Cutting & Notching in Cold-Formed Steel Framing
October 1, 2009
At some point on a project, generally after the mechanical trades begin their installations, we are advised by the code official that we have framing deficiencies that will most likely result in a “failed report” unless corrective action is taken. All too often these deficiencies are the result of mechanical trades cutting, notching or boring holes into our framing members. It may be difficult, but not impossible to get a 3½-inch pipe through a 35⁄8-inch stud, however all you may be left with are the flanges on either side, holding the stud together.
We see this type of situation all too often and once we report the damage to the general, we are asked something to the effect of, “Just how much material can be removed from studs without compromising their integrity?” The question is just a little puzzling, because as a light gauge metal framing contractor, we don’t notch or bore holes into our studs. We install them as they come from the factory, with the factory punch-outs and any further modifications to the members are generally by other trades. These factory punch-outs are intended to accommodate bridging members, as well as electrical, fuel gas, plumbing elements, etc., and when provided by the factory, are intended to prevent random notching or boring that could otherwise compromise the integrity of the stud.
The Steel Stud Manufacturers Association ICBO ER-4943P is very specific as to the location of these punch-outs. General Note #4 states: “When provided, factory punch-outs will be located along the centerline of the webs of the members and will have a minimum center-to-center spacing of 24 inches. Punch-outs will have a maximum width equals half the member depth (d/2) or 2½ inches, whichever is less, and a maximum length equals 4½ inches. The minimum distance between the end of the member and the near edge of the web punch-out equals 10 inches.” Engineering by the SSMA has determined that punch-outs meeting these criteria will not compromise the integrity of the stud.
CLEAR AND VAGUEAlthough the IBC is very specific about notching or boring holes in wood framing members, when it comes to cold-formed steel, the IBC is a little vague. The code references the General Provisions of the American Iron and Steel Institute, the AISI-NASPEC and ASTM Standards.
ASTM C1007 Section 8.9.4 reads, “Cutting of flanges in stud and joist framing members shall not be permitted.” Section 8.9.5 states, “Cutting of additional holes other than those provided by the manufacturer in framing members shall not be permitted.”
Whereas the IBC may be slightly vague, the International Plumbing and Fuel Gas Codes, and state Building Codes are very specific about modifying light gauge framing members. Even though the section reference may vary per discipline, the standards are by and large addressed in Section 302 “Protection of Structure” or “Structural Safety,” and are consistent in how to address modifications to light gauge framing members. They state the following: “Cutting, notching and boring holes in nonstructural cold-formed steel wall framing. Flanges and lips of nonstructural cold-formed steel wall studs shall not be cut or notched. Holes in webs of nonstructural cold-formed steel wall studs shall be permitted along the center-line of the web of the framing member, shall not exceed 1½ inches (38 millimeters) in width or 4 inches (102 millimeters) in length, and shall not be spaced less than 24 inches (610 millimeters) center to center from another hole or less than 10 inches (254 millimeters) from the bearing end.”
If punch-outs are provided in a stud member, no other punch-outs or holes are allowed unless they are within the criteria established by the SSMA. The stud flanges and lips of stud members shall not be cut or notched. If additional holes are bored or flanges and lips notched or cut, the integrity of the damaged member cannot be guaranteed and must therefore be evaluated by an engineer to confirm their performance capabilities and/or to determine a suitable method of repair.
This is not the responsibility of the framing contractor. If notching or boring appears to be necessary to accommodate MEP elements, it is the responsibility of the affected MEP trade to request direction from the Design Professional. Furthermore, it is the responsibility of the Design Professional to ensure the accuracy of the project documents and to make certain that the information presented in the documents will accommodate, without compromise, all building elements specified for the project. W&C