scholarly journals Measurements behind Internal Insulation on Solid Masonry Walls with Different Orientations and Degrees of Repair in a Danish Multi-story Building

2020 ◽  
Vol 172 ◽  
pp. 01008
Author(s):  
Lies Vanhoutteghem ◽  
Britt Haker Høegh ◽  
Thor Hansen
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Energy Use ◽  
Wood Decay ◽  
Large Temperature ◽  
Mould Growth ◽  
Insulation System ◽  
Measurement Results ◽  
Heritage Buildings ◽  
Story Building

Internal insulation is used in many heritage buildings to ensure a better indoor environment and reduce energy use. This article describes measurement results from installing an internal insulation system in a Danish multi-story building. The internal insulation system consists of a fully glued vapour tight insulated plasterboard. To reduce the risk for wood decay and mould growth at the wooden beam ends in the floor construction, a 100-200 mm uninsulated gap was left above and below the floor construction. Measurements include the effect of orientation, degree of façade repair and influence of indoor moisture content. Results show in general acceptable hygrothermal conditions behind the insulation system. However, a gradual increase in relative humidity at sun-exposed walls was registered due to ‘summer condensation’. The degree of surface repair also showed an influence on relative humidity levels during this period. At the uninsulated gap above the floor, a higher moisture content indoor resulted in a higher relative humidity, though without exceeding the threshold for mould growth. However, a large temperature range was registered. The influence of the uninsulated gap on reducing the risk of wood decay and mould growth at the beam ends could therefore not unambiguously be confirmed.

scholarly journals Damage risk assessment of building materials with moisture hysteresis

2021 ◽  
Vol 2069 (1) ◽  
pp. 012043
Author(s):  
Michele Libralato ◽  
Alessandra De Angelis ◽  
Paola D’Agaro ◽  
Giovanni Cortella ◽  
Menghao Qin ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Building Materials ◽  
Moisture Transfer ◽  
Lower Boundary ◽  
Wood Decay ◽  
Simplified Models ◽  
Desorption Curve ◽  
Decay Risk ◽  
Adsorption Curve

Abstract Heat and Moisture Transfer (HMT) simulations are used to evaluate moisture related damage risks in building envelopes. HMT simulations are commonly performed accepting the hypothesis of not considering the moisture hysteresis of materials. The results of HMT simulation of a timber wall with hysteresis are presented, and compared to the results of three simplified models, showing the effects of hysteresis on the simulation results and on the assessment of the risk of decay. Moisture content is the most influenced variable, while temperature and relative humidity are slightly affected. The wood decay risk analysis is performed using the simplified 20% moisture content rule. Similar temperature values and relative humidity values are calculated as simplified models, while the moisture content annual average values have differences up to 2.3%. The wood decay risk obtained with the simplified models could be overestimated if the simulation is performed using the desorption curve, while it could be underestimated with the adsorption curve. The best approximation is obtained with the mean sorption curve, while the desorption curve and the adsorption curve could be used to calculate the upper and lower boundary of the moisture contents respectively.

The storage of artificially dried grass

1941 ◽  
Vol 31 (2) ◽  
pp. 194-211 ◽  
Author(s):  
Norman C. Wright
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Low Power ◽  
Equilibrium Moisture Content ◽  
Early Stage ◽  
Smooth Curve ◽  
Storage Conditions ◽  
Mould Growth ◽  
Safe Storage ◽  
Winter Conditions

1. Experiments have been carried out to determine the relation between the moisture content of artificially dried grass and the relative humidity of the surrounding atmosphere. This relation is given by a smooth curve. At relative humidities which are typical of outdoor winter conditions in the British Isles (80–90%) the equilibrium moisture content lies between 18 and 30%.2. The rate of moulding is directly related to the relative humidity and therefore to the moisture content of the dried grass. For reasonably safe storage a relative humidity of 67 % should not be exceeded. This corresponds to a moisture content of roughly 13 %. Even this low value does not confer absolute immunity from mould growth.3. The importance of extending storage trials over long periods is stressed. In one instance storage for 300 days was required before mould growth occurred. Neglect of this fact may account for the widely held view that a relative humidity of 70–75 % provides safe storage conditions.4. Attempts to detect mould growth at an early stage by plating methods proved unsuccessful. It is shown that the two earliest and most reliable indications of mould growth are (i) the appearance of visible mycelium when the product is examined under a low-power objective, and (ii) the detection of a musty smell.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

A comparison of hygrothermal simulation results derived from four simulation tools

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.

Algorithms to predict moisture content of grain using relative humidity time-series

2020 ◽  
Author(s):  
Charles B. Delahunt ◽  
Wenbo Wang ◽  
Simon Ghionea ◽  
Andrew Miller ◽  
Austin Chan ◽  
...  
Keyword(s):  
Time Series ◽  
Relative Humidity ◽  
Moisture Content

Determination of readiness for laying based on material moisture, corresponding relative humidity, and water release

2020 ◽  
Vol 62 (10) ◽  
pp. 1033-1040
Author(s):  
Christoph Strangfeld ◽  
Sabine Kruschwitz
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Embedded Sensors ◽  
Residual Water ◽  
Floor Covering ◽  
Water Release ◽  
Content Determination ◽  
Two Samples ◽  
Moisture Content Determination

Abstract The moisture content of the subfloor has to be determined before installation to avoid damage to the floor covering. Only if readiness for layering is reached, can an installation without damage be expected in all cases. In general, three approaches exist to measure residual water content: determination of moisture content, determination of water release, or determination of the corresponding relative humidity. All three approaches are tested under laboratory conditions at eight screed types including two samples thicknesses in each case. Moisture content and water release are measured by sample weighing, the corresponding relative humidity is measured by embedded sensors. All three approaches are compared and correlated. The evaluations show only a weak correlation and, in several cases, contradicting results. Samples are considered ready for layering and not ready for layering at the same time, depending on the chosen approach. Due to these contradicting results, a general threshold for a risk of damage cannot be derived based on these measurements. Furthermore, the experiment demonstrates that the measurement of corresponding relative humidity is independent of the screed type or screed composition considered. This makes humidity measurement a potentially very promising approach for the installation of material moisture monitoring systems.

EFFECT OF MOISTURE CONTENT ON VIABILITY AND INFESTATION OF HULLESS TERRA OATS IN STORAGE

1979 ◽  
Vol 59 (4) ◽  
pp. 911-916 ◽  
Author(s):  
R. N. SINHA ◽  
N. D. G. WHITE ◽  
H. A. H. WALLACE ◽  
R. I. H. McKENZIE
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Mite Infestation ◽  
Tyrophagus Putrescentiae ◽  
Adsorption And Desorption ◽  
Safe Storage ◽  
Moisture Contents ◽  
Seed Moisture ◽  
Effect Of Moisture

The effects of various seed moisture contents in hulless (cv. Terra) and hulled oats (cv. Random) on susceptibility to mite infestation and on mycofloral growth and germination loss were studied at weekly intervals. Fat acidity values were determined for Terra oats only after 4 wk of storage. Moisture content-relative humidity adsorption and desorption curves were determined for Terra at 22 °C and at relative humidities of 35–100%. Terra oats, which had a higher level of Penicillium infection at 90–100% RH than Random oats, lost viability more rapidly than Random. Fat acidity values of Terra increased rapidly from 35 mg KOH/100 g of seed to 87–118 mg KOH/100 g of seed, only when seeds were stored at 90–100% RH. Terra offered a more favorable substrate for the multiplication of the mites Tyrophagus putrescentiae, Acarus farris, and Lepidoglyphus destructor than did Random. With the exception of susceptibility to mite infestation, safe storage criteria are similar for hulled and hulless oats at usual moisture contents.

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