Steel Framing Page - 9

ICBO Evaluation Service, Inc. 5360 WORKMAN MILL ROAD - WHITTIER, CALIFORNIA 90601-2299 A subsidiary corporation of the International Conference of Building Officials

LIGHT GAGE STRUCTURAL STEEL FRAMING PRODUCTS
TRI-CHORD SYSTEMS, INC.
344 COOGAN WAY
EL CAJON, CALIFORNIA 92020

1.0 SUBJECT

Light Gage Structural Steel Framing Products.

2.0 DESCRIPTION

2.1 General:

The Light Gage Structural Steel Framing Products consist of the Tri-Chord section and the EESI-STUD™ wall system. The Tri-Chord section is formed from cold-rolled structural-quality steel complying with ASTM A 653 SO, Grade 40 and Grade 5.0 class 1, having minimum yield strengths of 40,000 psi (276 MPa) and 50,000 psi (345 MPa), respectively. The EESI-STUD™ wall system is formed from cold-rolled structural-quality steel complying with ASTM A 653 SO, Grade 33, having a minimum yield strength of 33,000 psi (228 MPa) for 0.019 inch (0.483 mm) steel thickness, and Grade 40, having a minimum yield strength of 40,000 psi (276 MPa) for 0.029 and 0.035 inch (0.737 and 0.889 mm) steel thickness. The Tri-Chord sections are designed for use as components in truss assemblies which are not a part of this report. The EESI-STUD™ wall studs are for interior and exterior use under conditions noted in Table 4 of this report. Galvanized coating complies with ASTM A 653, G-60.

2.2 Tri-Chord:

The Tri-Chord section is formed as an equilateral triangle with parallel extensions forming a top flange as shown in Figure 1. The sections are available in nominal widths ranging from 3/4 to 2 inches, with minimum design base thicknesses of 0.029 inch (0.737 mm) (No. 22 gage), 0.035 inch (0.889 mm) (No. 20 gage), 0.045 inch (1.143 mm) (No.18 gage), and 0.057 inch (1.448 mm) (No. 16 gage). Section designations, dimensions and section properties are set forth in Tables 1 and 2.

2.3 EESI-STUD™ Wall Stud:

The EESI-STUD™ section is formed as an isosceles triangle with parallel extensions connected to each other with a continuous perforated web as shown in Figure 2. The section is formed in 3.5-inch and 5.5-inch (89 mm and 140 mm) depths from steel having a minimum design thickness of 0.019 inch (0.483 mm) (No. 25 gage), 0.029 inch (0.737 mm) (No. 22 gage) and 0.035 inch (0.889 mm) (No. 20 gage). Each stud end consists of bendable tabs for attachment to top and bottom wooden plates or metal runner tracks as shown in Figure 2. Section designations, properties and dimensions are set forth in Table 3. Allowable axial loads for the EESI-STUD™ sections are set forth in Table 4. The allowable axial loads in Table 4 are based on adequate lateral and rotational restraint provided by 3/8- to 5/8-inch (9.5 mm to 15.9 mm) gypsum sheathing on both sides of the wall assembly, fastened with No. 6, Type S-12, self-drilling, drywall pan or bugle-head screws spaced at 12 inches on center, in accordance with Section D 4, Chapter 22, Division V, of the code.

2.4 One-hour Fire-resistive Construction:

One layer of 5/8-inch-thick (15.9 mm) National Gypsum Company Type Fire-Shield G gypsum wallboard is applied vertically on both sides of 3.5-inch-deep (89 mm), 20-gage-thick (0.035 inch/0.889 mm) EESI STUD™ wall studs spaced 16 inches (406 mm) on center. Three-inch-wide (76 mm) , 20 gage (0.035 inch/0.899 mm) flat steel flashing is installed vertically at 48 inches (1219 mm) on center along the length of the wall, to both sides of the steel stud flange, with 11/2-inch-long (38 mm), Type S-12, self-tapping drywall screws, spaced at 12 inches (305 mm) on center. Stud ends are attached to the double 2-by-4-inch (51 by 102 mm) wood top plates and single bottom plate with a minimum of two 11/4-inch (32 mm) Tico roofing nails. Minimum 31/2-inch-thick (89 mm) mineral wool board insulation material having 8 pcf (128 kg/m³) density is f itted between stud framing members. The wallboard is attached with 1^5/8-inch-long (41 mm), Type S-12, self-tapping bugle-head drywall screws, at 8 inches (203 mm) on center at the joints and 12 inches (305 mm) on center in the field, to studs and strap and at each bottom and top plate. Wallboard joints and screw heads must be taped and treated with joint compound.

2.5 Miscellaneous:

Truss or other assemblies fabricated from the Tri-Chord sections is beyond the scope of this report and require testing to confirm design assumptions. Two full-scale tests of each truss design in accordance with Section 2230 F2 of the code must be performed to demonstrate a minimum safety factor of 2.5 on the allowable loads. In addition, each truss component must be subjected to 3 tests for each design load condition. The average results of 3 tests must demonstrate a minimum safety factor of 1.67. Each truss component to component connection must be tested a minimum of 3 tests for each design load condition. The average results of the 3 tests must demonstrate a minimum safety factor of 2.5.

2.6 Identification:

Each Tri-Chord section and EESI-STUD™ section is embossed with the name "Tri-Chord Systems," the manufacturer's initials (NS), the ICEIO ES evaluation report number ER-5210, and the minimum base steel thickness.

3.0 EVIDENCE SUBMITTED

Test reports, descriptive details, allowable load tables and structural calculations in accordance with the ICEIO ES Acceptance Criteria for Steel Studs, Joists and Tracks (AC46) dated January 1994, and fire test report in accordance with UBC Standard 7-1.

4.0 FINDINGS

That the Light Gage Structural Steel Framing Products described In this report comply with the 1994 Uniform Building Code™, subject to the following conditions:

4.1  The Tri-Chord sections and EESI-STUD™ sections are manufactured and installed in accordance with this report and Tri-Chord Systems' instructions.

4.2  Allowable loads for the EESI-STUD™ sections comply with Table 4.

4.3  Complete plans and calculations verifying compliance with  this report must be submitted to the building official for approval for each project.

4.4  Uncoated minimum steel thickness of cold-formed members, as delivered to the jobsite, shall be at least 95 percent of the uncoated thickness used in design.

4.5  When assemblies are fabricated from the Tri-Chard sections, plans, truss designs and engineering calculations must be submitted and approved by the building official for each project. Additional testing in accordance with Section 2.5 is required to confirm design assumptions.

4.6  The Light Gage Structural Steel Framing Products are manufactured at the North Star Company, Inc., facility located in Gardena, California.

4.7  Recognition of complete truss or other assemblies fabricated from the Tri-Chord sections Is beyond the scope of this report. Trusses must be fabricated by an approved fabricator monitored by a quality assurance program and incompliance with Section 1701.7 of the code.

1996 Accumulative Supplement: This report is unaffected by the supplement.

This report is subject to re-examination in one year.