U.S. patent number 3,884,133 [Application Number 05/499,129] was granted by the patent office on 1975-05-20 for fire control system for multi-zone buildings.
Invention is credited to Edward J. Miller.
United States Patent |
3,884,133 |
Miller |
May 20, 1975 |
Fire control system for multi-zone buildings
Abstract
A method of controlling smoke, ventilation and fire flash point
temperature in a multi-zone building served by a central
ventilation system uses a divided common return air duct having
separate branch damper connections for each zone for directing all
return air from a fire zone into one section of the common return
air duct for complete exhaust and for directing all return air from
a non-fire zone into the other section of the common return air
duct. The method also provides positive pressurization of the
non-fire ventilation zones relative to the fire ventilation zones
and maximum fresh air to all zones.
Inventors: |
Miller; Edward J. (Morton
Grove, IL) |
Family
ID: |
23983945 |
Appl.
No.: |
05/499,129 |
Filed: |
August 21, 1974 |
Current U.S.
Class: |
454/229; 165/250;
169/61; 236/49.2 |
Current CPC
Class: |
A62C
2/06 (20130101) |
Current International
Class: |
A62C
2/06 (20060101); A62C 2/00 (20060101); A62b
015/00 (); A62c 003/14 () |
Field of
Search: |
;98/33R,43 ;236/49
;169/60,61 ;165/16 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wayner; William E.
Attorney, Agent or Firm: Cagney; J. Patrick
Claims
I claim:
1. In a multi-zone building having a ventilation system that
includes a central station serving a plurality of ventilation
zones, common supply air duct means connecting the central station
to the ventilation zones, common return air duct means connecting
the ventilation zones to the central station, each zone having
branch supply duct means connected to the common supply air duct
means and branch return duct means connected to the common return
air duct means, and the central station including central supply
fan means, central exhaust/return fan means and main damper means
for controlling flow of fresh air into the common supply air duct
means and recycling of return air from the common return air duct
means to the common supply air duct means, the improvement
comprising partition means for dividing the common return air duct
means lengthwise into a main return air duct section and an
auxiliary return air duct section, separate branch damper means for
each zone for controlling communication of the branch return duct
means of such zone with each of the return air duct sections,
standby means for effecting isolation and exhaust of all return air
from the auxiliary return air duct section, and control means
including separate detection means for each zone operable upon the
occurrence of fire conditions therein for actuating the standby
means and the corresponding one of said separate damper means for
directing all of the return air from any fire zone to exhaust
through the auxiliary return air duct section and for directing all
of the return air from any non-fire zone into the main return air
duct section.
2. An arrangement as defined in claim 1 wherein said standby means
includes standby exhaust means having a standby damper controlling
communication of the auxiliary return air duct section to exterior
atmosphere, and auxiliary damper means for isolating the auxiliary
return air duct section from the main supply air duct means and the
main return air duct section to direct the return air in the
auxiliary return air duct section to the standby exhaust means in
the fire mode.
3. An arrangement as defined in claim 2 wherein the control means
is automatically responsive to any of the separate detection means
upon the occurrence of fire conditions in the corresponding zone
for operating the auxiliary damper means to close and isolate the
auxiliary return air duct section from the central exhaust/return
fan means for actuating the standby exhaust means and standby
damper means, for positioning the branch damper means for any fire
zone so that all return air from any fire zone is directed through
the auxiliary return air duct section until the corresponding fire
detection means returns to normal, for positioning the branch
damper means for any non-fire zone so that all return air for any
non-fire zone is directed through the main return air duct section
when the corresponding fire detection means are normal and for
returning all equipment to normal mode when all fire detection
means return to normal.
4. An arrangement as defined in claim 1 where said standby means
includes variable volume standby exhaust means to operate at a
capacity that depressurizes any fire zones and having a standby
damper normally preventing communication of the auxiliary return
air duct section with exterior atmosphere, and auxiliary damper
means for isolating the auxiliary return air duct section from the
main supply air duct means and the main return air duct section to
direct the return air in the auxiliary return air duct section to
the standby exhaust means in the fire mode.
5. An arrangement as defined in claim 4 and including static
pressure controller means responsive to pressure in the ventilation
system to control the capacity of the variable volume stand-by
exhaust means to effect the desired pressure reduction in the fire
zones.
6. An arrangement as defined in claim 1 wherein said control means
is connected to actuate said main damper means to control delivery
of as much as 100 percent fresh air to the ventilation zones during
fire mode.
7. An arrangement as defined in claim 1 wherein said common supply
air duct means includes air reheat means and said control means is
connected to actuate said main damper means and said air reheat
means to control delivery of as much as 100 percent fresh air to
the ventilation zones during fire mode regardless of exterior
temperature.
8. An arrangement as defined in claim 1 and including variable
volume sprinkler means disposed in the auxiliary return air duct
section and having a sprinkler head and temperature detector for
each zone and operable for automatically controlling return air
temperature from any fire zone.
9. An arrangement as defined in claim 1 wherein each of said
separate damper means comprises a dual damper having a normal mode
position to direct return air from the corresponding zone into both
return air duct sections and having a fire mode position to direct
all return air into the auxiliary return air duct section when the
corresponding zone is a fire zone.
10. An arrangement as defined in claim 1 wherein the ventilation
zones comprise separate floors of a multi-story building, the
common supply air and return air duct means and the partition means
are vertical and the branch supply and return duct means are
horizontal and the central supply fan means, the central
exhaust/return fan means and the main damper means are located at
the top of the common supply air and return air duct means and
wherein said standby means includes standby exhaust means to
operate at a capacity that depressurizes any fire zones and having
a connection to the auxiliary return air duct section at a location
beneath the central exhaust/return fan means and having a standby
damper for controlling communication of the auxiliary return air
duct section to exterior atmosphere, and auxiliary damper means
mounted in the auxiliary return air duct section between the said
connection and the central exhaust/return fan means for isolating
the return air duct section from the main supply air duct means and
the main return air duct section to direct the return air in the
auxiliary return air duct section to the standby exhaust means in
the fire mode.
11. A method of fire control and ventilation for multi-zone
buildings comprising: drawing fresh air into the building to form a
main supply air stream; subdividing the main stream into branch
streams each leading into a separate zone; drawing return air from
the zones to form a main return air stream and an auxiliary return
air stream; normally exhausting some of the air from the return air
streams while recycling the remainder into the main supply air
stream; and isolating the return air streams in response to fire
conditions occurring in any zone by exhausting all of the auxiliary
return air stream while directing all return air from any fire zone
into the auxiliary return air stream and directing all return air
from any non-fire zone into the main return air stream.
12. A method in accordance with claim 11 wherein exhaust of all of
the auxiliary return air stream in response to fire conditions is
effected at a rate to produce a multifold increase in return air
from any fire zone.
13. A method in accordance with claim 11 and including the step of
sensing the pressure in the ventilation system during fire
conditions and controlling the exhaust of the auxiliary return air
stream in accordance with the pressure in the system to effect a
pressure reduction in any fire zone relative to any non-fire
zone.
14. A method in accordance with claim 11 and including supplying
100 percent fresh air to all zones during the existence of fire
conditions while effecting a pressure reduction in any fire zone
relative to any non-fire zone.
Description
BACKGROUND OF THE INVENTION
This invention relates to fire control systems for multi-zoned
buildings, such as high rise office or apartment buildings, that
are served by a central ventilation system.
It is generally recognized that effective control of smoke,
ventilation and fire flash point temperature requires a system
capable of providing
1. maximum pressurization of the non-fire zones together with good
exhaust of ambient smoke;
2. maximum fire zone ventilation to prevent flashover temperatures;
and
3. maximum fire side exhaust for smoke removal.
There has been a continuing need for a system capable of satisfying
these criteria. Even though the importance of adequate fire control
for high rise buildings is recognized by all, no truly effective
solution has previously been developed.
SUMMARY OF THE INVENTION
The present invention provides a flexible system for controlling
smoke, ventilation and fire flash point temperature that is
simplified and economical and that satisfies the aforementioned
criteria by providing
1. 100 percent air to the fire and non-fire zones;
2. reduced return air from the non-fire zones;
3. a multifold increase in return air from the fire area to exhaust
smoke and heat and cause a larger percentage of the total fresh air
to be delivered to the fire zone than under normal conditions for
fire ventilation; and
4. maximum fresh air to both fire and non-fire zones.
More particularly, the invention provides a method of fire control
and ventilation for multi-zone buildings comprising drawing fresh
air into the building to form a main supply stream of supply air;
subdividing the main stream into branch streams and supplying each
branch stream into a separate zone; drawing air from each zone to
form a pair of common return air streams; normally exhausting at
least some of the air from the return air streams while recycling
the remainder into the main supply stream; and responding to fire
conditions occurring in any one of the zones to depressurize any
fire zone by directing all the air drawn from such zone into one of
the return air streams while exhausting all of said one return air
stream to pressurize the non-fire zones by directing all the air
drawn from the non-fire zones into the other return air stream.
AS applied to a typical multi-zone building arrangement that has a
ventilation system including a central station serving a plurality
of ventilation zones, common supply air duct means connecting the
ventilation zones to the central station, common return air duct
means connecting the ventilation zones to the central station, each
zone having branch supply duct means connected to the common supply
air duct means and branch return duct means connected to the common
return air duct means, and the central station including central
supply fan means, central exhaust return fan means and main damper
means for controlling flow of fresh air into the common supply air
duct means and recycling of return air from the common return air
duct means to the common supply air duct means, the improvement of
this invention comprises partition means for dividing the common
return air duct means lengthwise into a main return air duct
section and an auxiliary return air duct section, separate branch
damper means for each zone for controlling communication of the
branch return duct means of such zone with each of the return air
duct sections, standby means for effecting isolation and exhaust of
all return air from the auxiliary return air duct section, and
control means including separate detection means for each zone
operable upon the occurrence of fire conditions therein for
actuating the standby means and the corresponding one of said
separate damper means for directing all of the return air from any
fire zone to exhaust through the auxiliary return air duct section,
and for directing all of the return air from any non-fire zone into
the main return air duct section.
Additional features of the presently preferred embodiments include:
the provision of a standby exhaust fan for connection to the
auxiliary return air duct section in the fire mode to exhaust all
return air from fire zones; an automatically responsive control
system for sequencing the positioning of all necessary dampers both
in the normal mode and in the fire mode; the provision of static
pressure means for controlling the capacity of the standby means
for effecting a pressure reduction in the fire zones; the provision
of facilities to enable supply of 100 percent fresh air to all
ventilation zones during the fire mode; and the provision of
sprinklers for controlling return air temperature.
Other features and advantages of the invention will be apparent
from the following description and claims and are illustrated in
the accompanying drawings which show structure embodying preferred
features of the present invention and the principles thereof, and
what is now considered to be the best mode in which to apply these
principles.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic vertical sectional view showing a
multi-zone high rise building equipped with a central ventilation
system incorporating the fire control system of this invention;
FIG. 2 is a fragmentary sectional plan view taken as indicated on
the line 2--2 of FIG. 1;
FIG. 3 is a diagrammatic plan view of the central fan room of the
ventilation system;
FIG. 4 is a diagrammatic view similar to FIG. 1 and showing the
invention as applied to a ventilation system that uses free return
flow from a ceiling plenum arrangement on each floor;
FIG. 5 is a fragmentary plan view taken as indicated on the line
5--5 of FIG. 4;
FIG. 6 is a plan view of a horizontal type multi-zone ventilation
system;
FIG. 7 is a view similar to FIG. 1 and showing a modified fan
system to illustrate other adaptations of the system; and
FIG. 8 is a schematic control circuit diagram for the ventilation
systems disclosed herein.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring now to the drawings, an improved ventilation system to
provide for smoke, ventilation and temperature control in fire
management is illustrated in connection with a multi-story building
in FIG. 1 wherein 10 designates the floor line for a central fan
room at the top of the building, and 9, 8, and 7 designate the
floor lines for lower floors of the building, each of which
constitutes a separate ventilation zone, in the case of the
illustrated embodiment, with all of the ventilation zones being
served by a common ventilation system.
Such a common ventilation system typically includes a central
station or fan room 11, a common supply air duct 12 connecting the
central station with the ventilation zones and a common return air
duct 13 connecting the ventilation zones to the central station,
with each ventilation zone having a branch supply air duct 14
connected to the common supply air duct 12 and a branch return air
duct 15 connected to the common return air duct 13.
The central station typically includes a central supply fan 16
mounted in the top of the common supply air duct 12, a central
exhaust/return fan 17 mounted in the top of the common return air
duct 13 and a set of main dampers for controlling the flow of fresh
air into the common supply air duct and for controlling recycling
of return air from the common return air duct 13 to the common
supply air duct 12. As shown, the main dampers includes a fresh air
supply damper 18 mounted in a fresh air supply duct 19 that feeds
the supply fan, a main exhaust damper 20 mounted in a main exhaust
duct 21 that exits from the return air duct and a return air
shut-off damper 22 mounted between the supply fan 16 and the
exhaust/return fan 17.
In accordance with this invention improvements are incorporated in
the central ventilation system to provide for more effective fire
management by isolating return air from any fire zone from return
air from any non-fire zone and exhausting all of the return air
from the fire zone so that the non-fire zones are not affected by
any smoke or other fire conditions. In addition the non-fire zones
are preferably operated at elevated pressure and the fire zones are
maintained at reduced pressure to assist in isolating the fire
zones.
In the illustrated embodiment of FIGS. 1 to 3 the ventilation
system is provided:
with partition means 23 for dividing the common return air duct 13
lengthwise into a main return air duct section 13M and an auxiliary
return air duct section 13A;
with separate branch damper means 24 for controlling communication
of the branch return air duct 15 of each zone with each of the
return air duct sections 13M, 13A;
with stand-by means 25 for effecting isolation and exhaust of all
return air from the auxiliary return air duct section in the fire
mode;
and with control means 26 which may include connections to a
central control panel 27 at any suitable location in the building
and which may include separate detection means 28 for each zone,
the detection means being operable upon the occurrence of fire
conditions for actuating the stand-by means 25 and the separate
branch damper means 24 for directing all the return air from a fire
zone to exhaust through the auxiliary duct section 13A and for
directing all the return air from a non-fire zone into the main
return air duct section 13M.
stand-by means 25 as shown here includes the stand-by exhaust fan
29 located in the central fan room and having a backdraft damper
29D for controlling flow from the auxiliary duct section 13A to
exterior atmosphere and also includes an auxiliary damper 30
located in the top of the auxiliary duct section 13A for isolating
the same from both the main supply air duct 12 and from the main
return air duct section in the fire mode, thereby directing all the
return air from the fire zones through the stand-by exhaust fan
29.
As shown in FIG. 8 the central control panel 27 is individually
connected to each of the detectors 28 and to the branch dampers 24
for automatically controlling the same and is also connected to the
main dampers for automatically controlling these in the fire mode,
as well as for controlling the stand-by exhaust fan 29 and the
auxiliary damper 30.
It should be noted that while the partition 23 is shown centrally
of the common return air duct 13 it may be located to determine a
different relative size relationship between the main section and
the auxiliary section. Moreover, these sections may be separate
ducts rather than a dual duct as shown. It is contemplated that
numerous other variations may be made in adapting the system of
this invention to the requirements of a particular building or of
the local fire codes.
It should also be noted that the branch dampers 24 consist of dual
sections 24M, 24A located in the connection between each branch
return air duct and the main and auxiliary return air duct sections
13M, 13A respectively.
During normal operating conditions, both dual damper sections 24M,
24A are open but upon activation of the detector 28 on a fire
floor, the main damper section 24M is closed and the auxiliary
damper section 24A is open. Simultaneously, on each of the non-fire
floors the main damper section 24M is closed and the auxiliary
damper section 24A is open, under the control of the corresponding
detectors. Subsequent deactivation of a detector on any floor
shifts the corresponding branch damper to the same position then
occupied by the branch dampers on the non-fire floors until the
last fire floor detector becomes deactivated when the entire system
would revert to normal.
The detectors may be of any suitable type selected to respond to
smoke or heat or ionization products. Depending on requirements of
the local fire codes, the detectors are electrically connected to
the central control panel so that when activated any detector will
transmit a control pulse to the central control panel which is
programmed to supply actuating signals to convert the entire system
from normal mode to fire mode.
NORMAL MODE
In normal operation fresh air is drawn into the building through
duct 19 to form a main supply stream in the common main duct 12;
the main supply stream is subdivided into branch streams in the
branch supply ducts 14 that feed each of the separate ventilation
zones; return air is drawn from the ventilation zones to form a
pair of common return air streams in the ducts 13M, 13A; and a
portion of the return air streams is exhausted through duct 21
while the remainder is recycled into the main supply stream in duct
12. It is presently preferred that the ventilation system operate
at all times to provide the minimum air movement required to
faciliate fire detection by the detector 28 in any zone.
FIRE MODE
When fire conditions are sensed by a detector 28 in any one of the
ventilation zones, an electric impulse actuates the control panel
27 to reposition the components for directing all the air from any
fire zone into the auxiliary return air duct 13A and through the
standby fan 29 to the exterior while directing all the air from any
non-fire zone into the main return air duct 13M for partial or
complete exhaust as selected. During fire mode, the supply air
continues to all zones and may consist of 100% fresh air or of a
mixture of fresh air and return air recycled from the non-fire
zones.
More specifically, for the embodiment of FIGS. 1 to 3, the
activation of any detector 28 causes the control panel to isolate
the auxiliary duct 13A by closing damper 30, activating the
stand-by fan 29 and opening its back damper 29D, and for each fire
zone closing its branch damper 24M and for each non-fire zone
closing its branch damper 24A.
When any fire zone is cleared as sensed by its detector 28 while
other fire zones still exist, the cleared zone has its branch
dampers automatically reset to open damper 24M and to close damper
24A.
If 100 percent fresh air is to be supplied during fire mode, the
recycle damper 22 is also closed and a reheat coil 31 located in
the main supply duct is activated as required.
A static pressure control 32 is connected to control the capacity
of the standby fan 29 to provide a variable volume capability for
effecting the desired pressure reduction in the fire zone.
Typically, the standby fan 29 would be provided with adjustable
vanes controlled by the static pressure device to achieve this
function.
Finally, a variable volume sprinkler 33 is located in the branch
return duct of each zone and includes a sprinkler head and a
temperature detector located at each floor line to control exhaust
temperature from each fire zone.
ADDITIONAL EMBODIMENTS
A modified embodiment of a typical floor is shown in FIGS. 4 and 5
wherein the return air is drawn from a free return such as a plenum
ceiling into the main and auxiliary return air duct section 13M,
13A respectively. The main damper section 24M is omitted and the
auxiliary damper section 24A is open during normal operations.
Operation of any separate detection means 28 in any zone upon
occurrence of fire conditions therein causes an electric impulse to
activate the control panel 27 to close the auxiliary damper section
24A in each of the non-fire zones and reposition the components for
directing all the air from any fire zone into the auxiliary return
air duct 13A and through the standby exhaust fan means 29 to the
exterior.
Another embodiment as shown in FIG. 6 illustrates the partition
means 23 extended into the horizontal branch return air duct 15
serving each zone to achieve horizontal sub-zoning in addition to
the vertical zoning illustrated in FIG. 1. The separate branch
damper means 24 for controlling communication of the branch return
air duct 15 of each zone with each of the return air duct section
13M, 13A is relocated as shown to control communication of the
branch return air duct 15Z within each horizontal sub-zone with
each of the branch return duct section 15M, 15A. The separate
branch damper means 24 is open during normal operation. Operation
of any separate detection means 28 in any sub zone upon occurrence
of fire conditions therein causes an electrical impulse to activate
the control panel 27 to close the auxiliary damper section 24A in
all non-fire zones and sub-zones and close the main damper section
24M in the fire sub-zone and reposition all components for
directing all the air from the fire sub-zone into the branch return
duct auxiliary section 15A and the auxiliary return air duct 13A
and through the standby exhaust fan means 29 to the exterior. All
other components would operate as described for FIG. 1.
Still another embodiment, as shown in FIG. 7 utilizes a system
similar to that in FIG. 1 except that the standby exhaust fan means
29 is omitted and the central exhaust/return fan 17 is replaced by
two parallel fans, the non-fire area central exhaust/return fan 17M
and the fire area auxiliary exhaust/return fan 17A; the dividing
barrier 23 is extended into the main exhaust duct 21 dividing this
duct into a general area main exhaust duct 21M and a fire area
auxiliary exhaust duct 21A, controlled respectively by the general
area main exhaust duct damper 20M and the fire area auxiliary
exhaust duct damper 20A; the auxiliary damper 30 is retitled 30A
and moved to a point just after the fire area auxiliary
exhaust/return fan 17A to isolate the auxiliary return air duct
section 13A and the fire area auxiliary exhaust duct section 21A,
along with the fire area auxiliary exhaust/return fan 17A, from the
main return air duct section 13M and the non-fire area central
exhaust/return fan 17M during fire mode; the static pressure
control 32 is relocated to a point just before the fire area
auxiliary exhaust/return fan 17A.
Normal Operation of FIG. 7 Embodiment
The auxiliary damper 30A is wide open and the general area main
exhaust duct damper 20M and the fire area auxiliary exhaust duct
damper 20A operate together in conjunction with the recycle damper
22 and the fresh air supply duct damper 18 to provide fresh air as
desired to the conditioned area.
Fire Mode Operation of FIG. 7 Embodiment
The auxiliary damper 30A closes and the fire area auxiliary exhaust
duct damper 20A opens wide and all the air from the fire zone is
exhausted to the exterior atmosphere by the fire area auxiliary
exhaust/return fan 17A. The non-fire area central exhaust/return
fan 17M continues to deliver return air to the central supply fan
16. The general area main exhaust duct damper 20M operates in
conjunction with the recycle damper 22 and the fresh air supply
duct damper 18 to provide the maximum amount of fresh air
throughout the building consistent with exterior temperature and
the heating capability of the reheat coil 31 to avoid freeze-ups
during cold weather. The relative sizing of the two parallel
exhaust/return fans 17M, 17A respectively can be varied according
to local codes and design requirements as to the desired pressure
differential between the fire and non-fire zones. Alternately, the
non-fire area central exhaust/return fan 17M could be a two speed
fan to handle, at full speed, 100 percent return air from the
non-fire areas during fire mode, or, at 1/2 speed, 50 percent of
the return air from all areas during normal mode.
Thus, while preferred constructional features of the invention are
embodied in the structure illustrated herein, it is to be
understood that changes and variations may be made by those skilled
in the art without departing from the spirit and scope of the
appended claims.
* * * * *