Patent Publication Number: US-4584811-A

Title: Furring bracket for fireproofed beams

Description:
This invention relates to a method for attaching runners to steel beams having a sprayed fireproofing coating. The invention relates particularly to the use of a special furring bracket as a connector between the fireproofed beam and the runner. The invention relates more particularly to a furring bracket that may be attached to the beam before fireproofing is sprayed on the beam and serve as a base for the attachment of the runner when the proper location of the runner can be determined. 
     The use of gypsum board in the construction of the walls surrounding an elevator shaft or the like is becoming increasingly popular. The construction of such walls is described in U.S. Pat. Nos. 3,702,044 and 4,152,878, both of which are incorporated herein by reference, particularly the disclosures at column 4, line 9 to column 5, line 31 of the U.S. Pat. No. 3,702,044 and at column 4, line 42 to column 5, line 28 of the U.S. Pat. No. 4,152,878. A problem exists, however, when the ceiling runners which serve as a tracks into which the gypsum boards are placed must be attached to fireproofed steel beams. The fireproofing material is often sprayed on to a thickness of 2 inches. THe long power pins needed to fasten a runner to a beam covered with 2 inches of fireproofing may ricochet or bend before reaching the beam. Because of this, the U.S. Gypsum Company, assignee of the aforementioned patents, requires that the runners be attached to the beams before the fireproofing is sprayed on. This procedure is satisfactory except when elevator door frames are part of the shaft wall. The proper location of the runner in such a case is very critical and usually can not be known until the elevator car rails are installed or their position is otherwise known. Unfortunately, the installation of the car rails always seems to occur after the fireproofing is in place. Too often, the pre-attached runners are not properly located and must be removed and replaced. The fireproofing is damaged during the removal of the runner and to the cost of replacing the runner there is added the cost of repairing the layer of fireproofing. 
     Another problem arising from the attachment of the runners to the beams before the spraying of fireproofing is that the runner becomes clogged with the fireproofing material and can not perform its function until it is closed out. A further problem associated with the spraying of fireproofing material onto steel beams in general is the difficulty of applying a uniformly thick layer. The thickness sometimes varies from as little as 3/4 inch up to the desired 2 inches. 
     It is an object of this invention to provide a furring bracket which may be attached to a steel beam prior to the fireproofing of the beam so that the installation of a runner or the like is facilitated. 
     It is a related object of this invention to provide a furring bracket for steel beams which serves also as a thickness gauge during the spraying of fireproofing material onto the beam. 
     It is a further object of this invention to provide a construction system for cavity shaft walls supported by fireproofed steel beams. 
     It is another object of this invention to provide a method for building a cavity shaft wall in a building supported by fireproofed steel beams. 
    
    
     Other objects, features, and advantages of this invention will become apparent from the following detailed description and the attached drawings, wherein: 
     FIG. 1 is a perspective view of the furring bracket of this invention. 
     FIG. 2 is a perspective view of a modification of the furring bracket of FIG. 1. 
     FIG. 3 is a fragmentary cross-section of the construction system of this invention. 
    
    
     In FIG. 1, the generally channel-shaped furring bracket 10 has a horizontal web portion 12, an upright first leg 14 extending perpendicularly from one edge of the web 12, an upright second leg 16 extending perpendicularly from the opposite edge of the web 12 and beyond the first leg 14, a shoulder 18 extending parallel to the web 12 from the edge of the first leg 14 and away from the second leg 16, a tab 20 coplanar and co-directional with the shoulder 18 struck out from the second leg 16, and a clamp 22 extending angularly toward the web 12 from the edge of the second leg 16 to a plane spaced apart from but parallel to the plane of the tab 20. The clamp 22 is terminated by a lip 24 extending from its longitudinal edge 26 at an oblique angle to the clamp. 
     The furring bracket of FIG. 2 is similar to that of FIG. 1 except that the tab 20 is replaced by the two tabs 40 which are shear formed from the leg 42 and the clamp 44 is formed from the remainder. 
     The longitudinal edge 26 of the clamp 22 and the tab 20 define a slot 27 which receives a flange 28 of an I-beam 30 as shown in FIG. 3. A plurality of furring brackets thus may be snapped onto the flange 28 and moved into the desired places before the legs 16 and the shoulders 18 are fastened to the flange 32 by welding, power shot fasteners or other conventional means. The shoulder could be fastened to the flange 28 in like manner. A layer 34 of fireproofing material covers the beam 30 and all of the furring bracket 10 except the obverse surface 36 of the web 12. A runner 38 is fastened to the furring bracket 10 by the screw 39 or by welding. 
     The furring brackets 10 are spaced along the beam 30 at a maximum inteval of 24 inches o.c. The clamp 22 and the tab 20 are pushed onto the flange 28 and the shoulder 18 and the leg 16 are fastened to the beam 30 by, for example, MIG welding. The fireproofing material is then sprayed over the entire beam and the furring brackets 10 as stated above. The spaced between the beam 30 and the web 12 of the furring bracket 10 is used as a guide for the applicator to judge the depth of the fireproofing layer. The length of the leg 14 is preferably about 2 inches to aid in the compliance with the requirement of many building codes that the fireproofing be at least 2 inches thick. 
     The runner 38 may then be placed in the appropriate position with reference, in the construction of a shaft wall for an elevator shaft for example, the hoistway support rails. When properly located, the runner is fastened to each furring bracket 10 in the conventional manner such as with sheet metal screws 39. 
     While for the purpose of illustration, representation embodiments of the invention have been shown and described, other embodiments of the invention within the scope of the follwoing claims may become apparent to those skilled in the art.