Continuing Education Course

The Impact of Air ­Movement on High-Rise Commercial Fires BY Curtis Massey

TRAINING THE FIRE SERVICE FOR 137 YEARS

To earn continuing education credits, you must successfully complete the course examination. The cost for this CE exam is $25.00. For group rates, call (973) 251-5055. The Impact of Air ­Movement on High- Rise Commercial Fires

Educational Objectives On completion of this course, students will

1. Develop an understanding of where the air is going 3 review Thermal Stack Effect at high-rise fires 4. Discover ways to control the Stack Effect 2. Learn how high-rise construction-type effects on the Neutral Pressure Plane

BY CURTIS MASSEY

very high-rise breathes. Air moves Let us more closely examine this unique phenomenon and in and out and up and down. It is very important fire the reasons fire departments must understand it. Epersonnel responding to events in high-rises under- stand where the air is going. This will give the incident AIR BALANCE AND THE NEUTRAL PRESSURE commander (IC) a better idea of where the smoke and toxic PLANE (NPP) gases also may be going. If you understand how a build- Air balancing is easier to explain in relation to high-rise ing behaves and breathes, you will have a firmer grasp on commercial that are modern and use a “sealed where the problem areas are going to be and where the dan- envelope” approach to energy conservation. Hence, I will ger zones are within the confines of the building. You can break down that occupancy type. With newer buildings, literally predict where the smoke is most likely to go and, in do not open, and the curtain wraps the build- turn, where you should dedicate your resources to address ing up in a protective envelope, which allows for more cost- those problem areas, sometimes even before they begin to effective heating and cooling. However, the windows and expose themselves. You can minimize or even avoid poten- wall systems are rarely tightly sealed. Because of wind pres- tial casualty counts just by knowing how the building will sure or thermal air differences, the air squeezes in around be acting during the fire. Staying ahead of the game and tiny cracks that exist on each ’s exterior that are under not allowing yourself to have to play catch-up are vital to slight negative pressure (the bottom half of the building the successful outcome of a serious fire. Understand your in the winter/the top half in the summer). The air, then, is theater of operations. drawn into the core penetrations, because of a greater nega- Air balancing is directly associated with the concept of tive pressure, and pulled up (or down—summer) to stack effect. With stack effect, the temperature and pressure not under negative pressure and then pushed back out onto differentials between outside air and inside air dictate where those floors by the now greater positive pressure that exists the air currents will flow (horizontally and vertically) and in the core after the current of air has passed the NPP, thus where smoke is likely to follow. We know in cold weather pressurizing those upper/lower floors to a positive nature. that air is rushing up into the tower from the bottom of the The combined wind pressure and thermal differential may building and out onto upper floors, whereas in warm weather shift the NPP in the building. the reverse is true: Air is rushing down through the tower In the negative-pressure range of the building, the air is and out of the bottom. In cold weather, fires in high-rises act “pulled” into the building; in the positive-pressure range, the completely differently than they do in warm weather. What air discharges or “leaks” to the outside. When significant wind causes this flow of air to occur within the building relative to pressure is involved, it superimposes on the thermal balance temperature and pressure? The answer is the “air balance.” of the NPP and “shifts” it (depending on leakage rates). www.FireEngineeringUniversity.com ● Air Move­ ment

exchange in and out of vertical shafts in that area; therefore, Figure 1. Cold Weather Fire it is deemed to be neutral. It is under neither positive nor Air Balancing negative influences. Cold Weather On floors above and below this zone, air is rushing in and ROOF 25 25 out of the shafts and stairwells because of tempera- 24 24 ture and pressure imbalances. The farther floors are from the 23 23 NPP, the greater the differential air pressure is relative to the 22 22 outside and, thus, the velocity of air movement onto and off 21 21 20 20 of building floors. In cold weather (Figure 1), the air is being 19 19 drawn into the building through unsealed cracks at windows 18 18 and spandrel panels on each floor as well as through 17 17 16 16 entrances with revolving and swinging (and even load- 15 NPP NPP 15 ing docks). This is why when you enter a high-rise building 14No13 No13 14 through a lobby swinging , you instantly feel a rush of 12 12 air going past you into the building as the door is pulled 11 11 10 10 open—this is “makeup” air as a result of differential thermal 9 9 pressures entering the “” (the building). 8 8 In cold weather, air is sucked into the core because of the 7 7 6 6 negative pressure that exists on all floors below the NPP. 5 5 On floors above that zone, however, it is pushed out of the 4 4 core because of a positive-pressure influence. The infiltra- 3 3 2 2 tion, exfiltration, and air movement are relatively low just 1 1 above and below the NPP and are much greater at the top and bottom of the tower. The air travels up above the NPP Stairwell accessible at this oor and is pushed out of upper-floor curtain wall openings and Active elevator roof access doors, elevator machinery penthouses, and so Mechanical oor Massey on. The greater the differential pressure (outside vs. inside) Enterprises caused by the three influences (thermal/stack, wind pres- NPP - Neutral Pressure Plane © 2010 sure, and building pressurization), the higher will be the Note the intake “makeup” air being drawn into the core shafts, rate of air movement, leakage, and effect on the vertical lo- rising1312FEmasseyF1a above the neutral pressure plane (NPP), and pushing back cation of the NPP within a building. This also explains why out onto the upper floors. Air velocity into and out of core pen- etrations intensifies as the distance from the NPP increases. super tall high-rise buildings experience such severe stack effect problems while a typical 10-story building does not: The NPP shift also affects the building’s pressurization by The taller the tower, the greater the air intake and discharge mechanical HVAC (heating, ventilating and air-conditioning) caused by the significant height involved and floors distant systems—more outside air is brought into the building from the NPP. Positive-stack effect will be present in cold than is exhausted to the outside. Most buildings are slightly weather; negative-stack effect in warm weather. The higher pressurized (“bias”) by the HVAC systems to reduce cold air the building, the more pronounced the effects. infiltration, particularly in wintertime, which would affect The temperature difference between inside and outside the comfort conditions of occupants at the building perimeter and the height of a building play a major role—for example, zones. The building pressurization by HVAC systems is usu- if it is 34°F outside on a cold winter day and it is 74°F inside ally more significant than the thermal stack effect in moving a high-rise building, there is a 40°F temperature differential. the NPP. It is intentionally high to prevent the inrush of cold It can be expected that there will be a significant positive air into the ground-floor entrance through lobbies and into vertical stack effect taking place within the core penetrations elevator shafts (“whistling” doors) and stairwells. In highly with air channeling up and onto floors above the NPP while pressurized buildings, the surplus of outside air assists in negative-pressure influences will be in the bottom half of the pushing the thermal stack effect air back to the building’s tower, allowing the draw of “makeup” air into the building to lower levels, and thus the NPP has mechanically been shifted replace the warm air that is rising. downward in the building. In super tall high-rises during cold weather, the velocity From the aforementioned, it should be clear that the air of air channeling into the core from lower floors and lobby balance and NPP in a building shift up or down from the doors can be high enough to prevent elevator doors in the theoretical NPP midpoint in the building when air is moving lobby from opening or closing (photo 1) because of the horizontally as a result of wind pressure and through leakage sideward pressure on the elevator doors, tracks, or sliders as on nearly every floor. It also occurs vertically as a result of air is trying to rush into and up the elevator shafts. On lower stack effect and mechanical air pressurization. The NPP is floors, opened stairwell doors can be prevented from self- typically found for about one to three floors, depending on closing because of the pressure differential and air flow from the height of the building. There is virtually little to no air the floor into the shaft (photo 2). This should be a very real

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1 2 command center or created by fire department fans).

THERMAL STACK ­EFFECT One of history’s most prominent examples of cold/ winter stack effect was the 1993 bombing of the World Trade Center in . It occurred in February; the outside air temperature was 37°F, and there were light snow flurries. The tempera- ture inside the towers was ap- (1) Elevator doors unable to close as a result of the winter stack effect—air rushing into the shaft proximately 75°F. Four-and-a- from the lobby entrances. The doors will have to be forcefully closed by firefighters to begin Phase half minutes after detonation 2 operation. Lobby doorways must be closely controlled and supervised. (Photos by author.) (2) on the 2 level in This stair door is unable to self-close because of severe winter stack on Floor 13 of a 100-story the parking , there was building. These open doors well below the NPP can pull fire/smoke toward occupied exit , endangering evacuees on the floors above. Crews must check for these open doors to keep the a heavy smoke condition on stairway secure; stair pressurization is critical. the 110th floor of Tower 1 be- cause the bomb blast exposed concern if the fire is on a lower floor (below the NPP) in cold the base of the elevator and stair shafts of the nearby tower. weather. When evacuating these floors, the doors may not How did the smoke travel so far vertically so fast, approxi- self-close behind the fleeing tenants. This presents a serious mately 1,400 feet, in less than five minutes? Stack effect. problem for the IC from two perspectives: First responders could not control it that day because of the 1. The air (and smoke) being sucked into the stairwells effects of the vehicle bomb, but it can be controlled to a great is, of course, going to be drawn up to the NPP (located degree in typical high-rise fires by minimizing the time lobby roughly midway up the building) and discharged beyond the NPP onto occupied floors many levels above the Figure 2. Stack Effect actual fire area, thereby increasing the life threat to oc- cupants who may be in a “defend-in-place” posture as directed by fire command. 2. If one or both stair exit doors (in a two-stair core con- figuration) are not closing behind fleeing tenants (no stairwell pressurization), this ensures that the fire will also be drawn toward these openings, as the negative partial pressure of the shaftway will pull the fire and smoke toward it. Fire and smoke take the path of least resistance. Compromising one or both stairs on the fire floor where this situation is present would essentially Chimney turn both stair shafts into smoke towers and greatly endanger the people on upper floors staying put or Flues descending the stairs. Even though the attack has to be mounted through one of the stair openings, fire person- nel must verify that the other stair door is closed unless search teams are passing through it. Thinking through this equation with tall buildings, stair doors on lower floors would easily be pulled into the open Dampers position and may not close without human assistance while doors at the very upper floors will be fairly hard to open for tenants choosing to leave their floors since the strong air cur- rents caused by positive pressure will be pushing against the doors at these levels unless stairwell pressure relief dampers The building is a chimney, the core shaftways are flues, and the lobby entrances are dampers. The dampers 1312FEmasseyF2must be tightly are present and functioning. Fortunately, stair pressurization in controlled during high-rise fires to avoid pushing/pulling smoke modern buildings will minimize this effect once it is activated throughout the tower. The taller the building, the more pro- by the automated alarm system (or manually at the lobby fire nounced are the stack effect and air exchange.

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Figure 3. Hot Weather Fire 3 Air Balancing Hot Weather ROOF ROOF 25 25 24 24 23 23 22 22 21 21 20 20 19 19 18 18 17 17 16 16 15 NPP NPP 15 14 14 12No13 No13 12 11 11 10 10 9 9 8 8 7 7 (3) Hot weather fire. The lobby entrance door is being held open 6 6 by the outflow of cool air on a warm day. Failure to control these 5 5 doors can cause the loss of the staging floor below the NPP and 4 4 possibly also the lobby command post. 3 3 2 2 (and lobby entrance doors). Air moves around stairwell doors 1 1 and elevator hoistway landing doors at a higher rate than you might imagine. The better the elevator and stairwell Stairwell accessible at this oor door seals, the less potential for vertical air movement as a Active elevator result of stack effect. Even poor fire stopping on core poke- Mechanical oor Massey throughs (cable risers, for example) can feed the vertical air Enterprises flow going up or down within the core area. NPP - Neutral pressure plane © 2010 The winter air drawn into the building through curtain Note1312FEmasseyF1b the air being drawn into the core shafts and discharged wall leakage below the NPP into the plenum area below the NPP out onto the lower floors. Testing for carbon near the curtain wall is another concern relative to stack monoxide on the staging floor below NPP should be a standard effect in buildings in cold climates. In countless cases, this operating procedure. has resulted in the freezing and bursting of fire protection entrance doors (and external exit stair discharge doors if branch lines and piping systems supplying the heating coils present) are opened. Keep the “dampers” (street-level doors) of perimeter fan-powered variable air volume boxes or fan to the “flues” (core shafts) within the “chimney” (the build- coils; the lines do not contain antifreeze additives. As noted, ing) closed as much as absolutely possible (Figure 2). at the WTC complex during the 1993 bombing, numerous At this event, misguided media advised people to break windows were broken during the fire. Despite sprinkler windows on upper floors for fresh air (when, in fact, all but piping being insulated within 10 feet of the perimeter, the the top-most floors were only slightly affected by smoke freezing/bursting of these lines was a very valid concern in that truly impeded breathing). This just further exacerbated this midwinter incident after the utility company shut down the situation, as it provided a more efficient discharge point the steam service to perform necessary testing, which took a for the stack effect on floors well above the NPP, where the week. With the heat now down amid freezing temperatures outgoing pressure from core poke-throughs is greatest. It also and despite the loss of 300 windows, not even one sprinkler did not help the cause that the that served the lobby line froze. The management of the complex accomplished were being automatically recalled to lobby level and self- this by turning on all the fluorescent lights on all floors opening their doors, creating a more efficient intake point for once power was restored in the evening on the day of the the “makeup” air being drawn into these same shafts at the bombing. The lights created enough ambient heat to prevent base of the “chimney”—110 stories tall. a crisis within a crisis. Sometimes ingenuity proves its value How many fireground commanders would be contemplat- in aces. ing this threat from stack effect as part of their high-rise stan- In warm weather, outside air is drawn into the air-condi- dard operating procedures (SOP) checklist? Why is it not in tioned building on the upper floors (caused by negative-pres- every high-rise SOP that efforts need to be made to attempt sure influences by the descending of dense cool air), where it to control the stack effect in these types of fires? is quickly cooled by the HVAC system, pulled downward, and How does the air get into and out of the shaftways within discharged onto lower floors with the greatest “release” oc- the core of a building? The same way it squeezes through curring on the lowermost floors and at the lobby level (Figure unsealed or improperly sealed details of the curtain wall 3). When you enter a lobby through a swinging door in the

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summer (or a warm winter day), you can feel cool air rush out onto lower floors can channel a fair amount of smoke past you LEAVING the building—the opposite of what hap- onto the staging floor, contaminating it to the point of being pens during cold weather, when, at these entrances, the air untenable (especially if the HVAC system is turned off or not rushes past you and ENTERS the building. The natural flow in “pressurization” mode for the floors above and below the of air is important to note because it dictates where smoke fire). Fire crews would then be forced to drop down and re- will travel. Also, as previously noted, as air enters these stage several floors below, in turn moving equipment and re- shafts, the stair doors on the lower floors may not close be- lief crews farther from where they are needed. This includes hind fleeing tenants. Unbeknownst to the command post, the rapid intervention teams standing by “off air.” Losing your opposite can be true at the lobby level during warm weather staging floor is not a recipe for success; that is why it may be fires: Lobby doors may not be closing behind people leaving wise to also take CO readings BELOW the fire floor in warm the building or firefighters entering it (photo 3). Allowing this weather fires, especially on the staging floor, to ensure high- open channel for air to escape the tower will draw smoke level readings of CO do not exist where a great deal of smoke downward and further enhance the stack effect as this open- may not be present. This very real threat—is the staging floor ing becomes a notable “release point” for the negative draft. safe to occupy?—is easily overlooked in fires during warm It is important that responders be aware of this. weather. What about other tenant floors in this area where people may be maintaining a “defend-in-place” posture be- TRACKING OF CARBON MONOXIDE (CO) cause of the fire above them? This underscores the impor- The tracking of CO must be a part of the overall scope of tance of tracking CO movement at various intervals above the incident command process at high-rise fires. Tracking and below the fire area, in warm weather and cold weather CO above the fire and noting floor intervals where it may alike. In several high-rise fires in the United States, the lobby be collecting are vital to understanding where areas of great command post was lost because of the reverse stack effect’s danger might exist for fleeing tenants or tenants performing a pulling smoke down well below the fire floor and discharg- “defend-in-place” procedure dictated by the incident command ing it onto the lobby level, which was likely caused by open post when it is deemed unnecessary for upper floors to evacu- elevator cabs standing by in Phase 1 recall mode and prob- ate. Firefighters and command officers tend to focus mostly ably open stairwell doors that discharged into the lobby. on what is happening at and above the fire floor. However, we With a firm grasp of how air moves within a high-rise must monitor what is taking place below the fire floor as well. building in winter relative to temperature/pressure differen- tials, if you could choose where your fire would be the day FIRE FLOORS AND THE NPP you have to fight it, what would be the best option? If it is With an understanding of the air balance, NPP, and air at the base of the tower, smoke will get sucked into the core movement above the fire floor, we should ask ourselves the shafts and channeled up and out onto upper floors, so the question, What happens in high-rise buildings below the best place to have the fire would be on an upper floor—not fire floor in hot weather? We know that in cold weather, a just because the smoke does not have far to go as it rises positive stack effect is taking place, where air is rushing in but also because the air is pushing OUT of the upper-floor at the bottom of the tower, up past the NPP, and back out on penetrations. This air movement will assist in keeping much floors above. But, what is taking place when a fire strikes in of the smoke out of critical core chases since, in effect, it is summertime? If air is rushing into the core from the upper naturally “pressurizing” the upper floors and assisting in the floors, traveling down past the NPP, and pushing out the containment of smoke spread. base because of negative-temperature/pressure differentials On a hot summer day, the descending cool interior air will between inside/outside air, what happens in fires where the be rushing out of the vertical shafts below the NPP and onto air outside is much warmer than the air inside? the lower-level floors. This partial positive pressurization can Example: It is 95°F outside in July; inside, it is an average of be a major asset to smoke travel and containment although it 75°F on tenant floors. There is a 20°F temperature imbalance does provide one slight drawback: Air flowing onto the fire in play, and cooler air, being more dense, descends within the floor will be at a greater rate and will feed the fire to some tower. Let’s say the fire is on floor 15 of a 40-story building, degree once the attack stair door is propped open (the same below the NPP. If the smoke becomes significant and enters is true on upper floors in a cold-weather fire). However, the the core area, something important will occur. Surely, some of benefits of smoke containment outweigh this factor. There the smoke will rise because of the temperature of the heated may be some smoke migrating possibly because of greater gases from the fire. However, the air being channeled down positive pressure from the fire into the attack stair if no stair- from the upper floors with the negative stack effect will also pressurization capability is present and the fire is close to the pull some of the smoke (and toxic gases) down BELOW the core. This smoke will likely be drawn downward to floors fire floor, sometimes many floors below the fire. below (and sometimes well below) the fire in some propor- Why would this be an important concern? Where is the tion in these warm-weather events. staging floor? Typically, two floors below the fire. You can see where this area can easily be compromised, especially PRESSURIZATION SYSTEMS since it is below the NPP, where air is being forced back out Newer, modern commercial office buildings typically pos- of internal shaftways and poke-throughs. This air pushing sess stair (and sometimes elevator) pressurization systems,

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as well as at least floor pressurization capability during fires TESTING FOR HYDROGEN CYANIDE (HCN) and possibly full smoke removal capability, too, for the fire One other danger commonly overlooked is the threat of floor. Such systems provide a new air balance and a shift hydrogen cyanide (HCN) from the burning synthetic (foam, in the NPP of the building, and they assist tremendously in rubber) and natural (paper, wool) products present during containing vertical smoke movement in the building during a the combustion process. This gas is even deadlier than CO. working fire. Since many hospitals may not have the capability of testing Some building codes in milder climates require high-rise for HCN poisoning after a fatal fire, victims may often be buildings to have open vented elevator shafts for smoke pronounced dead from CO exposure when it could very well purging. Elevators serving the alarm floor would normally have been more directly related to the toxic gas HCN. Newer be recalled to the ground floor and remain out of operation gas sensors can test for and monitor the presence of HCN in (for civilian use) during a fire. In some high-rise buildings, addition to CO. Strongly consider having rapid ascent teams (heated) elevator pressurization systems have been installed and other crews take sample readings to check for high (i.e., the 52-story Manulife Centre in Toronto) to lower the levels of both of these deadly gases throughout the firefight- NPP and reduce the significant stack effect, the air pressure ing effort. on elevator doors (which can prevent doors from opening be- cause of sideway pressure on doors and tracks), and vertical ••• air movement from the lobby into the elevator shafts. It also curbs smoke going into the shaft and the machinery It is a widely acceptable standard practice that when a fire above during a fire. occurs in a high-rise building that the fire department ensure the evacuation of two floors above the fire floor, the fire WAYS TO CONTROL STACK EFFECT floor, and two floors below the fire floor. The remainder of You can control stack effect by doing the following: the occupants should remain in place. This is also commonly • Leave the building HVAC system on (unless it is clearly taught in fire warden training, as dictated by fire prevention proving detrimental to the cause), and allow it to main- bureau guidelines. Having a complete grasp on how far and tain positive pressure to floors above and below the fire. how fast smoke (and deadly CO/HCN) can travel remote from • Provide supervision for the lobby entrance doors. Mini- the immediate fire area because of air imbalance and stack mize open times, and verify throughout a warm-weather effect, it can be argued that these parameters must be reas- fire that they are closing after each use. sessed very early in a working incident. • Keep ground-level stair doors (interior or exterior Empowered with the knowledge of how air travels within discharge) closed when not being used by tenants or the confines of a multistory building, you can now predict fire crews. where the greatest threat from smoke spread will occur. If • Mechanically pressurize stairwells with fire department you can predict that, you can also predict and plan for where fans if a pressurization system is not present and operat- the greatest threat exists relative to occupant survival and ing (no gas-powered fans in the lobby, though, unless where you must concentrate your rescue teams. CO monitor- exhaust is vented to the exterior). ing, again, cannot be emphasized strongly enough. The next • Send elevator cars (except for one or two cabs) to the time you look at a 30-story building, look at it as a living/ second floor (if no is present) and place in hold, breathing 30-story chimney. Air balancing should be included monitored/controlled by a firefighter. Avoid opening in the training regimen of every department that responds to lobby hoistway doors, which will draw air into these fires in high-rises. ● shafts and enhance the existing stack effect and smoke movement. Author’s note: Thanks to Jack Smits, managing director • Ensure stairwell doors on the floors in the negative-pres- of engineering and technical services, Manulife Financial, sure zone are closing behind fleeing tenants and are not Real Estate Division, and Alan Reiss, former director of the oscillating in the open position. New York World Trade Center and current construction manager of the new Freedom Tower/ QUICK TIPS rebuilding project. • Cold weather: Expect rapid smoke spread to the upper floors from fires on the lower floors. ● CURTIS MASSEY is a former ladder company officer • Hot weather: Expect fires on the lower floors to contami- and manages Massey Enterprises Inc., which preplans nate several floors below the fire. Expect possible loss buildings for fire department operations in the United of the staging floor and possibly even the lobby com- States and Canada. He has been a high-rise instructor mand post. Most importantly, test early and often for CO and a lecturer and writer for many years. His concept of at designated floor intervals. Track it as you would your rapid ascent teams has been adopted and successfully personnel. used by departments across the country.

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COURSE EXAMINATION 1) Why is it important to understand where the air is going in a 8) In the negative-pressure range of the building, the air is high-rise incident? “pulled” into the building; in the positive-pressure range, the air discharges or “leaks” to the outside a. Allows the incident commander (IC) the probable location of a flow-path a. True b. Gives the IC a better idea of where the smoke and toxic gases b. False also may be going c. So that the truck company knows which windows to ventilate 9) What impact does heating ventilation and d. All of the above systems (HVAC) have on the NPP? a. Reduces air movement into the building 2) If you understand how a building behaves and breathes, you will b. Brings more air into the building than is exhausted to the have a firmer grasp on where the problem areas are going to be outside and where the danger zones are within the confines of the building c. Raises the NPP in center core buildings a. True d. All of the above b. False 10) The air balance and NPP in a building shift up or down from 3) you can minimize or even avoid potential casualty counts just by the theoretical NPP midpoint in the building when air is moving knowing how the ______will be acting during the fire horizontally as a result of wind pressure and thorough leakage on nearly every floor a. Smoke b. Fire gases a. True c. IC b. False d. Building 11) In super tall high-rises during cold weather, the velocity of air 4) Air balancing is directly associated with the concept of: channeling into the core from lower floors and lobby doors can be high enough to prevent which type of doors from opening or a. Stack effect closing? b. Neutral pressure plane (NPP) a. Fire doors c. Flow Path b. Office doors d. None of the above c. Elevator doors d. Entrance doors 5) When cold weather, air is rushing ______into the tower from the ______of the building 12) What could be the consequence of compromising one or both a. Down, Top stairs on the fire floor with an upward draft on the NPP during b. Up, Bottom cold weather? c. Down, Bottom a. Stabilization of the NPP d. Up, Top b. Turning both stairwell shafts into smoke towers, thereby endangering fleeing occupants 6) What building feature in newer high-rises seals the building like c. Overpressure of the attack stairs an envelope? d. None of the above a. Energy Efficient Windows b. Automatic fire doors 13) With regards to the Stack Effect, a commercial high-rise building c. Curtain is analogous to a ______as the core shaftways are flues d. Draft stops and the lobby entrances are dampers a. Chimney 7) Combined wind pressure and thermal differential may shift what b. Smokestack in the building? c. HVAC a. NPP d. None of the above b. Flow Path c. Fire gases d. None of the above www.FireEngineeringUniversity.com Continuing Education The Impact of Air Movement on High-Rise Commercial Fires

14) Even poor firestopping on core ‘poke-throughs’ such as cable 18) Which of the following is another way to control the risers can feed the vertical air flow going up or down within the Stack Effect? core area a. Mechanically pressurize stairwells with fire department fans a. True b. Send elevator cars to the second floor and place in the ‘Hold’ b. False position c. Ensure stairwell doors on the floors in the negative-pressure 15) What common fire gas should be tracked as part of the overall zone are closing behind fleeing tenants and are not oscillating scope of the IC process at high-rise fires? in the open position d. All of the above a. HCN b. CO 2 19) During cold weather, the IC should expect rapid smoke spread c. CO to the upper floors from fires on the lower floors d. O 2 a. True 16) On a hot summer day, the ______cool interior air will b. False be rushing ______of the vertical shafts below the NPP and on the lower-level floors 20) During hot weather, the IC should expect fires on the lower floors to contaminate several floors below the fire and possibly a. ascending, out the lobby command post b. descending, in c. ascending, in a. True d. descending, out b. False

17) Which of the following is a way to control the Stack Effect? a. Leave the building HVAC system on and allow it to maintain positive pressure to floors above and below the fire b. Provide supervision for the lobby entrance doors c. Keep ground-level doors closed d. All of the above Notes

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PROGRAM COMPLETION INFORMATION If you wish to purchase and complete this activity traditionally (mail or fax) rather than Online, you must provide the information requested below. Please be sure to select your answers carefully and complete the evaluation information. To receive credit, you must receive a score of 70% or better. Complete online at: www.FireEngineeringUniversity.com

PERSONAL CERTIFICATION INFORMATION: Answer Form Please check the correct box for each question below. Last Name (PLEASE PRINT CLEARLY OR TYPE) 1. ❑ A ❑ B ❑ C ❑ D 11. ❑ A ❑ B ❑ C ❑ D 2. ❑ A ❑ B ❑ C ❑ D 12. ❑ A ❑ B ❑ C ❑ D First Name 3. ❑ A ❑ B ❑ C ❑ D 13. ❑ A ❑ B ❑ C ❑ D 4. ❑ A ❑ B ❑ C ❑ D 14. ❑ A ❑ B ❑ C ❑ D Profession/Credentials License Number 5. ❑ A ❑ B ❑ C ❑ D 15. ❑ A ❑ B ❑ C ❑ D

Street Address 6. ❑ A ❑ B ❑ C ❑ D 16. ❑ A ❑ B ❑ C ❑ D 7. ❑ A ❑ B ❑ C ❑ D 17. ❑ A ❑ B ❑ C ❑ D Suite or Apartment Number 8. ❑ A ❑ B ❑ C ❑ D 18. ❑ A ❑ B ❑ C ❑ D 9. ❑ A ❑ B ❑ C ❑ D 19. ❑ A ❑ B ❑ C ❑ D City/State Zip Code 10. ❑ A ❑ B ❑ C ❑ D 20. ❑ A ❑ B ❑ C ❑ D

Daytime Telephone Number with Area Code Course Evaluation Fax Number with Area Code Please evaluate this course by responding to the following statements, using a scale of Excellent = 5 to Poor = 1.

E-mail Address 1. To what extent were the course objectives accomplished overall? 5 4 3 2 1

traditional compleTION INFORMATION: 2. Please rate your personal mastery of the course objectives. 5 4 3 2 1 Mail or fax completed answer sheet to 3. How would you rate the objectives and educational methods? 5 4 3 2 1 Fire Engineering University, Attn: Carroll Hull, 1421 S. Sheridan Road, Tulsa OK 74112 4. How do you rate the author’s grasp of the topic? 5 4 3 2 1 Fax: (918) 831-9804 PAYMENT & CREDIT INFORMATION 5. Please rate the instructor’s effectiveness. 5 4 3 2 1 Examination Fee: $25.00 Credit Hours: 4 6. Was the overall administration of the course effective? 5 4 3 2 1 Should you have additional questions, please contact Pete 7. Do you feel that the references were adequate? Yes No Prochilo (973) 251-5053 (Mon-Fri 9:00 am-5:00 pm EST).  ❑ I have enclosed a check or money order. 8. Would you participate in a similar program on a different topic? Yes No  ❑ I am using a credit card. 9. If any of the continuing education questions were unclear or ambiguous, please list them. My Credit Card information is provided below. ______ ❑ American Express  ❑ Visa  ❑ MC  ❑ Discover 10. Was there any subject matter you found confusing? Please describe. Please provide the following (please print clearly): ______Exact Name on Credit Card 11. What additional continuing education topics would you like to see? Credit Card # Expiration Date ______Signature PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS.

AUTHOR DISCLAIMER INSTRUCTIONS COURSE CREDITS/COST The author(s) of this course has/have no commercial ties with the sponsors or the providers of the unrestricted educational All questions should have only one answer. Grading of this examination is done manually. Participants will receive All participants scoring at least 70% on the examination will receive a verification form verifying 4 CE credits. grant for this course. confirmation of passing by receipt of a verification form. Participants are urged to contact their state or local authority for continuing education requirements. SPONSOR/PROVIDER EDUCATIONAL DISCLAIMER RECORD KEEPING No manufacturer or third party has had any input into the development of course content. All content has been derived The opinions of efficacy or perceived value of any products or companies mentioned in this course and expressed PennWell maintains records of your successful completion of any exam. Please go to www.FireEngineeringUniversity.com to from references listed, and or the opinions of the instructors. Please direct all questions pertaining to PennWell or the herein are those of the author(s) of the course and do not necessarily reflect those of PennWell. see your continuing education credits report. administration of this course to Pete Prochilo, [email protected]. Completing a single continuing education course does not provide enough information to give the participant the COURSE EVALUATION and PARTICIPANT FEEDBACK feeling that s/he is an expert in the field related to the course topic. It is a combination of many educational courses and © 2009 by Fire Engineering University, a division of PennWell. We encourage participant feedback pertaining to all courses. Please be sure to complete the survey included with the course. clinical experience that allows the participant to develop skills and expertise. Please e-mail all questions to: Pete Prochilo, [email protected]. www.FireEngineeringUniversity.com