave multiple floors of telecommunications equipment including several DC batteryrooms, various support services and administrative operations. Maintaining operation of

the switching equipment/power supplies and the service it provides is the paramountconcern in any fire fighting effort.

1.3 The construction requirements for central office buildings, given the

aforementioned criticality of maintaining telecommunications service, are necessarily

more stringent than for most other buildings. Basic among these requirements is

construction that meets local code requirements and the stringent fire-resistive

construction practices of the telecommunications industry. Compartmentation is a basic

principal of design providing rooms and floors that are separated by fire resistant walls

and floors including fire rated doors

and dampers. Telecommunications

equipment rooms are separated from

other uses of the building by fire

rated assemblies. Typical ceiling

heights are 14 to 16 feet in height.

Restricted for use by authorized local fire service personnel

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2.0

There mayalso be raised floor areas with in the building.

1.4 In general, the primary hazards on site are AC and DC electrical powerdistribution, DC battery rooms and stand-by generators fueled by diesel. The entrance tothe facility or spaces may be appropriately marked per the National Fire ProtectionAssociation (NFPA 704) signage as required bythe local authority having jurisdiction.With regard to potential exposure to asbestos buildingmaterials and other hazards,central offices are no different from any otherbuilding depending upon the ageof thestructure there will be different construction methods and building configurations.

1.5 Fire fighter access to the building is normally with a key or access card providedin the "LockBox" at the fire department access door of the building. In the event thatemergency access is required, no key/card is availabe, and no one is on site to provideaccess, forcible entry maybe considered.

NETWORK TELECOMMUNICATIONS EQUIPMENT

2.1 Switching Equipment

2.1.1 The telecommunications switching equipment processes all calls andsignals within the local exchange and provides for interconnection to regional,national, and international networks. Equipment is designed with fire resistantcomponents and treatments. This electronic equipment performs signal-

processing operations and paths that include, but are not limited to, switch and


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transport ofaudio, video, cable television, internet, U-Verse, broadband, wireless,and data signals. This equipment typically includes, switch and transport/accessequipment, servers, routers, computers, and cable television equipment thatestablishesany form of one- or two-way communications.

Equipment is typically arranged in rows. Cables are run under floor and overheadin multiple levels of cable trays. Aisle space between rows is nominally 30inches, butmay beas little as24 inches. Rows may have cross-aisles dependingupon room size and exitconfigurations. Theswitching equipment is very criticalfor communications and is needed to function to maintain emergency and life-saving activities suchas E911, fire, EMS, hospital and police emergency services.

In many Central Offices we house other Telephone Companies (known as Co-locators) equipment. This equipment is required to meet all industry fire safetystandards.

2.1.2 Primary Exposures:

Narrow aisle spaces limit a firefighter's visibility and ability to maneuver whilein turnout gear (PPE) and SCBA. Multiple rows of identical equipment maycontribute to disorientation and confusion, especiallywhen dimly lit and smoke-filled. When unoccupied, general lighting is turned off, check at entrance pointsfor lighting switches. Switchingequipment found in central offices originatesfrom a variety of manufacturers who constantlyseek to upgrade their products.Consequently, there is substantial variation in equipment configuration andvintage. Despite this variation, all major equipment is fire resistant and will self-extinguish once an ignition source is removed. Anticipated in this space would bea slowly developing fire producing corrosive vapors with low heat release rates.The equipment is very sensitive to products of combustion, soot, temperature andhumidity.

2.2 Main Distributing Frame (MDF)

2.2.1 The Main Distributing Frame (MDF) is normally located directly abovethe Cable Entrance Facility (See Sect. 2.3), and is a continuous, multi-level wirerack that, in a majority of offices, runs the full length of the building, and isadjacent to an exterior wall. It is the terminal point for the thousands of pairs ofinsulated wires and fiber optics brought into the building through the Cable

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Entrance Facility. Some offices may have a catwalk mezzanine provided for 2-level access to wire terminations.

2.2.2 PrimaryExposure: Thousands of small diameters, plastic insulated wiressplayed horizontallyand vertically throughout the frame may be fire resistant,however will create a smoke

condition.

2.3 Cable Entrance Facility(CEF)

2.3.1 Telecommunications

service is provided by large,underground cables that enter

into the building from the

community through a Cable

Entrance Facility (CEF), also

known as a "cable vault".

Cable vaults are normallyfound below-grade either as an

extension of a basement or as a

specifically constructed space.

Cable vaults typically run

below or beside the full length of the Main Distribution Frame (See Sect. 2.2).

Not all central offices have cable vaults. Smaller buildings may have the CEFlocated on the wall adjacent to the MDF, while larger buildings may have several

that extend outside the building footprint and be multi-level.

2.3.2 It is in the cable vault that the large cables are spliced into smaller cables

that tie into the telecommunications equipment. The cables, which are sheathed ineither lead, polyvinylchloride (PVC), or polyethylene, each contains hundreds and

thousands of pairs of low-voltage, low amperage, insulated signal wires or fiberoptic strands. These cables, regardless of their size, are not power cables and pose

no electrical danger to firefighters. These cables should be considered

combustible and have fire stop materials installed where exiting this fire ratedvault.


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2.3.3 Primary Exposures

Priorto entry into a cable vault, testing shall be conducted for the presence offlammable and combustibles gasses as well as oxygen deficiency unless entrancesignage specifies that the CEF has continoes mechcanical ventilation.

• Unless noted otherwise consider this Confined Space Entry.

• Explosive gasses may seep in from the underground into the vault.

• Highly toxic smoke resulting from burning cable sheathing may bepresent.

• Gravity ventilation is generally provided for this area; however, some

special conditions may warrant the provision of mechanical venting.

2.3.4 One noteworthy threat to a cable vault is flooding. For a number ofreasons, water in great quantities may penetrate into a cable vault threatening thenon-water-resistant splices. Vault flooding could result in major loss of service,and fire departments may be called upon to assist in such an emergency byproviding pumps to remove the water. Drains or sump pumps are normallyprovided.

2.4 Overhead Cable Trays

Switching equipment is interconnected by bundles of nominally inch-thick,polyethylene or PVC sheathed cables. These cables are stacked in abundance on

overhead racks and trays that run vertically and horizontally through the

equipment spaces and to different rooms or floors within the building.

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Over head Telecommunications Cable Tray

2.5 Power Equipment

2.5.1 Telecommunications switching and transmission equipment is primarily

powered by 48 volt DC power. The DC power equipment consists of stationary

lead acid batteries, rectifiers (AC-DC), and associated control panels. Whentelecommunications equipment needs AC power, AC-DC inverters or

Uninterruptible Power Supplies (UPS) may be in use. Battery Distribution Fuse

Bays (BDFB) are also provided within power areas for power distribution to

associated switching and other telecommunications equipment. Power areas may


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be located adjacent to the telecommunications switching equipment, in separaterooms or on different floor levels.

2.5.2 Battery Areas or Rooms

...

The Stationary Lead-Acid batteries are either Flooded (wet cell) Lead Acid and

Flooded Nickel-Cadmium (Ni-Cd) storage batteries or Valve Regulated (VRLA).The battery plant provides secondary back-up power in the event of both loss ofcommercial power and failure of the standby engine generator. In larger facilitiesthese batteries are in separate rooms and are labeled at each entrance that the

space contains energized battery systems, with battery electrolyte solutions that


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are corrosive. Depending upon the installation, normal ventilation of the spaceensures adequate diluting of any hydrogen gas in the space.

2.5.3 Generator Space

2.5.3.1 Generally, central office equipmentbuildings will also house adiesel or turbine optional standby AC power unit which maybe providedwith manual remote shutdown. In many installations, the standbygenerator starts automatically upon interruption of normal AC power.When multiple generators are provided, one usuallystarts automaticallyand the others may require manual start. Standbypower equipment isnormally housed in a separate fire rated room. Generator rooms may behoused in basements, on interiorfloors, or on the roof. There may also bea fuel storage tank (day tank) of less than 100 gallons to 600 gallonslocated adjacent to the standby engine generator. Most central offices arealso provided with Above Ground Fuel Storage Tanks (AST) orUnderground Fuel Storage Tanks (UST) for extend emergency generatorsituations. Fuel pump rooms or areas may be located within the building totransfer the fuel from these tanks to elevated stories. Some central offices

may have exterior generator enclosures/modules. These units will house a

day tank within, beneath or adjacent to the enclosures/modules.

2.5.3.2 Each central office is served by commercial power via ACswitchgear housing transfer breakers and electrical buss bars or a mainAC distribution panel. AC power serves lighting and general purposeloads throughout the building and AC power is distributed to the DCpower plant(s).

2.5.3.3 Automatic Transfer Switches (ATS) are housed in or adjacent tothe AC distribution panels and provide for the automatic switchingbetween commercial and generator supplied power.

2.5.4 Primary Exposures

Both AC and DC power is present. The DC power plant has exposed highamperage -48 volt bus bars. Fires tend to be slow growing fires with smoldering

corrosive smoke produced. If ventilation is not adequately provided it is

remotely possible a Hydrogen gas build-up may occur. Corrosive batteryelectrolyte spills are rare and usually occur during the replacement of batteries.

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Spill Control and Neutralization Kits are provided for battery installations Insome installations, theremay be spill containment curbs around the battery stringsor the entire room maybe a containmentarea. Containment is not required fornew installations in most communities. Standbyback-up generator(s) - typicallystart automatically in a commercial power failure to provide primary back-uppower.

3.0 NON-NETWORK AREAS

3.1 As is typical in any building there are various support areas continued within thebuilding. These may be Administrative spaces for general operations of the business,specific spaces for functions such as a call center, dispatch center, etc, the core areas forcorridors, stairwells, restrooms and break areas, and minor storage areas. Additionally,there will be mechanical and maintenance areas, loading docks, and designated storagefor support of the building and telecommunications operations.

3.2 Primary Exposures

Incidents within these areas will produce conditions found in any building administrativeor support area not unique to the telecommunications central office. The by-products of afire incident will greatly impact the network operations and may impacttelecommunications network operations. The non-thermal effects of an incident such as

water or smoke must be handled to protect the switching and power areas of the building.The use of agents other than water or dry chemical fire extinguishers, the redirection ofwater and venting of smoke and by-products of a fire incident away from the switchingand power areas is critical in operations at this site.

4.0 Fire Detection Systems

4.1 Automatic detection and alarm systems are installed in telecommunicationsequipment buildings and may exceed code requirements for providing detection.Systems may be designed to provide an early warning of pre-combustion, smoldering orflaming fire events. There may be several different types of detectors located within thebuilding. Depending upon the use of an area these may include: photo-electric orionization smoke detectors, heat detectors, flame detectors and air sampling smokedetection devices. Great care needs to be taken in determining the point of origin ofdetector activation given that there may not be readily identifiable signs of a firecondition. Odors, hazes or light smoke conditions may be the only indication a fire eventis taking place.

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4.2 Fire alarm control panels are typically located at or near the main entrance to thebuilding, receive signals fromthe various detectors and displaythem as to their zone orspecific location. This panel will also initiate local audible and visual notification

appliances. Depending upon the building design there may be elevator controls, smokeexhaust, fire pump, and other various emergency control panels located in this area.

4.3 In addition to activatingthe fire alarm in the building, the detection/alarm systemalso sends a fire signal to a remote, 24-hour, in-house monitoring facility. Localmanagement is similarly advised of the alarm. Concurrently, attempts are made to contactthe incident building to determine the validity of the alarm. If an alarm is found to be afalse/or nuisance activation, a subsequentcall may be made to the fire department to

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advise responding fire service units.

5.0 HEATING, VENTILATION, AIR CONDITIONING (HVAC) EQUIPMENT

Switching equipment and battery power rooms have tight temperature tolerances, especially withregard to cooling, and require substantive HVAC systems; the size, vintage, and configuration ofwhich will vary greatly from building to building. Exposure to smoke by products may impactthe reliability of the telecommunications equipment. Depending upon the building design variousindividual or grouped units may shutdown upon detector activation. In some locations, buildingoperations, at the direction of the Incident Command may be able to utilize some HVACsystem's capabilities to ventilate smoke and fumes, pressurize floors adjacent to the "fire" flooror activate special fans. Buildings having smoke purge or management systems may be used toexhaust smoke. Caution must be taken to ensure that ventilation activities DO NOT expose

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clean spaces and Network Equipmentto the smoke by-products. Use of Positive PressureVentilation and channeling of smoke away from telecommunications equipment and power areasis encouraged.

6.0 AT&T's RESPONSE

If the incidentbuilding is occupied the occupants will evacuate to their pre-designated inside oroutside assembly area. The Emergency Site Coordinator will coordinate with fire serviceIncident Command and with responding fire units. The EmergencySite Coordinatorand on sitepersonnel shall assist in the provision for additional Companyresources, e.g., a PowerTechnician, Communications Technician, Building Service Technician, etc., as appropriate. Ifunoccupied, local management will immediately dispatch the nearest employee to assistfirefighters.

7.0 CENTRAL OFFICE FIRE FIGHTING

7.1 Site specific Building Emergency Action Plans (BEAP) are provided in the mainlobby of Central Office Buildings. The BEAP will include emergency contactinformation. Few Central Office buildings are occupied 24 x 7. Network techniciansmay be dispatched any hour of the day or night to isolated areas of Central Offices forvarious issues. A thorough search may be necessary to ensure there are no occupants.

7.2 Operating Conditions

Any emergency incident should be treated with utmost caution to ensure firefightersafety. Be aware that many incidents may involve Class C fires and appropriate safetyguidelines should be followed. Use of proper Personnel Protective Equipment (PPE)included Self Contained Breathing Apparatus (SCBA) should be considered mandatory.Atmospheres within the building may contain hazardous atmospheres both thermal andnon-thermal threats including toxic gasses, vapors, and smoke by-products.

7.3 Extinguishing Agents

7.3.1 The use of carbon dioxide, Halon 1211 or a clean agent such as FE36 or

Halotron is preferred. Due to corrosive effects on switching equipment, water,

foam and dry chemical extinguishers or agents should not be used. A good option

is the use of portable fire extinguishers provided in the specific space of the

incident. These units are aligned to the hazards of the space and the correct

agents for the protection of the network operations.

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7.3.2 Water used in fire operations is a threat to telecommunications operations.Fire in switching equipment or power areas should not be fought with solidstream water streams. Spray (Fog) nozzles are an acceptable substitute in mostapplications. In multi- storybuildings water should not be employed whereswitching or power equipment is on the floor below the fire scene.

7.3.3 Power Exposures

Central office power provisioning is an extremely robust system involvingcommercial power, a standby back-up generator(s), and DC storage batteries.Even after turning off both commercial power AND the back-up generator, powerwill continue to flow to the switching equipment and other critical componentsfrom the batteries and associated equipment. There is no shut-offof this batterypower available to firefighters. Only when an AT&T Power Technician has pulledthe appropriate fuses will power be totally removed. Until that time fire crewsshould, within previously listed limitations, concentrate on fire containment.

8.0 FIRE SAFETY PLAN

Fire safety plans are typically located at the main entrance to the building. This book containsspecific information regarding the building and key contact names and phone numbers.

9.0 FIRE PROTECTION FLOOR PLANS

Floor plans, also known as "You Are Here Boards", are at the main entrance, elevator lobbiesand stairwells as required by local code. These plans may indicate exit paths, fire extinguisherlocations, water and gas shut-offs, etc.

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Documents

Firefighter'sGuide To · Cable vaults are normally found below-gradeeither as an ... withmanual remote shutdown. Inmanyinstallations, the standby ... (AST) or Underground Fuel Storage