Ceiling Tile Research Articles

Black on Black on Black on Black: An interview with Artist-Scholar Dr. Blair Ebony Smith

Black on Black on Black on Black: An interview with Artist-Scholar Dr. Blair Ebony Smith

Potential of waste woven polypropylene fiber and textile mesh for production of gypsum-based composite

The huge production of woven polypropylene bags has led to an increase generation of plastic waste. The recycling of waste woven polypropylene bags and textiles in construction applications can be a viable option. Therefore, an attempt has been made to utilize the woven polypropylene fibers and textiles in the production of gypsum-based composite false ceiling tile for an economical and sustainable construction product. In the current research work, different water-to-powder ratios (0.6 %, 0.7 %, 0.8 %, 0.9 %) and fiber contents (0.25 %, 0.35 %, 0.45 %, 0.55 %) in the gypsum-based composite were prepared. Flexural plates with different thicknesses (18, 15, 12, and 9 mm) incorporating different recycling fibers and reinforced with different types of meshes were manufactured to produce sustainable gypsum-based plates. The physical properties, compressive and flexural strength properties of the fiber-reinforced gypsum-based composite were also evaluated. The textile and woven polypropylene fiber mesh reinforced gypsum false ceiling plates were compared with the control specimen. The results revealed that the density of gypsum-based composite decreased up to 26 % with the increase in the proportion of waste fiber contents. The compressive and flexural strength of gypsum-based composites exhibited a decrease with an increase in fiber contents and water-to-powder ratio. However, all the specimens satisfied the acceptable limit of 1 MPa and 2 MPa, respectively, according to BS EN 14246. The bending strength of all the plates incorporating different fiber content and thicknesses satisfied the minimum specified flexural strength criteria according to BS EN 14246. Moreover, the plates with different thicknesses and fiber contents also satisfied the minimum specified flexural criteria except for the plate with a thickness of 9 mm. However, all the plates with varying thicknesses and reinforced mesh have also satisfied the minimum load criteria specified by BS EN 14246. Thus, it can be envisioned that the woven polypropylene fibers and textiles can be effectively utilized to produce sustainable gypsum-based composite leading to reduce waste generation.

Economic sustainability assessment of a gypsum ceiling tile with polyurethane foam waste

The amount of plastics deposited in the environment is constantly increasing. To improve their circularity, numerous research lines emerge, such as the creation of new construction materials that incorporate polymeric waste. This practice manages to extend the life cycle of the waste, avoids the consumption of limited natural resources and gives the product additional characteristics. The re-use of polyurethane foam waste as a substitute for gypsum in ceiling tiles carries technical improvements such as a decrease in the weight of the material and in its thermal conductivity, maintaining a positive fire reaction performance. The goal of this work is to analyse its economic viability. For this, the financial assessments of the PU-Gypsum product and its standard alternative are compared. The results show that the Life Cycle Cost Analysis (LCCA) of the new precast is 6% cheaper. Despite the fact that the waste processing entails an extra cost, this is widely offset by the increase in the factory’s production capacity due to its shorter drying time. The manufacturing stage represents 3/5 of the total cost for both materials. The PU-Gypsum precast is an ideal market alternative to the traditional gypsum one with improved properties and proficient in an economic level.

Towards an ecological transition in the construction sector through the production of new eco-efficient products

The economic model of the construction sector is becoming more circular by emphasizing sustainability at all stages from the design, the production phase, the installation, the use, the removal and finally its transport to landfill. This work analyses the influence of added polyurethane foam waste from refrigerated industry on the technical properties (bulk density, water vapor permeability, and reaction to fire performance). The environmental properties were also measured through a comparative Life Cycle Analysis (LCA) between the traditional gypsum ceiling tile and a new organic one. The re-use of polyurethane waste in ceiling tiles causes technical improvements. The most relevant improvements noticed are the decrease in the density (28%), reduction in thermal conductivity (27%) and A1 classification for fire reaction. The comparative (LCA) between both tiles shows that the new product that incorporates polyurethane waste has significant improvement in CO2 (14%) and lower use of energy during the manufacturing process (14%). The following impact categories were also reduced: 9% in the case of the acidification of the ground and water, 9% for eutrophication and 31% reduction for non-hazardous waste. This work intends to reduce the carbon footprint and increase the sustainability of polyurethane gypsum products.

Trajectory-Based Skill Learning for Overhead Construction Robots Using Generalized Cylinders with Orientation

Overhead work involving the construction and maintenance of civil infrastructure (e.g., tunnels, overpasses, and buildings) is strenuous and fatigue-inducing for human workers and is particularly well-suited for co-robotization. Such work is typically quasi-repetitive, and on-site robots must adapt to unexpected workface conditions. Methods such as learning from demonstration can leverage human experts’ demonstration to let robots directly learn new skills to perform tasks. This paper proposes a generalized cylinders with orientation approach to teach robots how to perform quasi-repetitive overhead construction tasks from human demonstration. The demonstration trajectories are first used to construct a generalized cylinder and generate the robot trajectory. To ensure that the construction component (e.g., tunnel lining segment, building ceiling tile) being installed can satisfy the geometric constraints of the workspace, orientation constraints need to be determined, and the robot must follow such constraints. A trajectory adaptation and human-in-the-loop refinement approach are developed to refine the robot trajectory. The proposed method was evaluated in a robot simulator with variable workspace. The results showed that the proposed approach achieves an improved success rate (82.0%) compared to that demonstrated in previous work (71.3%) and enables overhead construction robots to readily adapt to new worksite conditions.

Comparative Life Cycle Assessment (LCA) between standard gypsum ceiling tile and polyurethane gypsum ceiling tile

In this paper, the LCA of two gypsum ceiling tiles is compared, the first one is a traditional gypsum tile and the second is a new eco ceiling tile in which polyurethane foam waste has been incorporated. Both tiles were made at one of the largest gypsum tile factories in Europe. The life cycle assessment has been considered from cradle to grave for which the corresponding production stages have been defined. This includes the extraction and transportation of raw materials, the manufacturing process, transportation to the client, the use of the product and the end of its useful life. The results show that the tile with polyurethane has a better environmental performance than the standard commercial ceiling tile. This is quantified as a 14% reduction in energy consumption, a 14% reduction in CO2 emissions and a 25% reduction in water consumption compared with the standard tile, all the while maintaining the technical performance. An analysis of the results suggests that the new eco product has a competitive advantage on the market thanks to its environmental improvements and good technical performance.

Impact of air distribution on indoor formaldehyde abatement with/without passive removal material: A CFD modeling

In this paper, a computational fluid dynamic (CFD) model was developed to study the effect of various air distribution technologies on formaldehyde abatement indoors, with and without a sorptive ceiling tile as the passive removal material (PRM). An experiment was performed in a 22.6 m3 test room by a pulse injection of sulfur hexafluoride (SF6) as a tracer gas, and the turbulent diffusion coefficient was evaluated through the curve fitting of the CFD model to the experimental data. Formaldehyde adsorption on the sorptive ceiling tile was obtained in a laboratory test chamber (0.4 m3) via continuous injection of 100 μg m−3 formaldehyde at 21 ± 2 °C and 50 ± 5% relative humidity: The experiment was conducted over the period of 20 days. A one-dimensional mathematical model was developed to evaluate the adsorption coefficient of formaldehyde towards the PRM in the laboratory test chamber using curve fitting analysis. To study the impact of air distribution technologies for such application, six different scenarios were considered for CFD simulation. These included, displacement ventilation (DV), mixing ventilation (MV), and four different types of overhead mixing ventilations (OMV). Simulation results at the steady-state condition showed that when a sorptive ceiling tile was implemented as a PRM in the test room, a noticeable reduction of formaldehyde concentration was observed in the breathing zone, for all air distribution patterns. The health risk assessment of formaldehyde in the breathing zone showed a safer level of this compound when mechanical ventilation and PRM were applied together.

Attenuation of Several Common Building Materials: Millimeter-Wave Frequency Bands 28, 73, and 91 GHz

Future cellular systems will make use of millimeter wave (mmWave) frequency bands. Many users in these bands are located indoors, i.e., inside buildings, homes, and offices. Typical building material attenuations in these high frequency ranges are of interest for link budget calculations. In this paper, we report on a collaborative measurement campaign to find the attenuation of several typical building materials in three potential mmWave bands (28, 73, 91 GHz). Using directional antennas, we took multiple measurements at multiple locations using narrow-band and wide-band signals, and averaged out residual small-scale fading effects. Materials include clear glass, drywall (plasterboard), plywood, acoustic ceiling tile, and cinder blocks. Specific attenuations range from approximately 0.5 dB/cm for ceiling tile at 28 GHz to approximately 19 dB/cm for clear glass at 91 GHz.

Falseiling

Based on an urban myth in India, where people often question the use of drop (fall) ceiling in households wondering if they are hiding money up there; this series was my interpretation of what we are hiding. For me, this meant a literal exposure of what was exactly above each drop ceiling tile. My work does not happen to you, you happen upon it through subtle interventions I create. These interventions demand the viewer to introspect the space and my work makes visible the unnoticed elements of that space. After the viewers suspension of disbelief, there is a discrepancy in the moment of realisation, that my work is trying to be something it's not while simultaneously blending into the environment. This discrepancy is not alarming, but grows exponentially as one spends time with it, leaving little grasp of what is real and what is not.

Teaching robots to perform quasi-repetitive construction tasks through human demonstration

Robots can assist workers in performing physically-demanding construction tasks, which are typically quasi-repetitive, wherein the geometry of the workspace is dissimilar despite similar tasks. As a result, robots must determine motion trajectories based on the encountered workspace geometry. Learning from Demonstration (LfD) methods have the potential to be used in teaching robots specific tasks through human demonstration, such that robots can then perform learned tasks under different conditions. In this paper, the LfD method is investigated to teach robots how to perform quasi-repetitive construction tasks. Considering ceiling tile installation as the experimental process, the tasks of maneuvering and positioning tiles in a ceiling grid are defined as the target knowledge to be learned. Using a set of human demonstration videos, the designed approach first translates the physical work context, e.g., the pose of the tile, to the target digital twin, i.e., the workspace as-perceived by the robot. The Reinforcement Learning method is then applied to generate the control policy for the robot to perform the subsequent tasks. The proposed method is evaluated in the Robot Operating System (ROS) Gazebo simulator using a KUKA mobile industrial robotic arm emulator and 60 different scenes as test cases. The results show a 78% success rate in installing ceiling tiles based on 3000 virtual and 85 real demonstration videos. The success rate tends to continually rise with an increase in the number of real demonstration videos, confirming the promise and applicability of the LfD method in teaching robot apprentices to perform quasi-repetitive tasks on construction sites.

Design, simulations and experimental research in the process of development of sound absorbing perforated ceiling tile

This paper discusses the design, realization and acoustical performance of sound absorbing perforated gypsum ceiling tile. The scope of the research involved numerical simulations and experimental measurements. Each step was performed with the aim to achieve the best possible weighted sound absorption coefficient (αW), of the final product, not lower than 0.65. Those aims had to be accomplished within the boundaries of the production process, mechanical properties and costs. Product details and their influence on the acoustical and architectural properties are described, followed by the results of the impedance tube sound absorption measurements of two prototypes, and the full scale ISO 354 tests of the final product. Visual aesthetics surveys among architects and challenges in porous material selection for sound absorbing products are also discussed. The implemented methodology, calibration of prediction models with measurements and design decisions including the “backup strategy” successfully demonstrated the achievement of the product aims in respect of both sound absorption and aesthetics, as well as other boundaries of the process.

Production of Ceiling Tile with High Density Polyethylene (HDPE) and Polyethylene Terephthalate (PET) Plastic Wastes as Main Ingredients

Production of Ceiling Tile with High Density Polyethylene (HDPE) and Polyethylene Terephthalate (PET) Plastic Wastes as Main Ingredients

Removal performance of formaldehyde by ceiling tiles as sorptive passive panels

In this study a ceiling tile (CT) was selected as a sorptive passive panel, and the effect of environmental conditions on its formaldehyde removal efficiency was evaluated. Experiments were performed in a 0.4 m3 chamber with the air flow rate of 0.2 m3 h−1, the air exchange rate of the 0.5 h−1, and the loading ratio of 0.23m2m-3. The range of temperature humidity levels varied between 21 °C ± 2 °C–26 °C ± 2 °C, and 30% ± 5%–75% ± 5%, respectively, to simulate the indoor conditions for Canadian homes during most months of the year. Results demonstrated formaldehyde removal efficiency between 40% and 75% depending on the applied environmental conditions. GC/MS and HPLC trace analyses revealed that only very low concentrations of by-products were formed. The by-product formation increased slightly when exposing the ceiling tile to relatively high relative humidity (RH = 75%) and temperature (T = 26 °C). Given a loading factor of only 0.23 m2 m−3in our test chamber, which in most scenarios underestimates the loading factor in real settings, our findings suggest that ceiling tiles used as passive removal panels have the potential to lower formaldehyde concentrations under the Health Canada's guideline for residential settings under real-life conditions.

Design of Adhesive-free Bio-based Suspended Ceiling Tiles Using Nanocellulose

An adhesive-free, bio-based suspended ceiling tile (nanocellulose ceiling tile (NCT)) with mildew and mold resistance, fire retardancy, and water repellence was developed and compared with commercial products (M257, M266, and M935). The NCT produced the greatest contact angle values: 145.0° (1.37% coefficient of variation (CV)) on the top surface, 137.8° (2.15% CV) on the bottom surface, and 142.2° (3.41% CV) on the edges. The thermal resistivity (R-value) of the NCT was also greater (3.14 °F∙ft2∙h/BTU (1.32% CV)), so the thermal conductivity (k-value) was lower (0.046 W/(m∙K)) than the compared commercial products (M257, M266, and M935). The NCT demonstrated resistance to mildew and mold growth, with zero defacement. Each product (NCT, M257, M266, and M935) evaluated was fire retardant, with zero horizontal flame propagation. The results showed that the NCT was an advanced ceiling tile prototype treated against fire, water, and mildew and mold growth throughout its thickness, with promising results compared to current ceiling tiles on the market.

Measured acoustic conditions in the common spaces of two educational buildings at the University of Nebraska–Omaha

This paper presents results from an acoustical case study of the atria, corridors, stairways, and other common spaces within two buildings located on the campus of the University of Nebraska-Omaha: the Peter Kiewit Institute and the Barbara Weitz Community Engagement Center. Both buildings, while educational in nature, differ drastically in acoustical design. Impulse responses, noise levels, and transmission loss in both facilities are measured and the resulting acoustic metrics are compared to recommended values for the respective spaces. Descriptions of each building’s architectural features are presented and linked to the measurement results. In particular, many spaces in the Peter Kiewit Institute were designed to expose the building systems, and the lack of acoustical products such as acoustical ceiling tile results in higher noise levels than normally expected. The Weitz Center, however, was designed with great emphasis placed on achieving optimal indoor environmental conditions. The results of this...

An evaluation study of pressure-compressed acoustic absorbers grown on agricultural by-products

This research examines the use of a novel new renewable resource in acoustic absorption applications. The new material being tested is based on a fungi that is grown on semi-hydrophobic agricultural by-product substrates such as cotton burs, switch-grass, rice straw, sorghum stalks, corn stalks and kenaf; to form a light-weight all-natural bio-composite board. The study examines the impact of a new post-processing technique that converts the raw light-weight board into a much higher density compressed board that requires no additional glue or binder. The material traits of interest to this study are the acoustical absorption properties of this new high density variant. The study tested the boards over a range of compressed densities that resulted by increasing the compression force in a laboratory board press with a fixed temperature of 205° Celsius for the following applied pressures {0, 2644, 3051, 3661, 4678N/m2} to achieve the following five density levels that were tested, {0.042 (uncompressed), 0.057, 0.086, 0.120, 0.169g/cc}. Also included in the study were three reference materials {commercial acoustic ceiling tile, a cork flooring under-layment and birch plywood}. The acoustic properties of the material were characterized for acoustic absorption, in reflection and for through-transmission. The results of the study indicate this new class of densified mycelium based boards are a promising bio-based composite alternative for through-transmission acoustic shielding boards. Results show a progressive increase in sound shielding up to 0.087g/cc after which further increases in density are statistically insignificant. This new material provides an all-natural, sustainable alternative to modern composite boards such as medium density fiber boards, “MDF” and oriented strand boards, “OSB”.

A case for modular partitions in healthcare facilities

In healthcare, good acoustic separation between rooms is critical for speech privacy and user comfort. While there are multiple factors that contribute to acoustic separation, this is usually achieved by increasing the acoustical performance of the separating architecture between rooms. This is done by running a wall of a specific Sound Transmission Class (STC) to structure to minimize flanking paths. However, running a modular wall up to or slightly above the ceiling tile can reduce the cost of construction and improve programmatic flexibility. In situations where the wall runs only to the ceiling, the acoustic ceiling tile (ACT) and plenum condition begins to play a large role in the acoustic performance of the separating architecture. Given a high-performing ACT, a high-STC modular wall, and partially open plenum, is there a condition where good speech privacy can be achieved between rooms without running walls to structure? This was examined with a mock-up for EvergreenHealth in Kirkland, WA. The resu...

Comparison of latex body paint with wetted gauze wipes for sampling the chemical warfare agents VX and sulfur mustard from common indoor surfaces

Comparison of solvent-wetted gauze with body paint, a peelable surface sampling media, for the sampling of the chemical warfare agents VX and sulfur mustard from nine surfaces was performed. The nine surfaces sampled are those typical of interior public venues and include smooth, rough, porous, and non-porous surfaces. Overall, solvent-wetted gauze (wipes) performed better for the recovery of VX from non-porous surfaces while body paint (BP) performed better for the porous surfaces. The average percent VX recoveries using wipes and BP, respectively, are: finished wood flooring, 86.2%, 71.4%; escalator handrail, 47.3%, 26.7%; stainless steel, 80.5%, 56.1%; glazed ceramic tile, 81.8%, 44.9%; ceiling tile, 1.77%, 13.1%; painted drywall 7.83%, 21.1%; smooth cement, 0.64%, 10.3%; upholstery fabric, 24.6%, 23.1%; unfinished wood flooring, 9.37%, 13.1%. Solvent-wetted gauze performed better for the recovery of sulfur mustard from three of the relatively non-porous surfaces while body paint performed better for the more porous surfaces. The average percent sulfur mustard recoveries using wipes and BP, respectively, are: finished wood flooring, 30.2%, 2.97%; escalator handrail, 4.40%, 4.09%; stainless steel, 21.2%, 3.30%; glazed ceramic tile, 49.7%, 16.7%; ceiling tile, 0.33%, 11.1%; painted drywall 2.05%, 10.6%; smooth cement, 1.20%, 35.2%; upholstery fabric, 7.63%, 6.03%; unfinished wood flooring, 0.90%, 1.74%.

Low-cost redesign of a music rehearsal space for high school ensembles

This presentation describes the redesign of an existing multi-purpose practice room used by high school concert bands, drumlines, and choral groups. Resource and cost restrictions limited the redesign and evaluation process for surface finishes only. The existing space had minimal early reflections and reverberation due to copious amounts of thick acoustic wall panels, resulting in a dead sound for choral and band use. The biggest challenge was to reposition the wall panels by distributing them in a checkerboard pattern, thereby balancing them with the reflective surfaces of the painted cinderblock underneath. In addition, one third of the absorptive suspended ceiling tile was replaced with 5/8” gypsum panels, and one third of the ceiling tile was removed altogether in order to couple the interstitial space above the suspended ceiling and increase the effective volume of the space. Odeon was used to create auralizations of various configurations by convolving anechoic recordings of a snare drum with the c...

Reverberation mapping using instantaneous intensity estimates from a tetrahedron microphone array

For hearing aids, the directivity index is a benchmark defined under two acoustical conditions that a hearing-aid user won’t encounter, namely, the ratio of sound power signal arriving from the on-axis target in an anechoic condition to the isotropic spherical noise. It would be useful to benchmark the speech signal to noise that is encountered in a typical environment. The purpose of this study is to map the instantaneous acoustic intensity in a room using a head and torso voice simulator as the source and a regular tetrahedron microphone array in the field. Four impulse responses from a small tetrahedron were measured in a reverberant conference room of gypsum walls, carpet, and absorptive ceiling tile. Welch’s method was used to compute one-third octave estimates of the auto- and cross-spectra from the impulse responses, and these spectra were used to estimate the steady-state, 3D instantaneous acoustic intensity vector via the time-averaged active intensity and the maximum amplitude of the reactive intensity. A histogram of the instantaneous intensity vector revealed an angular estimate for the arriving sound power that was, in general, cylindrically rather than spherically “diffuse.”