The Effect of Party Wall Permeability on Estimations of Infiltration from Air Leakage

This study contributes to the development of quantifying and understanding building air tightness as it relates to Toronto semi-detached and row homes, particularly party walls. While infiltration characteristics of single family detached homes have been widely developed and understood, the isolation of semi-detached and row home single family dwelling units is relatively unexplored. When quantifying air leakage in a building attached to an adjacent dwelling unit, air is drawn through the exterior envelope as well as the party wall (i.e. shared common wall). The purpose of the proposed testing method, guarded blower door testing, is to isolate air leakage through the party wall from the envelope. Currently the party wall is considered a fire-rated assembly but is not part of the air barrier system. Issues associated with party wall air leakage include spread of fire, indoor air quality, transfer of tobacco smoke between dwellings, and heat loss through the party to attic detail. Data collected on buildings constructed between 1890 and 1920 (Century buildings) has been compared to the data collected on buildings constructed between 2012 to 2017 (new buildings). Air leakage has been collected on twenty-six of Century semi-detached homes with solid masonry construction and twenty-one new semi-detached/row homes of lightweight wood frame construction. Each unit was tested independently and simultaneously, or “guarded”, with the adjacent unit, to pressure neutralize allowing for quantification of envelope and party wall air leakage. Party wall leakage was found to be similar to leakage through the exterior walls. The leakage accounted for 22% of the total infiltration in Century old buildings and 38% in Modern dwellings.

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Quantifying air leakage through party walls in Toronto semidetached and row-home dwellings

10.32920/ryerson.14657412 ◽

2021 ◽

Author(s):

Austin Todd

Keyword(s):

Air Leakage ◽

Single Family ◽

Masonry Construction ◽

Common Wall ◽

Air Tightness ◽

Wood Frame ◽

Frame Construction ◽

New Buildings ◽

Adjacent Unit ◽

Party Wall

This study contributes to the development of quantifying and understanding building air tightness as it relates to Toronto semi-detached and row homes, particularly party walls. While infiltration characteristics of single family detached homes have been widely developed and understood, the isolation of semi-detached and row home single family dwelling units is relatively unexplored. When quantifying air leakage in a building attached to an adjacent dwelling unit, air is drawn through the exterior envelope as well as the party wall (i.e. shared common wall). The purpose of the proposed testing method, guarded blower door testing, is to isolate air leakage through the party wall from the envelope. Currently the party wall is considered a fire-rated assembly but is not part of the air barrier system. Issues associated with party wall air leakage include spread of fire, indoor air quality, transfer of tobacco smoke between dwellings, and heat loss through the party to attic detail. Data collected on buildings constructed between 1890 and 1920 (Century buildings) has been compared to the data collected on buildings constructed between 2012 to 2017 (new buildings). Air leakage has been collected on twenty-six of Century semi-detached homes with solid masonry construction and twenty-one new semi-detached/row homes of lightweight wood frame construction. Each unit was tested independently and simultaneously, or “guarded”, with the adjacent unit, to pressure neutralize allowing for quantification of envelope and party wall air leakage. Party wall leakage was found to be similar to leakage through the exterior walls. The leakage accounted for 22% of the total infiltration in Century old buildings and 38% in Modern dwellings.

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Sensitivity Analysis of the XR-3 Heave Equations to Changes in Plenum Air Leakage and Influx Rates

10.21236/ada522400 ◽

1978 ◽

Author(s):

Jr. Gerba ◽

Thaler Alex ◽

George J.

Keyword(s):

Sensitivity Analysis ◽

Air Leakage

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Molecular simulation of gases competitive adsorption in lignite and analysis of original CO desorption

Scientific Reports ◽

10.1038/s41598-021-91197-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jing Zhang ◽

Jiren Wang ◽

Chunhua Zhang ◽

Zongxiang Li ◽

Jinchao Zhu ◽

...

Keyword(s):

Adsorption Capacity ◽

Molecular Simulation ◽

Competitive Adsorption ◽

Air Leakage ◽

Adsorption Characteristics ◽

Adsorption Sites ◽

Simulation Based ◽

Lignite Coal ◽

Model C ◽

Grand Canonical

AbstractTo study the adsorption characteristics of CO, CO2, N2, O2, and their binary-components in lignite coal, reveal the influence of CO2 or N2 injection and air leakage on the desorption of CO in goafs, a lignite model (C206H206N2O44) was established, and the supercell structure was optimized under temperatures of 288.15–318.15 K for molecular simulation. Based on molecular dynamics, the Grand Canonical Monte Carlo method was used to simulate the adsorption characteristics and the Langmuir equation was used to fit the adsorption isotherms of gases. The results show that for single-components, the order of adsorption capacity is CO2 > CO > O2 > N2. For binary-components, the competitive adsorption capacities of CO2 and CO are approximate. In the low-pressure zone, the competitive adsorption capacity of CO2 is stronger than that of CO, and the CO is stronger than N2 or O2. From the simulation, it can be seen that CO2, N2 or O2 will occupy adsorption sites, causing CO desorption. Therefore, to prevent the desorption of the original CO in the goaf, it is not suitable to use CO2 or N2 injection for fire prevention, and the air leakage at the working faces need to be controlled.

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Size selection of the Ambu AuraOnce laryngeal mask in Chinese men weighing >70 kg: a pilot study

Journal of International Medical Research ◽

10.1177/03000605211016689 ◽

2021 ◽

Vol 49 (5) ◽

pp. 030006052110166

Author(s):

Jiahui Chen ◽

Chunhuan Chen ◽

Wei Xu ◽

Xiaoguang Zhang

Keyword(s):

Computed Tomography ◽

Success Rate ◽

Fiberoptic Bronchoscopy ◽

Laryngeal Mask ◽

Insertion Time ◽

Air Leakage ◽

Chinese Men ◽

Laryngeal Mask Insertion ◽

Laryngeal Anatomy ◽

Rate Requirement

Objective To collect computed tomography data of the laryngeal anatomy of Chinese men and to determine the feasibility of using the size 4 Ambu AuraOnce laryngeal mask (Ambu A/S, Copenhagen, Denmark) in Chinese men weighing >70 kg. Methods This prospective study involved men who underwent surgery from May 2018 to January 2019 at Jinshan Hospital. Pharyngeal and laryngeal parameters were measured by computed tomography. The laryngeal mask insertion success rate, requirement for tracheal tube insertion, laryngeal mask insertion time, fiberoptic bronchoscopy grading, air leakage pressure, and pharyngeal complications were analyzed. Results In a comparison of the size 4 and 5 Ambu AuraOnce devices, the first insertion success rate was 100% and 87% and the three-times insertion success rate was 100% and 93%, respectively, with no significant differences. However, the insertion time was significantly different at 19.6 ± 5.9 versus 31.1 ± 11.2 s, respectively, and the proportions of fiberoptic grading levels were also significantly different. There were no significant differences in the air leakage pressure or pharyngeal complications. Conclusion The size 4 Ambu AuraOnce is more adequate than the size 5 for Chinese men weighing >70 kg, with a shorter insertion time and higher fiberoptic bronchoscopic grading.

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Cell Wall Permeability of Pinto Bean Cotyledon Cells Regulates In Vitro Fecal Fermentation and Gut Microbiota

Food & Function ◽

10.1039/d1fo00488c ◽

2021 ◽

Author(s):

Yanrong Huang ◽

Sushil Dhital ◽

Feitong Liu ◽

Xiong Fu ◽

Qiang Huang ◽

...

Keyword(s):

Cell Wall ◽

Structural Changes ◽

Microbiota Composition ◽

Colonic Fermentation ◽

Pinto Bean ◽

Wall Permeability ◽

Cell Wall Permeability ◽

Cotyledon Cells ◽

Whole Foods

Processing induced structural changes of whole foods on regulation of colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from...

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Study of couple stresses and wall permeability effects on the flow in permeable membranes

Chinese Journal of Physics ◽

10.1016/j.cjph.2020.12.011 ◽

2021 ◽

Vol 69 ◽

pp. 271-284

Author(s):

Muhammad Kahshan ◽

Dianchen Lu ◽

A. Khan ◽

Naeem Faraz

Keyword(s):

Couple Stresses ◽

Wall Permeability

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Must attic ventilation be preserved in energy retrofits?

International Journal of Building Pathology and Adaptation ◽

10.1108/ijbpa-08-2018-0072 ◽

2019 ◽

Vol 37 (4) ◽

pp. 461-472

Author(s):

William Rose

Keyword(s):

Vapor Pressure ◽

Energy Efficient ◽

Design Methodology ◽

Air Leakage ◽

Content Type ◽

Buoyancy Flow ◽

Spreadsheet Model ◽

Radiation Exchange ◽

Moisture Performance ◽

Ashrae Standards

Purpose The addition of thermal insulation into attics along with air-tightening of the ceiling plane is a common first step in making homes more energy efficient. Attic ventilation was introduced decades ago on the assumption that air leakage across the ceiling was inevitable and not correctible – this was before the era of spray-applied foams. Often attic ventilation is provided at roof eaves, and ensuring good insulation in their location is critical to avoid cold corners in the rooms below. So may vents be blocked in the course of energy retrofits? The paper aims to discuss this issue. Design/methodology/approach This study consists of a simple spreadsheet model of attic performance. The model is built using material from ASHRAE Handbook Fundamentals and ASHRAE Standards. It includes: Glaser calculations for temperature, vapor pressure and vapor pressure excess; radiation exchange – solar and sky; buoyancy flow assumption for leakage from indoors; wind flow assumption for leakage from outdoors; and change in attic air RH as assumed indicator of change in sheathing moisture performance. Findings The model results show that lowered moisture contributions across air-tightened ceilings may compensate effectively for added insulation (which lowers the attic air temperature) and reduced moisture dilution from attic ventilation. Originality/value These results provide support for the policy of allowing attic ventilation reductions that are proportionate to ceiling air leakage reductions as part of weatherization efforts. Given the limitations of the model, continued field observations remain critical.

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