scholarly journals Hygrothermal conditions in Cross Laminated Timber (CLT) dwellings

2020 ◽  
Vol 172 ◽  
pp. 10009
Author(s):  
Merethe Solvang Tingstveit ◽  
Henrik Kofoed Nielsen ◽  
Birgit Risholt
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Indoor Air ◽  
Small Variation ◽  
Well Being ◽  
Indoor Climate ◽  
Apartment Building ◽  
Wood Moisture ◽  
One Year ◽  
House Standard

The use of CLT has been increasing the last decade, and a subsequently focus on documentation of the accompanying indoor climate and exposed wooden surfaces on human well-being. This study presents the results of a measurement campaign conducted over one year of a CLT apartment building in Grimstad, Norway. The apartment building consists of three floors with 35 apartments and comply with the Norwegian passive house standard and energy grade A. Measurements of the relative humidity (RH), indoor air temperature and wood moisture content (MC) were performed in the exposed CLT spruce panels in three apartments in two different floors. The results from the three apartments show a relatively small variation in the MC values regardless the residents behavior measured as RH variation through a complete year. Selected periods from a cold period (winter) and a warm period (summer) show the variation in relative humidity (RH) and moisture content in the CLT element. However, results from control measurements showed higher MC values. The gap between the measurements and methods are discussed.

scholarly journals Quality of life control by selected methods of air exchange in a typical apartment building

2021 ◽  
Author(s):  
Iveta Bullová ◽  
Peter Kapalo ◽  
Dušan Katunský
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Allergic Diseases ◽  
Well Being ◽  
Indoor Climate ◽  
Apartment Building ◽  
Change Rate ◽  
Air Change Rate ◽  
Negative Effect

Air change rate is an important parameter for quantification of ventilation heat losses and also affects the indoor climate of buildings. Indoor air quality is significantly associated with ventilation. If air change isn't sufficient, trapped allergens, pollutants and irritants can degrade the indoor air quality and affect the well-being of a building's occupants. Many studies on ventilation and health have concluded that lower air change rates can have a negative effect on people’s health and low ventilation may result in an increase in allergic diseases. Quantification of air change rate is complicated, since it is affected by a number of parameters, of which the one of the most variable is the air-wind flow. This study aims to determination and comparison of values of the air change rate in two methods - by quantifying of aerodynamic coefficient Cp = Cpe - Cpi – so called aerodynamic quantification of the building and the methodology based on experimental measurements of carbon dioxide in the selected reference room in apartment building.

Temporal change in wood quality attributes in standing dead beetle-killed lodgepole pine

2008 ◽  
Vol 84 (3) ◽  
pp. 392-400
Author(s):  
Steen Magnussen ◽  
Dave Harrison
Keyword(s):  
Moisture Content ◽  
Wood Quality ◽  
Basal Area ◽  
Wood Moisture ◽  
Moisture Regimes ◽  
Standing Dead ◽  
Blue Stain ◽  
Lodgepole Pines ◽  
Ring Analysis ◽  
One Year

The number and size of checks, wood moisture content, extent of blue-stain, rot and decay was examined by stem analysis in 360 mature standing beetle-killed lodgepole pines. Trees came from three areas (Burns Lake, Quesnel, and Vanderhoof) in Central British Columbia. Each area was represented by 14 to 16 sampling areas (stands) distributed evenly across three soil moisture regimes (dry, mesic, wet). Year of death was estimated from tree ring-analysis, local knowledge and insect and disease survey maps. An approximately equal number of trees had been dead for one or two years, three or four years, or for five or more years. During the first five years since death by beetle attack the number of checks per tree increased from 2.5 to 10.2 and the average depth of checks increased from 4.3 cm to 5.1 cm. Checks were deeper, wider, and longer on the drier sites than on mesic and wet sites. Moisture content of sapwood and heartwood was near the fibre saturation point (ca 30%) one year after death and continued to decrease at a rate of approximately 1.7% per year. Both the incidence and the extent (relative to basal area) of rot and decay increased significantly with time since death. All trees had an extensive blue-stain discoloration. Deterioration of wood quality was fastest during the first two years after a beetle attack. Key words: wood checks, moisture content, blue-stain, wood quality, spiral grain, bark beetle

scholarly journals Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

2021 ◽  
Vol 30 (1) ◽  
pp. e002
Author(s):  
Juan I. Fernández-Golfín ◽  
Maria Conde Garcia ◽  
Marta Conde Garcia
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Solid Wood ◽  
Wood Products ◽  
Wood Moisture Content ◽  
Accurate Estimation ◽  
Wood Moisture ◽  
Mathematical Functions ◽  
Measured Moisture Content

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and  maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

scholarly journals Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1672
Author(s):  
Hannes Stolze ◽  
Mathias Schuh ◽  
Sebastian Kegel ◽  
Connor Fürkötter-Ziegenbein ◽  
Christian Brischke ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Wood Moisture Content ◽  
Adhesive Systems ◽  
Wood Moisture ◽  
Near Surface ◽  
Finger Joints ◽  
Glued Laminated Timber ◽  
Delamination Resistance ◽  
Normative Requirements

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

scholarly journals Modeling Indoor Relative Humidity and Wood Moisture Content as a Proxy for Wooden Home Fire Risk

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5050 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Moisture Sorption ◽  
Fire Risk ◽  
Cold Weather ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Wood Panel ◽  
Fire Disaster ◽  
Strong Winds

Severe wooden home conflagrations have previously been linked to the combination of very dry indoor climate in inhabited buildings during winter time, resulting in rapid fire development and strong winds spreading the fire to neighboring structures. Knowledge about how ambient conditions increase the fire risk associated with dry indoor conditions is, however, lacking. In the present work, the moisture content of indoor wooden home wall panels was modeled based on ambient temperature and relative humidity recorded at meteorological stations as the climatic boundary conditions. The model comprises an air change rate based on ambient and indoor (22 °C) temperatures, indoor moisture sources and wood panel moisture sorption processes; it was tested on four selected homes in Norway during the winter of 2015/2016. The results were compared to values recorded by indoor relative humidity sensors in the homes, which ranged from naturally ventilated early 1900s homes to a modern home with balanced ventilation. The modeled indoor relative humidity levels during cold weather agreed well with recorded values to within 3% relative humidity (RH) root mean square deviation, and thus provided reliable information about expected wood panel moisture content. This information was used to assess historic single home fire risk represented by an estimated time to flashover during the studied period. Based on the modelling, it can be concluded that three days in Haugesund, Norway, in January 2016 were associated with very high conflagration risk due to dry indoor wooden materials and strong winds. In the future, the presented methodology may possibly be based on weather forecasts to predict increased conflagration risk a few days ahead. This could then enable proactive emergency responses for improved fire disaster risk management.

scholarly journals Probabilistic modeling of the indoor climates of residential buildings using EnergyPlus

2017 ◽  
Vol 41 (3) ◽  
pp. 225-246 ◽  
Author(s):  
Elizabeth Buechler ◽  
Simon Pallin ◽  
Philip Boudreaux ◽  
Michaela Stockdale
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Indoor Air ◽  
Air Conditioning ◽  
Residential Buildings ◽  
The United States ◽  
Climate Data ◽  
Indoor Climate ◽  
Oak Ridge ◽  
Simulation Engine

The indoor air temperature and relative humidity in residential buildings significantly affect material moisture durability, heating, ventilation, and air-conditioning system performance, and occupant comfort. Therefore, indoor climate data are generally required to define boundary conditions in numerical models that evaluate envelope durability and equipment performance. However, indoor climate data obtained from field studies are influenced by weather, occupant behavior, and internal loads and are generally unrepresentative of the residential building stock. Likewise, whole-building simulation models typically neglect stochastic variables and yield deterministic results that are applicable to only a single home in a specific climate. The purpose of this study was to probabilistically model homes with the simulation engine EnergyPlus to generate indoor climate data that are widely applicable to residential buildings. Monte Carlo methods were used to perform 840,000 simulations on the Oak Ridge National Laboratory supercomputer (Titan) that accounted for stochastic variation in internal loads, air tightness, home size, and thermostat set points. The Effective Moisture Penetration Depth model was used to consider the effects of moisture buffering. The effects of location and building type on indoor climate were analyzed by evaluating six building types and 14 locations across the United States. The average monthly net indoor moisture supply values were calculated for each climate zone, and the distributions of indoor air temperature and relative humidity conditions were compared with ASHRAE 160 and EN 15026 design conditions. The indoor climate data will be incorporated into an online database tool to aid the building community in designing effective heating, ventilation, and air-conditioning systems and moisture durable building envelopes.

Observations on the biology of Lycts Brunneus (Steph.)

1953 ◽  
Vol 1 (1) ◽  
pp. 102 ◽  
Author(s):  
FJ Gay
Keyword(s):  
Heat Treatment ◽  
Life Cycle ◽  
Relative Humidity ◽  
Sex Ratio ◽  
Moisture Content ◽  
Incubation Period ◽  
Developmental Period ◽  
Wood Moisture Content ◽  
Optimal Conditions ◽  
Wood Moisture

An account is given of certain aspects of the biology of Lyctus brunneus (Steph.). Female beetles are able to oviposit within 24 hr. after emerging from infested timber and deposit an average of more than 70 eggs per female over a period of 1-2 weeks. Eggs are deposited at depths of 1.0-6.5 mm. in the wood vessels, preferentially from a transverse surface, but also through radial and tangential faces. The incubation period of the eggs ranges from about 1 week at 26�C, to 3 weeks at 15�C. The egg-adult developmental period ranges from 4 months at 26�C. to 16 months or more at 15�C. Under optimal conditions of temperature, relative humidity (and hence wood moisture content), and nutrition, the life cycle may be as short as 2 months. The sex ratio of L. brunneus is 1 : 1 and the adult beetles live from 2.5 to 7 weeks, depending upon the temperature, females being somewhat longer-lived than males. The larvae of L. brunneus are somewhat more resistant to heat treatment than are the eggs, but one 1/2hr. exposure to 50�C. is completely lethal to both stages.

scholarly journals STUDY ON CONCENTRATIONS OF ACIDS AND ALCOHOLS EMITTED BY PINUS RADIATA DURING HIGH-TEMPERATURE DRYING

Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 427-436
Author(s):  
Jiangyi Chu ◽  
Jinghui Jiang ◽  
Chusheng Qi ◽  
Yongdong Zhou
Keyword(s):  
Acetic Acid ◽  
High Temperature ◽  
Relative Humidity ◽  
Moisture Content ◽  
Formic Acid ◽  
Pinus Radiata ◽  
Wood Moisture ◽  
Drying Temperature ◽  
Kiln Temperature ◽  
High Temperature Drying

The purpose of this paper is to investigate the influence of kiln temperature, relative humidity and wood moisture content on the content of acid and alcohol released in the drying process of high temperature kiln by studying the radiated pine sawn timber of 40mm thickness. The drying temperature was between 101°C and 115°C, the relative humidity in the drying kiln was reduced from 86.1% to 39.6%, the moisture content of the lumber was reduced from 106.16% to 11.98%, and gas extraction was executed nine times with an extraction speed of 1.0 L•min-1 and a sampling time of 30 min. The concentrations of acids and alcohols were analyzed by HPLC. The results showed that the concentrations of formic acid, acetic acid, and methanol emitted in the kiln during drying were 215.6-748.2, 4148.8-16803.2, and 6381.9-15648.9 mg•m-3, respectively, and these concentrations were significantly higher than the relevant standards. The concentrations of the emitted formic acid and acetic acid were proportional to the drying temperature, the concentrations of the emitted formic acid and acetic acid were inversely proportional to the relative humidity in the kiln and the moisture content of the lumber. The concentration of the emitted methanol was independent of the drying temperature, relative humidity in the kiln, and moisture content of the lumber. It is therefore suggested that formic acid, acetic acid, and methanol be separately recovered during the high-temperature drying of Pinus radiata lumber.

scholarly journals Thermal Comfort Evaluation of Offices Integrated Into an Industrial Building. Case Study of the Basque Country

2020 ◽  
Vol 24 (2) ◽  
pp. 20-31
Author(s):  
Iñigo Rodriguez Vidal ◽  
Xabat Oregi ◽  
Jorge Otaegi
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Indoor Air ◽  
Occupational Safety ◽  
Basque Country ◽  
Working Hours ◽  
Industrial Building ◽  
Inadequate Response ◽  
Indoor Climate ◽  
Environmental Conditioning

AbstractThis paper reports the indoor air operative temperature and relative humidity outcomes of a sixteen-month monitoring campaign of an administrative area in an industrial building in Tolosa (Spain). In a survey, users reported indoor climate dissatisfaction during the working hours, such as severe discomfort in the conference rooms due to excessive cold or overheating, poor indoor air quality or inadequate response of the HVAC systems. Internal operative temperatures and relative humidity have been analysed with and without environmental conditioning systems to study passive performance and effectiveness of active systems. These two parameters have been analysed in hourly intervals, during summer and winter periods. On the basis of the obtained data, the degree of thermal comfort of the users was evaluated, which allowed a comparison between the users’ self-reported perception obtained through surveys and the monitored data. Three different standards were used to assess thermal comfort, namely the European Standard UNE-EN ISO 7730, the Spanish Regulations for thermal installations in buildings (RITE) and the criteria established by the National Institute for Occupational Safety and Health (INSHT). The study has made it possible to detect the main aspects that have a direct influence on user discomfort.

scholarly journals Data mining methods of healthy indoor climate coefficients for comfortable well-being

2018 ◽  
Vol 29 (3) ◽  
pp. 7-12
Author(s):  
Grit Behrens ◽  
Klaus Schlender ◽  
Florian Fehring
Keyword(s):  
Machine Learning ◽  
Data Mining ◽  
Indoor Air ◽  
Well Being ◽  
Machine Learning Algorithms ◽  
Indoor Climate ◽  
Measurement And Analysis ◽  
Scientific Project ◽  
Mining Methods ◽  
Analysis System

Abstract This article provides information about a currently developed measurement and analysis system ‘Smart Monitoring’, which is used on scientific project in terms of healthy indoor air coefficients, as well as the processing of the collected data for machine learning algorithms. The target is to reduce CO2 emissions caused by wrong ventilation habits in building sector after renovation process in older buildings.

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