Patent Application
20150068777
This invention relates generally to fire sprinkler systems. More specifically, exemplary embodiments relate to a fire sprinkler system using non-metallic pipes, such as CPVC, that may be installed in an area which has exposed joists, such as an unfinished basement. This invention involves placing the sprinklers in an asymmetric pattern.
Fire sprinkler systems have become more popular in recent years as a way to save lives and property in a fire situation. Non-metallic pipes offer several advantages over competing materials for use in fire sprinkler systems, including cost benefits, non-corrosive, and ease of installation.
Currently, non-metallic pipes are used in fire sprinkler applications where a finished ceiling exists to enclose the non-metallic pipes, such as living areas on the first and second floors of homes. Fire sprinkler systems using non-metallic pipes are currently not approved for use in exposed composite or open web joist areas of a building.
One of the problems with using non-metallic pipes for fire sprinkler systems in areas having exposed composite or open web joists is in a normal 12 foot×12 foot spacing of the sprinklers, the water spray from the first sprinkler to activate, can deposit water on the adjacent sprinklers, thus cooling them to an extent that they do not activate.
It would be an advantage to have a sprinkler system using non-metallic pipes in an unfinished ceiling area, such as a basement, which has exposed joists.
The above described problem is solved by an asymmetric spacing of the sprinklers. The exemplary sprinkler system, discussed in more detail herein, may be included in a basement or any other area having exposed joists.
The exposed joists may be solid wood joists, such as 2×10, 2×12 and the like, or may be composite wood joists, or open web floor truss joists. The most preferred joists are composite wood joists and solid wood joists. Of course, joists made from other materials, such as metal, may be used, but are less common in the building industry. The spacing of the joists from each other is usually 16 inches or 24 inches on center, but can be any spacing which is engineered to sustain the required load. The bottom of the joist is usually about 8 to about 10 feet in height from the floor of the building. The joists are substantially parallel to each other. The term “substantially parallel” is intended to take account of the normal tolerances of the building trades and is usually within about 0.5 inch in width in a 24 ft. length of the joist from being exactly parallel. The building structure will have multiple spaced apart joists.
The non-metallic pipes referred to in this invention are intended to include any non-solid metal pipes. Solid metal pipes, such as copper, steel, iron, aluminum, and the like are excluded from this invention. Suitable non-metallic pipes include, but are not limited to, thermoplastic and thermoset polymer pipes, such as polyethylene, crosslinked polyethylene (PEX), polypropylene, and chlorinated polyvinyl chloride (CPVC). The polymer pipe material can be composite materials, such as the polymer reinforced with other fibrous materials. For example, PEX or polypropylene can be reinforced with fiberglass or aluminum. Since chlorinated polyvinyl chloride (CPVC) is the most preferred non-metallic material for use in fire sprinkler piping, the invention will be described in detail below using CPVC. CPVC has been found to be useful without the need of further reinforcement using fiber fillers. Since CPVC is the preferred non-metallic pipe, this invention will be described below using CPVC pipe and fittings. It should be understood that other non-metallic systems can be used and would require different fittings, as is well understood in the art. The common factor would be the asymmetrical spacing of the sprinklers.
The fire suppression system of this invention has multiple chlorinated polyvinyl chloride (CPVC) sprinkler conduits (pipes). In an exemplary embodiment, the system has a first conduit extending within the space defined by a first set of two adjacent substantially parallel joists. The first conduit extends substantially parallel to the first set of joists. The system also has a second CPVC sprinkler conduit extending within the space defined by a second set of two adjacent substantially parallel joists. The second CPVC conduit extends substantially parallel to the second set of joists. There can be third, fourth, fifth, etc., CPVC sprinkler conduits necessary to cover the area of the room where fire protection is desired. The CPVC conduits will normally contain a fire suppression fluid under pressure, usually as low as 7 psig up to about 175 psig. Psig refers to a pressure measurement in pounds per square inch above normal atmospheric pressure (normally stipulated as 1 atmosphere). The fire suppression fluid is most preferably water, but can be any non-flammable fluid or gas capable of extinguishing a fire. The CPVC conduits can vary in diameter, depending on the amount of fluid needed and the pressure available, from 0.75 inch to 4 inches, but for most applications 0.75 to 1.25 inches is preferred, with 1.0 inch being the most preferred diameter. The diameter specified is an iron pipe size (IPS) diameter.
In the exemplary embodiment, there are multiple thermally activatable automatic sprinklers attached to the first CPVC conduit. The thermally activatable automatic sprinklers are in fluid connection with the first CPVC conduit and are attached in a generally perpendicular relationship to the first CPVC conduit. The term “generally perpendicular”, as used herein, means that the sprinkler is no more than 1 inch off perpendicular per 1 foot in length, and preferably no more than 0.25 inch off perpendicular per 1 foot in length. The thermally activatable automatic sprinkler is attached to the CPVC conduit by the use of a short length of CPVC pipe (drop) of a diameter which is usually equal to or smaller than the CPVC sprinkler conduit. For example, if a 1.0 inch CPVC conduit is used, the short length of the drop CPVC pipe could be 0.75 inch in diameter. One end of the drop CPVC pipe is attached to the CPVC conduit by the use of a CPVC fitting, such as a “T” fitting. The other end of the drop CPVC pipe is attached to the sprinkler, usually by the use of a threaded fitting. The length of the drop CPVC pipe is sufficient to cause the lower most part of the sprinkler (deflection plate) to be about 1.5 inches below the bottom edge of the joist. Normally, the length of the drop CPVC pipe will be from about 1 to about 12 inches.
Each of the multiple thermally activatable automatic sprinklers is substantially equally spaced a first predetermined distance from adjacent sprinklers on the first sprinkler conduit. The first predetermined distance can be from 13 feet to 18 feet.
The multiple thermally activatable automatic sprinklers are selected to activate at a given temperature to release the fire suppression fluid. The activation temperature is usually from about 140° to about 190° F., more preferably from about 155° F. to about 175° F.
Multiple thermally activatable automatic sprinklers are also attached to the second CPVC conduit, at a second predetermined distance from adjacent sprinklers, in a similar fashion as described above for the first CPVC conduit. If a third, fourth, fifth, etc. conduits are used, the multiple thermally activatable automatic sprinklers would be attached at a predetermined distance from adjacent sprinklers on the same conduit. The first and second predetermined distances are substantially equal.
The first and second predetermined distance is at least one foot in length and up to 6 feet in length greater than the distance between the thermally activatable automatic sprinklers attached to the first CPVC conduit and the nearest thermally activatable automatic sprinkler attached to the second CPVC conduit. For example, this would result in a rectangular sprinkler spacing, such as 12 feet wide and 13, 14, 15, 16, 17, or 18 feet long. A spacing of 12 feet wide and either 14 or 16 feet long has been found to be preferred. Normal prior art sprinkler spacing is a square spacing, such as 12 feet wide by 12 feet long. The sprinkler spacing in this invention is asymmetric.
The foregoing summary, as well as the following detailed description of exemplary embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the exemplary embodiments, there is shown in the drawings certain exemplary systems. It should be understood, however, that these embodiments are merely exemplary and that the present invention is not limited to systems, arrangements and instrumentalities shown or described herein.
In
The fire suppression system 30 has a first chlorinated polyvinyl chloride (CPVC) conduit 20 (also referred to as a pipe) extending within the space defined by a first set of two adjacent substantially parallel joists 10 and 12. It is intended that the phrase “space defined by a first set of two substantially parallel joists” means the space between the joists extending from the top of the joists to the bottom of the joists. Since a sub-floor will be attached to the top of the joists, the space will be closed on three sides and open on the bottom side.
The CPVC conduit 20 will normally contain a fire suppression fluid under pressure, usually from about 7 to about 175 psig, preferably from about 30 to about 175 psig, and more preferably from about 80 to about 175 psig, with the most preferred pressure being from 100 to 150 psig. Thermally activatable automatic sprinklers are designed with specific optimal operating pressures. Activatable sprinklers may not give adequate water spray to satisfactorily extinguish a fire at pressures below about 7 psig, therefore the pressure of the fluid in the conduits should be well above this minimum pressure to assure optimal extinguishing effect. The fire suppression fluid is, most preferably, water but can be any non-flammable fluid or gas capable of extinguishing a fire. The CPVC conduit 20 can vary in diameter, depending on the amount of fluid needed and the pressure available, from 0.75 inch to 4 inches, but for most applications 0.75 inch to 1.25 inches is preferred, with 1.0 inch being the most preferred diameter. The diameter specified in this invention is an iron pipe size (IPS) diameter. The CPVC sprinkler conduit 20 may be in multiple lengths where the individual lengths of the conduit are attached by the use of CPVC fittings. When the term first CPVC conduit is used, it is intended to include all the separate pieces of the conduit that are joined in fluid communication by the use of a CPVC fitting.
In the embodiment shown in
Each of the multiple thermally activatable automatic sprinklers, attached to the first CPVC conduit 20, are substantially equally spaced a first predetermined distance X1, from adjacent sprinklers on conduit 20. The first predetermined distance can be from 13 feet to 18 feet. The term “substantially equally spaced” is intended to account for normal variations in installing the system and can be ±1.0 inch in length.
In the embodiment shown in
The first predetermined distance X1 for the sprinkler spacing on conduit 20 is substantially equal to the second predetermined distance X2 for the sprinkler spacing on conduit 18. The term “substantially equal” is intended to be within ±1 inch.
The multiple thermally activatable sprinklers are selected to activate at a given temperature to release the fire suppression fluid. The activation temperature is usually from about 140° F. to about 190° F., more preferably from about 155° F. to about 175° F. The sprinklers are commercially available from multiple suppliers. A particularly desirable sprinkler is sold by Tyco, as its Series LF II residential pendent sprinklers 3.0 K-factor. The K-factor determines the fluid flow out of the activated sprinkler. The fire suppression fluid flow is the K-factor multiplied by the square root of the supply pressure. For example, a 3.0 K-factor with a 100 psig pressure in the CPVC conduits would give a 30 gallons per minute of fluid flow.
The first and second predetermined distance X1 and X2 is at least one foot in length and up to 6 feet in length greater than the distance X3 between the thermally activatable automatic sprinklers attached to the first CPVC conduit 20 and the nearest thermally activatable automatic sprinkler attached to the second CPVC conduit 18. In the embodiment shown in
The asymmetric spacing solves the problem presented when one sprinkler activates and sprays water onto the thermal activating unit of the adjacent sprinkler, and causes a delay in the adjacent sprinkler activating. This phenomenon is called “cold soldering” of the adjacent sprinkler, and this situation can allow the fire to spread beyond where it would if the adjacent sprinkler activated in a timely manner. The “cold soldering” event is more likely to occur with a high supply pressure, such as 175 psig. At least one sprinkler should activate and release the fire suppression fluid within 3 minutes, and preferably within 2 minutes, under a test protocol by Underwriters Laboratory known as UL Project Number 10CA23869. In the most preferred embodiment, all sprinklers activate within 3 minutes, provided they reach the activation temperature.
The fire test specified by UL Project Number 10CA23869 results in a very intense fire. A 5 square foot pan is placed on the floor of the room and water placed in the pan. Five gallons of heptane is floated on the water and ignited. As the heptane is burning, some of the heptane vaporizes and the vapor also catches fire, resulting in a very intense fire. Because the joists are open, as in an unfinished basement, the most intense heat tends to travel down the length of the joists in the space between adjacent joists.
The fire suppression system described in this invention is intended for use in areas having unfinished ceiling with exposed joists, such as unfinished basements and the like.
Another embodiment is shown in
In the embodiment shown in
In
The spacing of the sprinklers on conduit 86 is a distance X3 from adjacent sprinklers on conduit 96. The distance X3 is from 12 feet to 14 feet, with the proviso that X3 must be at least 1 foot shorter than the first and second predetermined distance for the spacing of the multiple thermally activatable automatic sprinklers on conduits 86 and 96. This spacing gives an asymmetrical spacing of the sprinklers. The distance X3 is from 12 feet to 14 feet. If X3 is 12 feet then the sprinkler spacing on conduits 86 and 96 (first and second predetermined distances) is from 13 to 18 feet. If X3 is 14 feet, then the sprinkler spacing on conduits 86 and 96 is from 15 to 18 feet. A spacing pattern of 12×14 feet, 12×16 feet, and 14×16 feet have been found to be ideal for extinguishing fire and preventing water spray onto adjacent sprinklers, which can cause “cold soldering.”
Another advantage of the asymmetric spacing configuration is less sprinklers are required to protect a given area. The prior art square spacing of 12×12 feet covers 144 square feet of floor area per sprinkler, whereas an asymmetric spacing of 12×14 feet covers 168 square feet of floor area per sprinkler, or about 16% fewer sprinklers would be required for the asymmetric spacing versus the prior art square spacing. A reduction in the number of sprinklers saves material cost and installation time.
The joists, shown in
In the exemplary embodiment, the CPVC material used for the conduits, short drop length CPVC pipe, and CPVC fittings is sold under the BLAZEMASTER® brand name and the CPVC compound to make the CPVC articles is available from Lubrizol Advanced Materials, Inc. in Brecksville, Ohio, U.S.A.
The fire suppression system of this invention can be installed as a branch system or a loop system. The terms branch system and loop system are well understood by those skilled in plumbing systems. With a branch system there is usually a main supply line and branch pipes connected to the main line and the sprinklers are attached to the branch line. In a loop system, the conduits supplying the fire suppression fluid form a closed loop. The loop system is preferred for non-metallic piping systems because when a sprinkler activates water flows in both directions to the sprinkler, which helps to cool the conduits, non-metallic conduits can rupture and fail if they get too hot. The embodiments shown in this description for basements could be extended to connect with the sprinkler conduits on upper floors of the building, as is well understood by those skilled in the art of installing sprinkler systems.
The invention will be better understood by referring to the Examples, which show an unexpected improvement when an asymmetric sprinkler spacing is employed.
Examples 1 to 4 are presented to show the improvement when using an asymmetric spacing for the sprinklers. All tests were run in a 20 feet by 40 feet fire test building. A floor joist structure was constructed with dimensions 20 feet by 32 feet, with 32 feet long composite wood joists, each being 11.875 inches high. The distance from the bottom of the joists to the floor was 10 feet. The joists were spaced 24 inches on center. The fire test was conducted to simulate the UL10CA23869 test procedure and determine sprinkler activation time. The sprinkler conduits used were both 1 inch diameter BLAZEMASTER® CPVC pipes. The thermally activatable sprinklers were all Tyco Model LF II Residential Pendent sprinklers with a 3.0 K-factor and a temperature activation rating of 155° F. The fire suppression fluid was water and at a pressure of 100 psig. The fire fuel was 5 gallons of heptane. The time to activation after the fire started for each of the sprinklers were measured and recorded. The test was repeated with different sprinkler spacing. The results are shown in Table I below.
The results show that the symmetrical spacing (12′×12′) of the sprinklers, in Example 1, resulted in one of the sprinklers (118) not activating. It is believed this was due to cold soldering, where the first sprinkler to activate (120) sprayed cold water onto sprinkler 118 and kept it too cool to activate. In Examples 2, 3, and 4, with an asymmetrical spacing for the sprinklers, all sprinklers activated in a timely manner.
Examples 1 and 2 were repeated with a supply pressure of 175 psig. In Example 1, with the higher pressure sprinklers 118 and 120, both failed to activate and sprinklers 114 and 116 activated at 53 and 36 seconds respectively. At the higher pressure (175 psig) in Example 2, all four sprinklers activated at times ranging from 54 seconds for sprinkler 116 to 2:15 for sprinkler 120. This demonstrates that the “cold soldering” effect is more of a problem with higher water pressure and symmetrical spacing (12 ft.×12 ft.) of Example 1. With the asymmetrical spacing (12 ft.×14 ft.) of this invention, all sprinklers activated even with higher pressure.
In the foregoing description, certain terms have been used for brevity, clarity and understanding. However, no unnecessary limitations are to be implied therefrom because such terms are used for descriptive purposes and are not intended to be broadly construed. Moreover, the descriptions herein are by way of examples, and the invention is not limited to the details shown and described.
Having described the features, discoveries and principles of the invention, the manner in which it is made, and the advantages and useful results attained, the new and useful invention are set forth in the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US13/33088 | 3/20/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61617997 | Mar 2012 | US |
