Freeze-thaw risk in solid masonry : are moisture reference years able to represent real climate conditions?

Today, there is no consensus on the selection method of representative exterior boundary conditions when performing HAM (Heat Air Moisture) simulations on building envelopes. Many existing methods to select moisture reference years (MRY) fail to provide an acceptable validation in terms of quantified risk assessment. Although new methods have been suggested during the past few years, the influence of several parameters on the selection of “critical years” in long-term datasets still needs to be assessed. The objective of this paper is to validate the application of MRY’s to evaluate freeze-thaw risk in retrofitted solid masonry. Furthermore, the influence of the chosen wall assembly, damage criterion, preconditioning and start date of the evaluation period on the ranking of critical years is assessed, using a 31-year meteorological dataset of Brussels. Results indicate that for a given wall assembly and freeze-thaw criterion, as well as a smart start date of the evaluated period, single year simulations entail a similar ranking of critical years as the corresponding year in the 31-year simulation. The number of critical freeze-thaw cycles only varies between 0 - 2 cycles (0 - 2.9%). However, changing the wall assembly and damage criterion, alters the top 5 ranking of critical years substantially

De autoriteit van een kok: hoe van Jan van Leeuwen († 1378) een auctor werd gemaakt

During the Middle Ages the right to preach God’s Word was restricted to the Latin-educated members of the Church. Over the years they had claimed that only they had the authority to communicate and interpret divine doctrines, thereby assuring the faithful of the means by which they would achieve eternal life in heaven. It was unimaginable that an illiterate cook - officially excluded from all forms of religious authority - would be seen as capable of guiding the faithful in any way through spiritual tracts along the sublime path to the light of eternal salvation. This contribution makes clear how the lay brother Jan van Leeuwen († 1378) claimed his right to be heard, and the ways in which the Groenendaal monastery supported his mission by placing every possible facility at his disposal. By an in-depth analysis of the opera omnia manuscripts and the treatises of the ‘bonus cocus’, it will be shown how Jan van Leeuwen was styled as an auctor, worthy of faith and obedience, who could occupy a place beside the iconic Jan van Ruusbroec

Freeze-thaw risk in solid masonry : are ‘hygrothermal response based‘ analyses mandatory when studying the sensitivity of building envelopes to climate change?

The 5th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) reports important evolutions in the climate system. These changes are likely to affect the durability of the built environment. Although many contemporary studies investigate the future energy efficiency of buildings, research on the impact of climate change on the hygrothermal behaviour and degradation of building envelopes is rather scarce. Using climate projections, we studied the advantage of ‘hygrothermal response based‘ analyses over ‘climate based‘ analyses when assessing the impact climate change on façades. This paper presents a sensitivity study on solid masonry wall assemblies, before and after internal retrofitting, using three RCP (Representative Concentration Pathways) projections of the ALARO-0 Regional Climate Model at the grid point of Brussels (BE). The findings suggest the necessity of a ‘hygrothermal response based‘ analysis to study the sensitivity of the building envelope to climate change. Moreover, the largest sensitivity is observed for RCP 8.5, the scenario having the highest projected greenhouse gas concentrations by the end of the century

Factorial study on the impact of climate change on freeze-thaw damage, mould growth and wood decay in solid masonry walls in Brussels

Previous studies show that climate change has an impact on the damage risks in solid masonry facades. To conserve these valuable buildings, it is important to determine the projected change in damages for the original and internally insulated cases. Since historical masonry covers a wide range of properties, it is unknown how sensitive the climate change impact is to variations in different parameters, such as wall thickness, brick type, etc. A factorial study is performed to determine the climate change impact on freeze-thaw risk, mould growth and wood decay in solid masonry in Brussels, Belgium. It is found that the critical orientation equals the critical wind-driven rain orientation and does not change over time. Further, the freeze-thaw risk is generally decreasing, whereas the change in mould growth and wood decay depends on the climate scenario. Knowing the brick type and rain exposure coefficient is most important when assessing the climate change impact. For freeze-thaw risk and wood decay, it is found that simulating one wall thickness for the uninsulated and one insulated case is sufficient to represent the climate change impact. Finally, the effects of climate change generally do not compensate for the increase in damage after the application of internal insulation

Ressenyes

Obra ressenyada: Michel BALLARD (ed.), La traduction, contact de langues et de cultures (1) + (2). Arras: Artois Presses Université, 2005