Patent Publication Number: US-11654316-B1

Title: Fire protection systems and methods for the protection of sloped attic spaces

Description:
PRIORITY CLAIM &amp; INCORPORATION BY REFERENCE 
     This application claims the benefit of U.S. Provisional Application No. 62/768,691 filed Nov. 16, 2018 which is incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to fire protection sprinklers, systems and methods for the protection of attic spaces. In particular, the present invention is directed to fire protection sprinklers, systems and methods for the protection of combustible and non-combustible sloped attic spaces. 
     BACKGROUND ART 
     The design and installation of automatic fire sprinkler protection systems is dependent upon several factors including: the area to be protected, the occupants or items to be protected in the area being protected, the manner in which a fire is to be addressed. One particular area of interest is automatic fire protection systems for attic spaces beneath sloped roofs. Generally, a sloped attic space includes a floor in the form of a horizontal ceiling deck with two sloped roof decks supported above the ceiling deck to enclose the attic space. The roof decks are angled with respect to one another to form a ridgeline or peak of the attic space. Each of the roof decks slope down from the peak toward the ceiling deck to define the slope down direction and form eave regions with the lateral ends of the ceiling deck. In a gable roof construction, for example, the attic space, when viewed in elevation, is triangular with the peak forming the upper vertex and the eave region forming the other two vertices of the triangle proximate the ceiling deck. In plan, the length of the peak ridge line defines the axial length of the sloped attic space and the distance from eave to eave along the ceiling deck perpendicular to the ridge line defines the span of the attic space. 
     Attic fire protection systems locate one or more automatic fire protection sprinklers about the attic space for delivering and distributing firefighting fluid in response to a fire or sufficient level of heat. Generally, automatic fire protection sprinklers include a solid metal body and some type of deflector to distribute fluid discharged from the body in a defined spray distribution pattern. Fluid discharge from an automatic fire protection sprinkler is automatically controlled by operation of a heat-responsive actuator that maintains a fluid tight seal at the discharge orifice by exertion of pressure on a cap (button or disc) or other sealing assembly. When the temperature surrounding the sprinkler is elevated to a pre-selected value indicative of a fire, the actuator operates thereby permitting ejection and release of the cap by the discharge of fluid through the unsealed sprinkler. 
     Automatic sprinklers can be characterized by: its discharge characteristics, its installation orientation (pendent or upright), and its fluid distribution and coverage. Several factors can influence the fluid distribution patterns of a sprinkler and its coverage including, for example, the shape of the sprinkler frame, the sprinkler orifice size or discharge coefficient, the installation orientation and the geometry of the deflector. The discharge or flow characteristics from the sprinkler body is defined by the internal geometry of the sprinkler including its internal passageway, inlet and outlet (the orifice). As is known in the art, the K-factor of a sprinkler is defined as K=Q/(P) 1/2 , where Q is fluid flow rate from the sprinkler for a given fluid starting pressure P, each of which is measured in appropriate metric or English units. For example, Q represents the flow rate (in gallons/min GPM) and P represents the pressure (in pounds per square inch (psi.)) of water or firefighting fluid fed into the inlet end of the internal passageway though the sprinkler body. 
     Examples of known attic sprinkler configurations are shown and described in U.S. Pat. Nos. 9,149,818; 8,083,002; and 5,669,449. The sprinklers show a variety of deflector geometries for distributing for firefighting fluid within an attic space. For example, U.S. Pat. No. 9,149,818 shows and describes an upright sprinkler with a fluid deflector having a central deflecting portion, sidewalls and two angled flaps opposed about the central deflector for redirecting a divided fluid stream in opposed downward angled directions. U.S. Pat. No. 8,083,002 shows and describes an upright sprinkler with a circular fluid deflector for distributing firefighting fluid in a substantially circular cylindrical or radially uniform spray pattern about the sprinkler body. U.S. Pat. No. 5,669,449 shows and describes other attic sprinklers including an upright sprinkler with a deflector geometry for distributing firefighting fluid in a unidirectional or single direction. The fluid deflector includes a central deflecting portion with sidewalls to direct firefighting fluid in the designed single direction. In the directional fluid deflectors, the central deflecting portions are shown with a constant width about which the sidewalls extend. 
     In attic fire protection systems, automatic sprinklers are coupled to one or more fluid supplying branch lines that extend through the attic space. The number of sprinklers, their relative spacing and location within the attic space is dependent on several design factors including the fluid supply criteria or hydraulic demand to deliver a requisite flow rate or supply pressure of fluid to a number of design sprinklers or a requisite fluid density of fire fluid, i.e., flow per area measured in (gallons per minute (GPM) per square foot (sq. ft.)) to a design area of a specified size. Industry accepted installation standards generally require a delivered fluid density of 0.1 GPM/sq. ft over a design area to be protected. Alternatively, systems can demonstrate the requisite fluid distribution capability by using automatic sprinklers that have satisfactorily performed in full-scale actual fire test in which the automatic sprinkler delivered a constant flow of firefighting fluid when supplied with the fluid at a constant pressure. 
     The design sprinklers of a system are an identified number of “most hydraulically remote sprinklers” subject to one or more design criteria. As used herein, the most hydraulically remote sprinklers are those sprinklers that experience the greatest fluid pressure loss relative to the fluid supply source when supplying the sprinklers with the minimum fluid flowing operating pressure for the sprinkler. In satisfying the preferred hydraulic criteria of the system, it can be shown by hydraulic calculation that if all design sprinklers activate, the piping and supply can provide the required fluid flow. Alternatively, or additionally, the hydraulic criteria of the system can be shown by hydraulic calculation, that if all design sprinklers activate, the piping and supply can deliver a minimum operating pressure of firefighting fluid to the design sprinklers to provide for a minimum fluid density of 0.1 GPM/sq. ft. over the design area. 
     One design factor limiting the performance of an automatic fire protection system for attics is the roof span of the attic space to be protected. For example, one known system from Viking Corp. provides protection of sloped roof attic spaces having a roof span up to a maximum of sixty feet (60 ft.) for roof slopes that range from 4 inch of vertical rise for 12 inches of horizontal run (4:12) to 12 inches of rise for 12 inches of run (12:12). The system is shown and described in technical data sheet publication Form No. F-043015: “Model V-SD Specific Application Attic Sprinkler” (Feb. 19, 2016 Rev. 16.1) from The Viking Corp of Hastings, Mich. Generally, the Viking system provides one line of sprinklers aligned below and parallel the ridge line to provide a uniform radial spray pattern. Unidirectional type sprinklers are located between the roof peak and the eaves. These directional sprinklers direct their spray toward the eaves for the protection of this region of the attic. 
     Another known system from Globe Fire Sprinkler Corporation of Standish, Mich. provides for three branch lines to which sprinklers are connected for protection of sloped roof attic spaces having a roof span up to a maximum of seventy-two feet (72 ft.) for roof slopes that ranges from 3 inch of vertical rise for 12 inches of horizontal run (3:12) to 6 inch of rise for 12 inches of run (6:12). The system is shown and described in technical data sheet publication GFS-650: “Specific Application Attic Sprinklers” (July 2018) available at &lt;https://globesprinkler.com/uploads/files/GFS-650_20180730CM_745.pdf&gt;. Generally, the Globe system provides one branch line of sprinklers aligned below and parallel the ridge line with each of the other two branch lines of sprinklers aligned downslope of and parallel the ridge line between the peak and the eaves. These downslope sprinklers direct their spray toward the eaves for the protection of this region of the attic. With its three-branch line system alone, the Globe system is limited to protection of a maximum roof span of seventy-two feet. Protection of larger roof spans in the Globe or other attic fire protection systems require the installation of more branch lines and sprinklers and/or sprinklers installed in close proximity to the eave regions. 
     Expanding the range of roof span protection beyond seventy-two feet (72 ft.) can present additional problems for the fire protection system designer, installer and/or owner-operator. In particular, the addition of sprinklers and/or branch supply lines can increase the overall hydraulic demand and installation cost of the system. Moreover, requiring sprinklers to be installed close to the eave regions can make the installation difficult as the clearance for work space decreases as the sloped roof approaches the ceiling deck proximate the eave regions. Accordingly, a need remains for fire protection of roof spans over seventy-two feet and larger. 
     DISCLOSURE OF INVENTION 
     Preferred sprinklers, systems and methods are provided for protection of sloped roof attic spaces with maximum roof spans over seventy-two feet preferably ranging from seventy-two to eighty feet (72-80 ft.). A preferred sprinkler for protection of the eave regions includes a frame having a body defining an inlet, an outlet with a passageway extending between the inlet and the outlet along a sprinkler axis to define an orifice. A preferred deflector is affixed to the sprinkler frame at a fixed distance from the outlet for deflecting fluid in a direction of a radial axis that extends perpendicular to the sprinkler axis. The sprinkler and its preferred deflector provide for a horizontal throw of over twenty-four feet preferably up to twenty-eight feet when provided with a fluid flow rate of firefighting fluid of twenty-three gallons per minute (23 GPM) at a fluid pressure of seventeen pounds per square inch (17 psi). The fluid distribution provides for a fluid distribution density of 0.1 GPM/sq. ft. over a preferred (8 ft.×28 ft.) coverage area. 
     The preferred deflector includes a base mounted to the sprinkler frame having a leading edge with a flap extending angularly from the leading edge of the base. The flap forms a discharge channel extending in the radial direction with the channel being symmetrical about a bisecting plane. The discharge channel preferably widens in the radial direction and in preferred embodiments are trapezoidal in shape. In preferred embodiments of the deflector, the flap includes a central canopy portion intersecting the bisecting plane with a first end contiguous with the leading edge of the base and a second terminal end spaced from the first end. The flap includes a pair of sidewalls disposed about the central canopy portion. Each of the sidewalls are angled with respect to the bisecting plane to define an acute first included angle, preferably about fifteen degrees (15°) such that the discharge channel broadens in the direction from the first end to the second terminal end of the flap. 
     The preferred eave sprinkler alone and in combination with other types of sprinklers provides for a fluid distribution that defines a span of attic protection in a three-branch system that is over sixty feet (60 ft.) and at its maximum preferably ranges from seventy-two to eighty feet (72-80 ft.) and more preferably ranges from seventy-five feet to eighty feet (75-80 ft.). In a preferred three branch fire protection system for a sloped attic space, a plurality of sprinklers of a first type are aligned below the attic ridge and coupled to a first fluid supply branch line. Each sprinkler of the first type has a frame defining an inlet, an outlet with a passageway extending between the inlet and the outlet along a sprinkler axis and a deflector affixed to the sprinkler frame at a fixed distance from the outlet to generate a uniform spray about the sprinkler axis. Sprinklers of the first type are preferably embodied as upright attic sprinklers in which its fluid distribution provides for a fluid distribution density of 0.1 GPM/sq. ft. over a preferred (8 ft.×24 ft.) coverage area when provided with a flow rate of 20 GPM of firefighting fluid at 13 psi. 
     The preferred eave sprinkler provides a plurality of sprinklers of a second type to define a first group and a second group of sprinklers and preferably no more than two groups, in which each group is aligned in a row between the ridge and the eave parallel to the ridge with the first and second group being spaced apart from one another equidistantly about the ridge. The sprinklers of the second type are located at a maximum upslope distance of up to twenty-seven feet from the eave. Moreover, the sprinklers of the first type and the sprinklers of the second type are off-set from one another in the downslope direction from the ridge to one of the eaves. The sprinklers of the second type generate a spray from the sprinkler with a majority of the spray directed in a downslope direction from the ridge and toward one of the eaves. The first and second type of sprinklers each provide a fluid density sufficient to define a maximum roof span of protection which is preferably seventy-two feet or more and more preferably ranges from seventy-five feet to eighty feet (75-80 ft.) and in various embodiments of the preferred system, provide a maximum roof span of protection of eighty feet (80 ft.). 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and together, with the general description given above and the detailed description given below, serve to explain the features of the invention. It should be understood that the preferred embodiments are some examples of the invention as provided by the appended claims. 
         FIG.  1 A  is a front view of a preferred embodiment of an eave sprinkler. 
         FIG.  1 B  is a cross-sectional view of the sprinkler of  FIG.  1 A . 
         FIGS.  2 A- 2 C  are various views of a preferred deflector for use in the eave sprinkler of  FIG.  1   . 
         FIG.  3 A  is a schematic elevation view of a preferred automatic attic fire protection system. 
         FIG.  3 B  is a plan view of the automatic fire protection system of  FIG.  3 A . 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     Shown in  FIGS.  1 A- 1 B  is a preferred embodiment of a fire protection sprinkler  10  for the protection of attic spaces or portions thereof. More specifically, the preferred sprinkler  10  provides for protection of the eaves region of an attic space by providing a spray pattern from the sprinkler that is capable being focused or concentrated toward the eaves region. Moreover, the preferred sprinkler  10  alone and in combination with other types of sprinklers provides for a fluid distribution that defines a span of attic protection in a three-branch system that is over sixty feet (60 ft.), preferably seventy-two feet (72 ft.) or more and more preferably ranges from seventy-five feet to eighty feet (75-80 ft.) and in various embodiments of system protection described herein, provides a maximum roof span of protection of eighty feet (80 ft.). 
     The preferred eave sprinkler  10  includes a frame  12  including a body  14  defining an inlet  16 , an outlet  18  with a passageway  20  extending between the inlet  16  and the outlet  18  along a sprinkler axis X-X to define an orifice. The body is configured for coupling the sprinkler  10  to a fluid supply pipe SP. For example, the body  14  can include an external pipe thread  22  for coupling to a female fitting having a complementary thread for engagement with the sprinkler  10 . The preferred frame  12  includes a pair of frame arms  24  to support and locate a deflector  100  at a fixed distance from the outlet  18 . The pair of frame arms  24  extend from the body  14  at diametrically opposed sides of the outlet  18  with a deflector boss  25  that extends across the ends of the frame arms  24 . The boss  25  is preferably an annular formation centered along the sprinkler axis X-X and coaxially aligned with the outlet at a fixed distance from the outlet  18 . The deflector  100  is affixed and preferably mounted to the boss  25  to locate the deflector  100  at the fixed distance from the outlet. The deflector  100  is illustratively shown bent or formed for installation in an upright orientation in which supplied firefighting fluid is discharged from the outlet  18  to impact the deflector  100  in an upward direction. 
     Coupled to the frame  12  is a preferred deflector  100 . The deflector  100  is preferably affixed to the sprinkler frame  12  and spaced at a fixed distance from the outlet  18  for deflecting fluid in a direction of a radial axis Y-Y that extends perpendicular to the sprinkler axis X-X. The deflector  100  includes a base portion  102  mounted to the sprinkler frame having a leading edge  104  with a flap  106  extending angularly from the leading edge  104  of the base  102 . The flap  106  forms a preferred discharge channel  108  that extends in the direction of the radial axis Y-Y with the channel being preferably symmetrical about a bisecting plane P 1  defined by the intersection of the sprinkler axis X-X and the radial axis Y-Y. 
     As shown in  FIGS.  2 A- 2 C , the preferred flap  106  includes a central canopy portion  110  that intersects the bisecting plane P 1  with a first end  112  contiguous with the leading edge  104  of the base  102  and a second terminal end  114  forming the terminal end of the discharge channel  108  of the deflector  100 . The flap  106  includes a pair of sidewalls  116   a ,  116   b  disposed about the central canopy portion  110 . In the preferred deflector  100 , each of the sidewalls  116   a ,  116   b  is angled with respect to the bisecting plane P 1  to define an acute first included angle α such that the discharge channel  108  broadens or widens in the direction from the first end  112  to the second terminal end  114  of the flap  106 . Additionally, or alternatively, lateral edges of the canopy portion  110  extend between the first and second end  112 ,  114  at the preferred angle α. Accordingly, in a preferred embodiment of the canopy portion  110 , the second terminal end  114  has a width W 2  that is greater than the width W 1  of the first end  112  such that canopy portion  110  is substantially trapezoidal in shape. The second and first ends  114 ,  112  of the canopy portion  110  defines a preferred ratio W 2 :W 1  that preferably ranges from 1.33:1 to 1.67:1. In a preferred embodiment of the canopy portion  110 , the width W 2  at the second terminal end  114  is about one inch (1 in.) and the width W 1  of the canopy portion at the first end  112  is about 0.75 inch. The first acute preferably included angle α preferably ranges from ten to forty-five degrees (10°-45°), more preferably ranges from ten to thirty degrees (10°-30°), even more preferably ranges from ten to twenty degrees (10°-20°) and yet even more preferably is fifteen degrees (15°). Therefore, in preferred embodiments of the deflector flap  106 , the formed discharge channel  108  is also preferably trapezoidal in shape. 
     Each of the sidewalls  116   a ,  116   b  also define a second included angle β with respect to the canopy portion  110  in a plane P 2  that is disposed perpendicular to the first plane P 1 , as seen for example in  FIGS.  1 B and  2 A . In one preferred aspect, each of the sidewalls define a ninety degree (90°) second included angle β with the canopy portion. Alternatively, the sidewall can define an obtuse included angle β that is preferably less than 150 degrees (150°) and can more preferably be about 130 degrees (130°) or even more preferably 112 degrees (112°). 
     The flap portion  106  and its various features can define other dimensional relationships to the base portion  102  that can further define the spray characteristics of the sprinkler  10 . The base portion  102  includes a mounting portion  120  for affixing the deflector  100  to the frame  12 . Preferably, the mounting portion  120  is preferably configured as one or more flanges through which a fastener such as, for example, an Allen or hex-head screw is used to affix the deflector  100  to the frame  12 . The base portion  102  further includes a central deflecting plate  122  and a pair of lateral walls  124   a ,  124   b  disposed about the deflecting plate  122  to form an intermediate flow channel  126  that extends from the frame  12  to the discharge channel  108 . Preferably, the distance between the sidewalls  116   a ,  116   b  of the flap  106  is greater than the distance between the lateral walls  124   a ,  124   b  of the base  102  such that the base  102  portion is narrower than the flap portion  106 . Preferably, each of the sidewalls  116   a ,  116   b  of the flap  106  has an outer leading edge  118   a , an outer trailing edge  118   b , and an outer terminal edge  118   c . Each of the outer leading edge  118   a  and the outer trailing edge  118   b  are disposed at approximately the same angle with respect to the outer terminal edge  118   c , and, more preferably, the same angle is ninety degree (90°). The same angle allows for each outer trailing edge  118   b  to be offset in the direction of the radial axis from both of the pair of lateral walls  124   a ,  124   b . The offset provides an angular gap between the sidewalls  116   a ,  116   b  of the flap  106  and the pair of lateral walls  124   a ,  124   b  of the base  102 . 
     The central deflecting plate  122  includes the leading edge  104  that is proximate and preferably contiguous with the flap  106 . Opposite the leading edge  104 , the deflecting plate  122  includes a trailing edge  105  proximate and preferably contiguous with the mounting portion  120  and the lateral walls  124   a ,  124   b . The trailing edge  105  and the leading edge  104  of the base  102  are axially spaced apart from one another in the direction of the central axis X-X to define a preferred maximum deflector height HE To form the intermediate channel  126 , each of the lateral walls  124   a ,  124   b , is preferably formed and shaped so as to extend axially from the trailing edge  105  to the deflector plate  122  over the total length L 1  of the deflector plate  122 . Accordingly, the intermediate channel  126  preferably has a triangular volume. The deflecting plate  122  preferably intersects the sprinkler axis X-X to define a skew angle θ therebetween, as seen in  FIG.  1 B , that preferably ranges from thirty to sixty degrees (30°-60°) and is more preferably forty-five degrees (45°). Accordingly, water discharged from the outlet  18  of the frame  12  impacts the angled deflector plate  122  and with a majority of the fluid being directed toward the discharge channel  108  of the flap  106 . The flap portion is preferably angled with respect to a plane parallel to the Y-Y axis at an angle μ at less than thirty degrees (30°) to less than fifteen degrees (15°) and is more preferably five degrees (5°). Accordingly, in a preferred embodiment the canopy portion  110  of the flap  106  and the deflector plate  122  define a preferred included angle in between of about one hundred thirty degrees (130°). 
     Referring to  FIG.  2 C , the axial depth or height H 2  of the flap portion  106  and its discharge channel  108  preferably varies in the axial direction of the sprinkler axis X-X from the canopy portion  110  to a peripheral edge of the sidewalls  116   a ,  116   b  over the total length L 2  of the canopy portion  110 . The maximum height H 2 Max of the flap portion is preferably less than the maximum height H 1  of the base portion  102  and define a preferred ratio of base height-to-flap ratio (H 1 :H 2 Max) ranging from 1.3:1 to 2:1. The length L 2  of the canopy portion  110  is preferably less than the length L 1  of the deflecting portion  122 ; and in another preferred aspect, the ratio of the lengths L 1 :L 2  ranges preferably from 1.3:1 to 2:1. In a preferred embodiment of the deflector  100 , the length L 1  of the deflecting portion  122  is about one inch (1 in.) and the length L 2  of the canopy portion  110  is about 0.5 inch. 
       FIG.  1 B  shows the cross-sectional view of the frame body  14  and its internal passageway  20 . Fluid supplied to the sprinkler inlet  16  flows through the internal passageway  20  and is discharged from the outlet  18  to impact the deflector  100  to address a fire. The internal passageway  20  preferably tapers narrowly from the inlet  16  to the outlet  18 . The discharge characteristics from the sprinkler body  14  and its outlet orifice are preferably quantified by the industry accepted discharge coefficient or nominal K-factor defined from the formula: K-factor=Q÷√P where Q is fluid flow rate from the sprinkler for a given fluid starting pressure P, each of which is measured in appropriate metric or English units. The sprinkler body  14  defines a nominal K-factor that is preferably less than a nominal K 11.2 GPM/(PSI) 1/2  and is preferably a K 5.6 GPM/(PSI) 1/2  (hereinafter K5.6). Alternatively, the sprinkler body  14  can define a nominal K-factor of any one of 8.0 GPM/(PSI) 1/2 ; 4.2 GPM/(PSI) 1/2  or smaller. Further in the alternative, the sprinkler body  14  can define a nominal K-factor larger than that of a nominal K-factor 11.2 GPM/(PSI) 1/2 . 
     Preferred embodiments of the sprinkler  10 , are preferably configured as automatic sprinklers such that fluid discharge from the connected sprinkler  10  and its outlet  18  is controlled by a seal assembly  30  that is disposed within the passageway  20  proximate the outlet  18  to occlude the outlet. The seal assembly  30  is supported within outlet  18  of the sprinkler body  14  by a thermally responsive element or trigger  40  aligned along the sprinkler axis X-X between the sealing assembly  30  and a loading assembly  50 . The thermally responsive element  40  is preferably embodied as a thermally responsive frangible glass bulb but can be alternatively embodied as a thermally responsive mechanical or electrically actuated assembly provided the assembly can seat and unseat the seal assembly  30  in respective unactuated and actuated states of the sprinkler. In the presence of a sufficient level of heat, the thermally responsive element  40  operates or triggers to release the sealing assembly  30  and permit the supplied fluid to discharge from the outlet  18  to impact the deflector  100  and address a fire. 
     When provided with a supply of firefighting fluid at a flow rate of 23 GPM, the preferred eave sprinkler directs fluid forward of the deflector  100  to a horizontal throw distance of up to twenty-eight feet (28 ft.). Laterally of the direction of throw, the sprinkler discharges over a width of eight feet (8 ft.), so as to define a preferred 8 ft.×28 ft. coverage area. Moreover, the sprinkler  10  directs fluid rearward of the deflector  100  to a rearward distance of no more than five feet (5 ft.) and more preferably up to four feet (4 ft.). Accordingly, a majority of the spray distribution is forward of the sprinkler  10 . As described herein, the throw distance of the sprinkler is advantageous in protecting the low clearance eave region in sloped roof attic spaces, i.e., below gable roofs. The preferred eave sprinkler  10  provides for an attic fire protection system that can protect roof spans of over sixty feet (60 ft.) and more preferably over seventy-two feet (72 ft.) up to a preferred maximum of eighty-feet (80 ft.) with a preferred minimum number of branch lines and total sprinklers which in turn can preferably minimize the total hydraulic demand of the system. 
     Shown in  FIGS.  3 A- 3 B  are schematic views of a preferred attic fire protection system  200  installation for a sloped attic space ATTIC beneath a roof having a slope SL that ranges from 2½ inch of vertical rise for 12 inches of horizontal run (2½:12) to 12 inch of rise for 12 inches of run (12:12) and more preferably ranging from 4:12 to 12:12 and in preferred embodiments preferably ranging from 4:12 up to 6:12 and yet even more preferably ranging from 2½:12 up to 6:12. The sloped attic space ATTIC is formed between a ceiling base CB and a pair of sloped roof decks RD supported by a truss system TS defining a ridge peak RP in between with the ceiling base CB extending between and below the sloping roof decks to define a pair of eaves EV equally spaced about the ridge RP to define a preferred roof span SP of over sixty feet (60 ft.) and preferably ranging from 60 ft.-80 ft. The truss system TS generally includes a plurality of truss members TM each having a top chord TC, a bottom chord BC, and a group of angular web members WM. Shown in  FIG.  3 B  is a plan view of the attic space in which the truss members TM are spaced apart from one another on center by less than three feet (3 ft.) and more preferably spaced on two-foot (2 ft.) centers defining channels in between. 
     The fire protection system  200  includes a plurality of sprinklers of a first type  205  aligned below the ridge RP in which each sprinkler of the first type is aligned along a channel and more preferably centered between two truss members TM. Each sprinkler of the first type  205  preferably provides a uniform spray pattern radially about the sprinkler and its axis. An exemplary embodiment of a sprinkler of the first type of sprinkler  205  is an upright sprinkler shown and described in technical data sheet publication, Form No. F-042517: “Attic Upright Specific Application Sprinkler VK697” (Aug. 23, 2018 Rev. 18.2) from The Viking Corp of Hastings, Mich. Generally, the sprinklers  205  include a frame having a body with an inlet, an outlet and internal passageway extending between the inlet and the outlet to form the sprinkler orifice defining a preferred nominal K-factor of less than K 11.2 GPM/(PSI) 1/2  and is preferably K 5.6 GPM/(PSI) 1/2 . The preferred frame includes a pair of frame arms to support and locate a deflector at a fixed distance from the outlet. The deflector is bent or formed for installation in an upright orientation in which supplied firefighting fluid is discharged from the outlet to impact the deflector in an upward direction and distributed radially in a preferred uniform distribution about the sprinkler. 
     The sprinklers of the first type  205  are coupled to a first branch line BL 1  disposed below and parallel to the ridge RP with the deflector of the sprinkler preferably one to twelve inches (1-12 in.) of the ridge RP. The sprinklers  205  are preferably spaced from one another along the branch line BL 1  at a sprinkler-to-sprinkler spacing SS 1  that ranges from seven to twelve feet (7-12 ft.) and is more preferably at a sprinkler-to-sprinkler spacing of eight feet (8 ft.). When provided with an appropriate operating flow of firefighting fluid, each sprinkler  205  and its spray pattern define a preferred maximum coverage area of one hundred ninety-two square feet (192 sq. ft.) to provide a preferred minimum fluid delivery density of no less than 0.1 GPM/sq. ft. In one preferred installation, the sprinklers of the first type  205  are supplied with a minimum fluid flow of 20 GPM at 13 psi. Accordingly, each sprinkler  205  provides a preferred fluid delivery density of about 0.1 GPM/sq. ft. 
     The preferred eave sprinkler  10  of  FIGS.  1 A and  1 B  previously described provides a preferred embodiment of a sprinkler of second type  210  located downslope of the first type of sprinklers  205  between the ridge RP and each of the eave regions EV. Accordingly, the sprinklers of the second type  210  are preferably divided into two groups with a first group  210   a  and second group  210   b  with each group of sprinklers being aligned in a row between the ridge RP and an eave EV parallel to the ridge RP with the first and second groups  210   a ,  210   b  being spaced apart from one another preferably equidistantly about the ridge RP. Each sprinkler of the second type  210  is aligned along channel and more preferably centered between two truss members TM. Moreover, each sprinkler of the second type  210  is located within a channel that is spaced from a channel that includes a sprinkler of the first type  205 . Accordingly, in the preferred installation and direction of roof span SP, the sprinklers of the second type  210  are off-set OS from sprinklers of the first type  205 . The amount of off-set can range from two feet to six feet (2-6 ft.) and is preferably two feet when measured from sprinkler of a first type  205  to the next closest sprinkler  210  in a direction aligned with the peak RP. 
     In order to protect the eave regions EV and define the preferred roof span protection, each of the preferred eave sprinklers  210  is oriented with its axis X-X perpendicular to the sloped roof deck RD such that the majority spray distribution from the channel  108  of the deflector  100  is directed downslope toward the eaves and the minor rearward discharge is directed toward the ridge RP. The deflector  100  is preferably located within the channels beneath the roof deck RD at a preferred distance that ranges from sixteen to twenty-two inches (16-22 in.) and additionally or alternatively, one to three inches (1-3 in.) below the bottom of the top chord TC of the truss members TM. 
     The one group  210   a  of the eave sprinklers is coupled to a second branch line BL 2  disposed preferably downslope and parallel to the first branch line BL 1  and the other group  210   b  of the eave sprinklers is coupled to a third branch line BL 3  disposed preferably downslope and parallel to the first branch line BL 1  opposite the second branch line BL 2  about the ridge RP. The sprinklers of the second type  210  are preferably spaced from one another along each of the second and third branch lines BL 2 , BL 3  at a preferred sprinkler-to-sprinkler spacing SS 2  that ranges from four to twelve feet (4-12 ft.), preferably ranges from seven to twelve feet (7-12 ft.), even more preferably ranges from four to eight feet (4-8 ft.) and is more preferably at a sprinkler-to-sprinkler spacing of eight feet (8 ft.). 
     When provided with an appropriate operating flow of firefighting fluid, each sprinkler  210  is capable of providing a spray pattern with a forward horizontal throw in the direction of the eave EV of twenty-eight feet (28 ft.), a rearward throw in the direction of the ridge RP of four feet (4 ft.) and a maximum lateral throw about the forward discharge of about 8 ft. Preferably, each eave sprinkler  205  and its spray pattern define a preferred maximum coverage area of two hundred twenty-four square feet (224 sq. ft.) to provide a preferred minimum fluid delivery density of no less than 0.1 GPM/sq. ft. In one preferred installation, the sprinklers of the first type are supplied with a minimum fluid flow of 23 GPM at 17 psi. Accordingly, each sprinkler  205  provides a preferred fluid delivery density of about 0.1 GPM/sq. ft. 
     Individually and cumulatively, the first and second type of sprinklers  205 ,  210  their spray patterns and the fluid distribution densities define a preferred maximum roof span of protection PSP which is preferably seventy-two feet or more and more preferably ranges from seventy-five feet to eighty feet (75-80 ft.) and in various embodiments of the preferred system, provide a maximum roof span of protection of up to eighty feet (80 ft.). Additionally, the first and second type of sprinklers  205 ,  210 , their spray patterns and the fluid distribution densities individually and cumulatively can provide for protection over the range of roof slopes SL to define a roof slope of protection SLP that preferably ranges from 2½:12 to 12:12 to provide roof slope protection SLP ranging therebetween including 4:12 to 12:12, 4:12 to 6:12 and more preferably 2½:12 to 6:12. With reference to  FIG.  3 B , the directional spray sprinklers of the second type  210  are preferably located twelve to thirty feet (12-30 ft.) downslope DS of the uniform distribution sprinklers of the first type  205  and more preferably, fifteen to twenty-six feet (15-26 ft.) downslope and even more preferably a minimum sixteen feet (16 ft.) downslope of the uniform distribution sprinklers of the first type  205 . With the preferred downslope spacing between the first and second type of sprinklers  205 ,  210 , the system  200  with the preferred three branch system arrangement can provide for the preferred maximum roof span of fire protection PSP of up to eighty feet (80 ft.) when the sprinklers of the first type  205  are supplied with firefighting fluid at a minimum flow of at least 20 GPM and the sprinklers of the second type  210  are supplied with firefighting fluid at a minimum flow of at least 23 GPM. Moreover, the preferred installation of the directional sprinklers  210  provide for protection of the eaves EV at a maximum distance of up to twenty-seven feet (27 ft.) upslope US from the eave EV. By maximizing the installation distance from the eave EV, sprinkler installation can be made easier by providing for a greater clearance between the roof deck RD and the ceiling deck CD. The roof span of protection preferably varies directly with the fluid supply flow, pressure and/or the downslope distance between the sprinkler of the second type  210  and the sprinkler of the first type  205  such that one or more of the variable can be reduced to reduce the roof span of fire protection of the system  200 . For example, for protection of a roof span of seventy-two feet (72 ft.) the sprinklers of the first type  205  are supplied with firefighting fluid at a flow of at least 20 GPM and the sprinklers of the second type  210  are supplied with firefighting fluid at a flow of 20 GPM with the eave sprinklers  210  are preferably located sixteen feet (16 ft.) downslope of the sprinklers of the first type  205 . 
     The system  200  is preferably hydraulically configured by providing the preferred fluid flow to a number of design sprinklers which preferably range from 1 to no more than five (1-5) design sprinklers. The design sprinklers are an identified number of “most hydraulically remote sprinklers” subject to one or more design criteria. In satisfying the preferred hydraulic criteria of the system, it can be shown by hydraulic calculation that if all design sprinklers activate, the piping and supply can provide the required fluid flow. Alternatively, or additionally, the hydraulic criteria of the system can be shown by hydraulic calculation, that if all design sprinklers activate the piping and supply can provide a minimum operating pressure, for example, 7 psi. of firefighting fluid, the design sprinklers provide for a minimum fluid density of 0.1 GPM/sq. ft. over a design area defined by the number of design sprinklers defined by their respective coverage areas. 
     Preferably, the system  200  is hydraulically configured to satisfy the greatest hydraulic demand as defined from the following criteria: (i) one to no more than five adjacent design sprinklers of the first type  205  located at the peak having minimum flow at the preferred 20 GPM; (ii) one to no more than five adjacent design sprinklers of the second type  210  having a minimum flow at the preferred 23 GPM; (iii) no more than five adjacent design sprinklers that includes at least one sprinkler of the first type  205  and at least one sprinkler of the second type  210  each having minimum flows at the respective preferred flow rates; and/or (iv) no more than four adjacent design sprinklers that includes at least two sprinklers of the first type  205  and at least one sprinkler of the second type  210  each having minimum flows at the respective preferred flow rates. 
     Given the fluid distribution of the preferred eave sprinkler  10 , a preferred method of fire protection of an attic space is provided that can include obtaining sprinklers for protection of the eave regions with a directional fluid distribution; and providing the plurality of eave sprinklers for installation downslope of a plurality of sprinklers located at the ridge peak having a uniform fluid distribution to define a maximum roof span protection of up to eighty feet (80 ft.). Obtaining a preferred sprinkler can include any one of manufacturing or acquiring the preferred sprinklers; and providing can include any one of selling, specifying, or supplying the preferred sprinklers for installation in a preferred manner as described herein. 
     While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.