CA2426391A1 - Stairwell pressurization system - Google Patents
Stairwell pressurization system Download PDFInfo
- Publication number
- CA2426391A1 CA2426391A1 CA002426391A CA2426391A CA2426391A1 CA 2426391 A1 CA2426391 A1 CA 2426391A1 CA 002426391 A CA002426391 A CA 002426391A CA 2426391 A CA2426391 A CA 2426391A CA 2426391 A1 CA2426391 A1 CA 2426391A1
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- Canada
- Prior art keywords
- stairwell
- door
- air
- duct
- air duct
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04F—FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS
- E04F17/00—Vertical ducts; Channels, e.g. for drainage
- E04F17/04—Air-ducts or air channels
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/0001—Control or safety arrangements for ventilation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/32—Responding to malfunctions or emergencies
- F24F11/33—Responding to malfunctions or emergencies to fire, excessive heat or smoke
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/0001—Control or safety arrangements for ventilation
- F24F2011/0002—Control or safety arrangements for ventilation for admittance of outside air
- F24F2011/0004—Control or safety arrangements for ventilation for admittance of outside air to create overpressure in a room
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Building Environments (AREA)
- Respiratory Apparatuses And Protective Means (AREA)
- Ventilation (AREA)
Abstract
A stairwell pressurization system may be installed in either new or existing low-rise or high-rise buildings and has at least one air duct and a fan system consisting of one or more fans which are operable to force substantially smoke-free air into the duct under a positive pressure.
One or more air outlets are provided on the duct in the stairwell in the vicinity of each hallway exit door leading into the stairwell. The air outlets are most preferably vertically elongated and oriented so as to direct air from the duct at the opening edge of the stairwell entrance door. The air outlets are electrically, electronically or physically connected to the stairwell door so as to be selectively opened or closed with the movement of the adjacent door. In a simplified construction. one of the elongated air outlets opens into the duct and is normally maintained in a non-air flow position by a baffle door which is moved to open or close the air outlet. The stairwell entrance door has one end of a pulley cable coupled thereto, with the other end coupled to the baffle door. The baffle door is connected by a pivot and is biased in a closed position by a spring. As the stairwell entrance door is swung open. the pulley cable is drawn therewith.
moving the baffle door so as to be opened together with the stairwell exit door. Air is then directed from the pressurized air duct through the elongated air outlet and along the open edge of the stairwell door. As the door progressively opens, the air outlet opens wider to direct more air from the pressurized air duct at the stairwell door through an elongated air outlet.
One or more air outlets are provided on the duct in the stairwell in the vicinity of each hallway exit door leading into the stairwell. The air outlets are most preferably vertically elongated and oriented so as to direct air from the duct at the opening edge of the stairwell entrance door. The air outlets are electrically, electronically or physically connected to the stairwell door so as to be selectively opened or closed with the movement of the adjacent door. In a simplified construction. one of the elongated air outlets opens into the duct and is normally maintained in a non-air flow position by a baffle door which is moved to open or close the air outlet. The stairwell entrance door has one end of a pulley cable coupled thereto, with the other end coupled to the baffle door. The baffle door is connected by a pivot and is biased in a closed position by a spring. As the stairwell entrance door is swung open. the pulley cable is drawn therewith.
moving the baffle door so as to be opened together with the stairwell exit door. Air is then directed from the pressurized air duct through the elongated air outlet and along the open edge of the stairwell door. As the door progressively opens, the air outlet opens wider to direct more air from the pressurized air duct at the stairwell door through an elongated air outlet.
Description
STAIRWELL PRESSURIZATION SYSTEM
SCOPE OF THE INVENTION
The present invention relates to a stairwell pressurization system which can be employed to prevent the spread of smoke from hallways or corridors into the stviirwell of~n low-rise or l~i~.~h-rise building. More particularly, the stairwell pressurization system is operable to maintain a stairwell at a largely smoke-free low positive pressure (0.05-0.10 in.w.g.) relative m lmllways or corridors to reduce or eliminate asphyxiation in stairwells as a result of smoke inhalation.
thereby providing a passage of escape and facilitating the movement of firefighters throu~~hout the building to the fire and any trapped occupants. The difference between the existing pressurized system designs and the new invented system is that whcri;as the previous ones use 100% positive pressure in the stairways, tine new design uses 90% air velocity in front ol~cach individual exit door creating an air e.ortine that will keep the smoke out of the: stair shaft wl~iir at the same time using a very small volume of air thus avoiding the previous problem related to (ire overfeeding. The remaining 10% refers to low positive pressure in the stairwell.
BACKGROUND OF THE INVENTION
In Canadian residential apartment buildings, fire code regulations in most regions stipulate that in the event of a tire, residents are to stay inside their individual dwellings c>r apartment units, and ought not to use elevators or travel along hallways or in other common areas.
An area of concern is what happens to individuals who are in a hallway.
c~~n~n~on army. or stairwell when a fire alarm is first initialized, and smoke is originating from lower floor areas.
Occupants, who attempt exiting the building by going down the stairwell stairs towards tl~~ mnin floor and safety, may find themselves facing a stairwell that is full of smoke. In such a situation,
SCOPE OF THE INVENTION
The present invention relates to a stairwell pressurization system which can be employed to prevent the spread of smoke from hallways or corridors into the stviirwell of~n low-rise or l~i~.~h-rise building. More particularly, the stairwell pressurization system is operable to maintain a stairwell at a largely smoke-free low positive pressure (0.05-0.10 in.w.g.) relative m lmllways or corridors to reduce or eliminate asphyxiation in stairwells as a result of smoke inhalation.
thereby providing a passage of escape and facilitating the movement of firefighters throu~~hout the building to the fire and any trapped occupants. The difference between the existing pressurized system designs and the new invented system is that whcri;as the previous ones use 100% positive pressure in the stairways, tine new design uses 90% air velocity in front ol~cach individual exit door creating an air e.ortine that will keep the smoke out of the: stair shaft wl~iir at the same time using a very small volume of air thus avoiding the previous problem related to (ire overfeeding. The remaining 10% refers to low positive pressure in the stairwell.
BACKGROUND OF THE INVENTION
In Canadian residential apartment buildings, fire code regulations in most regions stipulate that in the event of a tire, residents are to stay inside their individual dwellings c>r apartment units, and ought not to use elevators or travel along hallways or in other common areas.
An area of concern is what happens to individuals who are in a hallway.
c~~n~n~on army. or stairwell when a fire alarm is first initialized, and smoke is originating from lower floor areas.
Occupants, who attempt exiting the building by going down the stairwell stairs towards tl~~ mnin floor and safety, may find themselves facing a stairwell that is full of smoke. In such a situation,
2 an individual is faced with a choice between potential asphyxiation in the stairwell or going hack towards the floor that is on fire.
Smoke in stairwells also hampers floe ability of f refighters to tight fires.
In particular, smoke in stairwells hampers both breathing and visibility, making it difficult and time consuming to penetrate the smoke in tile stairwell while going up the stairs towards the firs affected area.
Various individuals have proposed pressurizing stairwells with a vicv~.~ to removing smoke, so as to facilitate escape froth bunging buildings and the ability of lirefighters to reach their destinations quickly. To date, however, conventional stairwell pressurization systems have achieved only limited effectiveness, particularly with taller high-rise buildings in excess of four or more stories.
In particular, conventional stairwell pressurization systems operate with the objection c~f providing the stairwell with a constant high pressure relative to the building hall~~~ays. 'I l~c positive pressure maintained in the stairwell may make stairwell hallway exit doors difficult to open, particularly for very young children and the elderly. This problem of overpressurization is common to all previously designed systems. I3y design, the new system will eliminate the problem as well as the fire growth caused by high volume ofair escaped from the stairwell into the hallways. Furthermore, it has been found that opening hallway exit doors Iea~lin;~~ inta~ ihc stairwells for even a comparatively brief period of time results in a dramatic clecr~ase ion :;tuirwll pressure, particularly if multiple doors are opened on different levels. As a result, it may tnk~
several minutes for conventional pressurization systems to achieve or return to an effective positive pressure state.
SUMMARY OF THE IN VENTION
It is an object of the invention to develop a system for providing a substantially smoke-free stairwell, which reduces or eliminates the concern of individual asphyxiation in stairwells as a result of smoke inhalation.
Another object of the invention is to provide an economical stairway prcssuriiatic~n system which may be installed in either new or existing constructions, and which is conligumd to reduce smoke penetration into emergency stairwell areas.
Another object of the invention is to provide a stairwell pressurization system which may be used in conjunction with a conventionatl or existing fire alarm system.
A further object of the invention is to provide a stairwell pressurization system which. is configured to provide an increased positive pressure correlated with air velocity at ioclivi~lual vertical locations within a stairwell at the point where each stairwell exit door may be: opened.
A further object of the invention is to provide a stairwell pressurization system whirls is either mechanically, electrically or electronically coupled to individual stairwell exit doors and which is adapted to selectively provide a pressurized airflow at vertically spaced locations witl~iu the stairwell itself adjacent to a given hallway exit/stairwell entrance door which is opened.
It is a further object of the present invention to provide a stairwell pressurization system that is selectively operable to pressurize a high-rise stairwell concurrently with the nctivaiic~l~ oi~u conventional fire alarm system.
The present invention provides for a stairwell pressurization system which may be installed in either new or existing low-rise or high-rise buildings. The stairwell pressurization system has at least one air duct which, in a simplified construction, could consist of a stmt mct,ll pipe or duet, and a fan system consisting of one or more fans which are opcral,l,: to tore substantially smoke-free air into the duct under a positive pressure greater than almosphcrlc pressure. At least one and more preferably two air outlets arc provided on the duct in the stairwell and preferably in the vicinity of one or more hallway exit doors leading into the stairwell. The air outlets are most preferably vertically elongated and oriented so as to direct air from the duct at the opening edge of the stairwell entrance door. Optionally, the air duct may also include a duct opening for providing passive pressurizing airi7ow into the stairwell. In the preferred embodiment, one or both elongated air outlets are electrically, clrctronirally or physically connected to the stairwell door, as for example by an electric and/or electronic swiUh and/or by a pulley cable and hinge construction, so as to be selectively opened or closed with tl~c movement of the adjacent door.
In one simplified construction, a first one of elongated air outlets opens into the duct and is normally maintained in a non-air flow position by a baffle door which is moved to open or close the air outlet. 'The stairwell entrance door has one end oFa policy cable coupled thereto.
with the other end coupled to the baffle door. The pulley cable may be maintained in position and guided by threading the cable through pulleys or a rigid or flexible pipe.
The baffle dour is connected to the pressurized air duct by a pivot and is preferably biased in a closed position by a spring. As the stairwell entrance door is swung open, the pulley cable is dram.~n thwewith, moving the baffle door so as to be opened together with the stairwell exit door. Air is then directed from the pressurized air duct through the elongated air outlet and along the open cclge of the stairwell door. As the door progressively opens, the air outlet opens wider to direct more air from the pressurized air duct at the stairwell door through an elongated air outlet.
The second air outlet preferably extends at least half the height of the adjacent stairwell entrance door. The second air outlet is most preferably provided in gaseous communication ~a-iil~
the pressurized air duct or with the stairwell itself, and in a most preferred construction is lo~,otcd immediately adjacent to the first elongated air outlet. The second elongated air outlet is provided with an electric blower which is operable to draw air From within the air duct as a high velocity air flow and is simultaneously operating together with the buffer door at the exact momeW when the exit door to the stairways is opened. This type of design enables an instant response of the system correlated to the opening of a particular exit door at any level of the stair shaft. 'l~hc response time of the previous systems was of about ten minutes af~cer the door opening.
The blower and second air outlet is preferably activated siloultaneously with the loaf~tlc door causing the overall pressure in the stairwell to drop below a threshold amount, or in a nuost preferred construction if the adjacent stairwell entrance door is opened beyond a hredctcraninr:l distance.
Optionally, a bellowing smoke canopy or cover may be located above the stairwell door and which extends horizontally into the stGrirwell. The canopy serves as a physical barrier to prevent smoke from curling upwardly past the door jamb and into the stairwell when the stairwell entrance door is opened.
In a typical high-rise building, the air duct is connected to variable speed fans lclccrittl ~~n the building roof, in the basement, and/or on the ground floor of the building. 'fhe numhcr c~l~
fans and location is largely dependent upon the type of building. 1n the event of a iirc, the l~~rns are operated at the same time as the existing fire alarnl system to force substantially smoke-free;
air into the high pressure duct. The operation of the fans forces air from outside the builc.ling into the high pressure duct (is assumed to be 8-10 times higher than tl7e 1111r111111r111 pressure in tile stairwell) to create the possibility of air velocity in front of the exit door when a particulclr vloor i::
opened. The air cortine has the ability to inhibit the movement of smoke from floe buildin4.e.
hallways and common areas therein, creating a safe area for individuals to exit the l~uildin~~. 'I'hc system may be further configured to turn off any secondary rooftop ventilation system, which provides airflow to the building hallways or common areas.
A tripping mechanism to activate the fan system as well as an elongated air duct and blower, may also be provided. With such a construction, pressure sensors in the stairw:lls are used to sense a pressure drop in the case of several stairwell exist doors being opcnccl simultaneously. Upon sensing the pressure drop, the sensors provide a signal to fans to opcr,ri~
at increased power and speed until the stairwell pressure is returned to a predetermined threshold.
G
In the event of a fire, the stairwell pressurization system is activated to raise and maintain the pressure of the stairwell at a level greater than the pressure that exists in the hallv-ays ,~r corridors.
When a stairwell entrance door is Ilrst opened to a pre-selected degree, the movement of the door draws the cable to move the baffle door to open the first elongated air outlet. 'fit opening of the air outlet allows air to IZow from the duct via the air outlet anti towards the capon edge of the door. rfhe air flow maintains the pasitive pressure in the stairwell and forces anv smoke at the stairwell entrance door back into the hallway.
At the exact moment when the door is swung open an electric switch is triggered to activate the blower and provide additional air flow from the second air outlet. 'l~hc additional air flow acts to both compensate for the reduction in pressurization <:~ccurring as a result oCth c wider door opening, as well as providing still increased air Ilow towards the door opening to Ii~rthcr limit the amount of smoke which may enter the stairwell through the open door.
Optionally, the blower may be operable at variable speeds to provide increased air flow as the exit door is opened wider.
1n a more preferred construction, if many stairwell entrance doors arc opened simultaneously, resulting in a drop off ol~pressure in the stairwell, one or more blowers anti second vertically elongated air outlets are activated to direct more air velocity towards the now opened stairwell entrance door blocking smoke from the hallway back into the stairway. 'I'hc advantage created by the new system is that no volume of air will escape in the halUva~- during the period of time when the respective door is kept open.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects of the invention will become apparent upon reading the following detailed description and drawings, in wlaieh:
Figure 1 is a schematic illustration of a high-rise building stairwell incorporating stairwell pressurization system in accordance with a first embodiment of the invention:
Figure 2 illustrates an enlarged partial perspective view of the stairwell landing shown as "A" in Figure l, illustrating the air duct and air outlets used in the stairwell pressurization system of Figure 1;
Figure 3 illustrates a schematic cross-sectional view of the stairwell pressurization air duct used in the system shown in Figure 2 taken along lines 3-3;
Figure 4 illustrates an enlarged partial cross-sectional view of the stairwell door and duct shown in Figure 3;
Figure 5 illustrates a perspective view of a hallway exit/stairwcll entrance door shown in Figure 2 leading into the stairwell, in an initial partially open position;
Figure 6 illustrates schematically the stairwell shown in figure 1 with the stairavrll pressurization system in an activated condition during a fire;
Figure 7 illustrates a schematic perspective view of an air duct and air outlet used in nn air pressurization system in accordance with a further embodiment;
Figure 8 illustrates a cross-sectional view of an air duct and air outlets used in the pressurization system in accordance with a further embodiment of the invention; and Figures 9 and 10 illustrate a schematic perspective view of an air duct and air outlet used in an air pressurization system in accordance with another embodiment of the invention.
g DETAILED DESCRIPTION OF THE PREFERRED EMF30DIMEN fS
Reference is first made to Figure 1 which partially illustrates a multi-story buildinr 10.
For clarity, the building 10 is shown illustrating four floor areas I, II, III
and IV, each characterized by a respective hallway 12 providing access to individual floor units (not shown) and which terminates at a hallway exit/stairwell entrance door 14. In a conventional tnamlcr, a vertically extending stairwell 16 extends the height of the building 10 from the ground floor l 8 to the roof 20. Stairs 22 within the stairwell 16 lead from each stair~ve(1 entrance door 1 a and provide a secondary emergency exit from each of the high-rise floors I, II, II
I and 1V to cnahle occupants 8 (Figure 6) to exit the building 10 via emergency exit door 24 located on the ground floor 18. A pressure relief vent 26, not necessary required for this embodiment of the. invention may be provided in the stairwell 1 fi, which upon a predetermined threshold pressure being reached opens to prevent overpressurization of the stairwell.
Figure 1 illustrates best the building 10 as including a stairwell pressurization svsl~m identified generally as 30. As will be described, the pressurization system >0 is n~~rmallv maintained in an inactivated and non-pressurized state. The system 30 is electronically coupled to the building fire alarm system 32 so as to be concurrently activated therewith to prcssuri~~ the stairwell with substantially smoke-free air at a low pressure in the stairwell of between about 0.05 and 0.10 in.w.g. relative to the pressure in the hallways in the event of a hre.
The stairwell pressurization system 30 includes a high pressure air duct 34, a pair of air duct pressurization fans 36,38 not necessary required for all the embodiments ofthe invention. a stairwell propeller pressurization fan 40 (see 6g.1 ), and a number of pairs of high velocity air outlets 42,44 (Figure 2) located within the stairwell 16 adjacent to each of the staimvav entrance doors 14. In a simplified construction, the air duct 34 consists of a sheet metal duct which extends vertically the height of the stairwell 16 from building ground floor I
to tine toh Moor 1V, In the embodiment shown in Figure l, the duct pressurization fans 3Ci, 38 arc shown as bcin~
provided in gaseous communication with each end of the duct 34, with a first fan 3G hositionccl at the ground floor level adjacent to the exterior sidewall of the building 10 and a second lan 3S
<~
being positioned on the building roof 20. The fans 36,38 which are used to force air into the air duct 34 at a positive pressure above atmospheric pressure, and most preferably a pressure of between about 0.05 and 0.10 times atmospheric pressure. It is to be appreciated that the duct pressurization fans 36,38 are used to provide a pressurized source of substantially smoke-('rcc air into the stairwell 16. The final positioning of the d~~ct pressurization fans 36,38 thcretere is selected so as to be spaced remotely from any likely path of smoke in the event of tire.
'The stairwell low pressurization fan 40 most preferably consists of a regular hrohcllcr lao located at the top of the stairwell 16. A wind shield 46 may be provided around the I;m ~() to minimize or reduce the likelihood of the fan 40 drawing smoke into the stairwell 16 in the: event of a fire condition and also to minimize the external wind influence. In low-rise buildings, the stairwell pressurization fan 40 may be omitted in its entirety. 'fhe stairwell pressurization fan 40 and duct pressurization fans 36,38 are operable with the building tire alarm system 32 to provide a general positive pressure throughout the stairwell 16 and in particular in high-rise buildings of five stories or more. Optionally, each of the fans 36,38,40 may be provided with a smoke and/or heat sensor which when activated are operable to disable the operation of a given associated l~ar~
so as not to return smoke into the stairwell 16.
Figures 2 to 4 illustrate best the high velocity air outlets 42,44. which are used to divert pressurized air from the air duct 34 towards an adjacent stairwell entrance door 14 at cacl~
stairwell landing in the stairwell 16. It is to be appreciated that the stairwell pressurizalion system 30 is most preferably constmeted with the air outlets 42,44 shown in Fi~.ure 2 li~c~~t~ci adjacent the stairwell entrance door 14 on each building floor I, Il, III, IV.
In a more ecc~nc~mica~l embodiment, however, the outlets 42,44 may be provided on alternate floors or adjacent key entrance/exit doors only.
As seen best in Figures 2 and 3, the air outlet 42 is provided as a vertically elongated outlet which has a height which is at least 3/4 the vertical height of the door 14. The outlet 42 is positioned vertically along the duct 34 so as to be oriented towards and adjacent to the openin~~
edge 46 of the stairwell entrance door 14. The outlet 42 is fi.~rmed so that when activated, tlic outlet 42 directs an elongate flow of air fram the duct 34 between the edge of the door 46 and the door jamb 48 as an air curtain, to prevent smoke from the adjacent hallway 12 from moving bast the door jamb 48 and into the stairwell 16.
As shown best in Figures 3 and 4, the outlet 42 is activated to permit air flow 1?y rneaos of a spring biased baffle 50. The baffle 50 is formed as a generally rectangular panel which i hingely mounted on a swing arm 51 within the air duct 34 for movement about a pivot S2. 'I'hc baffle 50 is movable about the pivot 52 between a closed position when the baffle 50 substantially overlies and seals an inner end of the outlet 42 preventing air flow therefrom, and the open position shown in phantom where the baffle 50 is swung away from the outlet 42 to permit air to flow from the duct 34 outwardly therefrom. A spring 54 is rruvidcd to resiliently bias the baffle 50 to the normal closed position when the door 14 is closed relative to the door jamb 48.
The baffle 50 is mechanically coupled to the door 14 so as to be selectively ot~ea~e~l or closed therewith. In this manner, the air outlet 42 is only activated to direct a pressurized air flow from the air duct 34 when the adjacent stairwell door 14 is opened. In a simpli(icd construction, the baffle 50 is physically opened or closed by means of a llexiblc cable C0. The cable 60 extends from a first end coupled to the baf'flc 50 to a second end connected to the top of the stairwell entrance door 14. One or more pulley guide tubes 62 are provided fbr guiding the cable 60 as it is drawn by the moving door 14. Most preferably, the end of the cable 60 is coupled to the door 14 by a spring biased tensioner 64. 'The tensioner 64 may, in a simplii icd construction, consist of a spring biased plunger which is adapted to prevent ovcrtensioniug of the cable 60 as the door is moved to the fully opened position shown as P2 in phantom in figure 4.
In this manner, as the door 14 pivots inwardly into the stairwell 16, the movecncr~t of the door l~l draws the cable 60 so as to move the baffle SO against the bias of the sparing 54 allowing air to flow from the pressurized duct 34 via the air outlet 42. As the air outlet 42 forms an elon~at~cl opening and is oriented towards the opening door 14, there is a resulting airflow directed clung the length of the door opening. 'The airflow continues only as long as the door 14 is open a~ut acts as an air curtain to prevent smoke and air movement from the hallway 12 into the stairmll 16. Once the door 14 is closed, the spring 54 returns the baffle 50 to its closed position, drawing the cable 60 therewith.
Furthermore, it is appreciated that because the baffle 50 is mechanically coupled to the door 14, in the opening of the duct 42, the baffle 50 initially moves in direct proporlic~n to the degree of movement of the door 14. As such, as the door 14 moves i~rom the closed position as shown in Figure 3 to the initial partially opened position shown in phantom f1, the air ovitlet 4?
progressively opens to provide increased air flow in proportion with the degree oFdoor movement.
Figures 3 and 4 illustrate the second air outlet 44 as similarly comprising a vertically elongated outlet having a height substantially corresponding to that of the door 1 ~l. f~ lthou~~h nc~t essential, the air outlet 44 is for ease of installation most preferably located tmmedtately ad,jaccnt to the first air outlet 42. As with the outlet 42, the outlet 44 is formed so that when activated, it emits an elongated air flow towards the opening edge 46 of the door 14 and door jamb 48.
Figures 2 and 3 show best the air outlet 44 as being in gaseous communication, but not necessary required in all embodiments of the invention with the pressurized air duct 34.
An electric air blower 70 is mounted towards the rear of the air outlet 44. (fhe air blower is selectively operahlc to draw air from the duct 34 outwardly from the outlet 44 as a high velocity pressurizing uir flow. In an alternate embodiment., however, the second air blower 70 and air outlet 4~I nwv br configured to draw air from the stairwell I6 itself. The air blower 70 is electrically coupled to the door 14 so as to be actuated on the movement of the door. In particular, the tcnsioncr 64 is provided with a contact switch 72 which, for example, is configured so that when the door I 4 is opened beyond a first predetermined threshold amount P 1 (Figure 3), the contact switch 7? is closed completing the electric circuit to activate the air blower 70. ~fhc activation c~f tltc air blower 70 thus provides a second linear i7ow of air towards the opening side o1~ the door 1 ~ W
further prevent movement of smoke from the hallway 12 past the door jamb 48 and info the stairwell 16, as for example is shown best in Figure 5. In an alternate embodiment, the blower 70 may be adapted to provide a variable fan speed in proportion to the degree oFwhich the adjacent stairwell entrance door 14 is opened. In SLtch a configuration, as the door 14 opens wider, the speed of the blower fan 70 increases to provide an increasing counter-pressurizing air flow.
To avoid an overpressurization in the stairwell 16, the air blower 70 is electrically coupled to the door 14 so that the re-closing of the door 14 results in the release of the ccmtac t switch 72 to deactivate the blower 70. It is to be appreciated that an overprcssurization in tl~c stairwell 16 could otherwise prevent elderly persons or small children from opening the stairwell entrance doors 14 in the event of a tire.
As shown best in Figure 2, canopy 80 is further provided directly above the door 14. The canopy 80 comprises a horizontally e~ctending panel which projects inwardly into the stairwell 1 (i immediately above the door jamb 48. This panel 80 assists in directing pressurized air (low from the outlets 42,44 outwardly from the stairwell 16 into the hallway 12 and in the event of lire, oncl restricts smoke from the hallway 1'2 from curling under the door jamb 48 and above the door 1 ~I.
Reference may now be had to Figure 6 which illustrates schematically the operation of the stairwell pressurization system 30 on the occurrence ofa tire on floors III and IV. LJhon the occurrence of a fire, the fire alarm system 32 is activated either through a manual alarm, through a heat temperature sensor and/or through smoke detectors. The activation of the f ire al;~rn~
results in the concurrent activation of the duct blowers 36,38 and stairwell tan 40 oh tl~e st.~irwrll pressurization system 30.
Concurrently with the activation of the building fire alarm system 32, the air duct fans 36,38 and stairwell pressurization fan 40 are activated. It is to be appreciated that the activation of the stairwell fan produces an initial positive pressure in the stairwell 16. Furthermore. the activation of the duct pressurization fans 36,38 produces a positive pressure in the air ducts. 'I~Im stairwell pressurization fan 40 provides an overall positive pressure in the stairwell 1 (i wloicl~
most preferably is selected at between about I .OS and 1. 3 times atmospheric pressure. In addition, the operation of the fans 36,38 acts to draw smoke-free air from outside the building 10 into the air duct 34, preferably pressurizing the air duct to between about 1.2 and 1.C times atmospheric pressure.
Initially, on the activation of the system 30, the air outlets 42,44 at adjacent each stail~~ell entrance door 14 are closed. As the individual occupants 8 leave the building 10 via the stairwell entrance doors 14 and stairwell 16, the stairwell entrance doors 14 and individually opened. ~~hc opening of an individual stairwell exit door 14 results in the selective operation of the aiu outicts 42,44 which are positioned immediately adjacent thereto. r'1s the individual occupants 8 exit the hallway 12 through a stairwell entrance door 14, the opening of the door 14 produces a resulting counter linear airflow into the hallway 12 which is substantially aligned with the vertical door opening, effectively preventing smoke from entering from the hallway 12 into the stairwell 1 li.
If smoke envelopes one or more of the fans 42,44,46, the sensor associated therewith temhorurily disables the fan to prevent it drawing the smoke back into the stairwell 1 C
and building. :1s a result, smoke-free airflow required to prevent smoke from moving li~om the hal(vays 12 into tllc stairwell 1 C~ and for compensating for any loss in overpressure in the stairmil 1 G is praviaed from the duct 34 immediately adjacent to the open stairwell entrance door 14.
Furthermore, because pressurizing air flow is only affected as an individual door 14 is opened, there is no need to maintain the stairwell 16 at a high positive pressure which otherwise could impede the ability to open the stairwell entrance doors.
Figure 7 is a schematic illustration of an air outlet 42 used in the stairwell pressurization system 30 in accordance with a further embodiment of the invention, and Ii1 which like rclerencc numerals are used to identify like components. In Figure 7, the air outlet 42 is provided in the air duct 34 as an elongated opening oriented towards the open edge 48 of the hallway exlt/stalrwell entrance door 14. The air outlet 42 is selectively activated by opening a daring biased picot baffle 50 which is mechanically coupled to the door 14 by a cable GO fed throu~~lv a tuholar pulley guide 62 and secured to a tensioner 64. The baffle ~0 is mounted at its upper anti Ic>wcr ~ocl~ to an aligned pair of pivot shafts 100a, lOUb for pivotal movement thereabout.
Figure 8 illustrates a cross-sectional view of an air duct 34 and air opening 42 in accordance with a further embodiment of the invention. In the embodiment shown in l~i~urc 8, the air outlet 42 is closed by a baffle panel 50 which moves about a pivot 100 spac:c~1 a distance inwardly from a radial circumferential edge of the air duct 34. 'fhe baffle ~0 is nrovahle via a cable 60 threaded through a tubular pulley guide 62 and pulleys 164 against the bias of a sprin<~
54, so as to have an open edge which pivots inwardly towards the axial center of the air duct 34 and away from its circumferential edge.
Figure 9 illustrates a system that does not require the use of a hlgh pressure duct. It is envisioned that this type of system could be implemented for buildings (residential and commercial) with up to l4 floors height. The system in place at a particular floor incorporates an electric blower 70 which is operated by a door triggered switch and which is configured to be instantly activated upon the opening of the stairwell door 14 at that respective floor. During the time when the door 14 is kept open the blower 70 is operated to provide an outward ~rir ilow towards the open door 14 and functioning like an air curtain, keeps the smoke out of the stairway 16.
It is to be appreciated that the air duct represented in Fig. 9 which provides air to the blower 70 should be of an appropriate length selected to prevent air from being drawn from the hallway or from the blower outlet back into the duct.
Figure 10 illustrates a modified system similar to that shown in figure 9 and in which tl~e blower 70 has been attached to a smoke~deflectuig canopy 80 positioned above th a doer. It is to be appreciated that various blower configurations may be possible with the present invention depending on the final positioning of the blower relative to the door.
Optionally, the systems illustrated in Figures 9 and 10 may be used in conjunction with a conventional pressurized system in which a propeller fan on the roof and/or a fan on the bottom of the stairwell 16 is used to provide the stairwell area 16 with a positive pI'esSllre which IS
greater than the air pressure in the building units or hallway.
Although the preferred embodimel~t of the invention illustrates the stairwcl I
pressurization system 30 as including air intake fans 36,38 pressurizing both the lower and uppermost ends of the duct 34, the invention is not so limited. It is to be appreciated that with smaller buildings a single blower fan may be used to pressurize the air duct 34.
In an alternate construction, the stairwell pressurization fan 40 could he omitted in its entirety and the air duct 34 used to provide general pressurizing air (low to the stairwell 1 (~. In such a configuration, larger air openings 78 may be provided vertically along the: rna.in le~n:ah of the air duct 34.
Although the preferred embodiment of the invention illustrates the building 10 as having four floor areas I, II, III and IV, the invention is not so limited. It is to he ahpreciateci that the stairwell pressurization system of the present invention is equally suitable in high-rise construction having six or more stories in addition to love--rise buildings.
While the preferred embodiment of the invention describes the stairwell prcasurization system 30 as including a single pressurized air duct 34, it is to be appreciated ihat multiple alr ducts leading to either different floor areas and/or different air outlets could also be used wrlthou t departing from the spirit and scope of the invention.
Although the disclosure describes and illustrates certain preferred elllbOd1117C.'1115 Of~ the invention, it is to be understood that the invention is not restricted to thv particular hrcf~rred embodiments. Rather, the invention includes all embodiments, which are functional, electrical or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein.
Smoke in stairwells also hampers floe ability of f refighters to tight fires.
In particular, smoke in stairwells hampers both breathing and visibility, making it difficult and time consuming to penetrate the smoke in tile stairwell while going up the stairs towards the firs affected area.
Various individuals have proposed pressurizing stairwells with a vicv~.~ to removing smoke, so as to facilitate escape froth bunging buildings and the ability of lirefighters to reach their destinations quickly. To date, however, conventional stairwell pressurization systems have achieved only limited effectiveness, particularly with taller high-rise buildings in excess of four or more stories.
In particular, conventional stairwell pressurization systems operate with the objection c~f providing the stairwell with a constant high pressure relative to the building hall~~~ays. 'I l~c positive pressure maintained in the stairwell may make stairwell hallway exit doors difficult to open, particularly for very young children and the elderly. This problem of overpressurization is common to all previously designed systems. I3y design, the new system will eliminate the problem as well as the fire growth caused by high volume ofair escaped from the stairwell into the hallways. Furthermore, it has been found that opening hallway exit doors Iea~lin;~~ inta~ ihc stairwells for even a comparatively brief period of time results in a dramatic clecr~ase ion :;tuirwll pressure, particularly if multiple doors are opened on different levels. As a result, it may tnk~
several minutes for conventional pressurization systems to achieve or return to an effective positive pressure state.
SUMMARY OF THE IN VENTION
It is an object of the invention to develop a system for providing a substantially smoke-free stairwell, which reduces or eliminates the concern of individual asphyxiation in stairwells as a result of smoke inhalation.
Another object of the invention is to provide an economical stairway prcssuriiatic~n system which may be installed in either new or existing constructions, and which is conligumd to reduce smoke penetration into emergency stairwell areas.
Another object of the invention is to provide a stairwell pressurization system which may be used in conjunction with a conventionatl or existing fire alarm system.
A further object of the invention is to provide a stairwell pressurization system which. is configured to provide an increased positive pressure correlated with air velocity at ioclivi~lual vertical locations within a stairwell at the point where each stairwell exit door may be: opened.
A further object of the invention is to provide a stairwell pressurization system whirls is either mechanically, electrically or electronically coupled to individual stairwell exit doors and which is adapted to selectively provide a pressurized airflow at vertically spaced locations witl~iu the stairwell itself adjacent to a given hallway exit/stairwell entrance door which is opened.
It is a further object of the present invention to provide a stairwell pressurization system that is selectively operable to pressurize a high-rise stairwell concurrently with the nctivaiic~l~ oi~u conventional fire alarm system.
The present invention provides for a stairwell pressurization system which may be installed in either new or existing low-rise or high-rise buildings. The stairwell pressurization system has at least one air duct which, in a simplified construction, could consist of a stmt mct,ll pipe or duet, and a fan system consisting of one or more fans which are opcral,l,: to tore substantially smoke-free air into the duct under a positive pressure greater than almosphcrlc pressure. At least one and more preferably two air outlets arc provided on the duct in the stairwell and preferably in the vicinity of one or more hallway exit doors leading into the stairwell. The air outlets are most preferably vertically elongated and oriented so as to direct air from the duct at the opening edge of the stairwell entrance door. Optionally, the air duct may also include a duct opening for providing passive pressurizing airi7ow into the stairwell. In the preferred embodiment, one or both elongated air outlets are electrically, clrctronirally or physically connected to the stairwell door, as for example by an electric and/or electronic swiUh and/or by a pulley cable and hinge construction, so as to be selectively opened or closed with tl~c movement of the adjacent door.
In one simplified construction, a first one of elongated air outlets opens into the duct and is normally maintained in a non-air flow position by a baffle door which is moved to open or close the air outlet. 'The stairwell entrance door has one end oFa policy cable coupled thereto.
with the other end coupled to the baffle door. The pulley cable may be maintained in position and guided by threading the cable through pulleys or a rigid or flexible pipe.
The baffle dour is connected to the pressurized air duct by a pivot and is preferably biased in a closed position by a spring. As the stairwell entrance door is swung open, the pulley cable is dram.~n thwewith, moving the baffle door so as to be opened together with the stairwell exit door. Air is then directed from the pressurized air duct through the elongated air outlet and along the open cclge of the stairwell door. As the door progressively opens, the air outlet opens wider to direct more air from the pressurized air duct at the stairwell door through an elongated air outlet.
The second air outlet preferably extends at least half the height of the adjacent stairwell entrance door. The second air outlet is most preferably provided in gaseous communication ~a-iil~
the pressurized air duct or with the stairwell itself, and in a most preferred construction is lo~,otcd immediately adjacent to the first elongated air outlet. The second elongated air outlet is provided with an electric blower which is operable to draw air From within the air duct as a high velocity air flow and is simultaneously operating together with the buffer door at the exact momeW when the exit door to the stairways is opened. This type of design enables an instant response of the system correlated to the opening of a particular exit door at any level of the stair shaft. 'l~hc response time of the previous systems was of about ten minutes af~cer the door opening.
The blower and second air outlet is preferably activated siloultaneously with the loaf~tlc door causing the overall pressure in the stairwell to drop below a threshold amount, or in a nuost preferred construction if the adjacent stairwell entrance door is opened beyond a hredctcraninr:l distance.
Optionally, a bellowing smoke canopy or cover may be located above the stairwell door and which extends horizontally into the stGrirwell. The canopy serves as a physical barrier to prevent smoke from curling upwardly past the door jamb and into the stairwell when the stairwell entrance door is opened.
In a typical high-rise building, the air duct is connected to variable speed fans lclccrittl ~~n the building roof, in the basement, and/or on the ground floor of the building. 'fhe numhcr c~l~
fans and location is largely dependent upon the type of building. 1n the event of a iirc, the l~~rns are operated at the same time as the existing fire alarnl system to force substantially smoke-free;
air into the high pressure duct. The operation of the fans forces air from outside the builc.ling into the high pressure duct (is assumed to be 8-10 times higher than tl7e 1111r111111r111 pressure in tile stairwell) to create the possibility of air velocity in front of the exit door when a particulclr vloor i::
opened. The air cortine has the ability to inhibit the movement of smoke from floe buildin4.e.
hallways and common areas therein, creating a safe area for individuals to exit the l~uildin~~. 'I'hc system may be further configured to turn off any secondary rooftop ventilation system, which provides airflow to the building hallways or common areas.
A tripping mechanism to activate the fan system as well as an elongated air duct and blower, may also be provided. With such a construction, pressure sensors in the stairw:lls are used to sense a pressure drop in the case of several stairwell exist doors being opcnccl simultaneously. Upon sensing the pressure drop, the sensors provide a signal to fans to opcr,ri~
at increased power and speed until the stairwell pressure is returned to a predetermined threshold.
G
In the event of a fire, the stairwell pressurization system is activated to raise and maintain the pressure of the stairwell at a level greater than the pressure that exists in the hallv-ays ,~r corridors.
When a stairwell entrance door is Ilrst opened to a pre-selected degree, the movement of the door draws the cable to move the baffle door to open the first elongated air outlet. 'fit opening of the air outlet allows air to IZow from the duct via the air outlet anti towards the capon edge of the door. rfhe air flow maintains the pasitive pressure in the stairwell and forces anv smoke at the stairwell entrance door back into the hallway.
At the exact moment when the door is swung open an electric switch is triggered to activate the blower and provide additional air flow from the second air outlet. 'l~hc additional air flow acts to both compensate for the reduction in pressurization <:~ccurring as a result oCth c wider door opening, as well as providing still increased air Ilow towards the door opening to Ii~rthcr limit the amount of smoke which may enter the stairwell through the open door.
Optionally, the blower may be operable at variable speeds to provide increased air flow as the exit door is opened wider.
1n a more preferred construction, if many stairwell entrance doors arc opened simultaneously, resulting in a drop off ol~pressure in the stairwell, one or more blowers anti second vertically elongated air outlets are activated to direct more air velocity towards the now opened stairwell entrance door blocking smoke from the hallway back into the stairway. 'I'hc advantage created by the new system is that no volume of air will escape in the halUva~- during the period of time when the respective door is kept open.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects of the invention will become apparent upon reading the following detailed description and drawings, in wlaieh:
Figure 1 is a schematic illustration of a high-rise building stairwell incorporating stairwell pressurization system in accordance with a first embodiment of the invention:
Figure 2 illustrates an enlarged partial perspective view of the stairwell landing shown as "A" in Figure l, illustrating the air duct and air outlets used in the stairwell pressurization system of Figure 1;
Figure 3 illustrates a schematic cross-sectional view of the stairwell pressurization air duct used in the system shown in Figure 2 taken along lines 3-3;
Figure 4 illustrates an enlarged partial cross-sectional view of the stairwell door and duct shown in Figure 3;
Figure 5 illustrates a perspective view of a hallway exit/stairwcll entrance door shown in Figure 2 leading into the stairwell, in an initial partially open position;
Figure 6 illustrates schematically the stairwell shown in figure 1 with the stairavrll pressurization system in an activated condition during a fire;
Figure 7 illustrates a schematic perspective view of an air duct and air outlet used in nn air pressurization system in accordance with a further embodiment;
Figure 8 illustrates a cross-sectional view of an air duct and air outlets used in the pressurization system in accordance with a further embodiment of the invention; and Figures 9 and 10 illustrate a schematic perspective view of an air duct and air outlet used in an air pressurization system in accordance with another embodiment of the invention.
g DETAILED DESCRIPTION OF THE PREFERRED EMF30DIMEN fS
Reference is first made to Figure 1 which partially illustrates a multi-story buildinr 10.
For clarity, the building 10 is shown illustrating four floor areas I, II, III
and IV, each characterized by a respective hallway 12 providing access to individual floor units (not shown) and which terminates at a hallway exit/stairwell entrance door 14. In a conventional tnamlcr, a vertically extending stairwell 16 extends the height of the building 10 from the ground floor l 8 to the roof 20. Stairs 22 within the stairwell 16 lead from each stair~ve(1 entrance door 1 a and provide a secondary emergency exit from each of the high-rise floors I, II, II
I and 1V to cnahle occupants 8 (Figure 6) to exit the building 10 via emergency exit door 24 located on the ground floor 18. A pressure relief vent 26, not necessary required for this embodiment of the. invention may be provided in the stairwell 1 fi, which upon a predetermined threshold pressure being reached opens to prevent overpressurization of the stairwell.
Figure 1 illustrates best the building 10 as including a stairwell pressurization svsl~m identified generally as 30. As will be described, the pressurization system >0 is n~~rmallv maintained in an inactivated and non-pressurized state. The system 30 is electronically coupled to the building fire alarm system 32 so as to be concurrently activated therewith to prcssuri~~ the stairwell with substantially smoke-free air at a low pressure in the stairwell of between about 0.05 and 0.10 in.w.g. relative to the pressure in the hallways in the event of a hre.
The stairwell pressurization system 30 includes a high pressure air duct 34, a pair of air duct pressurization fans 36,38 not necessary required for all the embodiments ofthe invention. a stairwell propeller pressurization fan 40 (see 6g.1 ), and a number of pairs of high velocity air outlets 42,44 (Figure 2) located within the stairwell 16 adjacent to each of the staimvav entrance doors 14. In a simplified construction, the air duct 34 consists of a sheet metal duct which extends vertically the height of the stairwell 16 from building ground floor I
to tine toh Moor 1V, In the embodiment shown in Figure l, the duct pressurization fans 3Ci, 38 arc shown as bcin~
provided in gaseous communication with each end of the duct 34, with a first fan 3G hositionccl at the ground floor level adjacent to the exterior sidewall of the building 10 and a second lan 3S
<~
being positioned on the building roof 20. The fans 36,38 which are used to force air into the air duct 34 at a positive pressure above atmospheric pressure, and most preferably a pressure of between about 0.05 and 0.10 times atmospheric pressure. It is to be appreciated that the duct pressurization fans 36,38 are used to provide a pressurized source of substantially smoke-('rcc air into the stairwell 16. The final positioning of the d~~ct pressurization fans 36,38 thcretere is selected so as to be spaced remotely from any likely path of smoke in the event of tire.
'The stairwell low pressurization fan 40 most preferably consists of a regular hrohcllcr lao located at the top of the stairwell 16. A wind shield 46 may be provided around the I;m ~() to minimize or reduce the likelihood of the fan 40 drawing smoke into the stairwell 16 in the: event of a fire condition and also to minimize the external wind influence. In low-rise buildings, the stairwell pressurization fan 40 may be omitted in its entirety. 'fhe stairwell pressurization fan 40 and duct pressurization fans 36,38 are operable with the building tire alarm system 32 to provide a general positive pressure throughout the stairwell 16 and in particular in high-rise buildings of five stories or more. Optionally, each of the fans 36,38,40 may be provided with a smoke and/or heat sensor which when activated are operable to disable the operation of a given associated l~ar~
so as not to return smoke into the stairwell 16.
Figures 2 to 4 illustrate best the high velocity air outlets 42,44. which are used to divert pressurized air from the air duct 34 towards an adjacent stairwell entrance door 14 at cacl~
stairwell landing in the stairwell 16. It is to be appreciated that the stairwell pressurizalion system 30 is most preferably constmeted with the air outlets 42,44 shown in Fi~.ure 2 li~c~~t~ci adjacent the stairwell entrance door 14 on each building floor I, Il, III, IV.
In a more ecc~nc~mica~l embodiment, however, the outlets 42,44 may be provided on alternate floors or adjacent key entrance/exit doors only.
As seen best in Figures 2 and 3, the air outlet 42 is provided as a vertically elongated outlet which has a height which is at least 3/4 the vertical height of the door 14. The outlet 42 is positioned vertically along the duct 34 so as to be oriented towards and adjacent to the openin~~
edge 46 of the stairwell entrance door 14. The outlet 42 is fi.~rmed so that when activated, tlic outlet 42 directs an elongate flow of air fram the duct 34 between the edge of the door 46 and the door jamb 48 as an air curtain, to prevent smoke from the adjacent hallway 12 from moving bast the door jamb 48 and into the stairwell 16.
As shown best in Figures 3 and 4, the outlet 42 is activated to permit air flow 1?y rneaos of a spring biased baffle 50. The baffle 50 is formed as a generally rectangular panel which i hingely mounted on a swing arm 51 within the air duct 34 for movement about a pivot S2. 'I'hc baffle 50 is movable about the pivot 52 between a closed position when the baffle 50 substantially overlies and seals an inner end of the outlet 42 preventing air flow therefrom, and the open position shown in phantom where the baffle 50 is swung away from the outlet 42 to permit air to flow from the duct 34 outwardly therefrom. A spring 54 is rruvidcd to resiliently bias the baffle 50 to the normal closed position when the door 14 is closed relative to the door jamb 48.
The baffle 50 is mechanically coupled to the door 14 so as to be selectively ot~ea~e~l or closed therewith. In this manner, the air outlet 42 is only activated to direct a pressurized air flow from the air duct 34 when the adjacent stairwell door 14 is opened. In a simpli(icd construction, the baffle 50 is physically opened or closed by means of a llexiblc cable C0. The cable 60 extends from a first end coupled to the baf'flc 50 to a second end connected to the top of the stairwell entrance door 14. One or more pulley guide tubes 62 are provided fbr guiding the cable 60 as it is drawn by the moving door 14. Most preferably, the end of the cable 60 is coupled to the door 14 by a spring biased tensioner 64. 'The tensioner 64 may, in a simplii icd construction, consist of a spring biased plunger which is adapted to prevent ovcrtensioniug of the cable 60 as the door is moved to the fully opened position shown as P2 in phantom in figure 4.
In this manner, as the door 14 pivots inwardly into the stairwell 16, the movecncr~t of the door l~l draws the cable 60 so as to move the baffle SO against the bias of the sparing 54 allowing air to flow from the pressurized duct 34 via the air outlet 42. As the air outlet 42 forms an elon~at~cl opening and is oriented towards the opening door 14, there is a resulting airflow directed clung the length of the door opening. 'The airflow continues only as long as the door 14 is open a~ut acts as an air curtain to prevent smoke and air movement from the hallway 12 into the stairmll 16. Once the door 14 is closed, the spring 54 returns the baffle 50 to its closed position, drawing the cable 60 therewith.
Furthermore, it is appreciated that because the baffle 50 is mechanically coupled to the door 14, in the opening of the duct 42, the baffle 50 initially moves in direct proporlic~n to the degree of movement of the door 14. As such, as the door 14 moves i~rom the closed position as shown in Figure 3 to the initial partially opened position shown in phantom f1, the air ovitlet 4?
progressively opens to provide increased air flow in proportion with the degree oFdoor movement.
Figures 3 and 4 illustrate the second air outlet 44 as similarly comprising a vertically elongated outlet having a height substantially corresponding to that of the door 1 ~l. f~ lthou~~h nc~t essential, the air outlet 44 is for ease of installation most preferably located tmmedtately ad,jaccnt to the first air outlet 42. As with the outlet 42, the outlet 44 is formed so that when activated, it emits an elongated air flow towards the opening edge 46 of the door 14 and door jamb 48.
Figures 2 and 3 show best the air outlet 44 as being in gaseous communication, but not necessary required in all embodiments of the invention with the pressurized air duct 34.
An electric air blower 70 is mounted towards the rear of the air outlet 44. (fhe air blower is selectively operahlc to draw air from the duct 34 outwardly from the outlet 44 as a high velocity pressurizing uir flow. In an alternate embodiment., however, the second air blower 70 and air outlet 4~I nwv br configured to draw air from the stairwell I6 itself. The air blower 70 is electrically coupled to the door 14 so as to be actuated on the movement of the door. In particular, the tcnsioncr 64 is provided with a contact switch 72 which, for example, is configured so that when the door I 4 is opened beyond a first predetermined threshold amount P 1 (Figure 3), the contact switch 7? is closed completing the electric circuit to activate the air blower 70. ~fhc activation c~f tltc air blower 70 thus provides a second linear i7ow of air towards the opening side o1~ the door 1 ~ W
further prevent movement of smoke from the hallway 12 past the door jamb 48 and info the stairwell 16, as for example is shown best in Figure 5. In an alternate embodiment, the blower 70 may be adapted to provide a variable fan speed in proportion to the degree oFwhich the adjacent stairwell entrance door 14 is opened. In SLtch a configuration, as the door 14 opens wider, the speed of the blower fan 70 increases to provide an increasing counter-pressurizing air flow.
To avoid an overpressurization in the stairwell 16, the air blower 70 is electrically coupled to the door 14 so that the re-closing of the door 14 results in the release of the ccmtac t switch 72 to deactivate the blower 70. It is to be appreciated that an overprcssurization in tl~c stairwell 16 could otherwise prevent elderly persons or small children from opening the stairwell entrance doors 14 in the event of a tire.
As shown best in Figure 2, canopy 80 is further provided directly above the door 14. The canopy 80 comprises a horizontally e~ctending panel which projects inwardly into the stairwell 1 (i immediately above the door jamb 48. This panel 80 assists in directing pressurized air (low from the outlets 42,44 outwardly from the stairwell 16 into the hallway 12 and in the event of lire, oncl restricts smoke from the hallway 1'2 from curling under the door jamb 48 and above the door 1 ~I.
Reference may now be had to Figure 6 which illustrates schematically the operation of the stairwell pressurization system 30 on the occurrence ofa tire on floors III and IV. LJhon the occurrence of a fire, the fire alarm system 32 is activated either through a manual alarm, through a heat temperature sensor and/or through smoke detectors. The activation of the f ire al;~rn~
results in the concurrent activation of the duct blowers 36,38 and stairwell tan 40 oh tl~e st.~irwrll pressurization system 30.
Concurrently with the activation of the building fire alarm system 32, the air duct fans 36,38 and stairwell pressurization fan 40 are activated. It is to be appreciated that the activation of the stairwell fan produces an initial positive pressure in the stairwell 16. Furthermore. the activation of the duct pressurization fans 36,38 produces a positive pressure in the air ducts. 'I~Im stairwell pressurization fan 40 provides an overall positive pressure in the stairwell 1 (i wloicl~
most preferably is selected at between about I .OS and 1. 3 times atmospheric pressure. In addition, the operation of the fans 36,38 acts to draw smoke-free air from outside the building 10 into the air duct 34, preferably pressurizing the air duct to between about 1.2 and 1.C times atmospheric pressure.
Initially, on the activation of the system 30, the air outlets 42,44 at adjacent each stail~~ell entrance door 14 are closed. As the individual occupants 8 leave the building 10 via the stairwell entrance doors 14 and stairwell 16, the stairwell entrance doors 14 and individually opened. ~~hc opening of an individual stairwell exit door 14 results in the selective operation of the aiu outicts 42,44 which are positioned immediately adjacent thereto. r'1s the individual occupants 8 exit the hallway 12 through a stairwell entrance door 14, the opening of the door 14 produces a resulting counter linear airflow into the hallway 12 which is substantially aligned with the vertical door opening, effectively preventing smoke from entering from the hallway 12 into the stairwell 1 li.
If smoke envelopes one or more of the fans 42,44,46, the sensor associated therewith temhorurily disables the fan to prevent it drawing the smoke back into the stairwell 1 C
and building. :1s a result, smoke-free airflow required to prevent smoke from moving li~om the hal(vays 12 into tllc stairwell 1 C~ and for compensating for any loss in overpressure in the stairmil 1 G is praviaed from the duct 34 immediately adjacent to the open stairwell entrance door 14.
Furthermore, because pressurizing air flow is only affected as an individual door 14 is opened, there is no need to maintain the stairwell 16 at a high positive pressure which otherwise could impede the ability to open the stairwell entrance doors.
Figure 7 is a schematic illustration of an air outlet 42 used in the stairwell pressurization system 30 in accordance with a further embodiment of the invention, and Ii1 which like rclerencc numerals are used to identify like components. In Figure 7, the air outlet 42 is provided in the air duct 34 as an elongated opening oriented towards the open edge 48 of the hallway exlt/stalrwell entrance door 14. The air outlet 42 is selectively activated by opening a daring biased picot baffle 50 which is mechanically coupled to the door 14 by a cable GO fed throu~~lv a tuholar pulley guide 62 and secured to a tensioner 64. The baffle ~0 is mounted at its upper anti Ic>wcr ~ocl~ to an aligned pair of pivot shafts 100a, lOUb for pivotal movement thereabout.
Figure 8 illustrates a cross-sectional view of an air duct 34 and air opening 42 in accordance with a further embodiment of the invention. In the embodiment shown in l~i~urc 8, the air outlet 42 is closed by a baffle panel 50 which moves about a pivot 100 spac:c~1 a distance inwardly from a radial circumferential edge of the air duct 34. 'fhe baffle ~0 is nrovahle via a cable 60 threaded through a tubular pulley guide 62 and pulleys 164 against the bias of a sprin<~
54, so as to have an open edge which pivots inwardly towards the axial center of the air duct 34 and away from its circumferential edge.
Figure 9 illustrates a system that does not require the use of a hlgh pressure duct. It is envisioned that this type of system could be implemented for buildings (residential and commercial) with up to l4 floors height. The system in place at a particular floor incorporates an electric blower 70 which is operated by a door triggered switch and which is configured to be instantly activated upon the opening of the stairwell door 14 at that respective floor. During the time when the door 14 is kept open the blower 70 is operated to provide an outward ~rir ilow towards the open door 14 and functioning like an air curtain, keeps the smoke out of the stairway 16.
It is to be appreciated that the air duct represented in Fig. 9 which provides air to the blower 70 should be of an appropriate length selected to prevent air from being drawn from the hallway or from the blower outlet back into the duct.
Figure 10 illustrates a modified system similar to that shown in figure 9 and in which tl~e blower 70 has been attached to a smoke~deflectuig canopy 80 positioned above th a doer. It is to be appreciated that various blower configurations may be possible with the present invention depending on the final positioning of the blower relative to the door.
Optionally, the systems illustrated in Figures 9 and 10 may be used in conjunction with a conventional pressurized system in which a propeller fan on the roof and/or a fan on the bottom of the stairwell 16 is used to provide the stairwell area 16 with a positive pI'esSllre which IS
greater than the air pressure in the building units or hallway.
Although the preferred embodimel~t of the invention illustrates the stairwcl I
pressurization system 30 as including air intake fans 36,38 pressurizing both the lower and uppermost ends of the duct 34, the invention is not so limited. It is to be appreciated that with smaller buildings a single blower fan may be used to pressurize the air duct 34.
In an alternate construction, the stairwell pressurization fan 40 could he omitted in its entirety and the air duct 34 used to provide general pressurizing air (low to the stairwell 1 (~. In such a configuration, larger air openings 78 may be provided vertically along the: rna.in le~n:ah of the air duct 34.
Although the preferred embodiment of the invention illustrates the building 10 as having four floor areas I, II, III and IV, the invention is not so limited. It is to he ahpreciateci that the stairwell pressurization system of the present invention is equally suitable in high-rise construction having six or more stories in addition to love--rise buildings.
While the preferred embodiment of the invention describes the stairwell prcasurization system 30 as including a single pressurized air duct 34, it is to be appreciated ihat multiple alr ducts leading to either different floor areas and/or different air outlets could also be used wrlthou t departing from the spirit and scope of the invention.
Although the disclosure describes and illustrates certain preferred elllbOd1117C.'1115 Of~ the invention, it is to be understood that the invention is not restricted to thv particular hrcf~rred embodiments. Rather, the invention includes all embodiments, which are functional, electrical or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein.
Claims (5)
1. A pressurization system for providing a positive pressure in a building stairwell adjacent a stairwell entrance door and which is selected greater than atmospheric pressure, the system including:
an air duct extending vertically in said stairwell;
a fan source in fluid communication with the air duct and including a fan selectively actuatable to force air from outside the building into the air duct under a positive pressure selected greater than atmospheric pressure; and at least one pressurized air outlet in gaseous communication with said air duct, said air duct being elongated vertically and being positioned to direct air flow from the pressurized air duct towards an opening edge of the stairwell entrance door.
an air duct extending vertically in said stairwell;
a fan source in fluid communication with the air duct and including a fan selectively actuatable to force air from outside the building into the air duct under a positive pressure selected greater than atmospheric pressure; and at least one pressurized air outlet in gaseous communication with said air duct, said air duct being elongated vertically and being positioned to direct air flow from the pressurized air duct towards an opening edge of the stairwell entrance door.
2. The system as claimed in claim 1, wherein the fan is electronically coupled to a building fire alarm so as to be actuatable concurrently therewith.
3. A system as claimed in claim 2, which further comprises a second blower activated air outlet, the blower activated air outlet including an electric blower and a door activated switch wherein this switch is operable to activate said electric blower when the door is moved open by a predetermined threshold amount.
4. The system as claimed in claim 3, wherein the blower activated air outlet is elongated vertically and is positioned generally adjacent to a selected one of said pressurized air outlets.
5. The system as claimed in claim 1, wherein the fan source comprises a plurality of fans, a first of said fans being provided in fluid communication with a bottom portion of the air duct; and a second of the fans being provided in fluid communication in an uppermost portion of the air duct, wherein the first and second fans are adapted for concurrent operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002426391A CA2426391A1 (en) | 2003-04-23 | 2003-04-23 | Stairwell pressurization system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002426391A CA2426391A1 (en) | 2003-04-23 | 2003-04-23 | Stairwell pressurization system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2426391A1 true CA2426391A1 (en) | 2004-10-23 |
Family
ID=33163792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002426391A Abandoned CA2426391A1 (en) | 2003-04-23 | 2003-04-23 | Stairwell pressurization system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2426391A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110179732A1 (en) * | 2008-10-08 | 2011-07-28 | Ermer Horst A | High Rise Building With A Stairwell And A Intake Air Shaft |
| EP2314943A3 (en) * | 2009-10-20 | 2014-10-29 | Smay Sp. z.o.o. | A method to control pressures in vertical escape routes |
| CN113389674A (en) * | 2021-05-21 | 2021-09-14 | 华北水利水电大学 | High-rise building district bath power generation system |
-
2003
- 2003-04-23 CA CA002426391A patent/CA2426391A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110179732A1 (en) * | 2008-10-08 | 2011-07-28 | Ermer Horst A | High Rise Building With A Stairwell And A Intake Air Shaft |
| US9187918B2 (en) * | 2008-10-08 | 2015-11-17 | Swiss Raltec Gmbh | High rise building with a stairwell and a intake air shaft |
| EP2314943A3 (en) * | 2009-10-20 | 2014-10-29 | Smay Sp. z.o.o. | A method to control pressures in vertical escape routes |
| CN113389674A (en) * | 2021-05-21 | 2021-09-14 | 华北水利水电大学 | High-rise building district bath power generation system |
| CN113389674B (en) * | 2021-05-21 | 2023-04-14 | 华北水利水电大学 | High-rise building district bath power generation system |
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