MULTIPLE ROOF CURBS FOR SUPPORTING A ROOFTOP MECHANICAL UNIT

Abstract

A building including a roof and a rooftop mechanical unit, the rooftop mechanical unit being supported on top of the roof by at least a first roof curb and a second roof curb, a gap being provided between the roof curbs, each of the roof curbs being less than 15 feet in length; wind can blow snow through the gap and out the other side, which inhibits the buildup of a snowdrift which undesirably increases roof load.

Claims

1. A building comprising a roof and a rooftop mechanical unit, the rooftop mechanical unit being supported on top of the roof by at least a first roof curb and a second roof curb, a gap being provided between the first roof curb and the second roof curb, each of the first roof curb and the second roof curb having a length extending in a longitudinal direction, each of the first roof curb and the second roof curb being less than 15 feet in length, the gap extending between said roof curbs in a direction transverse to said longitudinal direction.

2. The building according to claim 1, wherein the roof is a flat roof, the building is an enclosed building, and each of the first roof curb and the second roof curb is at least 10 feet in length.

3. The building according to claim 1, wherein the rooftop mechanical unit is selected from the group consisting of a fan, a ventilator, an air-conditioning unit, a refrigeration unit, a freezer unit, an air handling unit, an air makeup unit, a heat recovery unit, and a pollution control unit.

4. The building according to claim 1, wherein the rooftop mechanical unit has a length of at least 20 feet.

5. The building according to claim 1, wherein the rooftop mechanical unit has a length of at least 35 feet.

6. The building according to claim 1, wherein the first roof curb and the second roof curb have the same height, wherein the gap has a height of at least 12 inches and not more than 52 inches and wherein the gap has a width of at least 30 inches and not more than 106 inches.

7. The building according to claim 1, wherein the gap has a width between the first and second roof curbs and a length perpendicular to the width and wherein the width is less than 50% of the length.

8. The building according to claim 1, wherein the building is situated in an area having a ground snow load of at least 15 pounds per square foot.

9. The building according to claim 1, wherein the rooftop mechanical unit has a weight of at least 100 pounds per foot of length.

10. The building according to claim 1, wherein the rooftop mechanical unit is further supported by a third roof curb, the second roof curb being located between the first roof curb and the third roof curb; a gap being provided between the second roof curb and the third roof curb, the third roof curb being less than 15 feet in length.

11. The building according to claim 1, wherein the building is situated in an area which is subject to a local building code which provides, for that building, that, but for each of said roof curbs being less than 15 feet in length, the roof would have to be strengthened to support the addition of a drifted snow load.

12. A method of providing a rooftop mechanical unit on a roof of a building, comprising the following step: (a) mounting or providing the rooftop mechanical unit on the roof of the building, the rooftop mechanical unit being supported on the roof by at least a first roof curb and a second roof curb, each of the first roof curb and the second roof curb having a length extending in a longitudinal direction, each of the first roof curb and the second roof curb being less than 15 feet in length, the gap extending between said roof curbs in a direction transverse to said longitudinal direction.

13. The method according to claim 12, wherein the step of mounting or providing occurs during the construction of the building or during an addition of or a replacement of a rooftop mechanical unit on the roof of the building.

14. The method according to claim 12, wherein the roof is a flat roof, the building is an enclosed building, and each of the first roof curb and the second roof curb is at least 10 feet in length.

15. The method according to claim 12, wherein the rooftop mechanical unit is selected from the group consisting of a fan, a ventilator, an air-conditioning unit, a refrigeration unit, a freezer unit, an air handling unit, an air makeup unit, a heat recovery unit, and a pollution control unit.

16. The method according to claim 12, wherein the first roof curb and the second roof curb have the same height, wherein the gap has a height of at least 12 inches and not more than 52 inches and wherein the gap has a width of at least 30 inches and not more than 106 inches.

17. The method according to claim 12, wherein the building is situated in an area having a ground snow load of at least 15 pounds per square foot.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 schematically illustrates an accumulation of snow in a snow drift adjacent a rooftop mechanical unit on a roof of a building;

[0007] FIG. 2 is a perspective view of a roof curb as known in the prior art;

[0008] FIG. 3 schematically illustrates an elevated roof platform according to the prior art;

[0009] FIG. 4 schematically illustrates a rooftop mechanical unit mounted on a pair of roof curbs on a roof of a building according to the invention;

[0010] FIG. 5 is a front elevational schematic view, not to scale, of a rooftop mechanical unit mounted on a pair of roof curbs on a roof (shown in cross-section) according to the invention;

[0011] FIG. 6 is a top plan view, not to scale, taken along line 6-6 of FIG. 5; and

[0012] FIG. 7 is a front elevational schematic view, not to scale, of a rooftop mechanical unit mounted on three roof curbs on a roof (shown in cross-section) according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0013] As used herein, when a range such as 5 to 25 (or 5-25) is given, this means preferably at least 5, and separately and independently, preferably not more than 25.

[0014] With reference to FIGS. 4-6, there are shown embodiments of the present invention wherein the rooftop mechanical unit 12 is supported on a roof 10 of a building 8 by a first roof curb 18 and a second roof curb 20. The rooftop mechanical unit 12 can be provided during the construction of the building or during an addition of or a replacement of a rooftop mechanical unit on the roof of the building. The roof 10, which is conventional and known in the prior art, is preferably a flat roof, a low-slope roof, or a sloped roof, all as determined or defined in ASCE7-10 Chapter 7 (ASCE7-10 is published by the American Society of Civil Engineers, having an address at 1801 Alexander Bell Drive, Reston, Va. 20191 USA). Preferably, each of the rooftop mechanical unit 12, the first roof curb 18 and the second roof curb 20 is rectangular or substantially rectangular in plan view. The roof 10, which preferably comprises roof girders 7 and roof joists 11, is supported by columns 9, as known in the art. The building 8, which is conventional and known in the prior art, can be, for example, a manufacturing plant, a warehouse, a store, a commercial building, an industrial building, a residential apartment building, an office building, preferably an enclosed building, or any building which has one or more rooftop mechanical units on the roof. The building is preferably located or situated in an area having a ground snow load of at least 15, 20, 25, 30, 35, 40, 50 or 60 pounds per square foot; as used herein and in the claims, “ground snow load” means ground snow load as determined according to ASCE7-10 Section 7.2 and an area having a ground snow load of at least X pounds per square foot is an area having a ground snow load of at least X pounds per square foot as determined according to ASCE7-10 Chapter 7.

[0015] Each roof curb 18, 20 has a length 46 (the roof curbs 18, 20 can have the same length or different lengths) which is less than 15 feet, so that, under current building codes, snow drift load does not need to be considered. Preferably, the building 8 is situated in an area which is subject to a local building code which provides, for that building, that, but for each of said roof curbs being less than 15 feet in length, the roof 10 would have to be strengthened to support the addition of a drifted snow load. Each roof curb 18, 20 preferably has a width 47 the same as the width of the rooftop mechanical unit 12; the width 47 of each roof curb 18, 20 is typically 6 to 8 feet, preferably at least 6 feet and preferably not more than 9 feet, more preferably about 8 feet. Each roof curb 18, 20 has a length 46 which is preferably at least 8, 9, 10, 11, 12, 13, 14, 14.5 or 14.9 feet in length. Preferably each roof curb 18, 20 has a length 46 which is not more than 14.9, 14.8, 14.5, 14.2, 14, 13.5, 13, 12.5, 12, 11 or 10 feet. Each roof curb 18, 20 has a length extending in a longitudinal direction 46a, and, as can be seen in FIG. 6, the gap 22 extends between the roof curbs 18, 20 in a direction 47a transverse to said longitudinal direction 46a. Each roof curb 18, 20 is preferably hollow and is constructed as known in the prior art using materials as known in the prior art and is attached to the roof as known in the prior art and is attached and sealed to the rooftop mechanical unit 12 as known in the prior art.

[0016] Between the adjacent roof curbs 18 and 20 is a gap 22 which has a height 48 preferably at least 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 or 36 inches and preferably not more than 52, 48, 44, 40, 36, 34, 32, 30, 28, 26, 24, 22 or 20 inches. The height of the gap 22 is preferably at least 2, 4, 6 or 8 inches more than the height (if known) of the ground snow load for the region or location where the building is located. The gap 22 has a width 45 preferably at least 30, 36, 40, 44, 48, 52 or 56 inches and preferably not more than 106, 100, 96, 92, 88, 84, 80, 76 or 72 inches. The width 45 of the gap 22 optionally can be less than, or at least, 70, 60, 50, 40 or 30% of the length 47 of the tunnel between the adjacent roof curbs 18, 20; as can be seen in FIG. 6, gap 22 has a width 45 and a length 47. Each roof curb 18, 20, 38 is constructed as roof curbs known in the art are constructed. Each roof curb 18, 20 preferably has a height 48 as high as, or corresponding to, the preferred heights 48 of the gap 22 described above.

[0017] The rooftop mechanical unit 12, which is conventional and known in the prior art, is preferably a fan, a ventilator, an air-conditioning unit, a refrigeration unit, a freezer unit, an air handling unit, an air makeup unit, a heat recovery unit, or a pollution control unit (each of which is shown schematically as item 12 in FIG. 4), has a length 50 preferably at least 20, 25, 30, 35, 40, 45, 50 or 60 feet, preferably not more than 70, 60, 55, 50, 45, 40, 35 or 30 feet, has an average height 49 preferably at least 3, 4, 5 or 6 feet, preferably not more than 12, 11, 10, 9, 8 or 7 feet (wherein the average height 49 is the average of the heights along the length of the rooftop mechanical unit 12), and has a weight (per foot of length of the rooftop mechanical unit 12) preferably at least 70, 80, 90, 100, 125, 150, 200, 250, 300, 350 or 400 pounds and preferably not more than 750, 700, 650, 600, 550, 500, 450 or 400 pounds.

[0018] When the rooftop mechanical unit is particularly long or for other reasons, more than 2 roof curbs can be used, such as 3 or 4 roof curbs, resulting in 2 or more gaps. For example, as shown in FIG. 7, there is a rooftop mechanical unit 34 supported by roof curbs 36, 39 and 42, resulting in gaps 37 and 41. Preferably, these roof curbs and gaps have the same dimensions as the roof curbs and gaps described above.

[0019] When a gap is provided between adjacent roof curbs, the wind can blow the snow through the gap and out the other side, which inhibits the buildup of snowdrifts.

[0020] Although the hereinabove described embodiments of the invention constitute the preferred embodiments, it should be understood that modifications can be made thereto without departing from the scope of the invention as set forth in the appended claims.