US3698481A

US3698481A - Method and apparatus for fighting fire

Info

Publication number: US3698481A
Application number: US116536A
Authority: US
Inventors: William L Livingston
Original assignee: Factory Mutual Research Corp
Current assignee: Factory Mutual Research Corp
Priority date: 1971-02-18
Filing date: 1971-02-18
Publication date: 1972-10-17
Anticipated expiration: 1989-10-17

Abstract

A method and apparatus for fighting fire wherein a plurality of extinguishant-discharging heads are supported in an elevated position within the space to be protected and are adapted to discharge the extinguishant in a substantially square pattern over the area to be protected. The heads are arranged in spaced parallel rows with the location of the heads of each row being staggered relative to the location of the heads of its adjacent row, and the diagonal of the square pattern of each head of each row being canted relative to the diagonal of the square pattern of the heads of its adjacent rows.

Description

United States Patent Livingston METHOD AND APPARATUS FOR FIGHTING FIRE [72] Inventor: William L. Livingston, Sharon,

Mass.

[73] Assignee: Factory Mutual Research Corporation, Norwood, Mass.

[22] Filed: Feb. 18, 1971 21 AppllNo; 116,536

[52] US. Cl ..l69/16, 239/DIG. 1 [51] Int. Cl ..A62c 35/00 [58] Field of Search... ....l69/l R, l A, 2 R, 5, 14,15,

, 169/16; 239/DIG. 1

[56], References Cited UNITED STATES PATENTS 3,533,560 10/1970 Meek., ..239/DIG. 1 2,515,473 7/1950 Rider ..169/5 2,814,526 11/1957 Blair ..239/DIG. 1

Palmer ..239/1 59 X [4 1 Oct. 17, 19,72

FOREIGN PATENTS OR APPLICATIONS 546,435 8/1922 France .16 9/14 283,348 1/1928 Great Britain 169/14 1,134,822 11/1968 Great Britain ..l69/l5 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Thomas C. Culp, Jr. Attorney--Lane, Aitken, Dunner & Ziem [57 ABSTRACT A method and apparatus for fighting fire wherein a plurality of extinguishant-discharging heads are supported in an elevated position within the space to be protected and are adapted to discharge the extinguishant in a substantially square pattern over the area to be protected. The heads are arranged in spaced 1 parallel rows with the location'of the heads of each row being staggered relative to the location of the heads of its adjacent row, and the diagonal of the square pattern of each head of each row being canted relative to the diagonal of the square pattern of the heads of its adjacent rows. 1 I

2 Claims, 7 Drawing Figures PATENTEBIJBI 17 m2 SHEET 1 OF 4 INVENTOR WILLIAM L. LIVINGSTON PATENTED 11 I 3.698.481 SHEET 2 BF 4 a 3 I F/G.4. l I -Q e v I87 I 20d 208 INVENTOR WILLIAM L. LIVINGSTON QRNEYS PATENTED 1 7 I97? 3 6 98,48 1" SHEET 3 or 4 W- WT" I INVENTOR WILLIAM L LIVINGSTON ATTORNEYS PATENTEUIICT 17 I972 SHEU 0F 4 INVENTOR WILLIAM L LIVINGSTON METHOD AND APPARATUS FOR FIGHTING FIRE BACKGROUND OF THE INVENTION guishant, usually in the form of water. These sprinkler heads are normally aligned in parallel rows, with each sprinkler head being given a particular area of coverage responsibility. The spray developed by each head is a result of impinging a jet of water, either upwardly or downwardly, against a deflector disc or plate to develop an initial circular pattern of extinguishant spray over the area to be wetted by each head. The heads in such systems are usually spaced so that the area to be wetted by one head not only covers its particular area of responsibility, but also overlaps a substantial portion of the area of responsibility of its adjacent heads, in order to insure that all portions of the space protected will lie within an area to which extinguishant can be delivered by one or more heads, and to prevent lateral spreading of any fire developing in the space.

This type system has been found in practice to be reasonably well suited for the protection of building spaces where the overall floor-to-ceiling height of the space is on the order of 10 feet or less. Inasmuch as the height of combustible materials or fuel in such space, as

' well as the supply of air therein, is limited, the danger of a high-intensity, laterally localized fire is not present. However, in building spaces higher than 10 feet, such as warehouses and the like, which may be as high as 30 feet or more and contain piles of combustible materials exceeding 90 per cent of the height of the space, the effectiveness of these conventional fire extinguishing systems is somewhat limited for several reasons. In the first place, a fire in such a space, once started, is able to develop very rapidly in a vertical direction because of the availability of fuel and oxygen to support a relatively localized but high temperature column of combustion. While the sprinkler head or heads positioned directly above the column will be quickly actuated and will discharge the available extinguishant, the density of the extinguishant delivered to the burning fuel surface is inadequate because of the relatively large area of coverage responsibility for the first head that is actuated. As a result, before the extinguishant can be effective to put out such a fire, the fire has developed sufficiently so as to bring extremely strong convective effects tending to throw the droplets of extinguishant passing from the head off to the side of the burning fuel. While additional heads will in time be actuated, the tire by that time may develop to such an extent that the basic structure defining the space in which the fuel is located may be damaged to the point of failure, not to mention the combustibles stored in the structure.

Also, as a result of the opening of each additional head in these prior art systems, there is a corresponding drop in line pressure of theextinguishant available to each head previously opened. Since each head has a relatively large area of responsibility, the result is that 2 V less and less extinguishant is delivered to the burning fuel surfaces as the fire grows. This presents an additional reduction of the overall fire fighting capability of the system.

SUMMARY OF THE INVENTION A It is therefore an object of the present invention to provide an apparatus and method for controlling fire wherein the extinguishant-discharge heads are arextinguishant in a substantially square spray pattern,

BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings for a better understanding of the nature and objects of the present invention. The drawings illustrate the best mode presently contemplated for carrying out the objects of the invention and are not to be construed as restrictions or limitations of its scope. In the drawings:

FIG. 1 is a perspective view of the fire-fighting system of the present invention shown installed in a building;

' FIG. 2 is a vertical cross-sectional view of the direct discharge nozzle utilized in the system of the present invention;

FIG. 3 is a bottom plan view of the nozzle of FIG. 2;

FIG. 4 is a diagrammatic view of the patternof extinguishant discharge provided by the nozzle of FIGS. 2 and 3;

FIG. 5 is a diagrammatic view depicting the location of a plurality of nozzles according to the present invention and their particular areas of responsibility;

FIG. 6 is a view similar to FIG. 5, but showing the coverage areas of two adjacent nozzles according to the present invention; and

FIG. 7 is a view similar to FIG. 5, but showing the coverage areas of several adjacent nozzles according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS understood that the submain 16 and the branch lines 18 are all fastened relative to the ceiling of the building 10 at a slight distance therefrom. A plurality of extinguishant-dispensing head preferably in the form of direct discharge nozzles, are shown diagrammatically in FIG. 1 by the reference numeral 20. The nozzles are disposed at spaced intervals along each branch line 18 and extend throughout the entire structure to be protected. The locations of the nozzles 20 of each branch line 18 are staggered relative to the location of the nozzles of the adjacent branch lines, for reasons that will be explained in detail later.

The details of a nozzle 20 are shown in FIGS. 2 and 3. The nozzle 20 comprises a cylindrical body 22 having an upper end portion which is internally threaded as shown at 24 for connection to a branch line 18, and a lower end portion which defines an outlet orifice 26 of a reduced cross section. A- pair of spiral vanes 28a and 28b are fixed within the body 22 for imparting a swirling motion to water flowing downwardly therethrough in a conventional manner. The vanes'28a and 28b support a hollow central hub 30 which, in turn, slidably supports a rod 32 having a head 34 fixed on its lower end. A pair of

sealing rings

36 and 38 are positioned about the periphery of the head 34 and sealingly engage the inner wall of the body 22.

The rod 32 is latched in the position shown in FIG. 2 by a rod 42 whichslidably extends through an externally threaded boss 44 projecting from the side of the body 22. One end of the rod 42 slidably extends through the vane 28a and the wall of the central hub 30 into a slot 46 in the rod 32 to latch it in the position shown in FIG. 2.

A sleeve 48 is threaded on the end of the boss 44 and the outer end of the sleeve is closed off by an externally threaded stub shaft 50 having a ring or yoke 52 thereon. The rod 42 slidably extends through the stub shaft 50, and the other end of the rod engages a conventional thermal fuse element 54 positioned within the ring 52. The fuse element 54 prevents movement of the rod 42 to the right as viewed in FIG. 1, until the heat of a fire fuses the element so that it collapses. Since the fuse element 54 is the standard type commonly used in conventional sprinkler heads now on the market, it will not be described in greater detail.v

The rod 42 has a piston head 56 mounted thereon which slidably engages the internal wall of the sleeve 48. A spring 58 is positioned between the piston head 56 and the end of the stub shaft 50 to bias the piston head and rod 42 to the left with a predetermined biasing force. A passage 60 is formed in the boss 44 to communicate the space on the left side of the piston head 56 with the interior of the body 20. This allows the pressure of the source of water to bias the piston head 56 to the right against the opposing force of the spring 58 to exert a positive pressure on the thermal fuse element 54. v

With the above arrangement, the rod 42 will be driven to the right as soon as the fuse element 54 collapses in response to the heat of the fire, to unlatch the rod 32. This enables the source pressure to act on the piston head 56 to expel it and the rod 32 from the nozzle and allow the water to spray out through the outlet orifice 26. If the system pressure in the nozzle 20 drops below a predetermined minimum pressure level, the biasing force of the spring 58 will maintain the piston head 56 and the rod 42 in a position illustrated in FIG. 2 against the force developed by the reduced water pressure so that the rod 32 will not be unlatched when the thermal fuse element 56 collapses. Consequently,

even if the heat of the fire is sufficient to collapse the thermal fuse element 54, the nozzle 20 will remain closed until or unless the system water pressure in the nozzle exceeds the minimum predetermined pressure level.

As shown in FIGS. 2 and 3, four flanges 62 are provided around the periphery of the body portion 12 adjacent to, and extending slightly below, the outlet orifice 26. The flanges 62 are spaced at ninety degree intervals, and their purpose is to enable water to discharge from the nozzle 20 in the square pattern shown by the reference numeral 64 in FIG. 4. I

In particular, the water discharges from the outlet orifice 26 in a direction having a radial component by virtue of the swirling action imparted to the water by the vanes 28a and 28b, and the flanges 62 direct a portion of the water further radially outwardly than it would normally extend. In this manner, the square pattern 64 is achieved, with the corners of the pattern corresponding to the location of the four flanges 62.

The particular location of the nozzles relative to each other is depicted in the diagrammatic view of FIG. 5, with three adjacent branch lines 18 being shown by the

reference numerals

18a, 18b, and 18c, and a plurality of adjacent nozzles 20 being shown by the reference numerals 201-20g. As shown, the spacing between the adjacent nozzles 20 is substantially equal to the spacing between adjacent branch lines 18, and the nozzles of a particular branch line are staggered relative to the nozzles along its adjacent branch lines. As an example of the latter, the nozzle 20a coincides with an imaginary line drawn through the midpoint between the

nozzles

20d and 20e, and through the midpoint between the nozzles 20f and 203.

The area of responsibility of each nozzle is selected simply by developing the geometry that has the shortest distance between two adjacent nozzles. For example, the shortest distance between the nozzles 28a and each of its adjacent nozzles can be developed along a series of lines a, 70b, 70c, 70d, 70e, and 70f, which together form a hexagonal pattern. Thus, as shown in FIG. 5, the area of responsibility of each nozzle 20 is hexagonally shaped, with each nozzle disposed in the center of the hexagon. It is understood that this hexagonal configuration is the configuration at or near the floor of the space to be protected, and implies a divergence of the spray pattern from the nozzle at its elevated position.

FIG. 6 is identical to FIG. 5, but shows the orientation of two square spray patterns 64a and 64d of water discharge from the

nozzles

20a and 20d, respectively, which patterns are assumed to be at or near the floor of the space to be protected, as in the case of the hexagonal areas of responsibility. As shown, the square patterns 64a and 64d are canted in opposite directions relative to a vertical plane as viewed in FIG. 6, and are sized so that a corner of the square pattern 64d overlaps a portion of the square pattern 64a, with each of the latter square patterns overlapping the common boundary line 70a of the respective hexagonal areas of responsibility of the

nozzles

20a and 20d.

The square patterns of the nozzles 201 20g are shown in FIG. 7, with the square patterns being given the same letter suffix as their corresponding nozzles.

It is noted that, due to the staggered arrangement of the nozzles and the canted orientation of the square patterns 64, approximately 50 per cent of each square pattern from a nozzle on a particular branch line will be overlapped by a corner of two square patterns of nozzles from the two adjacent branch lines. For example, the square pattern 64a is overlapped by a comer of the square pattern 64d and by a corner of the square pattern 643. The purpose of this is to achieve a highly efficient use of the extinguishant, as will be apparent from the following. i

In operation it will be assumed that the fire condition is such that the thermal fuse 54 of the nozzle 20a is initially fused, permitting a release of the plug 24 from the nozzle and a resulting discharge of water therefrom, which takes the pattern 64a as shown in FIG. 7. Assuming that the fire is of a magnitude to cause the actuation of all of the nozzles surrounding the nozzle 20a, the respective square patterns of the nozzles will be oriented as shown in FIG. 7. Since the fire was very probably initially located within the square pattern 64a, and since the

square patterns

64d and 64g overlap approximately 50 per cent of the square pattern 64a, there is a good chance that a double extinguishant discharge directly towards the fire will be achieved.

Since a fire will traditionally take the path of least resistance, it might attempt to avoid the above-mentioned overlapped portions and move towards the vicinity of the square patterns 64b, 64c, Me, or 64f. However, this will result in a longer escape pattern for the fire, which will permit accumulated pre-wetting of any combustibles in the space to be protected, or alternately, the fire will be located much closer to an adjacent nozzle, thus effecting a quicker response; All this is achieved without completely overlapping the adjacent spray patterns and thus sacrificing a very substantial amount of valuable water.

The efficiency of the system of the present invention is even further enhanced since it can be designed so that the pressure required to overcome the force of the spring 58 in each nozzle relative to the total water pressure available is such that only a selected number of nozzles can be actuated at one time, such as the seven depicted in FIG. 7. This, of course, insures the availability of a maximum water pressure at the nozzles more directly over the fire.

Since the nozzles of the present invention are capable of discharging a relative high volume of water directly to the fire, it is apparent that the system of the present invention has excellent fire-fighting capabilities, while making extremely efficient use of the extinguishant.

Of course, variations of the specific construction and arrangement of the method and apparatus disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

Iclaim:

1. An apparatus for controlling fire in a space to be protected, comprising a plurality of spaced parallel rows of extinguishant discharge headssupported at an elevated position within said space mea'ns to supply extinguishant to said heads, and fire responsive means for actuating said heads in a sequence dictated by information received from the fire, each head bein adapted to discharge the extinguishant in a substant1a y square spray pattern, the location of the heads of each row being staggered relative to the location of the heads of its adjacent rows, the spray patterns of all the heads of each row being parallel to each other and canted relative to the spray patterns of the heads on an adjacent row, a corner of each spray pattern being aimed at the center of the spray pattern of one of the two closest heads on an adjacent row and overlapping a portion of the latter spray pattern at a predetermined vertical distance from said heads.

2. A method of controlling fire comprising the steps of supporting a plurality of spaced parallel rows of extinguishant discharge heads at an elevated position within the space to be protected, supplying extinguishant to said heads, and actuating said heads in a sequence dictated by information received from the fire, each head being adapted to discharge the extinguishant in a substantially square spray pattern, the location of the heads of each row being staggered relative to the location of the heads of its adjacent rows, the spray patterns of all the heads of each row being parallel to each other and canted relative to the spray patterns of the heads on an adjacent row, a corner of each spray pattern being aimed at the center of the spray pattern of one of the two closest heads on an adjacent row and overlapping a portion of the latter spray pattern at a predetermined vertical distance from said heads.

wggy UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION P t n N 3.698.481 Dated October 17, 1972 w g William L. Livingston Itis certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 26, "20l-20g." should read 20 a-20g. Column 4, line 65 "201-20g" should read -20a' 20g- Signed and sealed this 15th da'y of May 1973.

(SEAL) Attest:

EDWARD MVFILETCHERJR. l ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

Claims

1. An apparatus for controlling fire in a space to be protected, comprising a plurality of spaced parallel rows of extinguishant discharge heads supported at an elevated position within said space, means to supply extinguishant to said heads, and fire responsive means for actuating said heads in a sequence dictated by information received from the fire, each head being adapted to discharge the extinguishant in a substantially square spray pattern, the location of the heads of each row being staggered relative to the location of the heads of its adjacent rows, the spray patterns of all the heads of each row being parallel to each other and canted relative to the spray patterns of the heads on an adjacent row, a corner of each spray pattern being aimed at the center of the spray pattern of one of the two closest heads on an adjacent row and overlapping a portion of the latter spray pattern at a predetermined vertical distance from said heads.