When curving metal panels on the job site, there are many things to keep in consideration. While there are no restrictions on panel
lengths or the degree of radius, George Jones, director of fi eld services at IMETCO, Norcross, Ga., notes that fi eld-forming panels risks leaving them exposed to weather and job-site conditions. It is important that the panels and/or coil are protected from weather conditions, such as cold tempera- tures, rain, snow and wind. Wind-blown debris can also interfere with equipment and personnel, delay- ing fi eld operations. It is also important to make sure that there
is adequate curving and staging space at the job site. In some cases, the site must be prepared and graded level to receive the equipment, Jones adds. Any delays can result in increased costs for the project. Running shorter test panels to check the roof’s
actual radius is one of the most important things a contractor can do, says Michael Gorski, machine department manager at Englert Inc., Perth Amboy, N.J. “If the radius is too much, or too little, this will cause oil-canning of the panels when they are put down on the roof.” Kurt Schievelbein, technical manager of roll-
forming operations at San Antonio-based Berridge Manufacturing Co., agrees, saying that structures are not always built exactly to the design drawings, and if the panels are curved to an incorrect radius,
Photo courtesy of Berridge Manufacturing Co.
that may not be usable. “With on-site curving, live measurements and
dimensions can be taken, rather than the design drawing dimensions to provide accurately produced curves,” explains Paul Stringer, technical support engineer at Kalzip’s U.K. location. Gorski says contractors need a special seam-
er to seam the panels together, and as the panels get longer, the more manpower is required to handle them. “As panels are curved in the vertical position, [contractors] should also have enough stands for the panels to run out on,” he says. “This makes the panels more consistent from one to the next.” One of the biggest mistakes Gorski sees is
that contractors don’t seam the panels together as they go along. “They put down a bunch of panels and then come back and seam them,” he says. “This is bad practice even on fl at roofs.” Jones notes that it is important to have
adequate personnel to handle the panels, as they are more susceptible to buckling and kinking dur- ing handling than straight panels. This is espe- cially true during installation. “Material handling will require more care and attention to the listing operation,” he says. “These panels must be inter- mediately supported and stabilized during the rig- ging and lifting operation. The curved panel shape is inherently unstable and will tend to buckle, fold and distort to the point of product damage with- out adequate support.” “The curved substrate is diffi cult to use the
standard string line method to check the sub- strates for a suitable installation,” Jones adds. “Special care must be taken to look for high and low spots in the substrate deck. Using adequate shim heights at the panel clips will level the panel height and allow for proper material thermal movement. If the panels are not allowed to ex- pand and contract freely, this thermal movement can result in oil canning.” Some manufacturers will send trained per-
sonnel to the job sites with the curving machines, while others, like Englert, offer a training program for fi rst-time users.