scholarly journals AIR TIGHTNESS OF STRAW BALE CONSTRUCTION

2015 ◽  
Vol 10 (1) ◽  
pp. 99-113 ◽  
Author(s):  
Larisa Brojan ◽  
Ben Weil ◽  
Peggi L. Clouston
Keyword(s):  
Air Flow ◽  
Grade System ◽  
Grading System ◽  
Air Tightness ◽  
Straw Bale Walls ◽  
Straw Bale ◽  
Building Methods

Straw bale construction offers a renewable, sustainable and proven alternative to mainstream building methods; still, little is known about its airflow characteristics. To this end, the intent of this paper is to evaluate airtightness of fully constructed and plastered straw bale walls as well as individual plain straw bales. The first experiment entailed measuring the influence of straw bale orientation on airflow characteristics with the finding that straw bale considered alone has poor air flow-retarding characteristics and that plaster is the primary air barrier. A second experiment involved thirty plastered straw bale specimens using three different plaster types. From this experiment, a crack grading system was developed and is herein proposed as a tool to evaluate plaster performance as an air barrier. A third experiment validated the crack grade system through application on four fully constructed straw bale walls. Practical use of the crack grading system was demonstrated on a case study straw bale house in Radomlje, Slovenia, where the predicted air tightness results were validated through comparison to results of blower door tests.

scholarly journals Research on Prediction Model for Durability of Straw Bale Walls in Warm (Humid) Continental Climate—A Case Study in Northeast China

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3007 ◽  
Author(s):  
Xunzhi Yin ◽  
Qi Dong ◽  
Mike Lawrence ◽  
Daniel Maskell ◽  
Jiaqi Yu ◽  
...  
Keyword(s):  
Low Carbon ◽  
Isothermal Model ◽  
Hygrothermal Environment ◽  
Low Carbon Energy ◽  
Straw Bale Walls ◽  
The Impact ◽  
Straw Bale ◽  
Continental Climate

This research analyses straw degradation inside straw bale walls in the region and develops the prediction of degradation inside straw bale walls. The results show that the straw inside straw bale walls have no serious concerns of degradation in the high hygrothermal environment in the region with only moderate concerns of degradation in the area 2–3 cm deep behind the lime render. The onsite investigations indicate that the degradation isopleth model can only predict straw conditions behind the rendering layer, whereas the isothermal model fits the complete situation inside straw bale walls. This research develops the models for predicting straw degradation levels inside a straw bale building in a warm (humid) continental climate. The impact of this research will help the growth of low carbon energy efficient straw bale construction with confidence pertaining to its long-term durability characteristics both in the region and regions sharing similar climatic features globally.

Hot box method to investigate U-values for straw bale walls with various structures

2021 ◽  
pp. 110706
Author(s):  
Liu Yang ◽  
Jingjing Yang ◽  
Yan Liu ◽  
Yungang An ◽  
Jingheng Chen
Keyword(s):  
Box Method ◽  
Straw Bale Walls ◽  
Straw Bale

scholarly journals Hygrothermal Behaviour of the Timber-Framed Sauna with Straw-Bale Walls

2018 ◽  
Author(s):  
Martti-Jaan Miljan ◽  
◽  
Rain Allikmäe ◽  
Andres Jürgenson ◽  
Matis Miljan ◽  
...  
Keyword(s):  
Straw Bale Walls ◽  
Straw Bale ◽  
Hygrothermal Behaviour

Allowable Shears for Plastered Straw-Bale Walls

2015 ◽  
Vol 141 (2) ◽  
pp. 06014008
Author(s):  
M. Aschheim ◽  
S. Jalali ◽  
C. Ash ◽  
K. Donahue ◽  
M. Hammer
Keyword(s):  
Straw Bale Walls ◽  
Straw Bale

scholarly journals ENHANCING THE EFFICIENCY OF INDOOR LOCAL VENTILATION USING CROSS-FLOW FANS: CASE STUDY FOR A SMOKING CABIN

2016 ◽  
Vol 21 (3) ◽  
Author(s):  
DRAGOMIRESCU ANDREI ◽  
CIOCĂNEA ADRIAN
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Cross Flow ◽  
Flow Coefficient ◽  
Air Flow Rate ◽  
Low Velocity ◽  
Original Solution ◽  
Local Space ◽  
Local Ventilation

<p>The paper presents an original solution for increasing air quality and reducing energy consumption of the local indoor ventilation by using cross-flow fans. The solution is a combination between the local exhaust ventilation (LEV) technique from industry, negative-pressure isolation rooms used in hospitals, and air curtains (AC) used for isolating of indoor/outdoor spaces. The solution provides a high air flow rate at low velocity due to the high value of the flow coefficient of the cross flow fans and, in the same time, allows modular setup according to local space geometry. A case study is proposed regarding the isolation of a smoking area where smell and airborne particles appear. A 3D numerical simulation was performed, in which one cross-flow fan with long axial length was considered. The optimum air flow rate and flow pattern was obtained in order to isolate the local space. The results show that a new approach for reducing sick building syndrome could be addressed by providing modular and local ventilation using cross-flow fans.</p>

scholarly journals Laboratory and In-Situ Measurements for Thermal and Acoustic Performance of Straw Bales

2019 ◽  
Vol 11 (20) ◽  
pp. 5592 ◽  
Author(s):  
Stefano Cascone ◽  
Gianpiero Evola ◽  
Antonio Gagliano ◽  
Gaetano Sciuto ◽  
Chiara Baroetto Parisi
Keyword(s):  
Thermal Conductivity ◽  
Phase Shift ◽  
In Situ Measurements ◽  
Sound Insulation ◽  
Initial Water Content ◽  
Acoustic Performance ◽  
Thermal Transmittance ◽  
Straw Bale Walls ◽  
Straw Bale

This paper investigates the performance of timber-framed walls insulated with straw bales, and compares them with similar walls containing expanded polystyrene (EPS) instead of straw bales. First, thermal conductivity, initial water content, and density of the straw bales were experimentally measured in a laboratory set-up, and the dependence of the thermal conductivity of the dry material on temperature was described. Then, the two insulation solutions were compared by looking at their steady and periodic thermal transmittance, decrement factor, phase shift, internal areal heat capacity and surface mass. Finally, the acoustic performance of both wall typologies was analyzed by means of in situ measurements in two-story buildings built in Southern Italy. The weighted apparent sound reduction index for the partition wall between two houses and the weighted standardized level difference for the façades were assessed based on ISO Standard 16283. The results indicate that the dry straw bales have an average thermal conductivity of k = 0.0573 W/(m·K), and their density is around 80 kg/m3. In addition, straw bale walls have good steady thermal performance, but they still lack sufficient thermal inertia, as witnessed by the low phase shift and the high periodic thermal transmittance. Finally, according to the on-site measurements, the results underline that the acoustic performance of the straw bale walls is far better than the walls adopting traditional EPS insulation. Overall, the straw bales investigated are a promising natural and sustainable solution for thermal and sound insulation of buildings.

scholarly journals Development of air tightness prediction method of masonry walls

2020 ◽  
Vol 172 ◽  
pp. 05009
Author(s):  
Valdemaras Geležiūnas ◽  
Karolis Banionis ◽  
Valdas Paukštys ◽  
Jurga Kumžienė
Keyword(s):  
Thermal Insulation ◽  
Air Flow ◽  
Measurement Data ◽  
Air Permeability ◽  
Mineral Wool ◽  
Masonry Walls ◽  
Air Movement ◽  
Protection Layer ◽  
Air Tightness ◽  
Flow Resistances

Recently, the construction of external walls of various blocks, which are externally insulated with mineral wool thermal insulation layer, with ventilated air gap and external finishing (ventilated wall structures) is becoming popular for public and office buildings. These blocks are used without internal rendering because they have a good interior surface, stable dimensions, and various filling of masonry joints provide an attractive architectural appearance. This reduces the cost and duration of construction work, however, problems with airtightness of such walls often occur. The air can penetrate through blocks or their joints, and the thermal insulation and wind protection layer does not usually provide the required air tightness of the wall. Currently, there are no standard methods to predict the air tightness of such wall, in practice, samples of particular walls are produced and their air permeability is measured at the laboratories. This is a costly job, which is only suitable for a combination of particular building materials. For the broader use of results of laboratory air permeability measurements, a methodology has been developed to predict the air permeability of block masonry walls using experimentally determined air flow resistances of the individual layers. The masonry from blocks, made of ceramic, expanded clay and aerated concrete with various joints, were used for the research; mineral wool boards of various air permeability were used for thermal insulation and wind protection layer. After measuring the air resistance of masonry units, thermal insulation and wind protection boards, the air flow resistances of the walls of different construction were calculated. The comparison of calculated and measured air permeability of wall samples showed that in cases where the nature of air movement (laminar to turbulent) through a single material remains similar with the nature of air movement through the product incorporated in the structure, the calculation and measurement data differ no more than 12-15%. In structures with building products with very different air permeability properties, especially at high thicknesses of air permeable thermal insulation products, air movement parameters change occurs and calculated and measured results have larger differences.

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