Development of moisture reference years for assessing long-term mould growth risk of wood-frame building envelopes

Abstract A moisture reference year (MRY) is generally used to assess the durability, or long-term performance of building envelopes within a long climatological time period, e.g. a 31 year timeframe. The intent of this paper is to develop a set of moisture reference years that can be used to assess risk to the formation of mould growth in wood-frame buildings over the long-term. The set of moisture reference years have been developed based on 15 realizations of 31-year climate data. Replicated Latin Hypercube Sampling is applied to select 15 sub-realizations with 7 representative years having different levels of moisture index (MI) from each realization. Thereafter, hygrothermal simulations are performed for a brick veneer clad wood-frame wall assembly using the 15 sub-realizations; that sub-realization which produces the highest value of maximum mould growth index over 7-year period is selected as the MRY. The selection process is then implemented for all 15 realizations of the 31-years of data sets, from which 15 sets of 7-year long MRYs are selected to represent the original 15 realizations. It is shown that the 15 sets of 7-year long MRYs can produce the same value of maximum mould growth index as well as the uncertainty as compared to the original 15 realizations having a 31-year climate data set.

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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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Intention, Principle, Outputs and Aims of the Experimental Pavilion Research of Building Envelopes Including Windows for Wooden Buildings

Civil and Environmental Engineering ◽

10.1515/cee-2017-0005 ◽

2017 ◽

Vol 13 (1) ◽

pp. 42-51 ◽

Cited By ~ 3

Author(s):

Daniela Štaffenová ◽

Ján Rybárik ◽

Miroslav Jakubčík

Keyword(s):

Experimental Research ◽

Climatic Conditions ◽

Point Of View ◽

Physical Parameters ◽

Data Sets ◽

Data Set ◽

Building Envelopes ◽

Climate Conditions ◽

Time Period

AbstractThe aim of experimental research in the area of exterior walls and windows suitable for wooden buildings was to build special pavilion laboratories. These laboratories are ideally isolated from the surrounding environment, airtight and controlled by the constant internal climate. The principle of experimental research is measuring and recording of required physical parameters (e.g. temperature or relative humidity). This is done in layers of experimental fragment sections in the direction from exterior to interior, as well as in critical places by stable interior and real exterior climatic conditions. The outputs are evaluations of experimental structures behaviour during the specified time period, possibly during the whole year by stable interior and real exterior boundary conditions. The main aim of this experimental research is processing of long-term measurements of experimental structures and the subsequent analysis. The next part of the research consists of collecting measurements obtained with assistance of the experimental detached weather station, analysis, evaluation for later setting up of reference data set for the research locality, from the point of view of its comparison to the data sets from Slovak Hydrometeorological Institute (SHMU) and to localities with similar climate conditions. Later on, the data sets could lead to recommendations for design of wooden buildings.

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Constructing a long-term monthly climate data set in central Asia

International Journal of Climatology ◽

10.1002/joc.5259 ◽

2017 ◽

Vol 38 (3) ◽

pp. 1463-1475 ◽

Cited By ~ 4

Author(s):

Hang Zhou ◽

Elena Aizen ◽

Vladimir Aizen

Keyword(s):

Central Asia ◽

Climate Data ◽

Data Set

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How long do satellites need to overlap? Evaluation of climate data stability from overlapping satellite records

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-15069-2017 ◽

2017 ◽

Vol 17 (24) ◽

pp. 15069-15093 ◽

Cited By ~ 6

Author(s):

Elizabeth C. Weatherhead ◽

Jerald Harder ◽

Eduardo A. Araujo-Pradere ◽

Greg Bodeker ◽

Jason M. English ◽

...

Keyword(s):

Solar Radiation ◽

Spectral Irradiance ◽

Data Sets ◽

Climate Data ◽

Data Set ◽

Long Term Stability ◽

Earth Observations ◽

Earth’S Climate ◽

The Stability

Abstract. Sensors on satellites provide unprecedented understanding of the Earth's climate system by measuring incoming solar radiation, as well as both passive and active observations of the entire Earth with outstanding spatial and temporal coverage. A common challenge with satellite observations is to quantify their ability to provide well-calibrated, long-term, stable records of the parameters they measure. Ground-based intercomparisons offer some insight, while reference observations and internal calibrations give further assistance for understanding long-term stability. A valuable tool for evaluating and developing long-term records from satellites is the examination of data from overlapping satellite missions. This paper addresses how the length of overlap affects the ability to identify an offset or a drift in the overlap of data between two sensors. Ozone and temperature data sets are used as examples showing that overlap data can differ by latitude and can change over time. New results are presented for the general case of sensor overlap by using Solar Radiation and Climate Experiment (SORCE) Spectral Irradiance Monitor (SIM) and Solar Stellar Irradiance Comparison Experiment (SOLSTICE) solar irradiance data as an example. To achieve a 1 % uncertainty in estimating the offset for these two instruments' measurement of the Mg II core (280 nm) requires approximately 5 months of overlap. For relative drift to be identified within 0.1 % yr−1 uncertainty (0.00008 W m−2 nm−1 yr−1), the overlap for these two satellites would need to be 2.5 years. Additional overlap of satellite measurements is needed if, as is the case for solar monitoring, unexpected jumps occur adding uncertainty to both offsets and drifts; the additional length of time needed to account for a single jump in the overlap data may be as large as 50 % of the original overlap period in order to achieve the same desired confidence in the stability of the merged data set. Results presented here are directly applicable to satellite Earth observations. Approaches for Earth observations offer additional challenges due to the complexity of the observations, but Earth observations may also benefit from ancillary observations taken from ground-based and in situ sources. Difficult choices need to be made when monitoring approaches are considered; we outline some attempts at optimizing networks based on economic principles. The careful evaluation of monitoring overlap is important to the appropriate application of observational resources and to the usefulness of current and future observations.

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Twentieth-century variations in temperature and precipitation in the Nordic Arctic

Polar Record ◽

10.1017/s0032247400017721 ◽

2002 ◽

Vol 38 (206) ◽

pp. 203-210 ◽

Cited By ~ 20

Author(s):

E. J. Førland ◽

I. Hanssen-Bauer ◽

T. Jónsson ◽

C. Kern-Hansen ◽

P.Ø. Nordli ◽

...

Keyword(s):

Twentieth Century ◽

Temperature Trend ◽

Annual Precipitation ◽

Data Series ◽

Positive Trend ◽

Positive Temperature ◽

Climate Data ◽

Data Set ◽

Temperature And Precipitation

AbstractIn a joint Nordic effort, a high-quality climate data set for the Nordic Arctic is established. The data set consists of monthly values from 20 stations in Greenland, Iceland, the Faeroes, and the Norwegian Arctic. The data set is made available on the web. Ten climate elements are included, and most of the series covers the period 1890–2000. The data series illustrate the large climatic contrasts in the Nordic Arctic, and demonstrate that parts of the region have experienced substantial climate variations during the last century. Despite increasing temperatures during recent decades, the present temperature level is still lower than in the 1930s and 1950s in large parts of the region. The pattern of long-term precipitation variations is more complicated, but in parts of the region the annual precipitation has increased substantially. At Svalbard Airport and Bjørnøya the annual precipitation has increased by more than 2.5% per decade during the twentieth century.Variations in atmospheric circulation can account for most of the long-term positive trend in precipitation in the Norwegian Arctic, and also for the positive temperature trend from the 1960s. The positive temperature trend before 1930 and the negative trend during the following decades, are, however, not accounted for by the circulation models.

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Application of Support Vector Regression to the Prediction of the Long-Term Impacts of Climate Change on the Moisture Performance of Wood Frame and Massive Timber Walls

Buildings ◽

10.3390/buildings11050188 ◽

2021 ◽

Vol 11 (5) ◽

pp. 188

Author(s):

Naman Bansal ◽

Maurice Defo ◽

Michael A. Lacasse

Keyword(s):

Relative Humidity ◽

Full Range ◽

Support Vector ◽

Data Series ◽

Climate Variables ◽

Climate Data ◽

Moisture Performance ◽

Wood Frame ◽

Massive Timber

The objective of this study was to explore the potential of a machine learning algorithm, the Support Vector Machine Regression (SVR), to forecast long-term hygrothermal responses and the moisture performance of light wood frame and massive timber walls. Hygrothermal simulations were performed using a 31-year long series of climate data in three cities across Canada. Then, the first 5 years of the series were used in each case to train the model, which was then used to forecast the hygrothermal responses (temperature and relative humidity) and moisture performance indicator (mold growth index) for the remaining years of the series. The location of interest was the exterior layer of the OSB and cross-laminated timber in the case of the wood frame wall and massive timber wall, respectively. A sliding window approach was used to incorporate the dependence of the hygrothermal response on the past climatic conditions, which allowed SVR to capture time, implicitly. The variable selection was performed using the Least Absolute Shrinkage and Selection Operator, which revealed wind-driven rain, relative humidity, temperature, and direct radiation as the most contributing climate variables. The results show that SVR can be effectively used to forecast hygrothermal responses and moisture performance on a long climate data series for most of the cases studied. In some cases, discrepancies were observed due to the lack of capturing the full range of variability of climate variables during the first 5 years.

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Effects of climate change on the moisture performance and durability of brick veneer walls of wood frame construction in Canada

Journal of Physics Conference Series ◽

10.1088/1742-6596/2069/1/012063 ◽

2021 ◽

Vol 2069 (1) ◽

pp. 012063

Author(s):

M Defo ◽

M A Lacasse ◽

L Wang

Keyword(s):

Climate Change ◽

Growth Index ◽

Annual Rainfall ◽

Mold Growth ◽

Climate Data ◽

Minimum Requirements ◽

Moisture Performance ◽

Brick Veneer ◽

Wood Frame ◽

Frame Construction

Abstract The objective of this study was to assess the potential effects of climate change on the moisture performance and durability of red matt clay brick veneer walls of wood frame construction on the basis of results derived from hygrothermal simulations. One-dimensional simulations were run using DELPHIN 5.9 for selected moisture reference years of the 15 realizations of modelled historical (H: 1986-2016) and future (F: 2062-2092) climate data of 12 Canadian cities. The mold growth index at the outer layer of the OSB sheathing panel was used to compare the moisture performance under H and F periods. Results for the base design that meet the minimum requirements of the National Building Code of Canada showed that cities within the interior of the country, characterized by a low annual rainfall, are less likely to develop significant mold growth under H and F periods, whereas cities in coastal areas, characterized by high annual rainfall, present a heightened risk to mold growth under both H and F periods. For cities located on the west coast, a possible solution could be to use a 38-mm ventilated drainage cavity as this measure would help dissipate moisture from within the cavity. On the east coast, apart from using a 38-mm ventilated drainage cavity, other measures aiming at reducing the wind-driven rain deposition (i.e., increasing overhang ratio or the height of the roof) could be introduced. However, the feasibility of such measures needs to be considered in respect to whether these are to be implemented as part of a new building or retrofit of an existing one.

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Exterior Wood-Frame Walls—Wind–Vapour Barrier Ratio in Denmark

Buildings ◽

10.3390/buildings11100428 ◽

2021 ◽

Vol 11 (10) ◽

pp. 428

Author(s):

Martin Morelli ◽

Torben Valdbjørn Rasmussen ◽

Marcus Therkelsen

Keyword(s):

Building Materials ◽

Frame Structure ◽

Diffusion Resistance ◽

Mould Growth ◽

Climate Data ◽

Safe Side ◽

Air Tightness ◽

Wood Frame ◽

And Diffusion ◽

Exterior Wood

Wood-frame walls in cold climates are traditional constructed with a vapour barrier that also constitutes the air-tightness layer. Polyethylene foil as a vapour barrier is likely used; however, other building materials can be used to obtain correspondingly sufficient properties. 1D hygrothermal simulations were conducted for a wood-frame structure to investigate the wind–vapour barrier ratio, and if the vapour barrier of polyethylene foil could be omitted and replaced by other materials. The results were postprocessed using the VTT mould model. The results showed how wood-frame walls can be designed with respect to internal humidity class and diffusion resistance divided into three categories: no risk for mould growth, needs further investigation, and is not performing well as the risk for mould growth is present. For internal humidity classes 1–3, the ratio between wind and vapour barrier must be about 1:5, and 1:10 for classes 4 and 5 to be on the safe side. Simulations were performed for the climate of Lund, Sweden, which were used to simulate climate in Denmark too. Nevertheless, the results are related to climate data and, thus, the location.

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A long-term Northern Hemisphere snow cover extent data record for climate studies and monitoring

Earth System Science Data ◽

10.5194/essd-7-137-2015 ◽

2015 ◽

Vol 7 (1) ◽

pp. 137-142 ◽

Cited By ~ 107

Author(s):

T. W. Estilow ◽

A. H. Young ◽

D. A. Robinson

Keyword(s):

Snow Cover ◽

Northern Hemisphere ◽

Environmental Data ◽

Climate Data ◽

Data Set ◽

Snow Cover Extent ◽

Data Record ◽

Climate Data Record ◽

Climate Studies

Abstract. This paper describes the long-term, satellite-based visible snow cover extent National Oceanic and Atmospheric Administration (NOAA) climate data record (CDR) currently available for climate studies, monitoring, and model validation. This environmental data product is developed from weekly Northern Hemisphere snow cover extent data that have been digitized from snow cover maps onto a Cartesian grid draped over a polar stereographic projection. The data have a spatial resolution of 190.6 km at 60° latitude, are updated monthly, and span the period from 4 October 1966 to the present. The data comprise the longest satellite-based CDR of any environmental variable. Access to the data is provided in Network Common Data Form (netCDF) and archived by NOAA's National Climatic Data Center (NCDC) under the satellite Climate Data Record Program (doi:10.7289/V5N014G9). The basic characteristics, history, and evolution of the data set are presented herein. In general, the CDR provides similar spatial and temporal variability to its widely used predecessor product. Key refinements included in the CDR improve the product's grid accuracy and documentation and bring metadata into compliance with current standards for climate data records.

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A long-term record of blended satellite and in situ sea-surface temperature for climate monitoring, modeling and environmental studies

Earth System Science Data ◽

10.5194/essd-8-165-2016 ◽

2016 ◽

Vol 8 (1) ◽

pp. 165-176 ◽

Cited By ~ 184

Author(s):

Viva Banzon ◽

Thomas M. Smith ◽

Toshio Mike Chin ◽

Chunying Liu ◽

William Hankins

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Large Scale ◽

Sea Surface ◽

Climate Data ◽

Data Set ◽

Volcanic Aerosols ◽

Climate Data Record

Abstract. This paper describes a blended sea-surface temperature (SST) data set that is part of the National Oceanic and Atmospheric Administration (NOAA) Climate Data Record (CDR) program product suite. Using optimum interpolation (OI), in situ and satellite observations are combined on a daily and 0.25° spatial grid to form an SST analysis, i.e., a spatially complete field. A large-scale bias adjustment of the input infrared SSTs is made using buoy and ship observations as a reference. This is particularly important for the time periods when volcanic aerosols from the El Chichón and Mt. Pinatubo eruptions are widespread globally. The main source of SSTs is the Advanced Very High Resolution Radiometer (AVHRR), available from late 1981 to the present, which is also the temporal span of this CDR. The input and processing choices made to ensure a consistent data set that meets the CDR requirements are summarized. A brief history and an explanation of the forward production schedule for the preliminary and science-quality final product are also provided. The data set is produced and archived at the newly formed National Centers for Environmental Information (NCEI) in Network Common Data Form (netCDF) at doi:10.7289/V5SQ8XB5.

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