30 November 1998
Depending on the degree of rerolling that occurs, the material will have a higher steel yield strength,
less ductility, and a more rounded stress-strain curve above the yield point of the steel than would be
seen in the virgin steel sheet materials. Design guidance that is provided in chapter 3 recognizes this
material property variability. Diagonal bracing materials are to be ASTM A653 steel without rerolling,
and will be a Category I submittal for approval by the designer of record.
d. Damaged Materials.
(1) General. Steel framing materials can be rejected for the following reasons: physical
damage (dents, cuts, twists, buckles); corrosion; length; metal thickness; yield stress; protective coating
or forming. Physical damage and corrosion are easily identified. Length variations and forming
problems are relatively easy to identify with standard measuring devices. The metal thickness must be
checked with a micrometer and one must know what the required thickness should be. The yield
strength and protective coating can only be checked through testing.
(2) Tolerances and Coatings. The allowable physical tolerances and standard protective
coatings for steel framing products can be found in current ASTM Standards. ASTM C-645 covers
tolerances and standard protective coatings for nonstructural partition framing and ASTM C-955 covers
the same information for structural framing. The yield strength for structural framing is normally
specified in the project specifications or on the drawings. Special protective coating requirements are
also specified in the project specifications.
(1) General. Fire rating of assemblies denotes a length of time that a given assembly will
resist fire penetration under controlled laboratory conditions; Table 1-2 lists many Fire Rated
Assemblies. These fire-rating tests are performed in accordance with the existing consensus standards
of ASTM or ANSI. A fire rating is only valid for the tested assembly. Although most materials cannot
be added or changed in a fire rated assembly, stronger steel framing sections can be used. The
specified depth and gauge of steel framing in a tested assembly are considered minimums. The fire
rating will still apply to the assembly when steel framing members that are deeper and/or heavier than
the specified members, are used.
(2) Fire Tests. There are numerous fire rated assemblies for interior walls, exterior walls,
floors, ceilings, and roofs, incorporating steel framing. Various laboratories throughout the country have
performed fire rating tests of loadbearing steel stud walls. Currently, within the AISI Residential
Advisory Group (RAG), a task group has been assigned to compile a listing of all available fire rated
assemblies, using steel framing. The following sources list many fire rated assemblies that can be
used if cold-formed design.
Fire-Resistance Ratings of Load-Bearing Steel Stud Walls (AISI, Publication Z-4)
Fire Design Manual (Gypsum Association)