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Field monitoring of hygrothermal performance of a wood-frame house in the Lower Mainland of BC built to the passive house standard

https://library.fpinnovations.ca/en/permalink/fpipub6071
Author
Wang, Jieying
Mistretta, S.
Date
March 2014
Edition
43873
Material Type
Research report
Field
Sustainable Construction
Author
Wang, Jieying
Mistretta, S.
Contributor
Forestry Innovation Investment
Natural Resources Canada. Canadian Forest Service.
Date
March 2014
Edition
43873
Material Type
Research report
Physical Description
30 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Moisture content
Series Number
W-3100
Language
English
Abstract
A single-family wood-frame house in the Lower Mainland of British Columbia built to the German Passivhaus (Passive House) standard was monitored to investigate its thermal performance and durability in this mild climate. Two double-stud walls, south- and north-facing, were instrumented during construction to measure moisture and thermal performance. A limited amount of thermal modelling was conducted to compare with the field measurements. Monitoring over the past 20 months showed that:
The double-stud walls, south- and north-facing, were both performing well in terms of durability. The moisture content (MC) measured at the bottom of the studs was in general below 15% after the construction was completed. The MC of the south-facing wall dropped from an initial 20%, measured during construction, to about 11% after construction was completed. During the same period of time, the MC of the north-facing wall fell from about 19% to 15%; the slightly higher MC in this wall compared to that in the south-facing wall was a result of lower amounts of solar gain in this orientation.
The relative humidity (RH) measured on the interior side of the medium-density fibreboard (MDF) exterior sheathing in the south-facing wall ranged from 70% to 80%, and occasionally up to 90% during the winter. Being typical of exterior sheathing conditions without exterior insulation in this mild climate, the corresponding RH ranged from 80% up to 100% in the north-facing wall in the winter, indicating potential vapour condensation at this critical location.
Based on vapour pressure analysis, no steep vapour pressure gradients between any specific layers were found in these two walls, indicating the overall vapour permeable nature and good drying performance of the wall design. This could be partially attributed to the use of plywood as structural sheathing located between the double-stud walls as the air barrier and vapour retarding layer, and using MDF as the exterior sheathing.
In the south-facing wall, the vapour pressure analysis showed a vapour drive in the summer from the exterior layers towards the interior layer, primarily due to high temperature outside. The exterior sheathing should have good drying potential if wetting occurred. On the other hand, the partial vapour pressures were largely consistent across the north-facing wall in the winter, not showing a strong vapour drive from interior to exterior in this mild climate. The exterior sheathing would have poor drying performance if wetting occurred in this location.
The simulated temperature distributions based on THERM 6.3 simulations were generally in good agreement with the measured temperatures across the walls, indicating that the thermal simulation was reasonably accurate. The effective R-value of the double-stud walls of this passive house was calculated to be approximately R-50 (hržft2žF/Btu) or RSI-8.8 (m2K)/W) (i.e. with a thermal transmission coefficient of 0.114 W/m2žK). The use of heat flux sensors was not successful in this work, probably due to improper sensor calibration or in-situ installation. Its use needs further exploration to measure heat flow in building envelopes in order to validate calculated effective thermal insulation.
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Humidimètres pour la biomasse

https://library.fpinnovations.ca/en/permalink/fpipub39765
Author
Volpé, Sylvain
Date
February 2014
Material Type
Research report
Field
Fibre Supply
biofuels – Determination of moisture content – Oven dry method – Part 2: Total moisture – Simplified
Author
Volpé, Sylvain
Date
February 2014
Material Type
Research report
Physical Description
17 p.
Sector
Forest Operations
Field
Fibre Supply
Research Area
Forestry
Subject
Biomass
Moisture content
Sampling
Measurement
Heat
Advantage
Series Number
Avantage ; Vol. 14, No. 5
Language
English
ISSN
14933381
Abstract
One of the challenges to the use of biomass in heat applications is to find a suitable technology to take quick and accurate moisture content (MC) measurements of comminuted forest biomass. In this study, we tested three difference technologies (electric, nuclear and infrared) and five different tools. Of the three technologies tested, electric is the most promising. It is usually inexpensive (<$1000), requires small-sized samples (10 L), is fast to read (<1 minute) and is relatively accurate with more than 70% of measurements within 5% MC of the oven-dried method.
BIOMASS
MOISTURE CONTENT
TECHNOLOGY
ELECTRIC ANALYZERS
NUCLEAR RADIATION
INFRARED DETECTORS
ACCURACY
MEASUREMENT
TIME
Sample size
Abstract
L’une des difficultés associées à l’utilisation de la biomasse forestière broyée pour produire de la chaleur consiste à trouver une technologie convenable pour prendre rapidement des mesures précises de la teneur en humidité (TH). Pour la présente étude, nous avons mis à l’essai trois technologies (électrique, nucléaire et infrarouge) et cinq appareils différents. Parmi les trois technologies, c’est la technologie électrique qui est la plus prometteuse. Les appareils sont généralement peu coûteux (< 1000 $), nécessitent des échantillons de petite taille (10 L), donnent les résultats rapidement (<1 minute) et sont relativement précis, plus de 70 % des mesures se situant à plus ou moins 5 % de la TH obtenue par la méthode de séchage à l’étude.
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Matapedia roundwood tarping trials

https://library.fpinnovations.ca/en/permalink/fpipub39799
Author
Volpé, Sylvain
Date
March 2014
Material Type
Research report
Field
Fibre Supply
. ........................................................................................ 5 Figure 3. Disc samples to determine the initial moisture content in January 2012
Author
Volpé, Sylvain
Date
March 2014
Material Type
Research report
Physical Description
12 p.
Sector
Forest Operations
Field
Fibre Supply
Research Area
Forestry
Subject
Biomass
Moisture content
Drying
Storing
Logs
Advantage
Series Number
Advantage ; Vol. 14, No. 8
Language
English
ISSN
14933381
Abstract
The effects of natural drying in relation to the use of tarps on the moisture content of stacked softwood roundwood were examined. Biomass quality logs were stored for a period of 15 months in a mill yard in the Bas Saint-Laurent region of Quebec. The results of the study showed that the roundwood dried naturally during the summer season with moisture content at the end of the season below 30%. Tarping the roundwood piles during the fall and winter prevented an average increase in moisture content of 6%.
Abstract
Cette étude d'entreposage de la biomasse forestière visait à évaluer les effets du séchage naturel par rapport à l'utilisation de bâches sur la teneur en humidité de bois rond résineux au cours d'une période de 15 mois. Des billes de qualité biomasse ont été empilées dans un parc d'usine de la région du Bas-Saint-Laurent, au Québec. Les résultats de l'étude ont démontré que la biomasse séchait très bien naturellement pendant l'été avec un taux d'humidité en fin de la saison estivale en-dessous de 30%. La bâchage des empilements de biomasse au cours de l'automne et de l'hiver a permis d'éviter une augmentation moyenne du taux d'humidité de 6 %.
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Phase I : Drying performance of experimental wood roof assemblies

https://library.fpinnovations.ca/en/permalink/fpipub42987
Author
Wang, Jieying
Date
February 2014
Material Type
Research report
Field
Sustainable Construction
the changes in the average moisture content (MC) of each wood deck. In total, 111 assemblies were tested
Author
Wang, Jieying
Contributor
Natural Resources Canada. Canadian Forest Service.
Date
February 2014
Material Type
Research report
Physical Description
37 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Building Systems
Subject
Drying
Moisture content
Roofs
British Columbia
Series Number
Transformative Technologies
W-3070
Language
English
Abstract
A study was initiated in late 2012 to assist in designing panelized wood roofs and other wood roof assemblies as part of the work supporting the British Columbia (BC) Advisory Group on Advanced Wood Design Solutions. The test aimed primarily to assess and compare the drying performance of different roof assemblies with built-in moisture under worst-case scenarios in the coastal climate of BC. A range of roof assemblies were built using plywood, OSB, cross-laminated timber (CLT), or laminated veneer lumber (LVL) as the roof deck. Each deck specimen was wetted using hourly spray of water for 15-20 days in the laboratory. Either self-adhered impermeable membrane, or standard roofing felt plus asphalt shingles, was used to cover the wetted top surface. Closed-cell spray foam insulation was applied on the bottom surface in several roof assemblies to assess its impact on the drying performance. Subsequent drying was carried out under three ambient conditions for three groups of specimens, beginning in February or March, 2013. Limited drying forces, except natural moisture diffusion and evaporation, were created, except for one roof assembly placed under controlled temperature gradients. The drying rates of each wood deck were monitored by weighing the roof assemblies periodically, followed by calculating the changes in the average moisture content (MC) of each wood deck. In total, 111 assemblies were tested to compare the drying rates between different wood decks and between different assemblies. The major test results included:
The MCs of the plywood, OSB, CLT, and LVL specimens, after hourly spray in the laboratory for 15 to 20 days, were all highly comparable with those of the naturally exposed reference specimens after about two months of natural exposure from January to March. This validated the use of such laboratory wetting to simulate severe wetting scenarios on construction sites.
The four types of roof deck materials in this study showed very different water absorption and wetting potentials. The CLT specimens, as a mass timber product tested in this study, showed the lowest wetting potential, closely followed by LVL. The plywood and the OSB specimens tested had the highest MCs after wetting under both conditions.
In general the higher the material’s wetting potential, the faster it would dry under conditions allowing drying.
The CLT and LVL assemblies, covered with impermeable membrane on the wetted surfaces, showed little drying during the test periods. The use of two layers of plywood as a roof deck also showed much slower drying compared with the one-layer assemblies, when covered with an impermeable membrane on the wetted surfaces.
The combination of 15-pound roofing felt and asphalt shingles showed only slightly better vapour permeance, as indicated by the slightly better drying performance of roof assemblies, compared with the impermeable membrane used in this test.
All of the roof deck materials tested had very poor drying performance when enclosed in materials with low vapour permeance, such as impermeable membranes and closed-cell spray foam.
Among the three main drying conditions used in this study, the plywood and OSB assemblies in the shed showed the lowest drying, and those in the lab showed the fastest drying, with those in the conditioning chamber providing intermediate drying rates. Such differences appeared to correlate well with the vapour pressure differences between the saturated pressures and the partial pressures of the environments. The shed was intended to simulate covered on-site conditions in this climate. This test indicated that, when roof panels get wet, drying during construction can be improved fairly easily for relatively permeable panels or assemblies, such as one layer of plywood or OSB, one layer of plywood or OSB covered with other materials only on one side. Favourable weather conditions and mechanical methods (e.g., ventilation and space heating) can accelerate drying. However, the ambient environment may not have much effect on the drying performance of relatively impermeable products or assemblies, including massive wood members and wood enclosed in impermeable materials. The test data also indicates that drying could take a long time, typically weeks and even months depending on environmental conditions, once wood panels get severely wet. This could allow mould growth and even decay to occur under severe circumstances. This study confirms the importance of keeping wood dry in the first place, and drying wood before enclosure when wetting occurs as the second strategy, in order to minimize moisture-related risks. Guidelines are needed to recommend best practices for on-site wood protection and moisture management in wet climates, for the use of innovative engineered wood products in larger building projects in particular.
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Preventing sinkage of western hemlock, Best practices guide

https://library.fpinnovations.ca/en/permalink/fpipub53003
Author
Friesen, Charles
Date
January 2020
Material Type
Research report
Field
Fibre Supply
-222-5622 charles.friesen@fpinnovations.ca 3 Western hemlock can have higher moisture content than
Author
Friesen, Charles
Date
January 2020
Material Type
Research report
Physical Description
12 p.
Sector
Forest Operations
Field
Fibre Supply
Research Area
Forestry
Subject
Trees
Moisture content
Water
Transport
Series Number
Special Publication ; SP 538
Language
English
ISBN
9780864885890
ISSN
19250509
Abstract
Hemlock can have higher moisture content than most other native trees, causing them to sink. Hemlock lumens have large pits (valves) that allow easy transport of water into the wood. Bigger rings = bigger lumens. Younger hemlock or hemlock tops are more susceptible to sinking. The bigger the rings the more likely to take on water.
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Short-term evaluation of the Kobelco BladeRunner ED150 for road rehabilitation

https://library.fpinnovations.ca/en/permalink/fpipub39815
Author
Partington, Mark
Date
May 2014
Material Type
Research report
Field
Fibre Supply
Author
Partington, Mark
Date
May 2014
Material Type
Research report
Physical Description
11 p.
Sector
Forest Operations
Field
Fibre Supply
Research Area
Transportation & Infrastructure
Subject
Biomass
Moisture content
Drying
Storing
Logs
Advantage
Series Number
Advantage ; Vol. 15, No. 1
Language
English
ISSN
14933381
Abstract
FPInnovations performed short-term productivity studies on a road rehabilitation operation that utilized a Kobelco ED150 BladeRunner. The BladeRunner is a multi-purpose machine that can function as an excavator and a bulldozer, due to its front blade attachment. Productivity studies were also performed on an excavator (John Deere 200C) and bulldozer (Caterpillar D6M) team that performed the same work as the BladeRunner.
ROADS
MACHINERY
HARVESTERS
Abstract
FPInnovations a effectué des études de productivité à court terme dans le cadre d’une opération de remise en état de routes effectuée à l’aide d’un BladeRunner, modèle Kobelco ED150, une machine multifonctions qui peut être utilisée comme excavatrice ou bulldozer en raison de sa fixation frontale pour lames. Des études de productivité ont aussi été réalisées sur une combinaison excavatrice (John Deere 200C) et bulldozer (Caterpillar D6M) qui effectuent les même tâches que le BladeRunner.
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Study to examine the effects of log moisture sorting on OSB manufacturing

https://library.fpinnovations.ca/en/permalink/fpipub39823
Author
Groves, C. Kevin
Date
May 2014
Material Type
Research report
Field
Wood Manufacturing & Digitalization
) study was carried-out to better understand the effects of log moisture content on the manufacturing
Author
Groves, C. Kevin
Contributor
Natural Resources Canada. Canadian Forest Service.
Date
May 2014
Material Type
Research report
Physical Description
28 p.
Sector
Wood Products
Field
Wood Manufacturing & Digitalization
Research Area
Advanced Wood Manufacturing
Subject
Logs
Moisture content
OSB
Sorting
Series Number
W-3096
Language
English
Abstract
In the Canadian OSB industry raw log moistures are generally thought to be a significant factor effecting mill operation. In 2012/13 an FPInnovations study was carried out to better understand the effects of log moisture content on the manufacturing operations at a western Canadian OSB mill. The information collected was intended to assist the mill to make informed decisions on log yard management and harvesting and also to understand the best possible scenarios for producing a quality product as cost effectively as possible. Of particular interest was whether benefits could be made by processing dryer wood as a means of increasing dryer capacity but without incurring significant costs resulting from lower strand quality, especially fines and the associated costs of increased resin usage and panel density.
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Évaluation de courte durée de la Kobelco BladeRunner ED150 pour la réfection des route

https://library.fpinnovations.ca/en/permalink/fpipub39941
Author
Partington, Mark
Date
May 2014
Material Type
Research report
Field
Fibre Supply
Author
Partington, Mark
Date
May 2014
Material Type
Research report
Physical Description
11 p.
Sector
Forest Operations
Field
Fibre Supply
Research Area
Transportation & Infrastructure
Subject
Biomass
Moisture content
Drying
Storing
Logs
Advantage
Series Number
Avantage ; Vol. 15, No. 1
Language
French
ISSN
14933381
Abstract
FPInnovations performed short-term productivity studies on a road rehabilitation operation that utilized a Kobelco ED150 BladeRunner. The BladeRunner is a multi-purpose machine that can function as an excavator and a bulldozer, due to its front blade attachment. Productivity studies were also performed on an excavator (John Deere 200C) and bulldozer (Caterpillar D6M) team that performed the same work as the BladeRunner.
ROADS
MACHINERY
HARVESTERS
Abstract
FPInnovations a effectué des études de productivité à court terme dans le cadre d’une opération de remise en état de routes effectuée à l’aide d’un BladeRunner, modèle Kobelco ED150, une machine multifonctions qui peut être utilisée comme excavatrice ou bulldozer en raison de sa fixation frontale pour lames. Des études de productivité ont aussi été réalisées sur une combinaison excavatrice (John Deere 200C) et bulldozer (Caterpillar D6M) qui effectuent les même tâches que le BladeRunner.
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8 records – page 1 of 1.