Two strategies for containing moisture migration

For the building team, the design of library, archives and museum facilities brings with it special responsibilities. Archive and conservation facilities require the highest levels of preservation and maintenance of the building environment. Understanding how to maintain and preserve vulnerable materials is a key component to developing a successful design solution.

Dynamic buffer zone - Controlling moisture and heat flow

The building envelope is primarily an environmental separator, which allows indoor spaces to bemaintained at different conditions from the outside environment. Intentional humidification during the heating season is a common practice in cold climates. Moisture escaping from a humidified building due to air leakage through flaws in the air barrier system can negatively affect the durability of the building envelope.

Moisture accumulation in imperfect hydraulic contact building materials

This paper presents the results of a series of specially designed experiments to study moisture transport across bonded or natural contact interfaces between building materials. The results showed that the bonded or natural contact interfaces between aerated concrete and mortar are imperfect hydraulic contact. In addition, all the tested cases were simulated using a numerical model. The results showed that there was good agreement between experimental results and predictions made by the model.

Study on indoor humidity distributions

This study investigates the behavior of vapor in a ventilated room in which vapor is being produced. A test chamber equipped with three types of ventilation ducts and a vessel filled with heated water for evaporation was analyzed both experimentally and numerically. Experimental results showed that temperature and moisture distributions differed depending on the ventilation types. A numerical model of vapor generation from the heated water was introduced to simulate the evaporation.

Numerical modelling of unsteady humidity transport and accumulation in walls

The purpose of the work is the determination of unsteady variation of the moisture content in the walls. The mathematical model is based on humidity transport equations in porous media. The humidity transport takes place as a result of the presence of both moisture content and vapour pressure differences. Using the proposed mathematical model, a computer program was developed in EES (Engineering Equations Solver). Numerical simulations were made for an office room, considering interior walls containing a gypsum board layer.

Moisture transport in building materials with imperfect hydraulic contact interfaces

Based on the experimental results and predictions of a numerical model, the effects of uncertainty in estimation of imperfection of the interface on moisture transport were studied in the present study. It was found that, even though the imperfection of the interface varied with moisture content during the wetting process, the prediction using a constant resistance of the interface was close to that using an actual value.

Sufficiency of cleaning after repair of mold damage evaluated by microbiological methods

Constructional aspects and the use of school building had led to moisture and mold damages confirmed by microbiological analysis from material, surface and air samples. Cultivation methods were used to assess mesophilic fungi and actinobacteria. High concentrations of microbes (10 5 -10 6 cfu/g in different materials) were recovered from the samples. Microbes included great variety of moisture indicating species (e.g. Aspergillus versicolor, Trichoderma, Fusarium, Stachybotrys, Chaetomium, Streptomyces).

Interstitial condensation due to air leakage: A sensitivity analysis.

This paper presents an approach to evaluate the sensitivity of a roof design to condensation problems, given the uncertainty to achieve continuity of airtightness in practice. The approach consists of a repeated number of simulations with a 2D heat, air and vapour transfer model to predict the variation in roof moisture performance due to various discontinuities in roof geometry. The set of discontinuities is calibrated by comparing measuring data of roof airtightness to simulation results.

Displacement ventilation for room air moisture control in hot and humid climate

Few studies dealing with the effect of displacement ventilation on humidity gradient in a hot and humid region have been made . In this paper it is done with a case-study approach (measurements were made in a factory located in the Tropics). The results indicate that the humidity gradient is as significant as the temperature gradient..

A zonal model for predicting simultaneous heat and moisture transfer in buildings

A zonal model was developed to predict temperatures and moisture in a room taking into account the adsorption/desorption by building materials. Results show how adsorption/desorption influences the moisture field.

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