Sensitivity analysis of hygrothermal performance of wood framed wall assembly under different climatic conditions: the impact of cladding properties

Abstract One of the parameters that influences the moisture performance of the wood framed wall assembly is the material properties of exterior cladding. The uncertainties of its properties, would result in a range of wall performance. The objective of this study was to investigate the impact of uncertainties in cladding material properties on moisture performance of wood framed wall assembly under different climatic conditions. A wood framed (2×6 wood stud) wall with exterior brick cladding was simulated assuming 1% rain leakage deposited on the exterior side of sheathing membrane. A parametric study was carried out to analyze the impact of the cladding properties on the moisture response of OSB. The simulations were conducted in five different cities located in different climate zones across Canada. The aim was to identify the most influential cladding property on the moisture response of OSB, i.e., mould growth index and moisture content, to the varying cladding properties under different climatic conditions i.e., different cities under historical and future conditions. In general, it was found that liquid diffusivity is the parameter that has the most influence on moisture response of OSB in all the five cities. Also, the significance of this influence varies depending on the climatic conditions.

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A comparison of hygrothermal simulation results derived from four simulation tools

Journal of Building Physics ◽

10.1177/1744259120988760 ◽

2021 ◽

pp. 174425912098876

Author(s):

Maurice Defo ◽

Michael Lacasse ◽

Abdelaziz Laouadi

Keyword(s):

Relative Humidity ◽

Outer Layer ◽

Growth Index ◽

Mould Growth ◽

Simulation Tools ◽

Assembly Design ◽

Hygrothermal Simulation ◽

Moisture Performance ◽

Wood Frame ◽

Wall Assembly

The objective of this work was to compare the hygrothermal responses and the moisture performance of four wood-frame walls as predicted by four hygrothermal (HAM) simulation tools, namely: DELPHIN, WUFI, hygIRC and COMSOL. The four wall systems differ only in their cladding type; these were fibreboard, vinyl, stucco and brick. Three Canadian cities having different climates were selected for simulations: Ottawa, Ontario; Vancouver, British Columbia and Calgary, Alberta. In each city, simulations were run for 2 years. Temperature and relative humidity of the outer layer of OSB sheathing were compared amongst the four simulation tools. The mould growth index on the outer layer of the OSB sheathing was used to compare the moisture performance predicted by the respective hygrothermal simulation tools. Temperature profiles of the outer layer of the OSB sheathing were all in good agreement for the four HAM tools in the three locations. For relative humidity, the highest discrepancies amongst the four tools were found with stucco cladding where differences as high as 20% could be found from time to time. Mould growth indices predicted by the four HAM tools were similar in some cases but different in other cases. The discrepancies amongst the different HAM tools were likely related to: the material property processing, how the quantity of wind-driven rain absorbed at the cladding surface is computed and some implementation details. Despite these discrepancies, The tools generally yielded consistent results and could be used for comparing the impacts of different designs on the risk of premature deterioration, as well as for evaluating the relative effects of climate change on a given wall assembly design.

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Experimental investigations of wooden beam ends in masonry with interior insulation: Measured data in real-scale experimental walls exposed to semi-continental climatic conditions

Journal of Building Physics ◽

10.1177/1744259119867461 ◽

2019 ◽

Vol 43 (3) ◽

pp. 147-170 ◽

Cited By ~ 4

Author(s):

Pavel Kopecký ◽

Kamil Staněk ◽

Michal Bureš ◽

Jan Richter ◽

Pavla Ryparová ◽

...

Keyword(s):

Relative Humidity ◽

Growth Index ◽

Climatic Conditions ◽

Experimental Investigations ◽

Rain Event ◽

Insulation Material ◽

Mold Growth ◽

Single Beam ◽

Hygrothermal Performance ◽

Real Scale

This article deals with the hygrothermal performance of wooden beam ends embedded in brick masonry walls. The real-scale experiment involving three interior insulation systems with different water vapor resistances and different treatments of joist pockets was monitored for three consecutive years. The moisture load of test walls was controlled during the experiment. First, humidity of indoor air was increased in the cold season (2016–2017). Then, an artificial short-time intensive rain event brought liquid water onto the external surface of the test walls in July 2017. Despite relatively mild external climatic loads, relative humidity was unsatisfactorily high in unsealed joist pockets. Vapor and airtight sealing of the joist pockets improved the microclimate of the wooden beam ends. However, even in this case, relative humidity approached critical values for the onset of mold growth. The artificial rain load applied on the experimental walls noticeably worsened the hygrothermal conditions in the joist pockets. Relative humidity in the joist pockets further increased to a level where massive mold growth could be expected. Visual inspection of the wooden beam ends during reconstruction of the experiment, however, revealed only a small spot of mold on a single beam located in an unsealed joist pocket. Mold growth on samples of organic thermal insulation material was found by microscopic investigations. Molds were localized in small separated colonies. These in situ and laboratory investigations do not confirm the calculated values of mold growth index. In conclusion, sealing of wooden beam ends improved their hygrothermal performance in the experiment.

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Effects of Climate Change on the Moisture Performance of Tallwood Building Envelope

Buildings ◽

10.3390/buildings11020035 ◽

2021 ◽

Vol 11 (2) ◽

pp. 35

Author(s):

Maurice Defo ◽

Michael A. Lacasse

Keyword(s):

Climate Change ◽

Growth Index ◽

Building Envelope ◽

Historical Period ◽

Mold Growth ◽

Water Penetration ◽

Moisture Performance ◽

Wall Assembly ◽

Mass Timber ◽

Relative Change

The objective of this study was to assess the potential effects of climate change on the moisture performance and durability of massive timber walls on the basis of results derived from hygrothermal simulations. One-dimensional simulations were run using DELPHIN 5.9.4 for 31 consecutive years of the 15 realizations of the modeled historical (1986–2016) and future (2062–2092) climates of five cities located across Canada. For all cities, water penetration in the wall assembly was assumed to be 1% wind-driven rain, and the air changes per hour in the drainage cavity was assumed to be 10. The mold growth index on the outer layer of the cross-laminated timber panel was used to compare the moisture performance for the historical and future periods. The simulation results showed that the risk of mold growth would increase in all the cities considered. However, the relative change varied from city to city. In the cities of Ottawa, Calgary and Winnipeg, the relative change in the mold growth index was higher than in the cities of Vancouver and St. John’s. For Vancouver and St. John’s, and under the assumptions used for these simulations, the risk was already higher under the historical period. This means that the mass timber walls in these two cities could not withstand a water penetration rate of 1% wind-driven rain, as used in the simulations, with a drainage cavity of 19 mm and an air changes per hour value of 10. Additional wall designs will be explored in respect to the moisture performance, and the results of these studies will be reported in a future publication.

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Effect of rain leakage on hygrothermal performance of highly insulated wood-framed walls: a stochastic approach

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2019-0223 ◽

2019 ◽

Vol 46 (11) ◽

pp. 979-989 ◽

Cited By ~ 1

Author(s):

Lin Wang ◽

Hua Ge

Keyword(s):

Significant Risk ◽

Stochastic Modelling ◽

Stochastic Approach ◽

Moisture Damage ◽

Hygrothermal Performance ◽

Rain Infiltration ◽

Wall Assembly ◽

The Impact ◽

Damage Risk ◽

Wall Components

Wind-driven rain is one of the most important moisture sources that may lead to moisture damage risks of building envelopes, particularly when the rainwater unintentionally infiltrates into the envelope assembly through defects of the wall components. This paper proposes a stochastic modelling approach to evaluate the impact of rain infiltration on hygrothermal performance of highly insulated wood-framed walls, including an I-joist deep cavity wall, two exterior insulated walls, and a conventional 2×6 stud wall as the baseline wall. The stochastic hygrothermal models of the walls are created based on the uncertainties of material properties and rain deposition factor under different scenarios with rain infiltration deposited at different locations of the wall assembly. The stochastic simulation results show that the rainwater deposited on a water resistive barrier does not cause any moisture damage risk, but there is a significant risk when the rainwater is directly deposited on the exterior or interior surface of wood sheathing, and the interior deposition has the highest risk.

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Impact of roof shading on building energy performance in warm & humid climatic places of India

iCRBE Procedia ◽

10.32438/icrbe.202037 ◽

2020 ◽

pp. 50-64

Author(s):

Kuladeep Kumar Sadevi ◽

Avlokita Agrawal

Keyword(s):

Energy Consumption ◽

Energy Conservation ◽

Energy Performance ◽

General Assumption ◽

Climatic Conditions ◽

Building Envelope ◽

Passive Cooling ◽

Base Case ◽

U Value ◽

The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

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A Predictive Model of the Impact of the Skidding System on Forest Soil in Severe Climatic Conditions

Lesnoy Zhurnal (Forestry Journal) ◽

10.37482/0536-1036-2020-5-131-144 ◽

2020 ◽

pp. 131-144

Author(s):

S.E. Rudov ◽

◽

V.Ya. Shapiro ◽

O.I. Grigoreva ◽

I.V. Grigorev ◽

...

Keyword(s):

Forest Soil ◽

Warm Season ◽

Climatic Conditions ◽

Soil Freezing ◽

Class Iii ◽

Freezing And Thawing ◽

Metal Structures ◽

Rapid Adjustment ◽

Soil Freezing And Thawing ◽

The Impact

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

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Conventional and Organic Honeys as a Source of Water- and Ethanol Soluble Molecules with Nutritional and Antioxidant Characteristics

Molecules ◽

10.3390/molecules26123746 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3746

Author(s):

Magdalena Polak-Śliwińska ◽

Małgorzata Tańska

Keyword(s):

Antioxidant Activity ◽

Immune System ◽

Vitamin C ◽

Geographical Area ◽

Production Method ◽

Climatic Conditions ◽

Organic Production ◽

Organoleptic Characteristics ◽

Nutritional Characteristics ◽

The Impact

The benefits of natural honeybee products (e.g., honey, royal jelly, beeswax, propolis, beevenom and pollen) to the immune system are remarkable, and many of them are involved in the induction of antibody production, maturation of immune cells and stimulation of the immune system. The type of plants in the geographical area, climatic conditions and production method have a significantly influence on the nutritional quality of honey. However, this variability can influence consumer liking by the sensory attributes of the product. The aim of this work was to compare the most popular honeys from Poland in terms of nutritional value, organoleptic properties and antioxidant activity. In the study, five varieties of honey (honeydew, forest, buckwheat, linden and dandelion) from conventional and organic production methods were tested. The nutritional characteristics of honey samples included acidity, content of water, sugars, vitamin C, HMF and phenolics (total and flavonoids), while honey color, taste, aroma and consistency were investigated in the organoleptic characteristics. The antioxidant activity was determined in water- and ethanol-soluble honey extracts using DPPH and ORAC tests. The results showed that organoleptic and nutritional characteristics of popular Polish honeys differ significantly in relation to plant source and production method. The significant effect of honey variety on the content of HMF, saccharose and phenolics, as well as acidity and antioxidant capacity were noted. The impact of variety and variety × production method interaction was significant in the case of the content of vitamin C, glucose and fructose. A visible difference of buckwheat and forest honeys from other samples was observed. The highest content of total phenolics with antioxidant activity based on the SET mechanism was found in buckwheat honeys, while forest honeys were richer in flavonoids.

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Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

Sustainability ◽

10.3390/su13084139 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4139

Author(s):

Muriel Diaz ◽

Mario Cools ◽

Maureen Trebilcock ◽

Beatriz Piderit-Moreno ◽

Shady Attia

Keyword(s):

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Primary Schools ◽

Co2 Concentration ◽

Building Design ◽

Climatic Conditions ◽

Indoor Environmental Quality ◽

Co2 Concentrations ◽

The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

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Impact of climatic conditions on the parameters of failure flow of military vehicles

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211020228 ◽

2021 ◽

pp. 095440702110202

Author(s):

Nikolaj Dobrzinskij ◽

Algimantas Fedaravicius ◽

Kestutis Pilkauskas ◽

Egidijus Slizys

Keyword(s):

Climatic Factors ◽

Armed Forces ◽

Climatic Conditions ◽

Operating Conditions ◽

Technical Equipment ◽

Factors Affecting ◽

Military Vehicles ◽

Equipment Reliability ◽

Number Of Factors ◽

The Impact

Relevance of the article is based on participation of armed forces in various operations and exercises, where reliability of machinery is one of the most important factors. Transportation of soldiers as well as completion of variety of tasks is ensured by properly functioning technical equipment. Reliability of military vehicles – armoured SISU E13TP Finnish built and HMMWV M1025 USA built were selected as the object of the article. Impact of climatic conditions on reliability of the vehicles exploited in southwestern part of the Atlantic continental forest area is researched by a case study of the vehicles exploitation under conditions of the climate of Lithuania. Reliability of military vehicles depends on a number of factors such as properties of the vehicles and external conditions of their operation. Their systems and mechanisms are influenced by a number of factors that cause different failures. Climatic conditions represent one of the factors of operating load which is directly dependent on the climate zone. Therefore, assessment of the reliability is started with the analysis of climatic factors affecting operating conditions of the vehicles. Relationship between the impact of climatic factors and failure flow of the vehicles is presented and discussed.

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