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Experimental evaluation of potential movement of airborne mold spores out of building envelope cavities using full size wall panels
Published in Paul Fazio, Hua Ge, Jiwu Rao, Guylaine Desmarais, Research in Building Physics and Building Engineering, 2020
J. Rao, G. Miao, D.Q. Yang, K. Bartlett, P. Fazio
Depending on the assembly configuration, either two moldy studs or two clear kiln-dry jack pine studs were installed to form the stud cavity in the assembly. Then, insulation from a newly opened bag was applied to the central stud cavity only and not to the guarded cavities on the sides of the stud cavity. A precut polyethylene sheet was then added over the entire assembly that called for this vapor barrier. The dry-wall, cut to size, was applied and screwed onto the studs with regular drywall screws. Drywall compound was then forced into cracks all along the perimeter of the drywall to achieve an airtight seal. Except for the moldy studs when required, all materials had no visible mold appearance at the time of purchase. Holes and slots were then drilled and cut according to the air leakage pattern and arrangement of the wall assembly described in §2.3. The wall assembly preparation was then complete. It usually was kept standing for one hour or, in a few cases, overnight. The stainless steel sampling chamber was then tightened to the drywall with W-shaped rubber gaskets in between for airtightness.
Mold Investigation and Mitigation
Published in Benjamin Alter, Environmental Consulting Fundamentals, 2019
Some building materials, such as drywall covered with vinyl wallpaper, carpet, or wood paneling, may act as vapor barriers, trapping intrusive moisture underneath their surfaces and thereby providing a moist environment where mold can grow. Therefore, the investigator also should observe “hidden areas” such as crawl spaces, utility tunnels, and the tops of ceiling tiles. Several types of meters are available to aid the inspector in identifying building materials that have experienced water intrusion.
What are architectural building systems?
Published in Samuel L. Hurt, Building Systems in Interior Design, 2017
Beginning in the 1950s, wet plastering was used less and less and “drywall” was used more and more. “Drywall” consists of gypsum board sheets (solid gypsum between outer layers of heavy paper) installed on the framing, and then wet-taping and finishing joints and nail or screw heads. Drywalling is much faster than plastering, but it is also inherently less durable, although this is less of an issue on ceilings than for walls.
Applying a comfort model to building performance analysis
Published in Architectural Science Review, 2020
Mark Luther, Olubukola Tokede, Chunlu Liu
Results indicate that the application of radiant systems in a hot, humid climate is effective in improving comfort. In particular, the idea of cooling interior ceiling, floor and possibly wall surfaces through hydronic systems is explored by others (Tye-Gingras and Louis 2012). The introduction of lightweight capillary hydronic mats (German and Japanese manufacturers) integrated with gypsum drywall construction or tiled and even wooden floors as a possible cooling solution is proposed. Surface temperature levels that are between 24°C and 26°C and well above dew point (2–3°C) indicate promising results for improved comfort in these environments. Furthermore, radiative conditioning, for leaky and poorly insulated houses, offers an improved energy cost–benefit when compared to convective air-conditioning systems.
Application of end-of-shift respirable crystalline silica monitoring to construction
Published in Journal of Occupational and Environmental Hygiene, 2020
Chih-Hsiang Chien, Gan Huang, Benjamin Lopez, Alyssa Morea, Simon Y. Sing, Chang-Yu Wu, Michael L. Kashon, Martin Harper
Hemihydrate calcium sulfate (2CaSO4 H2O) is commonly found in plaster, while calcium sulfate dihydrate (CaSO42H2O) is commonly found in drywall. These chemicals are similar and thus plaster and drywall have similar characteristic IR absorption bands (Hlavay et al. 1978) as shown in Figure 2, at 1,140 − 1,080 cm−1 and 600 − 680 cm−1, resulting from asymmetric SO42- stretching and SO42- bending (symmetric and anti-symmetric), respectively. Cement has a different spectrum than drywall and plaster and, as noted by Derrick et al. (1999), shares the same absorption band resulting from CO32- stretching (1,370–1,490 cm−1) as limestone or chalk (CaCO3). Brick has significant absorption in the range 1,000 − 1,100 cm−1, which can be referred to asymmetric Si-O-Si stretching that is also found in kaolin (Hlavay et al. 1978). Note that brick contains a significant level of quartz and peaks at both 800 and 780 cm−1 were found in our samples. In summary, the target quartz absorption spectrum does not greatly overlap with the construction dust spectra except for brick samples, where quartz is known to be present.
Improving workflow and resource usage in construction schedules through location-based management system (LBMS)
Published in Construction Management and Economics, 2018
Hylton Olivieri, Olli Seppänen, Ariovaldo Denis Granja
Logic is defined at the task level, not between individual locations. There are four different layers of logic for automatically creating links between tasks and locations and a fifth layer links any location to any other location, as in basic CPM logic. The first logic layer copies the same logic to all locations that share two tasks. For example, if there were a finish-to-start relationship between the drywall and plaster tasks, the logic would apply in any apartment where both tasks are done. Therefore, the logic link is handled at the task level, which decreases the number of logic links in a project, even with repetitive tasks.