Suspended Ceiling Systems Research Articles

Earthquake Simulator Testing and Seismic Evaluation of Suspended Ceilings

Past seismic events have demonstrated the vulnerability of suspended ceilings, classified as nonstructural components, to earthquake damage. Engineers, architects, and manufacturers all participate to help ensure that the units perform satisfactorily during earthquakes. To address the seismic susceptibility, the U.S. national codes and federal and regulatory guidelines recommend two distinct approaches. The first mandates capacity and installation requirements and the second addresses damage states, introducing performance based. Application of these methods entails either accurate structural analysis or seismic qualification by experimentation. Until recently, scant data were available to evaluate the adequacy of the required installations or the damage states. To address this issue, full-scale earthquake laboratory tests of suspended ceiling systems have been undertaken by researchers and manufacturers. Experimentation showed that ceilings meeting the code requirements performed well. The only mode of failure observed during the tests was the loss of panels. Laboratory data were also used to construct fragility curves for the specimen. Large vertical accelerations, typically not observed in the field, dislodged panels close to the center of the test frame. This type of response differs from that presented in past earthquake reconnaissance reports and thus necessitates further examination.

Seismic Fragility of Suspended Ceiling Systems

Full-scale dynamic testing of suspended ceiling systems was performed to obtain fragility data suitable for performance-based assessment and design. On the basis of the fragility data derived from testing, (1) the use of retainer clips improves the performance of ceiling systems in terms of loss of tiles, (2) including recycled cross tees in the suspension grid increases the vulnerability of the ceiling systems, (3) undersized (poorly fitting) tiles are substantially more vulnerable than properly fitted tiles, and (4) the use of compression posts improves the seismic performance of ceiling systems for the limit states of minor and moderate damage. Fragility curves are provided for four damage states.

Grid accent and ceiling boards

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Standard measurement of sound transmission through suspended ceilings

Sound transmission through the space above the suspended ceiling commonly limits insulation between offices where interoffice partitions do not extend above the suspended ceiling. This paper presents a detailed comparison of standard test methods for evaluating suspended ceiling performance. A laboratory has been constructed that can readily be converted to satisfy requirements of ISO Standard 140 Part 9, or a corresponding ASTM draft standard, or the Acoustical Manufacturers' Association standard (AMA I-II) from which these descended. Characteristics of the test environment have been studied, and a series of suspended ceiling systems have been tested using all three standard methods. Significant differences and their causes will be discussed.

Measuring sound transmission through suspended ceilings

In most modern office buildings, interoffice partitions stop at the suspended ceiling. Sound insulation between such offices is generally inadequate for speech privacy. This paper presents the first stages of a project to develop practical acoustical solutions. A new laboratory has been constructed; this simulates a pair of adjacent offices with a common plenum space above the suspended ceiling. Characteristics of the test environment and pertinent standard test procedures have been studied. A series of suspended ceiling systems has been tested. The results indicate the relative importance of major physical factors controlling sound transmission through typical suspended ceilings.

Suspended ceiling tile system

A method for refurbishing a suspended acoustical tile ceiling when the tiles become soiled comprises inserting a tile insert beneath each soiled tile to provide a new face to the suspended ceiling. The tile insert comprises a thin layer of substantially rigid material with an acoustical pattern of holes extending therethrough. The tile insert has a front face which is of washable material. In this manner, an entire suspended ceiling system can be refurbished without the need to remove the existing tiles. The tile insert may include a moisture barrier on the rear face of the tile insert. The moisture barrier improves washability of the tile and significantly enhances the noise reduction properties of the refurbished suspended ceiling.

Acoustical design of the Dalhousie Athletics Complex

The necessity of introducing a major scale athletics complex within a residential neighborhood, which had already shown considerable opposition to the project, resulted in the selection of an inflated stainless steel‐membrane roof structure to minimize the visual impact of the 150 000‐sq‐ft complex. The steel membrane roof structure, because of its minimal thickness and load‐carrying capacity, presented challenging acoustical problems in sound isolation, to minimize the impact of activity noise within the field house on the surrounding neighborhood, and to control the interior noise from rainfall on the exposed metal roof surface. A suspended acoustical ceiling system was developed to control external noise radiated, attenuate rain noise, and simultaneously control reverberation within the field house and control potential echoes from the shallow‐domed ceiling. This ceiling system was designed to permit partial deflation of the membrane, and subsequent recovery, without damage, and within the severe weight restrictions. A sound‐reinforcement system, consisting of concentric rings of separately amplified high‐frequency horns and low‐frequency loudspeakers was used, with electronic signal delay to control echoes and enhance directional realism.

Laboratory Measurements of Sound Transmission through Suspended Ceiling Systems

A laboratory facility is described as evolved for the measurement of sound transmission through suspended acoustical ceilings under field conditions of erection over part high partitions. The results of exploratory measurements are reviewed for a wide range of the dimensional and acoustical parameters of the ceiling-plenum system. Consideration is extended to the ceiling-partition system and to the importance of an accurate simulation of field conditions of erection for the testing of all elements, individually and interacting, in the ceiling-plenum-partition system. The compatibility of this approach with conventional test methods is suggested.