• Aucun résultat trouvé

The Science of rain


Academic year: 2021

Partager "The Science of rain"

En savoir plus ( Page)

Texte intégral


Publisher’s version / Version de l'éditeur:

Canadian Property Management, 16, September 5, pp. 33-34, 2001-09-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la

première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

NRC Publications Archive

Archives des publications du CNRC

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at The Science of rain

Noble, S.


L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

NRC Publications Record / Notice d'Archives des publications de CNRC:

https://nrc-publications.canada.ca/eng/view/object/?id=5b24f05e-5cb6-42bd-bedd-090fee636a94 https://publications-cnrc.canada.ca/fra/voir/objet/?id=5b24f05e-5cb6-42bd-bedd-090fee636a94


The Science of rain

Noble, S.

A version of this paper is published in / Une version de ce document se trouve dans :

Canadian Property Management, v. 16, no. 5, Sept. 2001, pp. 33-34



The Science of rain

By Sheila Noble

Published in Canadian Property Management Abstract

This article discusses the purpose and operation of a new environmental exposure facility developed for building envelope research at the National Research Council’s Institute for Research in Construction.


Cet article traite de la finalité et du fonctionnement d’un dispositif simulant l’exposition des murs aux conditions climatiques mis au point pour la recherche sur l’enveloppe du bâtiment à l’Institut de recherche en construction du Conseil national de recherches.

Testing in a new test facility at the National Research Council of Canada’s Institute for Research in Construction (IRC) could hold important trickle-down effects for North American property managers—in more ways than one.

IRC’s Building Envelope and Structure Program has developed an innovative “weather machine” for testing building materials to exact specifications under controlled

conditions—with many changes over an extended period if necessary. The chamber’s inaugural run involved testing moisture management strategies for exterior wall systems, and the results could have a significant impact on property investments in the long run. Here’s the story.

Climatic simulator one of a kind in North America

Unique in North America, IRC’s new Envelope Environmental Exposure Facility (EEEF) can simulate interior and exterior climatic conditions, including temperatures (ranging from –47 to +48ºC), humidity levels (ranging from 10 to 100% RH), and most recently, wind (up to 70 kilometres/hour). Still a work in progress, the facility will also integrate the effects of rain and some aspects of infrared radiation when it reaches its full

capability in the near future.

“The building materials industry really needed a facility capable of simulating realistic North American weather conditions to conduct research and to develop new products,” says Dr. Wahid Maref, IRC Assistant Research Officer, Wall and Window Systems. “Our chamber allows companies to test their products for performance under fully controllable conditions.”

Even better, researchers can arrange for these conditions to change to cover a wide range of conditions that may occur in the natural environment. These changes include rising and falling temperatures and humidity, and dynamic wind pressure and water spray. This


feature is an important advancement for testing because previously these conditions stayed at constant levels in less advanced facilities, which was less realistic.

In addition to changing conditions, the facility’s other innovations include:

• a weighing system that detects water evaporating from the wall by measuring the weight precisely in grams and tracking this weight over time to create a drying curve;

• a frame and gasket technique for sealing the wall specimens to the enclosure without interfering with the weighing process;

• state-of-the-art moisture meters for mapping differential drying on the face of the wall to determine the different degrees of moisture build-up throughout the system; and

• a complete data acquisition package to control and monitor experiments, integrated with a comprehensive data analysis technique for interpreting the results.

IRC-industry collaboration first test for new facility

The first test for the new facility came from IRC’s Consortium for Moisture Management for Exterior Wall Systems (MEWS). The Consortium brings together IRC researchers from the Building Envelope and Codes and Evaluation programs and 11 industry partners in a four-year project that draws to a close in 2001.

To develop guidelines for moisture management strategies in wall systems for long-term performance and durability in a wide range of climate zones across North America, the MEWS Consortium is using the EEEF to study drying behaviour at the junctions of walls with other building elements, such as windows and service penetrations.

In addition, they are comparing the thermal and moisture performance of walls in various simulated climates against the predictions for this performance of an IRC computer model called hygIRC. This combined heat, air and moisture transfer—or

“hygrothermal”—modeling tool can simulate the behaviour of materials under different climatic conditions in different areas of North America, predicting quickly and efficiently for the researchers how the materials will perform in managing moisture.

Because moisture has such wide-ranging effects, each of the MEWS industry partners represents a different segment of the building industry, including membrane, plywood and insulation manufacturers, masons, and even a prominent hotel chain, which represents the interests of the property management industry. Each member has a different interest in water’s behaviour in the wall system.

“If we understand how water behaves in the wall system, we can learn how to control it and even prevent it from entering the system,” says Maref. “This includes minimizing moisture entry into the system from construction, indoor and outdoor humidity, precipitation and human activity, and maximizing moisture exit so that no component stays wet for a long time.”


Experiment’s results exceed expectations

When researchers tested current wall assemblies in the chamber, they gathered valuable information for the MEWS team on drying behaviour, particularly how quickly the wall dries under various conditions and where it dries fastest. In addition, they created a valuable body of information with which to calibrate, or benchmark, their computer model.

“We’ve had good results from the first experiments in the facility,” says Maref. “These are proving more useful than expected in benchmarking hygIRC. And the comparisons between the results of the experiment and the model predictions have given us a lot of insight into how water redistributes itself within the wall before drying out.”

With the database of information obtained from the experiments, hygIRC is well on its way to becoming a powerful modeling tool that will allow researchers and industry partners to test different parameters for building products before going into full-scale experimentation—saving time and money in the long run.

Moisture management strategies the eventual outcome

In combination with the model, the chamber will also save the industry partners time and money by allowing them to test their building products under different sets of conditions. This testing will allow them to see how the products perform in managing moisture and how quickly they dry out afterwards. Ultimately, this information could help

manufacturers find the best blend of durability, moisture resistance and drying time before going into full-scale production and wide-scale use in wall systems.

For property owners and managers, the new systems that result from this testing could result in big savings on property maintenance and operation by ensuring that the wall system used on their building is managing moisture to the greatest possible extent. These savings would come from reducing the routine maintenance schedule necessary for the property, preventing structural problems from occurring down the road and extending the service life of the building—all of which would protect the life cycle and durability of the property investment.

Currently, IRC researchers are compiling their EEEF research plan for the next few years. The next set of experiments planned for the facility involve testing window-wall interfaces for service life and durability. The researchers will also work to integrate rain and solar heating effects into the existing climatic effects.

For more information, contact Dr. Wahid Maref by telephone at (613) 993-5709, fax (613) 998-6802, or e-mail at wahid.maref@nrc.ca.


Documents relatifs

Throughout the experiments, we measure the power consumption and the mixing time in the Maxblend impeller as a function of various operating conditions. The

Spécialité PhIT Méthodologie de l’essai clinique Modèles des maladies Méta-analyse (synthèse des essais cliniques) Impact de Santé Publique Évaluation des

développement des agglomérations et la limitation des ressources en eaux souterraines, font que le pays a de plus en plus recours aux eaux superficielles provenant, principalement,

A slotted disc is attached to the shaft mnd an optical system used to produce light pulses on a phototube when the shaft rotateso The resulting electrical pulses

يناثلا لصفلا : نتلا ةطلسلا ةفك حيجرت ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ ىرخأا تاطلسلا باسح

For the Z+electron final state the lepton candidate is required to have most of its energy deposited in the electromagnetic calorimeter and satisfy the electron isolation criteria,

a IPA downstream effects analysis identifies functions that are expected to increase or decrease, given the observed gene expression changes the experimental dataset. Downstream

À l'intérieur des restrictions prescrites dans le CNÉB, l'équation utilisée dans la méthode simple des solutions de remplacement exige que la somme du produit des coefficients

Forest conservation and slippage: Evidence from Mexico ’s national payments for ecosystem services program.. Corbera E, González Soberanis C,

Methods for exploring the state sequences that explain a given observed sequence X = x for a known HMC model may be divided into three categories: (i) enumeration of state

In general, it can be seen that the copper particles did not experience significant amounts of plastic deformation on the polymeric substrates, even though the process

3 we found three types of pesticide concentration dynamics: [1] undetected pesticides (all pesticides applied on the catchment but never found in water samples), [2] chronic

The improved cycling performance of the SiX/GA nanocomposites in this work can be ascribed to the following reasons: (1) smaller sizes of silicon nanocrystals minimize pulverization

In deltaic contexts, our analysis differentiates five harbour types: (1) fluvial harbours, affected by floods, rapid sedimentation and river-channel changes; (2a)

Cette étude a pour objectif de caractériser l’élevage bovin laitier au niveau des exploitations situées dans la wilaya Bouira. Une enquête a été réalisée via un

Nous avons aussi les enjeux de coordination entre les différents acteurs de la chaîne d'approvisionnement en médicaments que nous soyons en situation de pénuries de

Le recours à des opérateurs privés pour l’accompagnement des chômeurs est encore au stade de l’expérimentation en France. Les auteures souhaitent éclairer le cas français

As a part of Parks Canada's celebration of the centennial of Canada's first National Park, two new World Heritage Sites were added to the six which have been previously designated

The model was used to investigate correlations between times trends in post-smolt survival and environmental covariates integrated over different space-time domains occupied by

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des

• Analyze flood flows from newly-assembled dataset comprising daily streamflow from minimally altered basins in North America (United States and Canada) and Europe (France,

The first step of the proposed framework allows framing (or reframing) the issue of preparedness or management of the response to a situation of long-lasting radioactive