Static structures (e.g. – buildings) – Processes – Barrier construction
Reexamination Certificate
2003-06-04
2004-11-30
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Processes
Barrier construction
C052S588100, C052S528000
Reexamination Certificate
active
06823642
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to standing seam metal roofs, and more particularly but not by way of limitation, to a roofing system based on roof demand and zone determination.
2. Discussion
Metal panels are common architectural features for a class of buildings commonly called pre-engineered buildings. The roofs of such buildings are usually made of metal panels that are mounted on, and cover up, the structural members of the building, which are usually purlins, the metal panels making up the external roof facade. The metal roof panels serve both as functional and as aesthetic features of such buildings.
Further, all roofs have multiple functional demands that such roofs must meet. To understand the scope of such demands, it should be noted that a roof function can be viewed as any one of a set of qualities or traits that are desirable or required for a roof in its particular location. A roof function is any requirement that a building code, regulatory agency, governing agency or authority, a specifier or a customer may demand, require, conceive or specify for the roof, or for any portion thereof. A demand is the particular level of performance required of a roof to meet its requirement for a particular function.
Within these parameters, “demand zones” are those areas of a roof that require or that perform different levels of the functional performance required of the whole. Also, a “demand zone quality level” is the level of quality that a specific demand zone should possess to meet the imposed qualify for the specific area or location of the roof. Of course, it will recognized that demand zones for various functions can coincide or overlap.
As one considers a roof in its multi-layered functional performance requirements, it will be appreciated that the quality required by a roof will vary from zone to zone over a range of quality levels for the type of roof being constructed. Within the scale of quality levels imposed on a particular roof design, and as used herein to describe the quality selection for a discrete zone, the term “over qualified demand zone” will mean that such zone has a level of performance that meets the design requirements of at least the next higher demand zone quality level imposed by the design requirements for the roof.
In describing the present invention, it is desirable to deal with the broader aspect of a roof zone, while at the same time, dealing with specific variants or attributes that are available to a designer to achieve the required performance level specified or required for any particular roof. Thus, the variant of panel to panel seaming is useful to illustrate one method available to the designer to optimize performance and cost effectiveness. Likewise, the variant of panel wind uplift resistance is useful to illustrate one method available to the designer to optimize performance and cost effectiveness of the performance of one roof function.
Broadly, a roof shelters the interior of a building from the natural elements of wind, sun, rain and snow, and with the building walls, encloses the building interior for environmental control. Numerous types of metal panel roofs have been utilized to resist these elements of nature while permitting the metal panels to face the constant demands imposed by their environment.
The purlin members supporting the metal roof panels are themselves typically supported by rafters that extend from the roof eaves to the ridge peak. The purlins serve as underlying cross members that are interconnected to extend the length of the building.
Metal roofs can be classified by the manner in which the side-adjacent and end-adjacent overlapping panels are sealed at joints. “Shed roofs” are roofs that shed water and achieve water tightness because gravity pulls the water down and away from panel joints more effectively than wind or capillary action can propel water through the joints. On the other hand, “gasket roofs” are made watertight by gasket material disposed between the panel joints and secured in place by encapsulating pressure imposed against the gasket material. Generally, gasket roofs can be installed where the roof slope is down to about 1 to 48.
An environmental condition encountered by all roofs is the load imposed by ambient wind conditions. Wind passing over a roof peak often creates reduced pressure immediately above the roof, resulting in a pressure gradient on the panels, with lower pressure above the roof than below. This pressure gradient causes an uplift force on the metal roof panels, causing the panels to be pulled upwardly and away from the purlins. This often is the primary cause of failure for metal roofs.
There are a number of apparatuses that affect the quality of performance and that can be selectively varied by varying the specific configuration of the apparatus to achieve a desired performance level of metal roofs. This can be illustrated by considering the means by which standing seam roof panels can be joined together in their side to side, and end to end, arrangements and mounted to their underlying support structure. As known in the art, standing seam roof panels are designed to withstand environmental elements such as wind, snow and rain, and since a metal roof is essentially a large area heat sink continually exposed to atmospheric weather conditions, the standing seam panels must accommodate thermal expansion and contraction over a wide range of ambient temperature.
Standing seam roof panels have interlocking sidelap portions, a female sidelap portion of one panel engaging and locking with a male sidelap portion of a side-adjacent panel. As used herein, the term “side-adjacent” is meant to indicate that a first panel is disposed to lay along side, and adjacent to, a second panel on the roof. The female and male sidelap portions of the panels are elevated, or standing, to extend upwardly from a central flat or corrugated medial portion of the panels.
The metal panels are attached to the supporting purlins by clips that engage the standing seams, and by fasteners that penetrate and extend through the panels. The fasteners, sometimes referred to as through-fasteners, typically are sheet metal screws that extend through the medial portions of the panels to attach to the purlins, preventing differential movement between the panels and supporting purlins.
Clips are devices that connect the standing seam joints, that is, the interlocked standing sidelap portions, to the supporting purlins. Both fixed and sliding clips are utilized. Fixed clips are metal devices that attach to the underlying purlins and to the side-adjacent metal panel standing seams. Sliding clips, also referred to as floating clips, attach to the side-adjacent metal panels at the standing seams and to the underlying purlins while permitting a degree of differential movement between the panels and the purlins. The selection of the type and spacing of such clips has a pronounced effect on the performance of several of the roof functions, as well as affecting the cost, of metal roofs.
The interlocking engagement of the sidelaps of the metal panels provide functional requirements such as stiffness and strength to a flexible roof structure. The use of floating clips allows the roof structure to expand and contract as a function of the coefficient of thermal expansion of the panel material, and the temperature cycles of the roof panels.
Another apparatus or mechanism providing several variants that determine the performance quality of a metal roof is that of the type of seaming process selected to interlock and seam the side-adjacent, and end-adjacent, panels. Several types of seaming processes have been developed for interlocking the sidelaps of adjacently disposed panels. Most such seaming processes involve the operation of inelastically bending or rolling portions of the female sidelap and the male sidelap together. This inelastic or plastic deformation of the sidelap portions forms interlocked joints, or locks, of varying strength. That is, the interlocked sidelaps can b
Neyer Leo E.
Salisbury Clarence S.
Simpson Harold G.
Fellers , Snider, et al.
Friedman Carl D.
Harold Simpson, Inc.
McCarthy Bill D.
Slack Naoko
LandOfFree
Roof demand and zone based roofing system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Roof demand and zone based roofing system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Roof demand and zone based roofing system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3280927