ShortSpan Brochure1 6/14/05 4:39 PM Page 1 CEILING SYSTEMS

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1 CEILING SYSTEMS

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3 Armstrong Short Drywall Grid System was introduced to the North American commercial building market early in Many of its properties are similar to other framing systems commonly used today, but the designs and the installation system depart somewhat from current industry practice. Use this data to qualify Short as acceptable for use on your project or with your building code. If you have questions after reviewing this information, contact Armstrong at This document will provide the following information: Physical Performance Summary Mechanical Performance Summary Section Properties Seismic performance Summary To assist you in the use of this brochure, please obtain a copy of the Short DGS Technical Guide (CS-3590) from your Armstrong representative. 3

4 The information contained in this technical paper will provide the user of the Armstrong Short DGS (drywall grid system) with a summary of the performance of the product. The summary contains information on the physical, mechanical and seismic performance of the system. The Armstrong Short DGS consists of the following; 8, 10, 12 and 14 T-bar; 12 locking angle mold and 12 knurled angle molding. The Short system is designed for use in drywall ceiling framing where the spans are less than 14 feet. The individual Short Tees are not designed to be used independent of the Locking Angle molding or optional Knurled Angle molding as instructed in our technical guide. The Short DGS is to be used with drywall, up to 5/8, weighing up to 2.50 lbs/ft 2. The attached charts reflect the Short Systems capacities. Although the Armstrong Short DGS performance is comparable to current construction practices for framing short spans, the building codes do not clearly provide provisions for the use of a Short grid framing system for installation of a drywall ceiling. Therefore, as the manufacturer we are providing additional data including a summary of the mechanical test data as prescribed by the recognized ASTM test methods used in the industry today to document the performance of these systems and to give a comparison to traditional framing components. Installation Standards ASTM C635-04, Standard Specification for the Manufacture, Performance and Testing of Metal Suspension Systems for Acoustical Tile and Lay-In Panel Testing ASTM C Standard Specification for Nonstructural Steel Framing Members ASTM E Standard Practice for Application of Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels in Areas Requiring Moderate Seismic Restraint ASTM E8-04 Standard Test Method for Tension Testing for Metallic Materials ASTM A-653 Standard Specification for Steel Sheet, Zinc- Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process 4

5 Physical Performance Summary Tees installed 16 or 24 on center with 5/8 drywall Up to 6 0 span No vertical support required 6 1 to 12 0 span Mid-span vertical support required 12 1 to 14 0 span Two vertical supports required at 1/3 points (max. 14 span) Tees installed 16 on center only with 1/2 drywall Up to 7 0 span No vertical support required 7 1 to 14 0 span Mid-span vertical support required Maximum Load in (L/240 per ASTM C 645) Item Number Item Length O.C. Spacing **Requires mid-span vertical support *** Requires two vertical supports at 1/3 points NOTE: 5/8 drywall weighs 2.4 lbs./sf (tees installed 16 or 24 on center) 1/2 drywall weighs 2.0 lbs/sf (tees installed 16 on center only) 7 8 S ** S ** 10 S ** S ** S ** S ** S ** S ** 9.53*** S ** 6.36*** Load Test per ASTM C Mechanical Performance Summary Part Number Description Length S7708, S7710, S7712, S7714 LAM12 / KAM 12 8, Short (0.018 ) Drywall Tee 12 Short (0.018 ) Wall Molding Tested 48, 60 and 72 on Center 24 on Center 5

6 Load Test Average per ASTM C 635 The following tables contain a summary of test results: Part Number Load at L/360 (LBS/LF) Load at Failure (LBS/LF) S7708, S7710, S7712, S span S7708, S7710, S7712, S span S7708, S7710, S7712, S span (L/240 = 23.2) 8.48 (L/240 = 12.11) 4.33 (L/240 = 6.18) Total Load at Failure (LBS) Short Wall Molding Load Test Average Part Number Test Condition Supported Load (LBS/LF) LAM 12/ KAM 12 Average of 4 tests 100 Section Properties Tensile Test Per ASTM E 8-04 Property Sample Value Average Base Metal Thickness All Average Yield Strength by Offset Method All 47,792 psi Average Yield Point by Graphical Method All 0.34% in./in. Young's Modulus (Modulus of Elasticity) Maximum Average Tensile Strength Average 61,321 Ultimate Load Average lbs Elongation Average 35.6% Reduction of Area Average 32.0% 34, 339, 100 psi 32, 118, 980 psi Nominal Test Section Dimension (Thickness x Width Prior to Testing) Average x The complete report from Architectural Testing and Section Properties (Moment of Inertia, Section of Modulus and Yield Strength) are available upon request from your Armstrong Representative. 6

7 Additionally, full-scale seismic testing was performed utilizing the University at Buffalo Earthquake Simulation (Shake Table) apparatus. The full-scale dynamic testing was performed according to a modified ICC Acceptance Criteria for Seismic Qualification Testing of Nonstructural Components, AC 156. This criterion was modified to make it specific for the testing of grid system types, i.e. Short. The complete test protocol and test program is contained in Report No.UBCSEE/SEESL , dated March 1, Armstrong conducted tests on the Short system using the seismic simulation based on the mapped spectral accelerations at short periods of SS up to 1.75G (from the International Building Code, 2003). Spectra were generated for horizontal and vertical earthquake shaking. Three separate configurations were tested. The first consisted of two 16 ft. (4.88 m) long and 5 ft. (1.52 m) high walls running in the northsouth direction constructed of 3-5/8 in. (92 mm) 20 gauge steel studs spaced at 16 in. (406 mm) on center; a distance of 14 ft. (4.27 m) was maintained between the two walls. A single layer of 5/8 in. (16 mm) thick drywall was attached to the exterior surfaces of the walls using 1-1/4 in. (32 mm) #6 bugle-head drywall screws. A locking angle molding was screwed directly to the steel studs with #7 x 7/16 in. (11 mm) sheet metal screws; the molding had perforated tabs to lock the drywall Tees into the proper spacing and alignment. Drywall Tees were spaced at 2 ft. (0.61 m) on center. All drywall Tees ends were screwed to the locking angle molding with #7 x 7/16 in. (11mm) sheet metal screws. Each Tee had two soft annealed galvanized number 12 gage steel suspension wire located 6 ft. (1.83 m) and 6-1/3 ft. (1.93 m) from the west and east wall of the test frame, respectively. Stabilizer bars were installed to maintain the 2 ft. (0.61 m) spacing between the drywall Tees. Type X 5/8 in. (16mm) thick drywall panels were screwed to the Tees using 1-1/4 in. (32 mm) #6 bugle-head drywall screws spaced at 12 in. (305 mm) on center. The drywall was not screwed to the locking angle molding or to the drywall Tees within 4 in. (102 mm) of any wall. For the second configuration, the screws anchoring the Tees to the locking angle molding were removed and the ceiling was tested again. The third configuration consisted of two simulated corridors both running in the north-south direction of the test frame. One corridor consisted of two 16 ft. (4.88 m) long and 5 ft. (1.52 m) high walls running in the north-south direction constructed from 3-5/8 in. (92 mm) 20 gauge steel studs spaced at 16 in. (406 mm) on center. The walls were located 6 ft. (1.83 m) apart from each other. A single layer of 5/8 in. (16 mm) drywall was attached to the exterior surfaces of the corridor by using 1-1/4 in. (32 mm) #6 bugle-head drywall screws. The locking angle was screwed directly to the steel studs with #7 x 7/16 in. (11 mm) sheet metal screws, and had perforated tabs to lock the drywall Tees into the proper spacing and alignment. The drywall Tees were spaced at 2 ft. (0.61 m) on center installed between the two walls of the west corridor. The drywall Tees were Seismic Performance Summary 7

8 screwed to the locking angle molding. No suspension wires were used in the system. Type X 5/8 in. (16 mm) drywall panels were screwed to the Tees using 1-1/4 in. (32 mm) #6 bugle-head drywall screws spaced at 12 in. (305 mm) on center. The second corridor consisted of two 16 ft. (4.88 m) long and 5 ft. (1.52 m) high walls running in the north-south direction constructed from 2-1/2 in. (64 mm) 25 gauge steel studs spaced at 16 in. on center. The two walls were located 6 ft. (1.83 m) apart from each other. A single layer of 5/8 in. (16 mm) drywall was attached to the interior surfaces of the corridor by using 1-1/4 in. (32 mm) #6 bugle-head drywall screws. The locking angle molding was screwed to the wall by anchoring through the 5/8 in. (16 mm) thick drywall using 1-1/4 in. (32 mm) #6 bugle-head drywall screws. The drywall Tees were spaced at 2 ft. (0.61 m) on center. The drywall Tees were not screwed to the locking angle molding and no suspension wires were used. Type X 5/8 in. (16 mm) drywall panels were screwed to the Tees using 1-1/4 in. (32 mm) #6 bugle-head drywall screws spaced at 12 in. (305 mm) on center. All corridor walls were laterally braced to the structure above. Support walls were tied directly to the structure. Seismic Conclusion For the Short grid system, two performance limit states were defined as: 1.) no damage to the suspension system and 2.) no damage to or loss of any drywall panel or component. Qualification levels were determined as the level of shaking at which the limit state was not reached. The results for each test configuration was that there was no damage to the drywall or any suspension system component. For these evaluations testing was done to a maximum shaking intensity of 1.75g. Testing Series Ceiling system ID System description Qualification level (g) Limit state 1 Limit state 2 K8 8a L9 8b M9 9 Test of a Short (14 ft.) drywall grid system Short (14 ft.) drywall grid system of 8a retested after removing the screws anchoring the Tees to the locking angle molding. Tests of two Short (6 ft.) drywall grid systems For the official seismic test report, please contact your Armstrong Representative. CEILING SYSTEMS ARMSTRONG ( ) armstrong.com/ceilings CS AWI Licensing Co. Printed in the United States of America