Belimo Fire System

8/9/2019 Belimo Fire System

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• Basic Smoke Control

Strategy and Tactics

• Engineered Smoke

Control Systems

• Fire and Smoke Control

Containment Dampers• Engineered Smoke

Control System Damper

Controls

• Actuators & Accessories

Actuator Dampers

in Smoke Control Systems


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Contents

I. Basic Smoke Control Strategy and Tactics.................................................3 Introduction............................................................................................3 Balanced strategy..................................................................................3 Smoke control tactics ............................................................................ 5 Compartmentation – containment Dampers ......................................... 5

II. Engineered Smoke Control Systems .........................................................7 Fire fighters’ smoke control system panel .............................................7 Stairwell pressurization .........................................................................8 Elevator lobby pressurization ..............................................................10 Hoistway shaft pressurization..............................................................10 Smoke exhaust or extraction...............................................................10 Smoke vents........................................................................................11 Smoke shafts.......................................................................................11

Zoned smoke control...........................................................................11 Corridor pressurization ........................................................................11

III. Fire and Smoke Control Containment Dampers .....................................13 Compartmentation/containment vs. engineered system dampers......13 Fire dampers ....................................................................................... 14 Smoke dampers ..................................................................................15 Combination fire and smoke dampers.................................................16 Older combination fire and smoke dampers ....................................... 17

IV. Engineered Smoke Control System Damper Controls........................18 Auxiliary switches for smoke control system dampers........................ 18 Wiring for reopenable smoke control system dampers.......................19 Introduction.......................................................................................... 20 Building, zone, and floor pressurization systems ................................ 21

Corridor dampers.................................................................................23 Smoke exhaust – large spaces ........................................................... 25 Other smoke exhausts and smoke purge ...........................................27 Stairwell Pressurization .......................................................................27 Hoistway Venting.................................................................................29 Elevator Hoistway Pressurization........................................................29 Underfloor air conditioning systems ....................................................29 Summary .............................................................................................30

VI. ACTUATORS ..........................................................................................32 VII. ACCESSOIRES ..................................................................................... 33

Larry Felker was the primary author of this document. He is a mechanical engineer andmember of the International Code Council, National Fire Protection Association, and

American Society of Heating, Refrigeration Air Conditioning Engineers. He is ProductManager Fire & Smoke Actuators for Belimo Americas. He has specialized in fire and smokedampers and actuators since 2002. Previously he was a temperature control systemdesigner and before that a mechanical and electrical contractor. He is the author of Dampersand Airflow Control, (with Travis Felker) published by ASHRAE Special Publications, 2010.


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I. Basic Smoke Contro l Strategy andTactics

Introduction

The International Building Code (IBC. 2009)is the model code for most building codes in theUnited States. Along with the mechanical and firecodes, it defines the requirements for fire andsmoke dampers and their operation in case of fire.The various codes have exceptions and specificcases where one or more of the smoke controlmethods discussed here may or may not berequired.

The purpose here is to explain how dampersoperate in those systems so that the fire fighter,fire prevention officer, code official, consultingengineer, or building owner can better understand

the technology. The specific code requirementsare not the subject, but it is sometimes necessaryto keep them in mind.

Chapter 3 of the IBC gives use andoccupancy classifications; that is, the differentactivities and uses that define, for example, amercantile occupancy or high-rise businessoccupancy. Chapter 4 gives special detailedrequirements based on the classifications.Chapter 7 gives the requirements for construction,including fire and smoke dampers in barriers andwalls. Chapter 9 covers the requirements forsprinklers, alarms, and smoke control systems.

Chapter 10 is Egress Solutions and Chapter 30covers elevators. These chapters cover most ofthe code provisions for fire and smoke dampers.Most of the provisions in the code are based onexperience either in building construction orlessons learned in past fires or disasters.

Some cities have damper requirements inthe Mechanical and/or Fire codes also. Forexample, the New York City Codes haveprovisions in all three codes (NYC 2008). TheNYC Mechanical Code, section 405, covers someof the requirements for high-rise business buildingmanual or automatic control of some dampers andsection 513 covers some requirements for smokeexhaust systems. Sections 606 and 607 coversmoke detector and some remote controlrequirements. The NYC Fire Code section 704.1covers floor openings and shafts.

Many other cities and states have codeswith modified provisions based on the modelcodes. Many states have strong smoke

control provisions as seismic activity can tear gaslines from the ground causing fire hazard andsimultaneously breaking water lines thusdisrupting sprinkler action.

Balanced strategy

Good fire and smoke protection and lifesafety practices involve use of any and all thedifferent tactics that have been developed. Thestrategy is the overall plan and the tactics are thecomponents of the mechanical systems. Onecould say the fire alarm, sprinkler flow switches,and smoke control programming logic are primarilystrategic and the sprinkler heads, ducts, fans, anddampers are the tactical methods. In actualpractice the two blur together. The Fire FightersSmoke Control System (FSCS) panel is the

interface between strategy and tactics. Figure 1shows the ideas that are more strategic thantactical.

The strategy coordinates the variouscomponents in the system. For example, whenthe fire alarm is activated, the stairwellpressurization system is automatically turned onso that occupants can exit without being exposedto toxic smoke.

The strategy is based on a number ofoverriding concepts and the codes prescribecertain practices in most buildings. The mix oftactics is a function of the prescriptions in the code

and the fire protection engineers’ design.Fire alarms alert occupants to danger and

the likelihood that they need to exit. External alarms bring fire department assistance.

Annunciation may be used to give directions tooccupants, particularly in buildings with largefootprints and in high-rise buildings.

Emergency planning and fire drills areexpected in many buildings although occupationby the general public diminishes the effect ofplans.

Egress paths from burning buildings allowescape and provide entrance ways for fire fighters.

Exit lights & signs, corridor & stairwell smokecontrol, and elevator pressurization or lobbiesprotected by smoke barriers are all important inegress.


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Figure 1. Strategic elements in fire and smoke control.

Codes are not always clear about theprimary function of smoke control. Life safety isthe first purpose. Protection of the building andfurnishings from smoke damage is of secondaryimportance. However, it is important to note thatprotecting property, particularly from collapse,protects occupants and fire fighters who may bein the building after occupants have exited.

Sprinklers extinguish fires about 20% of thetime (Koffel, 2005) and help control the spread offires. Hidden or sheltered fires – particularly

electrical fires in walls, fires that originate outsidethe building or outside the area covered bysprinklers, low water pressure, closed valves inwater lines, explosions, and collapse of buildingscan negate the operation of sprinklers. Smokethat has been cooled by water or air-mixing canmove down stairwells and open shafts. Smokecontrol complements sprinklers in some cases. Inothers, it allows clear egress paths wheresprinklers cannot reach the fire.

Statistics vary somewhat; however, it can besaid that wet sprinklers are from 68% to 94%effective depending on the type of occupancy(NFPA 2010). Over 50% of failures are attributedto water shut-off before the fire.

Structural compartmentation includinglimited size of areas enclosed by fire and smokedoors, walls, and barriers prevents both smokeand fire spread. Small compartments allow fire-hose streams to reach across to the fire.Smaller spaces mean more walls to restrict theceiling or roof from collapse. Sealing all wall

penetrations in barrier walls helps restrict smokeand fire to the area of origin.

Architectural ceiling reservoirs or drop downcurtains to prevent smoke spread and guide it to fanintakes are also used to control smoke movement.

Fire and smoke dampers are used in twoways. All fire dampers and about 85% of actuatedsmoke dampers are used to maintain integrity offire and smoke barrier walls – they seal ducts andany large openings in fire and smoke compartmentwalls.


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About 15% of actuated dampers are employedin engineered smoke control systems and arecontrolled automatically unless the FSCS paneloverrides are used to help suffocate a fire or toventilate and purge smoke. Smoke control systemsinclude pressurization of some spaces to stop smoke

spread and also exhaust fans for smoke removal;dampers are used to direct airflow as necessary.

Maintenance is required. Fire preventionconsists of any number of good practices includingperiodic inspections, control of flammable materials,and isolation of fuel burning equipment. Maintenanceis critical to prevention and deferred maintenance is afrequent danger.

The various tactics are sometimes divided intoactive and passive protection. Active protectionmethods include maintenance, sprinklers, fire andsmoke dampers and doors, fire extinguishers,kitchen hood suppression, and exhaust fan systems.

Passive methods comprise all the fire and smokerated wall and ceiling compartmentation, structuralcomponent strength, and penetration fire stopping.Homeland security measures can be passive oractive. Barricades that prevent vehicles from closeproximity to the building and moving air handlingintakes away from easy access by the public aremore or less passive while sensors to detect toxinsare active.

A balanced strategy uses many methods inparallel to achieve the same goal. Back-up systemsprotect against the failure of one method. Forexample, water pressure can be lost but then

firewalls restrain passage of flames until the firedepartment can put water on the fire. A synergy canbe achieved using several methods – for example,sprinklers are better able to control a fire if thecompartment is small and sealed well. Spread oftoxic and sometimes explosive smoke is thus alsorestricted.

Smoke contro l tactics

Where strategy looks at the overall picture, theindividual tactics are used to achieve the goals. The

main purpose of this booklet is to explain details ofhow these mechanical and electrical systems operatewith respect to dampers. The Fire Marshals, BuildingOfficials, design engineers, and contractors are oftencalled upon to go beneath the overall operation of asubsystem and look at the details.

Where devices and wiring interconnect twodisciplines, there is a tendency for those involved tohave only a fuzzy concept of the whole, interrelateddesign.

Figure 2 shows the primary mechanicalsystems that are used in smoke control. While all

the different tactics work together in the smokecontrol system, they can be divided into two basicgroups – those that contain fire and smoke to ensurecompartmentation and those that use mechanicalmeans to manage the movement of smoke. It is thislatter that is more complicated and is the mainsubject here.

Some system dampers are applied in otherways to control air flow and smoke. Air Handling Units(AHU) are often shut down if any smoke detector inthe area they serve senses smoke. However, inengineered smoke control systems the fans may

continue to run while the AHU dampers position sothat all return air is dumped outside and only fresh airis brought into the building. For large spaces thatexhaust smoke in case of an event, dampers locatedon outside walls (with ducts where appropriate) opento allow outside air to enter to replace air and smokepulled out by exhausts.

Compartmentation – containment Dampers

Common sense and confirmation by lessonslearned from past fires show that restricting the spread

of fire and smoke is a significant defense to avoid lossof life and property damage. Fire and smoke doorsare required in stairwell entrances and exits to preventsmoke and fire from traveling into the stairwell.National Fire Protection Association (NFPA) Standards80 (fire doors and other opening protectives) andNFPA 105 (smoke door assemblies and other openingprotectives) cover requirements for installation andrepair of fire and smoke doors and dampers.

While the distinction is not perfect, it helps clarifyapplications by distinguishing between dampers thatare primarily meant to maintain compartmentation andthose which actively control smoke. Containment

dampers maintain compartmentation. Smoke control dampers are used to exhaust smoke or pressurizespaces to prevent movement of smoke. Theautomated dampers used in an engineered smokecontrol system are essentially the same as those usedfor containment. The differences will be in the factorymounted controls and in the field control methods.


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,

CORRIDOR DAMPERS

STAIRWELLPRESSURIZATIONCORRIDOR

PRESSURIZATION

& EXHAUST

DAMPERS

FSCS

ZONE OR FLOOR

SANDWICH

PRESSURIZATION

SMOKE

AIR HANDLER SHUTDOWN

OR CHANGEOVER TO

SMOKE PURGE MODE

ELEVATOR HOIST WAY

PRESSURIZATION SHAFTDAMPERS

DUCT SMOKE

DETECTION

DOOR

UNLOCK

AUTOMATIC SMOKE& FIRE DOORS

COMPARTMENTATION

DAMPERS

ATRIA SMOKE

EXTRACTION

FANS

ELEVATOR

SHAFT VENTS

Figure 2. Common engineered smoke control system components.

With some exceptions, dampers arerequired in fire walls and smoke barriers whereany duct or air-transfer opening passes through.The penetrations of supply and return air ducts inshafts running up and down a building must havedampers. Large amounts of smoke can travelthroughout the interconnected air ducts if dampersare not present.

Hot smoke expands and pushes everywhereout of the compartment, tending to rise. Assmoke cools, it will drop down shafts andstairwells. It must be contained. Smoke willpass out of fire zones into unprotected zoneswithout dampers to help protect smokebarriers. See Figure 3.


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Figure 3. Left. Without dampers, whether air handler is on or off, smoke will spread via ducts.Right. Containment dampers limit spread of fire and smoke to exit corridor.

II. Engineered Smoke Contro l Systems

Fire fighters’ smoke control system panel

Smoke control systems use any and allmethods possible to protect from smoke spread.Doors, fans, sprinklers, dampers, and alarms areunified into one coordinated system. Coordinationof all the smoke control tactics is typicallyperformed by a fire alarm/smoke control panel. Inmost systems, fire fighters have override control

from a Fire Fighters’ Smoke Control System(FSCS) Panel located in a lobby or a protectedarea. Overrides and status indication of allequipment are present on the face of the FSCS ora computer screen display. Figure 4 shows adetail of a typical override switch and indicatorlights on a FSCS panel.

Figure 4. Detail of FSCS panel.


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Figure 5. Relief damper variation of stairwell pressurization.

Stairwell pressurization

Stairwell pressurization can be

accomplished a number of ways. One methoduses a constant volume fan capable of pushing airthrough any stair door that opens. A barometricdamper in the stairwell roof or wall relievesexcessive pressure. See Figure 5. This methodcan be combined with other features such as thevestibule discussed next.

In some designs, ventilated vestibulesseparate occupied spaces from stairwells. TheIBC contains details about the method. SeeFigure 6. The lobby is kept negative byexhausting per IBC. However, in some designs,the vestibule is positively ventilated so that it

pushes against any smoke that might be pushedtowards the vestibule.

Another method uses a duct system run theheight of the stairwell and proportional actuateddampers every few floors with local pressuresensors. If a floor door opens, the damper(s)nearest it modulates open as necessary to

maintain pressure. A certain amount of smoke

may enter the stairwell when any door isopened if there is a lot of pressure behind it.Typically, the expansion of heated air doesprovide pressure. It takes some time for thesensor, controller, and actuatorto respond and open the local dampers further.See Figure 7.

Other variations are possible andresearch is incomplete with regards to which isbest in what geometric arrangement of stairs,stack effect, or height of stairs. One variation isa second fan that turns on when the egress

level door is opened. Then the exit door doesnot relieve all the pressure necessary for thefloors. Some research has shown thatsufficient ventilation alone during a fire will keepthe stairwell tenable. This employs a supplyfan at the bottom of the stairwell and anexhaust fan at the top. It can be combined withdoor pressurization by using variable frequencydrive (VFD) fans.


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Figure 6. Vestibule variation of stairwell pressurization.

Figure 7. Stairwell pressurization system using proportional damper control.


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Stairwells are built to be smoke proofcompartments. The occupants can escape into thestairwells and be protected from smoke while theyescape the building. When floor doors are opened,smoke must not enter the stairwell. Since severalarchitectural and control design methods are used

examination of each system is necessary tounderstand its intent. Testing using smokegenerators helps to ensure the system works asrequired. Pressure in the stairwell must be below thatwhich would hinder the opening of doors.

Elevator lobby pressurization

The lobbies of elevators can be pressurized tokeep smoke from entering. These lobbies aresometimes areas of refuge and must be kept clear ofsmoke. The codes typically require that the elevatorlobbies, where pressurized as a smoke compartment,

be kept positive with respect to the occupied spaces.This is achieved by balancing the air systems toprovide more air to the lobbies or by injecting air witha separate unit.

Hoistway shaft pressurization

Any hoistway, for example a dumbwaiter,provides a path for smoke to travel throughout abuilding. Elevators are typically the largest shaft ina building and provide a path for smoke travel.

In order to protect elevator (or other thehoistway) shafts, the shaft can be pressurized withfresh air. The pressure prevents smoke fromentering the shaft itself and from traveling to otherareas via the hoist way. Due to the large volumesof air and consequently very large fans required, a

more common alternate is to provide lobbies withsmoke barriers. The geometry of the application isvery similar to that in Figure 5 for stairwells. Useof elevators that are in protected hoistway shafts isa developing area of study as of this writing. Insingle elevator car shafts, fans above and belowthe car may be necessary if the free spacebetween the car and the shaft walls is insufficientfor air movement when needed.

Smoke exhaust or extraction

In large spaces, there is no way to pressurize

the large area to prevent smoke movement into thespace. It is best to exhaust high volumes toremove the smoke. Atria and large spaces,particularly malls, have exhaust fans to removesmoke and keep it at least six feet above theoccupied levels for 20 minutes to allow escape.Lower level make-up air dampers open to theoutside to admit fresh air to replace the smoke.See Figure 8.

Figure 8. Atrium with exhaust fan.


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Smoke vents

In certain warehouse and storage occupancies,smoke vents are prescribed by the codes. These canbe automatic or manually operated. The goal is toremove hot, buoyant smoke to provide clear air for

occupants and fire fighters. When wind is a potentialproblem, powered fans are used. These are part of anengineered system with the switches to operate themlocated outside the building where the fire service hasquick access. (Section 910. IBC2009.)

Smoke shafts

In some buildings there are shafts extending theheight of the building. Fans are mounted at the topand closed dampers are mounted in the wall of eachfloor. In case of fire, the fan turns on and the damperon the fire floor opens. Smoke is pulled out of the firefloor.

A variation of this is the use of the HVAC ductsto pull smoke out of a building by sucking with thereturn air fan and opening the exhaust damperand closing the return air damper.

The HVAC components are not typicallydesigned for this application and the volume of smokeremoved may be insufficient.

Zoned smoke control.

In some buildings entire zones or floors are

exhausted or pressurized to prevent smokemigration. The fire zone or floor is placed under anegative pressure, often by the HVAC return ductdamper and fan. The adjacent floors are placedunder a positive pressure to prevent smokemigration. This is a “sandwich pressurization

system.” If all the floors except the fire floor arepositive, the system is known as a “buildingpressurization system.” Zoned smoke control wasmandatory in high-rise buildings in the legacy codes,but the present IBC does not require them. Theymay still be found in some local codes and inunderground buildings which are particularlydangerous since escape paths are highly restricted.See Figure 9.

Corridor pressurization

If only the corridors are zone pressurized as

above, the system is called a corridor pressurizationsystem. When smoke fills a corridor, it is very hardto see exit signs and people become disoriented. Acombination of intake and exhaust fans can clearsmoke.

Corridor dampers normally provideventilation air and exhaust stale air. However, theycan be converted to smoke control dampers veryeasily. If a fire starts, the floors above and below thefire floor open their corridor ventilation dampers100% to pressurize the floors while they close theirreturn air dampers. This is identical in concept tothe floor pressurization system discussed above.

See Figure 10.

Figure 9. A building pressurization system


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Figure 10. Supply and return ducts in cor ridor pro tected by fire & smoke dampers.

Special fire and smoke proportional orthree-position actuators can be used to controlthe corridor dampers. The dampers must bepartially closed for balancing, however they mustreopen 100% to pressurize the floors adjacent toa smoke floor or to exhaust smoke as quickly aspossible. Two speed fan motors or VFD’sprevent noise due to dampers that must be near

closed during normal operation to avoidimbalance in design flow. Standard balancingdampers would restrict the full flow whenneeded. All other floors’ corridor dampers closeso that a higher pressure and more airmovement are available for the sandwich floors.

Smoke causes most of the deaths in firesand smoke exhaust or pressurization methodscan constrain it. However, in all of the methodsdiscussed, too much oxygen cannot be injectedand thus feed the fire. When fans are used topressurize or add air for smoke removal, smokedetection on the inlet of the fan is used to avoidinjecting smoke if the fire is near the inlet of the

fan.Sprinklers are essential for fire protection.

However, they are insufficient for fully balancedprotection in large buildings. A balancedapproach between active and passive measuresproduces the safest conditions.

Compartmentation is the primaryprotection method for fire and smoke control.Maintaining the integrity of walls prevents fire

passage and smoke spread. Containmentduct and shaft dampers protect from smoketransport across compartment walls. About 85%of smoke dampers are used to maintaincompartment containment. All means of egressmust be protected – stairwells, elevatorhoistways, lobbies, corridors, and paths to the

outside.In addition, dampers are required whereducts penetrate shaft walls. Shaft dampers arethe only way to restrict smoke movement. Airhandling unit shutdown is insufficient alone.

Large spaces like atriums, stages, malls,and stadium seating require smoke exhaust tokeep the smoke layer above the level of theoccupants’ heads.

Engineered smoke control systems usemostly pressurization to prevent smokemigration. About 15% of actuated dampers areinstalled in them.


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III. Fire and Smoke ControlContainment Dampers

Compartmentation/containment vs. engineered

system dampersFigure 11 shows a building with typical

locations of fire and smoke control dampers.Dampers in barrier walls are usually open andclose in case of fire or smoke. Fire dampers closeonly if the temperature at the damper rises totypically 165ºF (74ºC) melting the fusible link.Smoke dampers can open or close much soonersince smoke spreads quickly and is sensed fasterthan temperature by the electronics. Fire dampershave one action – they close if temperature ishigh. Smoke dampers can close to block smokespread through duct systems or, in engineered

smoke control systems, they can be opened to

exhaust smoke or to push air into a space tomanage smoke movement.

Dampers that are employed in maintainingcompartmentation are referred to as“containment” dampers. They maintain theintegrity of fire and smoke compartment walls

and automatically close if fire or smoke issensed. The dampers used in engineeredsmoke control systems are referred to as“smoke control” dampers.They are of the same general construction andare often identical except for the controls.These are UL555 (fire) and UL555S (smoke)rated dampers (UL555; UL555S). Many smokedampers are installed in barrier walls to stopsmoke transport and are controlled by ductsmoke detectors. Some containment dampersare controlled by area smoke detection and acentral panel.

,

STAIRWELL

PRESSURIZATION

DAMPERS

ZONE SMOKE

CONTROL DAMPERS

AIR HANDLER DAMPERS

CHANGEOVER

SHAFTDAMPERS

COMPARTMENTATION

DAMPERSFAN DISCHARGE

DAMPERS

SMOKE EXHAUST

DAMPERS

CORRIDOR

DAMPERS

MAKE-UP AIR

DAMPERS

SHAFT VENT

DAMPERS STAIRWELL

PRESSURE

RELIEF

DAMPER

HOIST WAY FAN

DAMPERS

Figure 11. Locations of fire and smoke dampers.


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Fire dampers are not typically actuated andhave fusible links or temperature sensors thatcause them to close when the duct rises to 165°F(74ºC). Building codes describe where each typeof damper is required. Figure 12 shows what thetypical damper looks like and the thermal sensors

for closing the damper in case of fire.It simplifies thinking to distinguish between

containment dampers and those used inengineered systems. Containment damperscannot be overridden and are not usuallymonitored and do not give position indication tothe Fire Fighters Smoke Control System (FSCS)panel. Applications of smoke control systemdampers are covered in Section 4 below.

While the UL testing of the dampers is thesame, installed testing requirements are differentfor the different applications. Per the IBC, both fireand smoke containment dampers are tested at

commissioning, one year after installation, andthen once every 4 years, except hospitals wherethey are tested again after every 6 years.Engineered smoke control systems and theirdampers are tested once a year. Some

jurisdictions require that dedicated systems –those used for smoke only – be tested twice ayear.

Fire dampers

Fire dampers are installed to prevent thepassage of fire through walls or ducts from onespace to another. Fire dampers arecompartmentation dampers.

Curtain dampers installed in heating andair conditioning ducts which pass thru fire wallsor floors are the most common fire dampers.They are held open by a fusible link whichtypically melts at 165ºF (74ºC) allowing theblades to fall into the air stream and block hightemperature air. In some cases 210ºF (100ºC)or higher are used. See Figure 13.

Unless specially made for out-of-wallinstallation, fire dampers must be within theplane of the wall they are protecting. For thisreason, when combination fire and smokedampers, discussed below, are installed,

jackshafts are used (see Figure 12). This allowsattaching the actuator to the jackshaft where it isaccessible from outside while the damper bladesare still within the wall plane. Many smokedampers are jackshafted also as the samedamper is used in the combination fire andsmoke application. However, a smoke dampermay be installed up to two feet away from thewall.

Figure 12. Combination fire and smoke damper. (Photograph courtesy of Pottorff.)


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Figure 13. Curtain fire dampers

(Photograph courtesy of Pottorff.)

Ceiling radiation dampers guard diffuserswhich supply or return air. These are usuallyfusible link operated although some applicationsuse actuated dampers. UL555C regulates

construction and installation of ceiling dampers.These assist in restraining fire to thecompartment where it originates. See Figure 14.

Figure 15. Multisection fire damper withactuator. (Photograph courtesy GreenheckFan Company.)

Figure 14. Ceiling radiation damper(Courtesy o f Ruskin Manufacturing)

There are uncommon cases where a firedamper is very large and requires multiplesections. All the sections must closesimultaneously and fusible links would notachieve that as each can melt at a different time.

An electrical thermal sensor is used to cut power

to the actuator(s), thus closing all sectionssimultaneously. This is the same method usedfor multiple combination fire and smoke dampersdiscussed below.

Heat and smoke vents can be foundfrequently in warehouse storage roofs. They arenormally closed and can open to release heatand smoke. Fusible links, electric, andpneumatic methods are all used to open them.These are not covered here.

Smoke dampers

Smoke dampers have no temperaturesensors. See Figure 16. Note that there is notemperature sensor like there is in the damper inFigure 15.

Figure 16. Two section smoke damper withactuator. (Photograph cour tesy of Pottorff.)

There are two main applications wheresmoke dampers are used:1) In smoke barriers where they close tomaintain the smoke proof compartment whichthey protect. Once a smoke detector or areasmoke detection has closed them, they stayclosed until the event is over and they aremanually reset. Smoke dampers that areinstalled in smoke barriers serve to maintain


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compartmentation; typically a smoke detectorwithin five feet closes the damper.2) In many applications, discussed at lengthbelow, they can be controlled by the smokemanagement system to open or close as neededto pressurize, relieve, or exhaust a space. The

FSCS panel has override switches that connectto them. These are frequently termed“reopenable dampers” since they can beoperated remotely open or closed from the FSCSpanel.

About 10% of motorized dampers aresmoke dampers only. Since most smoke barriersare also fire barriers, 90% of motorized dampersare combination fire and smoke. Combinationdampers are installed in them – they are both fireand smoke dampers. At one time in the past twodampers would have been installed. Modernsystems use a combination.

All dampers in engineered smoke controlsystems, regardless of whether they are smokeonly or combination fire and smoke have positionindication that shows at the smoke control panel.Damper blade switches, magnetic switches, oractuator auxiliary switches are used for thesignaling. See Figure 4 for an example of FSCSindication.

Figure 17 shows the power wiring for asmoke damper. (Switches will be covered in afollowing section.) In reality, the wiring oftenlooks like a confusing pretzel; however, here aladder diagram shows how simple it actually is.

Hot power enters from the left. If the

smoke detector or smoke relay contact is closed,power continues to the actuator H terminal anddrives it open. When power is removed, the

actuator springs the damper closed. Poweris sometimes disconnected on the Commonterminal of the actuator. This is a two positionapplication – full open or full closed. The firealarm system must be notified that smoke hasbeen detected. This is accomplished by anothercontact on the smoke detector or by the fire alarmpanel if an area smoke detection system is used.

Combination fire and smoke dampers

Combination fire and smoke dampers areinstalled in walls that are both fire and smokebarriers. These dampers combine the smokeand the fire function. A thermal sensor is placedin the duct and if the temperature rises to typically165ºF it springs closed. Figure 18 shows adamper with electrical control of the actuator inboth smoke and fire functions.

Figure 17. Typical wiring for smoke damper actuator.


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Figure 18. Typical installation of a fire and smoke damper.

Figure 19 shows the typical, moderncombination fire and smoke damper wiring.There are no switches providing position indicationif the damper is not in an engineered application.The smoke detector signal does go back to the firealarm panel and would provide the location of thealarm. This is the most common wiring schemethat will be found in the field. Most installationsare wired like the drawing in Figure 19.

165ºF (74ºC), then power is cut to theactuator and it springs closed. Alternately, for thesmoke function, if the contact on the smokedetector or smoke relay opens, power is cut andthe damper closes.

Older combination fire and smoke dampers

Several slightly different methods ofcontrolling combination dampers have beenemployed over the years. When repairing themor replacing defective actuators, someinvestigation is necessary. Many older dampersused a fusible link similar to those on the curtainfire damper for the fire function and an actuatorfor the smoke function. Figure 20 shows thistype of damper with a detail of the fusible linkand a spring on the damper shaft. The smoke

closing function and reopening if needed isperformed by the actuator.

Figure 19. Typical wiring of a smoke detector, high temperature limit, and actuator of a combinationfire and smoke damper.


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Figure 20. Fusible link, shaft spring, motor with 2nd

external spring.

There is a spring on the outside for theactuator. The fire function is performed by thefusible link and 2

nd internal shaft spring. The

wiring for the fusible link variation is the same asthat in Figure 17. The electric power is cut onlyby the smoke detector or relay. The hightemperature fire function is performed by thefusible link opening.

In all cases the end result is the same. Ifthe ambient air passing through the damperreaches 165ºF (74ºC), then the damper closes. Ifsmoke is detected, then the damper closes.

UL has clearly stated that they do notregulate repair or replacement issues. The localFire Marshal or Building Official is usually the

Authority Having Jurisdiction.Equal or better actuators are required in

most cases. The specifications include equal or

better in torque, temperature tolerance, time todrive and spring, and lower or equal in amperagedraw. Voltage must be equal. The damper mustbe tested for performance afterwards. NFPA 80and 105 require that a record of repair be kept onpremises. (NFPA 80, NFPA 105.)

IV. Engineered Smoke ControlSystem Damper Controls

Auxi liary sw itches for smoke cont rol systemdampers

In engineered smoke control systems theposition of the damper is normally indicated at theFSCS panel. In some cities or states, the codesdo not require the indication; however, the IBCrequires them. In addition, the wiring mustusually be checked for integrity, usually by end ofline resistors – this is not covered here as the firealarm code has extensive information. There aresome codes that require that fire dampers arealso controlled – for example, New York in Boccupancy high rises.

Figure 21 shows the addition of switchesfor damper position indication. Actuator auxiliaryswitches, damper blade switches, or magneticswitches can be used. If the smoke relaycontacts open, the actuator springs the damperclosed. The contacts on the switches changefrom damper-open to damper-closed. This is nottypically seen in containment applications, only inengineered smoke control systems where statusmust be indicated at the FSCS panel.


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Figure 21. Switches provide indication to the FSCS for damper open or closed.

In older systems, wires actually ran from thedamper to the control panel. In modern systems,a network relay receives the switch indication and

the data is passed along the network wires to thecentral control system. In the drawings here,hardwired connections are shown for the overrideswitches and networks are assumed for theposition indication.

Wiring for reopenable smoke contro l systemdampers

Figure 22 shows the wiring for a reopenablesmoke damper in a smoke control system. Notethat the damper is the same as any other UL555S,

the controls are the difference. The smokedetector or relay is not integral to the damper andis shown outside the damper sleeve. The smoke

detector and any thermal sensors are manualreset. In the auto mode, the smoke relay canclose the damper. However, if the override switchat the panel is set to “On,” then the damper opens.There is no temperature sensing.

A combination fire and smoke dampertypical wiring is shown in Figure 23.

Dampers are used for two general purposesin fire and smoke control. They assist inmaintaining compartmentation and in engineeredsmoke control systems they help to pressurize andexhaust spaces.

N or

Com

Actuator

SwitchHOT

Auto

Off

Override

Open

Smoke Relay or Smoke

Detector contact

Reopenable smoke damper

Open

Closed

FSCS Panel

Switch shows hard

wired method. Indicatorlights shown using network.

Damper closed

Damper open Power

Single damper or zone

Network cable & power

Switches

Damper sleeve.

Figure 22. FSCS panel, override switch , swi tch indication, and smoke damper.


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Figure 23. Wiring of a FSCS panel, primary and secondary sensors, and actuator on a reopenabledamper.

The damper construction is the same forthose used for containment as those used inengineered smoke control systems. All are UL555(fire) and/or UL555S (smoke) listed by themanufacturer. Some variations occur amongmakes or models. Dampers can have singlethickness blades or double skin airfoil. Firedampers and combination are steel where smokecan also be aluminum. However, in general, there

is little difference in construction.The controls do vary as indication switches

on the dampers are typically used for engineeredsystems so that the FSCS panel can show statusof the dampers. In addition, override is possible toreopen the damper manually. Variations to fit theparticular system and building are common.

V. Engineered Smoke Contro l System Applications

Introduction

The preceding material presented thevarious smoke control system methods or tactics,

damper types, and the controls. This systempulls them all together and discusses how thesedampers are controlled and wired in engineeredsmoke control systems.

In general, any damper that is part of asmoke control system must be a UL555 (fire)and/or a UL555S (smoke) rated damper. Insome cases exceptions are allowed since thedamper is not meant to stop smoke. Examplesare outside make-up air intakes and exhaust

dampers on the outside of the building. Theyare usually open during an event and do notstop spread of fire and smoke.

Another exception case is where existingdampers have been operating for years and arebeing reused while the system is beingrefurbished. Each application needs to beexamined specifically to determine real needs.For new installations, UL rated dampers ensurequality and factory or actuator mounted switchesare needed for position signaling.

Figure 24 shows the smoke controlsystem components that can have dampers

associated with them. The following sections gointo details about the most common subsystemsand how dampers are applied.


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Figure 24. Locations of fire and smoke dampers.

Building, zone, and floor pressur izationsystems

Pressurization systems are sometimesrequired in high-rises and underground buildings.The principle behind them is used in manysystems. Pressurize an area with respect to anadjacent area and smoke cannot enter it. (Thefloors above and below the fire are the most likelyto become smoke filled.) Pull an area negativewith respect to adjacent spaces and the smoke willmove in that direction. (Pull smoke out of the firefloor.) The fire protection engineer may choose tosimply pull the fire zone negative. Since the otherfloors are positively pressurized to avoid infiltrationof unconditioned outside air, smoke will flow out ofthe floor.

Figure 25 shows a typical application with afire and accompanying smoke on floor three.

The supply damper on the fire floor is closed.The return damper is open and smoke is pulledout as the floor is negative. Smoke extractionshafts and fans could produce the same result;these are not discussed here.

The dampers in the air handling unitchange over and air is exhausted from the returnto the outside, thus removing smoke. Discussedbelow and see Figure 26. In the floors aboveand below the fire floor, the supply dampers are

open and the return dampers are closed. Thesefloors have excess pressure and the airpressure stops smoke which could make its waythru cracks or crevices and infiltrate those floors.Hot air expands a great deal and some smokemay make it into the adjacent floors, but verylittle.


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Figure 25. Building pressurization system. Smoke is pulled out of the fire floor and exhausted.

If only the floors adjacent to the fire floorare pressurized, the system is referred to as a“sandwich” pressurization system. Theunaffected floors continue to have both theirsupply and return dampers open; they shouldbe slightly positive. If all the floors except thefire floor have open supplies and closedreturns, then it is a “building” pressurizationsystem. If the floors are so large that anumber of zones are on the same floor andthose adjacent to the fire zone arepressurized, then it is referred to as a “zone”pressurization system.

The fan and damper arrangement hereis a “non-dedicated” system. The regularHVAC equipment is used for smoke control ifever required. A “dedicated” system wouldhave separate fans for pressurizing with airand/or exhausting smoke. Figure 26 showsthe air handling unit dampers.

Figure 26 (right ). Air Handl ing Unitdamper changeover from Normal toSmoke Exhaust. The return air damper isfully closed while the Outside Air andExhaust Air dampers are full open.


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Normally, air can flow through the unit. Insmoke mode, the supply fan delivers onlyoutside air to the zones or floors without fire.The return air fan becomes an exhaust. Therelief or exhaust damper opens fully to relieve

smoke.In the configuration shown, the Return Air

Damper should be a UL555S rated damper. Itmust be low leakage so that smoke is not pushedback into the supply air. If a relief fan were used,the damper is not pressurized by the return fanand smoke leakage should not occur.

Corridor dampers

When normally occupied, the corridor shouldbe ventilated with fresh air and stale air must beexhausted. The supply must deliver slightly more

air than the exhaust pulls out in order to keep thespace pressure positive with respect to theoutside. For this reason, balancing is necessaryand it is rare that a damper is fully open; thedampers are closed part way to adjust the air flowdifferences.

In event of a fire the corridors are used foregress; the corridor must be kept free of smoke.

Corridor dampers can provide both functions.See Figure 27 for a typical application. In thiscase, under normal conditions, there is aconstant air flow into the corridor from the supplydamper on the left and a constant exhaust via

the damper on the right.If there is a fire on the floor, then the

supply damper closes and the exhaust opensfully. Smoke is pulled out of the corridor so thatoccupants can escape. This is like the floor orzone pressurization system above.

The actuators are balanced by thebalancing and controls contractors so that theright amount of air enters each floor in normaloperation. The dampers are sized so that whenfull open they pull sufficient smoke out of thecorridor.

Figure 28 shows a special actuated

damper designed for corridor wall mounting andthe control wiring for the actuator. The FSCSpanel switches are the typical Auto-Closed-Override; however, the actuator works differentlyto accommodate the needs to balance the air innormal operation.

Figure 27. Corridor damper and application.


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Figure 28. An actuated balancing fire and smoke damper. (Photograph courtesy RuskinManufacturing.)

In normal operation when power is appliedacross 1 and 2, the actuator drives the damperopen to the position to which the potentiometer isset. The balancer adjusts the potentiometer to getthe required normal ventilation supply airflow.This is performed at all dampers.

If fire or smoke is detected on any otherfloor, then the fire alarm or smoke control system,via the smoke relays at the supply damper, doesnot change the damper’s position and it staysopen. At the exhaust damper, the smoke relay 1is powered and the contact opens. The damperthen springs closed. Since there is no exhaust,this corridor is pressurized.

If the fire is on the dampers’ floor, theopposite happens. At the supply damper, smokerelay 1 opens and the damper closes. At theexhaust damper, smoke relay 2 closes its contactsand the actuator drives full open to make the

corridor negative in pressure and to exhaustsmoke.

If the fire is close to the damper, the primarysensor opens up at 165ºF (74ºC). The exhaustdamper closes. This prevents fire from enteringthe shaft. If, however, the switch on the FSCSpanel is set to “Override” or “Open,” then smokerelay 2 closes and the damper again opens. Butagain, if the fire is intense or close enough toreach 250ºF (121ºC) at the damper, then the

secondary sensor opens and the damper closes.Both sensors are manual reset. The smokesystem logic controls these functions.

A number of variations exist. A sandwichor building pressurization type of corridorarrangement is sometimes used. The floorsabove and below the fire floor are fully

pressurized. That means their supply dampersopen fully and their return or exhaust dampersclose completely. However, the other floorscontinue normally. During this process, the fansmay ramp up to higher speeds if needed.

If make-up air is supplied by some othersource than a ducted supply, the floor may haveonly an exhaust duct and damper. In order tomake the fire floor negative with respect to theother floors, all exhausts except the one on thefire floor close. The open fire floor exhaustdamper will pull smoke out.

Another variation is use of a single

damper and duct on each floor which changeroles as needed. The fan normally runs forwardto supply air. In event of a fire, the dampersswitch over so that the fire floor damper is openand the other floors are closed. The fanreverses flow direction so it pulls air. Since thefan is pulling from only one damper, thepressure is very negative and smoke can bepulled out. See Figure 29.


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Figure 29. Single damper serving as supp ly or exhaust when fan reverses flow.

Other variations may not have the twotemperature sensors so that the fire fighters havefull and final control over the dampers. The fireprotection engineer designs the system to combatthe most likely and most dangerous scenariosThe mechanical engineer does the final designthat meets both the fire and smoke protectionrequirements while meeting the ventilation codes.

Smoke exhaust – large spaces

In very large spaces like covered shoppingmalls, auditoriums, and atria, it is nearlyimpossible to use dampers and fans to pressurizethe space. In addition, smoke quickly fills the

space and the typically large number of peoplein the space are in danger. The solution is toexhaust large volumes of smoke. This canprevent the entire space from filling and maintaina smoke-free lower region to allow escape. Italso prevents smoke from spreading into thespaces adjacent to the large space. See Figure30 for a typical concept.

In malls and some spaces there arearchitectural features that are sometimes

included to assist removal of smoke. A smokereservoir can be made by using barriers orcurtains that hang from the ceiling. They canprevent smoke from spreading while the fanspull the smoke out.

Figure 30. Atrium with multi ple entries.


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On the lower left corner of the atrium in

Figure 30 make-up air dampers are shown. Inorder to provide air to replace the smoke that iscleared out of the space, make-up air dampers areprovided. If smoke is detected in the atrium, the

exhaust fan turns on and the dampers are openedfor make-up air. The dampers may be installed inan outside wall or ducts may be used to obtainoutside air from a more remote location.

One fear is the effect of providing air thatmight feed the fire. The exact effects of where theair might hit the fire or its smoke plume areunknown and largely uncontrollable. The

American Society of Heating, Refrigeration, Air-Conditioning Engineers (ASHRAE) is researchingthis subject.

The codes require that any dampers used ina smoke control system be UL555S Listed. If the

wall is a fire wall or in some cases if it is within a

certain distance of another building or close tograde, then it is also a UL555 Listed fire damper.Homeland security concerns would require thatthe opening to the outside be high on the wall.

A smoke detector is placed in the inlet of the

damper to ensure that if there is a fire active atthe inlet that smoke is not pulled into thebuilding.

Regardless of whether the damper isUL555S or both UL555 and UL555S, there willbe auxiliary switches to signal the damper’sposition to the FSCS panel. This damper can beoverridden at the FSCS panel.

Figure 31 shows a typical wiring schemefor the smoke detection, fan, and the dampers’wiring. If the damper is smoke only – not fire –the thermal sensors are not present. While thewiring is shown between the override

Make-up air dampers

Tie bar

Jackshaft

On

Off

Open

Closed

Atria Smoke Exhaust

FanMake-up Air

Damper

N or

COM

Smoke detector

relay closes to

start exhaust.

Override selector switch

HOT

Auto

Off

On

FSCS PanelSingle damper or zone

Fan on

Fan Off

Power

Damper open

Damper closed

Power Network

Fan starter coil

Damper Actuator

Note

Note

This wiring is typically networked also.

1

2

1

2

1

2

1

2

See detail below for

multiple actuator wiring.

Detail multiple actuator wiring

Hot

Com

1 2

Figure 31. Typical FSCS and wiring to fan and actuators.


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27

switch and the actuator and fan starter coil, inmodern systems the fire alarm/smoke controlnetwork carries the commands between localinput-output devices.

In the Auto mode, power goes thru thesmoke system relay to the actuator. If the relay

closes, the damper opens to allow make-up airinto the atria and the fan starts. Auxiliaryswitches feed the indicator lights on the controlpanel. In the Off mode, the relay has no powerand the dampers close and the fan is off. In theOn or override mode, power is sent to theactuator and fan relay directly to start theexhaust. This is just an example with the wiringshown for educational purposes. In modernsystems, a digital network and program logicprovide all the correct actions.

An example of a large multi-section damperis shown below the FSCS panel. Wiring sends

power to all actuators simultaneously to ensureall sections open (or close) at the same time.

Other smoke exhausts and smoke purge

There are other smoke extraction systemsthat are used. Among them are smoke shaftspenetrating every zone in the building, kitchenexhaust hoods, and general exhausts that maybe used in event of a fire. The damper principlesare similar to the ideas presented above.

In some codes smoke purge systems arerequired. After a fire, the building can be flushed

with outside air and stale or smoky air exhausted. Any of the normal exhausts can contribute toremoving smoke. The main air handling units areoften used to provide fresh air by opening the OAand Exhaust air dampers 100%.

Stairwell Pressurization

The IBC requires that stairwells bedesigned as smoke proof enclosures. There arevariations allowed by the code for whenautomatic sprinkles are provided and somearchitectural differences. Figure 32 shows onetype of stairwell system. Here, the exit stairway

shaft is pressurized to between 0.10 inches ofwater (25 Pa) and 0.35 inches of water (87 Pa) inthe shaft with respect to the interior building withall the doors closed (2009 IBC 909.20.5).

There are no automated dampers usedwhich makes the system simple; the added costis the vestibules and the space they occupy.

(There are likely dampers on the inlet of the fansto prevent water from entering the system.) Therelief damper responds to pressure and isadjusted by weights on the blades. Thevestibules are fed fresh air by a fan which startswhen smoke or a fire is detected. An exhaust is

required in the proscribed IBC method and itmust pull 150% of the supply air out. Thereforethe vestibules are under a negative pressure andsmoke that enters the vestibule will beexhausted.

A variation of the vestibule system does nothave exhaust. It pressurizes the vestibule toprevent smoke from entering.

A large fan pressurizes the stairwell. Whendoors are open, the relief damper located nearthe top of the stairwell closes so that pressure ismaintained to keep smoke from entering thestairwell. When the doors are closed, the relief

damper opens to relieve excess pressure. If windis a problem, there may be another damper andlouver instead of a gooseneck as shown in Figure32. The pressure in the shaft is required by codeto be 0.10 in. w.g. (25 Pa) with respect to thevestibules when the doors are closed. (2009 IBC909.20.4.4).

In Figure 33 another approach topressurizing stairwells is shown. The stairwellconnects directly to the occupied spaces. A fanpushes air into a duct which is run up or down thestairwell to distribute air evenly. The dampers

are controlled by proportional actuators thatrespond to the pressure in the stairwell. About .1to .25” of pressure is maintained with respect tothe space so that smoke cannot enter thestairwell. Sometimes there is a VariableFrequency Drive (VFD) on the fan that adjusts italso. There are dampers every few floors thatrespond to the pressure near them. If thepressure increases, the dampers drive towardsclose. If the pressure falls, typically due to anopening of a door, then the damper opens.

The dampers must be UL555S (smoke)rated as they are part of a smoke system. If theyare in a fire wall they must also be UL555 (fire)Listed if the wall in which they are located is a fireand smoke wall. When the duct is run within thestairwell, then the dampers may not need to belisted depending on the local jurisdiction’s rules.


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Stairwell

FAN

ReliefDamper

Stairs

Occupied space

Vestibule

Doors

Occupied space

Vestibule

Fan

Reservoir

above doors

Figure 32. Vestibule stairwell pressurization system.

Figure 33. Stairwell pressurization system using proportional damper control.


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The actuator control is shown on the rightside of Figure 33. Power is delivered from atransformer which may be energized when the fanstarts. The control may be part of the building’sautomation system or may be discretecomponents. 4-20mA is common; 2-10V is shown

in Figure 33. The system only operates when afire alarm has occurred. At that time the fan andcontrols start to operate. When the controllersenses that the pressure in the stairwell has fallenbelow setpoint, it increases the signal to theactuator and opens the damper gradually. Thisbrings the pressure back up. If the controllersenses that the pressure has increased too high inthe stairwell, then it drives the damper towardsclosed until setpoint is achieved.

A smoke relay can cut power to the actuatorand controller to spring the damper closed ifoverride is required. Several methods are used.

Auxiliary switches can be used to indicate positionat the FSCS panel.

Other features may be used. In very tallbuildings where stack effect is extreme, there maybe walls and doors in the stairwell itself to restrictstack effect and smoke movement. A second fancould be used when the exit door is opened. Itturns on to prevent loss of pressure through theopen exit door.

Hoistway Venting

In some cases the shafts of elevators and

dumbwaiters must have smoke vents of specifiedarea at the top of the shaft. These could bedampered with actuators that open them if anyalarm goes off or they could be open permanently.Several exceptions exist including the presence ofan automatic sprinkler system. (2009 IBC 3004).

Elevator Hoistway Pressurization

Where no code exceptions exist, elevatorshafts must be pressurized or lobbies must beprovided. The hoistway must be pressurized to

between 0.10 inches of water (25 Pa) and 0.25inches of water (67 Pa) (2009 IBC 708.14.2.1 ).The geometry of the arrangement is very similar tostairwell pressurization. Very large fans areneeded for pressurization because elevator doorsare quite leaky – about ½ sq. ft. per door. For thisreason, sprinklers and lobbies are more common.Control is straightforward with the fan on if either

the alarm or smoke detection system respondsto fire or smoke.

Exhaust fans in the hoistway to assistvents are a possible alternative, but their use iscomplicated and it is not clear that they are agood method. Analysis is beyond the scope of

this article.Several ideas are being researched for

future consideration. Use of elevators forescape by the handicapped and entry of firefighters is allowed, but not covered here.

Underfloor air conditioning systems

Another proportional system can be foundin underfloor air distribution. The plenum underthe floor is pressurized with air to about 0.05 in.w.g. and dampers in boxes set into the flooropen and close to provide conditioned air into

the space. The walls of the plenum are typicallyfire and smoke barriers. A fire and smokedamper can be set into the wall and then a 2

nd

damper modulated to maintain the correct airpressure. Alternately, one damper may beprovided. It is a fire and smoke damper, but theactuator proportions to a 2-10V signal similar tothe method sometimes used in stairwells. SeeFigure 34. Note that this is not necessarily anengineered smoke control application and statusindication may not go back to the FSCS panel.

Elevator lobbies, with some exceptions,must be protected. The lobby walls are smoke

barriers if there are sprinklers and fire andsmoke walls if there are no sprinklers. Allsmoke barrier walls are designed to bepressurized.0.05 in. w.g. with respect to theadjacent space so the elevator lobby will resistsmoke entrance as long as fans are on;however, a formal pressurization system is nottypically used. The lobby will connect to astairwell. Some lobbies are designated areas ofrefuge. In those cases the lobby will have itsown ventilation air source and engineeredcontrols – it is more than just a lobby thatprovides part of the means of egress.

Containment dampers are prescribed inthe codes as they are critical to maintainingcompartmentation. Their operation is relativelysimple. Engineered systems are more complexand the fire protection or mechanical engineermust establish the size of design fires; calculateair flows and pressures; size fans and ducts:and ensure coordinated control.


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30

1

3

2

ComHot

24VAC

SignalCom

Signal2-10V

Power

DifferentialPressureController

Smoke Relaycloses uponactivation

Space

Stairwell

Typical for all

Actuator

Shaftcarrying

conditionedair

Underfloordistribution box

Combination fireand smokedamper with

2-10V control.Differentialpressuresensor

Controller Hot,Com24V

PressureSignal

Pressure must bemaintained at .05to .1 in w.c.

FAN

AHU

2-10VTo 0

reference

pressure

Safeties and

limits not shown

Figure 34. Underfloor air condition ing with proport ional actuation.

Summary

The systems and damper control wiringshown here are typical of the methods used tocontrol dampers in smoke control systems.Variations exist and each application must beexamined individually. Testing of smoke exhaustsystems by use of smoke generators whereappropriate allows confidence in the design andinstallations.

Dampers are required to maintain

compartmentation and restrict fire and smoke fromspreading outside of the area of origin. However,full engineered smoke control systems can

actively manage smoke and ensure means ofegress for occupants. Exhausting large spaceswith fans removes smoke. Preventing smokefrom entering exit corridors, lobbies, elevators,and stairwells is critical in allowing escape.Other smoke control methods prevent thespread of smoke in buildings and along witharchitectural planning can protect occupants.


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References

IBC. 2009 International Building Code,International Code Council, Inc. Country ClubHills, IL. www.iccsafe.org

Koffel, 2005. Table 3. Reliability of AutomaticSprinkler Systems. William E. Koffel, P.E., 2005.http://www.afscc.org/ReliabilityofSprinklerSystems.html

NFPA 80. Standard for Fire Doors and OtherOpening Protectives, 2007 Edition. NFPA, 1Batterymarch Park, Quincy, MA 02169-7471

NFPA 105. Standard for the Installation of SmokeDoor Assemblies and Other Opening Protectives,2007 Edition. NFPA, 1 Batterymarch Park,Quincy, MA 02169-7471

NFPA 2010. Table B. Combined SprinklerPerformance vs. Sprinkler Success in ConfiningFire to Room of Origin, by Property Use Group.

2003-2007 Structure Fires Reported to U.S.Fire Departments Where Sprinklers WerePresent in Fire Area, Fire Was LargeEnough to Activate Sprinklers, and BuildingWas Not Under Construction. U.S.Experience with Sprinklers and Other

Automatic Fire Extinguishing Equipment.John R. Hall, Jr. 2010. National FireProtection Association, Fire Analysis andResearch Division, Batterymarch Park,Quincy, MA 02169-7471http://www.nfpa.org/assets/files/PDF/OSsprinklers.pdf

NYC 2008. New York City AdministrativeCode, Title 29, New York City Fire Code.http://www.nyc.gov/html/fdny/pdf/firecode/2009/fire_code_ll26_2008_amended_ll37

_41_64_2009_final_complete.pdf . All

NYC codes can be accessed read only athttp://home2.nyc.gov/html/dob/html/model/construction_code.shtml


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VI. ACTUATORS

The requirements for actuators varies with damper size, temperature rating, and air velocity. Full information Belimo Americas product line can be obtained at www.belimo.us/firesmoke.

FSNF FSLF FSAF FSTF


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VII. ACCESSOIRES

BAE165 US

BAE165 US

www.belimo.us/firesmoke

Electrical thermal sensor. 165ºF

(50ºC). SPST opens on a rise intemperature. Manual reset.

This may be used for retrofits ofold, pre 2002, dampers only. Ithas passed UL555S with onemanufacturer. If the damper is acurrent UL555S listed assembly,use factory parts.

The FSAFB24-SR (-S)is available with 180in-lb & rev switch.


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For a catalog of kits: http://www.belimo.us/ishop/cms/sh/belimolibrary/acc/acc.html#MechanicalAccessories

In general the FSLF is not linkaged as it is direct coupled only. Ruskin makes a kit for replacement of MP2781 motorswww.ruskin.com. Enter FSLF120/MP or FSLF24/MP in Search.

REPLACEMENT INSTALLATION INSTRUCTIONS

Belimo publishes a number of replacement or retrofit ins tallation instructions atwww.belimo.us/firesmoke. Alternately, http://www.belimo.us/cms/sh/firesmoke/retrofit.php.

For cross reference go to:http://www.belimo.us/media/downloads/Technical_Documents/Fire_and_Smoke_Actuators/FS_Competitive_Replacement_Data_Cross_Reference.pdf

For a copy o f a general Fire Marshal or Bui lding Official form to leave on s ite after repair:http://www.belimo.us/media/downloads/Technical_Documents/Fire_and_Smoke_Actuators/3_MEA

_Fire_Marshal_Form_F&S_Actuators.pdf

Use of the specific form in the Belimo replacement instructions is recommended.


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Belimo worldwide: www.belimo.com

BELIMO Americas

USA Locations, 43 Old Ridgebury Road, Danbury, CT 06810

Tel. 800-543-9038, Fax 800-228-8283, [email protected]

1049 Fortunato Loop, Sparks, NV 89436

Tel. 800-987-9042, Fax 800-987-8875, [email protected]