IBC CEILING INSTALLATION REQUIREMENTS SUMMARY This document is intended as a guideline only. It is not a substitute for the full text of the referenced standards and does not reflect all building codes, laws, statutes, ordinances, rules and regulations that may be applicable to a particular installation. Armstrong is not licensed to provide professional architecture or engineering design services. Armstrong does not warrant the suitability of these guidelines for a particular installation. The user is advised to obtain complete copies of the referenced documents, to familiarize himself or herself with all building codes, laws, statutes, ordinances, rules and regulations applicable to the particular locale and circumstances of each installation, and to assure compliance with all applicable legal requirements. –1– INTERNATIONAL BUILDING CODE [2000/2003] SUSPENDED CEILING INSTALLATION REQUIREMENTS NOTE: IBC 2000 lists specific requirements for the installation of suspended ceilings in section 1621.2. Section 1621 of the 2003 edition of the code directs the reader to the American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures manual [ASCE 702]. The content has not materially changed. Source references are made to both texts in this summary. SEISMIC DESIGN CATEGORIES B, C, D, E, AND F Free Floating Components [Source: IBC 1621.2.1, ASCE 9.6.2.2] Architectural components supported by chains or otherwise suspended from the structure are not required to meet lateral seismic force requirements as long as they are capable of moving a minimum of 12" or swing 45° off vertical, without damage or contacting an obstruction. Gravity design loads must be three times operating load. ASCE 7-02 does not include the reference to 12” and 45°. SEISMIC DESIGN CATEGORIES A AND B The IBC does not require any special installation considerations for suspended ceiling installations in these categories. It is assumed that the basic standards listed in ASTM C 636, Standard Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels, should be followed. Wall Molding Wall molding is not mentioned in the C 636 standard. All options are available, and no standard practice for attachment is specified. Hangers Attachment of hangers to the building structure must be by means demonstrated to be suitable by standard construction practice or by certified test data. [Source: ASTM C 636-96, Section 2.1.2] Space hangers 4' on center, or adjust suspension system allowable load based on actual center spacing. [Source: ASTM C 636-96, Section 2.1.3] Hangers must be plumb within one in six [10] unless counter-sloping wire or horizontal bracing is provided. [Source: ASTM C 636-96, Section 2.1.4] Wire hangers must be minimum 12-gauge galvanized, soft-annealed, mild steel wire. [Source: ASTM C 636-96, Section 2.1.6] Devices used to attach wires to the grid must be certified to carry five times the design load. [Source: ASTM C 636-96, Section 2.1.7] –2– Wires loops must be tightly formed and secured by a minimum of three complete wraps completed within 3". [Source: ASTM C 636-96, Section 2.3.4] Main Beams No performance standard is given for load-carrying capacity of mains beams. Components are to be selected based on the design loads of the ceiling assembly. Mains are to be level within ¼" in 10'. [Source: ASTM C 636-96, Section 2.2.3.1] Connections must align properly [0.015" vertical or horizontal], and there shall be no visually apparent angular displacement. [Source: ASTM C 636-96, Section 2.6.1] Gaps between connected main beams must be less than 0.020". [Source: ASTM C 636-96, Section 2.6.3] All Armstrong suspension systems can be used. Cross Tees Must be installed within 1/32" of required center spacing. [Source: ASTM C 636-96, Section 2.4.1] Must form right angles with the main beams. No tolerance is specified. [Source: ASTM C 636-96, Section 2.4.2] Must be flush with the mains [-0.0"+0.015"]. [Source: ASTM C 636-96, Section 2.4.3] SEISMIC DESIGN CATEGORY C This section applies only to Seismic Use group III structures (essential facilities) and use group I & II structures three or more stories tall. IBC calls for suspended ceilings in this category to be installed in accordance with CISCA 0-2. These recommendations were first published July 1, 1991, and were reprinted September 1, 2002, with minor changes. The objective of this standard is to create an unrestrained ceiling. Or submit brochure CS-3543 as an alternate assembly tested under ICC-ES (AC156) Seismic Qualification Testing of Nonstructural Components. The following requirements are in addition to those listed for ASTM C 636. Ceiling Weight The actual weight of the ceiling system, including grid, panels, light fixtures, and air terminals, is to be no more than 2.5 PSF. All other services must be supported independently from the ceiling system. When the average ceiling weight exceeds 2.5 PSF, the ceiling is to be installed to meet the CISCA 3-4 provisions. [Source: CISCA 0-2, page 3, Section 4, #3] Wall Molding Moldings must have horizontal flange of at least ⅞". [Source: CISCA 0-2, page 4, Section 1, #5] –3– 7800, AL7801, EA7801, HD7801, SS7801, 7802, 7803, 7805, 7809, 7830, 7831, 7834, 7835 The terminal ends of the grid must rest on the molding with at least ⅜" clearance from the wall, and at least ⅜" perch on the molding. [Source: CISCA 0-2, page 4, Section 1, #5] Shadow molding may be used to meet this requirement. [Source: CISCA 0-2, page 4, Section 1, #5] 7820, 7822, 7824, 7826, 7828, 7829 Perimeter attachment is not permitted. [Source: CISCA 0-2, page 4, Section 1, #6] When the horizontal leg of the molding is less than ⅞" wide, the terminal ends of each cross tee and main beam must be independently supported within 8" of the wall or ceiling discontinuity. This support may be 12-gauge hanger wire or other support to prevent the grid from falling. These perimeter wires may attach to the structure above, or to the wall above the plane of the ceiling. Wires must be plumb within one in six, and the ⅜" end clearance must be maintained. [Source: CISCA 0-2, page 4, Section 1, #5] 7804, 780410 For essential facilities, the option to use a molding less than ⅞" wide is eliminated, the perimeter wires are required, and the minimum clearance between ends of suspension system components and the wall is increased to ½". [Source: CISCA 0-2, page 4, Section 1, #7] Hangers Normal hanger wires are not specified in CISCA 0-2. It is assumed that they must meet the requirements set in ASTM C 636. Suspension System Main Beam and cross tee intersections and splices must have connection strengths of at least 60 pounds in compression and in tension. [Source: CISCA 0-2, page 3, Section 4, #2] All Armstrong Suspension systems comply. Perimeter Spacers Perimeter components must have spacer bars, or some other suitable system, to prevent spreading. [Source: CISCA 0-2, page 4, Section 1, #6] BERC, 7425, 7445 Light Fixtures Fixtures weighing 56 pounds or less must have two 12-gauge wires attached at diagonal corners, and these wires must be slack. Fixtures weighing in excess of 56 pounds must be independently supported from the building structure. [Source: CISCA 0-2, page 3, Section 4, #1] –4– Partition Attachment The ceiling system may not be used to support walls or partitions. Any attachment mechanism must allow the ceiling to move ⅜" in any direction. [Source: CISCA 0-2, page 4, Section 1, #4] Penetrations All ceiling penetrations are to be treated as perimeter closures, and must allow the minimum ⅜" clearance by use of suitable escutcheons or closure details. [Source: CISCA 0-2, page 4, Section 1, #5] IBC only requires ¼” clearance at sprinklers and other penetrations [Source: IBC 2000 Section 1621.2.5.2.1] SEISMIC DESIGN CATEGORIES D, E, AND F Category D, E, and F ceilings are to be designed and installed according to CISCA 3-4, and eight additional requirements listed in Section 1621.2.5.2.2 of the IBC and Section 9.6.2.6.2.2 in ASCE 7-02. Ceiling areas of 144 square feet or less are exempted from lateral load design requirements. [Source: CISCA 3-4, page 1, Section 2, #1] Ceilings constructed of lath and plaster or screw-applied gypsum boards are exempt from lateral load design requirements. [Source: CISCA 3-4, page 1, Section 2, #2] This practice creates a restrained ceiling. The following is a combination of the requirements spelled out in the two referenced documents. Wall Molding [Source: IBC 1621.2.5.2.2 #2, ASCE 9.6.2.6.2.2 b] Moldings must have a horizontal flange of at least 2". 7810, 7812 or BERC2 and submit brochure CS-3543 as an alternate assembly tested under ICC-ES (AC156) Seismic Qualification Testing of Nonstructural Components. The ceiling grid must be attached to the molding at two adjacent walls. Unattached ends of the grid system must have ¾" clearance from the wall, and must rest upon and be free to slide on the molding. Hangers [Source: CISCA 3-4, page 1, Section 4, #1] Suspension wires must be minimum 12-gauge when spaced at 4' centers, or 10-gauge at 5'. Hanger wire attachment devices must be capable of supporting 100 pounds. Connections at main beam and at structure shall be secured with a minimum of three complete turns. –5– Perimeter Support [Source: CISCA 3-4, page 2, Section 1, #2] Terminal ends of each main beam and cross tee must be supported within 8" of each wall or ceiling discontinuity, with 12-gauge wire or approved wall support. These wires must be plumb to within one in six, and may attach to the adjacent wall or to the structure above. Perimeter Spacers [Source: CISCA 3-4, page 2, Section 1, #4] Ends of main runners and cross tees shall be tied together to prevent their spreading. 7425, 7445 or BERC2 Suspension System [Source: CISCA 3-4 and IBC 1621.2.5.2.2] Main beams must be heavy duty. [Source: IBC 1621.2.5.2.2 #1, ASCE 9.6.2.6.2.2 a] 56418, 7301, 730136, 7301G90, 7501, 7601, 76018, HD8200, 8301, HD8901, HD8906, HD8906G90 Main beam and cross tee intersections and splices must have connection strengths of at least 180 pounds in compression and in tension. [Source: CISCA 3-4, page 1, Section 3, #2] Prelude XL (7300 & 8300 series), Suprafine XL (7500 series), Silhouette XL (7600 series), DGS (8900 series) Note: the following systems meet the connection strength requirement but do not have a heavy duty main: AL & SS Prelude Plus, Interlude, Serpentina, Sonata, Extruded Aluminum Clean Room (with screw through tees). Cross tees supporting light fixtures must have the same load-carrying capacity as the main beams, or be fitted with supplemental hangers. [Source: CISCA 3-4, page 2, Section 2] XL7341, XL8341, XL8945, XL8945G90 Cross tees supporting mechanical services must have the same load-carrying capacity as the main beam. [Source: CISCA 3-4, page 2, Section 3] Lateral Force Bracing [Source: CISCA 3-4 and IBC 1621.2.5.2.2] Ceiling areas greater than 1000 square feet must have lateral force bracing. [Source: IBC 1621.2.5.2.2 #3, ASCE 9.6.2.6.2.2 c] Rigid bracing may be used instead of diagonal splay wires. [Source: IBC 1621.2.5.2.2 #3, ASCE 9.6.2.6.2.2 c] Bracing must limit ceiling movement to less than ¼" at the point of attachment. [Source: IBC 1621.2.5.2.2 #3, ASCE 9.6.2.6.2.2 c] –6– Splay wire bracing shall be clusters of four 12-gauge wires attached to the main beam within 2" of the cross tee intersection. Wires are arrayed 90° from each other at an angle not exceeding 45° from the plane of the ceiling. [Source: CISCA 3-4, page 2, Section 1, #3] A strut, with stiffness adequate to resist the vertical loads imposed, shall be attached to the suspension system, and to the structure above at each bracing location. [Source: CISCA 3-4, page 2, Section 1, #3 Table for selecting studs is ready (from Deitrich) waiting approval from legal to publish. Horizontal restraint points shall be no more than 12' on center in each direction, and the first point shall be within 6' of each wall. [Source: CISCA 3-4, page 2, Section 1, #3] Attachment of the bracing wires to the main beam and to the structure shall be capable of supporting the greater of 200 pounds or the actual design load with a safety factor of 2. [Source: CISCA 3-4, page 2, Section 1, #3] Light Fixtures [Source: CISCA 3-4, page 2, Section 2] All fixtures must be positively attached to the suspension system. The attachment device must be able to withstand 100% of the weight of the fixture acting in any direction. Fixtures weighing 56 pounds or less must have two 12-gauge wires attached at diagonal corners, and these wires may be slack. Fixtures weighing in excess of 56 pounds must be independently supported from the building structure. Pendant-mounted fixtures must be supported directly from the structure, using 9-gauge wire. They may not use the ceiling suspension system for support. Mechanical Services [Source: CISCA 3-4, page 2, Section 3] Must be positively attached to the suspension system main beams, or to cross tees with the same load-carrying capacity. Terminals or services weighing 20 pounds to 56 pounds must have two 12-gauge wires connecting them to the ceiling system hangers, or to the structure above. Terminals or services weighing more than 56 pounds must be independently supported. Partition Attachment [Source: IBC 1621.2.7, ASCE 9.6.2.8.1] Partitions attached to the ceiling suspension system shall be laterally braced to the building structure. This bracing is to be independent of any ceilings splay wire bracing. Exception: Partitions not taller than 9' as long as the horizontal seismic load does not exceed 5 PSF. UPC Penetrations [Source: IBC 1621.2.5.2.2 #5, ASCE 9.6.2.6.2.2 e] Except when rigid bracing is used, sprinkler heads and other penetrations must have 2" oversized trim to allow 1" horizontal movement in all horizontal directions. –7– Seismic Separation Joints [Source: IBC 1621.2.5.2.2 #4, ASCE 9.6.2.6.2.2 d] Ceiling areas greater than 2500 square feet must have seismic separation joints or full height partitions unless analyses are performed to demonstrate that the closure trims and angles provide enough clearance to accommodate the additional ceiling movement. Height Transitions [Source: IBC 1621.2.5.2.2 #6, ASCE 9.6.2.6.2.2 f] Changes in ceiling plane elevation must have positive bracing. Cable Trays [Source: IBC 1621.2.5.2.2 #7, ASCE 9.6.2.6.2.2 g] Cable trays and electrical conduits shall be independently supported and braced independently of the ceiling. Special Inspection [Source: IBC 1621.2.5.2.2 #8, ASCE 9.6.2.6.2.2 h] Suspended ceilings are subject to special inspection as described in Section 1704 of the 2000 code, and Section A.9.3.3.9 in ASCE 7, the 2003 IBC reference. This inspection entails manufacturer certification of component performance and periodic inspection of the suspended ceiling system anchorage system. USEFUL WEB SITE LINKS ASTM http://www.astm.org / American Society for Testing and Materials BSSC http://www.nibs.org/ Building Seismic Safety Committee FEMA http://www.fema.gov Federal Emergency Management Agency ICC http://www.intlcode.org/ International Code Council MCEER http://mceer.buffalo.edu Multidisciplinary Center for Earthquake Engineering Research USGS http://geohazards.cr.usgs.gov/eq/ United States Geological Service –8– min. 3/8" Spacer bar, or other suitable system, to keep perimeter components from spreading apart. Category C details min. 3/8" min. 7/8" min. 3/8" Spacer bar, or other suitable system, to keep perimeter components from spreading apart. 1 6 min. 3/8" min. 7/8" min. 3/8" Spacer bar, or other suitable system, to keep perimeter components from spreading apart. max. 8" min. 3/8" min. 3/8" min. 7/8" –9– Spacer bar, or other suitable system, to keep perimeter components from spreading apart. details min. 3/4" at un-attached walls min. 2" 1 8" MAX. 6 1 7 2" 8" max. 8" Attach one end of grid to molding at two adjacent walls. Perimeter wires or approved wall support required required at the terminal ends of all grid. compression post Splay wire bracing Typical bracing detail – 10 –