scholarly journals Degradation Control of Walls with Rising Damp Problems

2013 ◽  
Vol 334-335 ◽  
pp. 31-36 ◽  
Author(s):  
A.S. Guimarães ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Moisture Transfer ◽  
Ventilation System ◽  
Experimental Studies ◽  
Complex Problem ◽  
Treatment Technique ◽  
Historical Building ◽  
Treatment Techniques ◽  
New Treatment ◽  
Building Physics ◽  
Rising Damp

Degradation in walls of Historical Building with rising damp is a complex problem to solve, due to the thickness and heterogeneity of those walls. The traditionally treatment techniques used (such as watertight barriers, injection of hydrofuge products, etc.) show, sometimes, to be ineffective or too expensive, justifying the need to find a new approach. Experimental studies validate the effectiveness of a new treatment technique applied to the walls of old buildings wall base ventilation system. Building Physics Laboratory (LFC) is developing a model of this technique. The sizing of the treatment system is based on knowledge of the characteristics of the wall, of the geometry of the ventilation system and of the building being dealt with. In this work it is described the moisture transfer process between the moving air flux, inside the system, and the wall. Experimental results were used to validate the mathematical solution and the values obtained are very similar.

Characterization of a Hygro-Regulated Wall Base Ventilation System for Treatment of Rising Damp

2012 ◽  
Vol 326-328 ◽  
pp. 54-59 ◽  
Author(s):  
A.S. Guimarães ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Experimental Research ◽  
Ventilation System ◽  
Experimental Studies ◽  
Salt Crystallization ◽  
Historical Buildings ◽  
New Approach ◽  
Physics Laboratory ◽  
Building Physics ◽  
Rising Damp

The treatment of rising damp in the walls of historical buildings is very complex, due to the thickness and heterogeneity of the walls. The techniques traditionally used for dealing with this problem (such as watertight barriers, injection of hydrofuge products, etc.) have sometimes proved ineffective, and that is why it is necessary to find a new approach. In recent years, the Building Physics Laboratory at the Faculty of Engineering, University of Porto has been conducting experimental research on the effectiveness of the wall base ventilation system, using natural or mechanical higro-regulate systems to reduce the level of the damp area. This experimental research and the simulations that were performed, clearly show that wall base ventilation is a system with potential. This paper presents the characterization of the hygro-regulated systems operation based on experimental studies developed in laboratory, which allowed the influence of the velocity of the air, condensation risk and the possibility of salt crystallization.

scholarly journals Tratamento da humidade ascensional no património histórico

2014 ◽  
Vol 4 (1) ◽  
pp. 1-12 ◽  
Author(s):  
V. P. De Freitas ◽  
A. S. Guimarães
Keyword(s):  
Experimental Research ◽  
Treatment System ◽  
Historical Building ◽  
Physics Laboratory ◽  
Advantages And Disadvantages ◽  
Treatment Techniques ◽  
Building Physics ◽  
The University ◽  
Rising Damp

RESUMOA humidade ascensional associada aos sais é um fator de degradação das paredes dos edifícios antigos, pelo que se exige o conhecimento do seu comportamento higrotérmico, bem como o conhecimento das técnicas de tratamento e da sua eficácia. O tratamento, face à humidade ascensional, é muito complexo e muitas das técnicas para solucionar o problema não apresentem a eficácia desejável. O Laboratório de Física das Construções da Faculdade de Engenharia da Universidade do Porto tem desenvolvido investigação numérica e experimental que permitiu validar uma tecnologia baseada na ventilação higroregulável da base das paredes para tratar a humidade ascensional, patenteando o sistema – HUMIVENT. Nesta comunicação descrevem-se as patologias associadas à humidade ascensional; as vantagens e inconvenientes das tecnologias disponíveis no mercado para o seu tratamento; caracteriza-se o sistema – HUMIVENT, a sua implementação em edifícios em Portugal e a análise dos resultados obtidos.Palavras chave: humidade ascensional; património histórico; sistema higroregulável.ABSTRACTRising damp linked with the salts is a factor in old buildings walls degradation, which requires knowledge of its higrothermal behavior, as well as the treatment techniques and its effectiveness knowledge. The rising damp treatment is very complex and many of the techniques to solve the problem do not show the desirable effectiveness. The Building Physics Laboratory of the Faculty of Engineering of the University of Porto has developed numerical and experimental research that allowed the validation of a technology based on the wall base hygroregulated ventilation to treat rising damp, patent the system-HUMIVENT. This paper aims to describe the pathologies associated to rising damp; the advantages and disadvantages of the most common available technologies for its treatment; characterize the rising damp treatment system-HUMIVENT, their implementation in Portuguese buildings and the analysis of the obtained results.Keywords: rising damp; historical building; hygroregulated system.

Case Studies of Rising Damp Treatment in Historical Buildings

2017 ◽  
Vol 10 ◽  
pp. 107-119
Author(s):  
A.S. Guimarães ◽  
J.M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Building Materials ◽  
Ventilation System ◽  
Technical Specification ◽  
Residential Building ◽  
Ventilation Rate ◽  
Building Structures ◽  
Practical Application ◽  
Salt Damage ◽  
Building Physics ◽  
Rising Damp

Salt damage can affect the service life of numerous building structures, both historical and contemporary, in a significant way. Therefore, various conservation methods have been developed for the consolidation and protection of porous building materials exposed to the salt attack. As any successful treatment of salt damage requires a multidisciplinary attitude, many different factors such as salt solution transport and crystallization, presence and origin of salts in masonry, and salt-induced deterioration are to be taken into account. The importance of pre-treatment investigations is discussed as well; in a combination with the knowledge of salt and moisture transport mechanisms they can give useful indications regarding treatment options.Another important cause of building pathologies in buildings is the rising damp and this phenomenon it is particularly more severe with the presence of salts in water. The treatment of rising damp in historic building walls is a very complex procedure. At Laboratory of Building Physics (LFC-FEUP) a wall base hygro-regulated ventilation system was developed. This system patented, HUMIVENT, has been submitted to laboratorial monitoring and to in situ validation and a numerical simplified model was developed to facilitate the practical application. Having in mind the practical application of scientific and technological knowledge from Building Physics to practice, this paper presents the design of the system (geometry, ventilation rate and hygrothermal device), the detailing and technical specification of its different components and information about the implementation in three types of buildings: a church, a museum and a residential building.

scholarly journals Salt Damage and Rising Damp Treatment in Building Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
J. M. P. Q. Delgado ◽  
A. S. Guimarães ◽  
V. P. de Freitas ◽  
Iñigo Antepara ◽  
Václav Kočí ◽  
...  
Keyword(s):  
Building Materials ◽  
Environmental Control ◽  
Treatment Options ◽  
Ventilation System ◽  
Mineral Wool ◽  
Building Structures ◽  
Salt Damage ◽  
Complex Procedure ◽  
Building Physics ◽  
Rising Damp

Salt damage can affect the service life of numerous building structures, both historical and contemporary, in a significant way. In this review, various damage mechanisms to porous building materials induced by salt action are analyzed. The importance of pretreatment investigations is discussed as well; in combination with the knowledge of salt and moisture transport mechanisms they can give useful indications regarding treatment options. The methods of salt damage treatment are assessed then, including both passive techniques based on environmental control, reduction of water transport, or conversion to less soluble salts and active procedures resulting in the removal of salts from deterioration zones. It is concluded that cellulose can still be considered as the favorite material presently used in desalination poultices but hydrophilic mineral wool can serve as its prospective alternative in future applications. Another important cause of building pathologies is the rising damp and, in this phenomenon, it is particularly severe considering the presence of salts in water. The treatment of rising damp in historic building walls is a very complex procedure and at Laboratory of Building Physics (LFC-FEUP) a wall base hygroregulated ventilation system was developed and patented.

The Rising Damp in Cultural Heritage: From Physical and Numerical Analyse to Practical Application

2016 ◽  
Vol 7 ◽  
pp. 128-176 ◽  
Author(s):  
J.M.P.Q. Delgado ◽  
A.S. Guimarães ◽  
V.P. de Freitas
Keyword(s):  
State Of The Art ◽  
Ventilation System ◽  
Experimental Treatment ◽  
Practical Application ◽  
General Introduction ◽  
Treatment Techniques ◽  
Future Work ◽  
Rising Damp

The main goal of this work is to present a complete review of rising damp treatment in building heritage using a technique developed in our group to estimate and mitigate the height of the rising damp front and to predict the improvements of some experimental treatment techniques. The paper present a mathematical and a numerical analyse of the problem; an experimental and a practical application of the technique developed. This work is distributed into six main sections, in addition to this general Introduction: This book chapter is divided in several sections. Initially, it is presented the “state of the art” synthesis, where it is studied the techniques traditionally used for the rising damp treatment, showing the existing limitations on its application in monumental heritage and in old or ancient buildings, with specific characteristics. Then, it is performed the idea and the operating principle of the new technique, known as the wall base ventilation system, on the basis of previously conducted studies. An analytical, numerical and “in-field” study it is presented based in a case study described in detail. Finally, it is done a critical analysis of the results obtained, projecting the future work.

Rising Damp: Optimization of the Wall Base Ventilation System

2014 ◽  
Vol 353 ◽  
pp. 311-316 ◽  
Author(s):  
A.S. Guimarães ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Experimental Validation ◽  
Moisture Transfer ◽  
Transport Model ◽  
Ventilation System ◽  
Physical Parameters ◽  
Important Research ◽  
Evaporation Model ◽  
Water Vapour Transport ◽  
Distant Relative ◽  
Rising Damp

Rising damp constitutes one of the main causes of monumental heritage and old buildings degradation, especially, its thick walls with heterogeneous composition. The LFC-FEUP has been developed important research in rising damp domain. In recent years, was validated and experimentally characterized the operation principle of a technique called "wall base ventilation system" for the treatment of rising damp in monumental heritage and ancient buildings consisting of circulating air at the base of the buildings walls with high thickness and heterogeneity in its constitution, with a saturation distant relative humidity. The studies previously developed allowed the interest and viability of the proposed system, taking time to develop a methodology for optimizes it. In this paper it is presented the optimization of the wall base ventilation system based on some important physical parameters. To optimize the system, it was developed a 2D evaporation model that describes the moisture transfer between the system and the wall as well as the water vapour transport throughout the system (Evaporation and Transport Model – ETM). It was also used and adapted another 2D model, to describe the rising damp phenomenon in buildings walls, considering the wall base ventilation system (Rising Damp and Evaporation Model – RDEM). Finally, the design model was developed, using both models (ETM and RDEM) and some experimental validation was done, which allowed the comparison between the levels archived by the wet front analytically and experimentally.

Implementation and Monitoring of Higroregulated Wall Base Ventilation Systems to Control Rising Damp

2015 ◽  
Vol 365 ◽  
pp. 154-159
Author(s):  
A.S. Guimarães ◽  
J.M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Treatment Technique ◽  
Drying Process ◽  
The North ◽  
Building Physics ◽  
The Church ◽  
Rising Damp ◽  
Ventilation Systems

This work describes the implementation of two higroregulated wall base ventilation systems in a church in the North of Portugal for the treatment of rising damp and presents the results of four years of the systems monitoring. It is a work developed by LFC – Laboratory of Building Physics of FEUP, where the main goal is to validate and optimize this treatment technique. It was assessed the functioning and effectiveness of the implemented systems, minimizing the likelihood of condensation inside them and maximizing the drying process through the adoption of higroregulated systems. With the monitoring carried out it is possible to conclude that, for the analyzed climate, it is better to adopt a seasonal operation, where the air is admitted from the exterior, during the warm months, and in the cold months the air is admitted from the interior of the Church.

Numerical Simulation of Rising Damp Phenomenon

2012 ◽  
Vol 326-328 ◽  
pp. 48-53 ◽  
Author(s):  
A.S. Guimarães ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Direct Contact ◽  
Moisture Transfer ◽  
Historical Buildings ◽  
Soluble Salts ◽  
Water Absorption Coefficient ◽  
Fraunhofer Institute ◽  
Building Physics ◽  
Rising Damp

The treatment of rising damp in historical buildings walls is very complex. Moisture transfer in walls of old buildings, which are in direct contact with the ground, leads to a migration of soluble salts responsible for many building pathologies. The present work describes an extensive numerical analyse of rising damp phenomenon, using the software WUFI-2D, developed by Fraunhofer Institute for Building Physics. The results show that the numerical simulation describes very well the rising damp front for different boundary conditions and materials. The influence of the wall thickness, boundary conditions, composition of walls and material properties, such as, porosity and water absorption coefficient were analysed in detail.

Copper corrosion control in the Netherlands

2001 ◽  
Vol 1 (3) ◽  
pp. 75-82 ◽  
Author(s):  
P.G.G. Slaats ◽  
H. Brink ◽  
T.J.J. van der Hoven
Keyword(s):  
Drinking Water ◽  
The Netherlands ◽  
Treatment Techniques ◽  
Copper Pipe ◽  
Copper Release ◽  
Average Intake ◽  
Split Treatment ◽  
New Treatment ◽  
Monitoring Protocols ◽  
Copper Solubility

Copper is the most commonly used material for pipes in domestic installations in the Netherlands. Depending on the composition of the water the copper pipes can add a significant amount of copper to drinking water. In the new European Drinking Water Directive (98/83/EC) the parametric value for copper in drinking water is decreased from 3 to 2 mg/l. The new directive also stipulates that copper levels should be determined on the basis of a sample ‘taken at the consumers' tap’ representative of the weekly average intake by humans. Harmonisation of monitoring protocols for copper in the European member states is necessary. In the Netherlands about 45% of the drinking water is already softened or de-acidified in order to decrease copper concentrations in drinking water. In the Netherlands two new treatment techniques have been studied for their impact on copper release; these are Reverse Osmosis (RO) and the addition of inhibitors. Copper pipe rig tests have shown that RO treatment decreases copper release. Split treatment of water with RO reduces copper solubility of drinking water through a decrease in both total inorganic carbon (TIC) and sulphate level. Remarkable was the relatively small decrease in copper release after split treatment with RO, compared to previous experiences in the Netherlands, suggesting an effect of natural organic matter. A new promising technique in the Netherlands is the addition of the inhibitor carbonate-activated silicate. At the test sites, the reduction in copper solubility due to the use of carbonate-activated silicate was 15 to 35%.

scholarly journals Removal of Toxic Elements and Microbial Contaminants from Groundwater Using Low-Cost Treatment Options

2021 ◽  
Author(s):  
Dana A. Da’ana ◽  
Nabil Zouari ◽  
Mohammad Y. Ashfaq ◽  
Mohammed Abu-Dieyeh ◽  
Majeda Khraisheh ◽  
...  
Keyword(s):  
Cost Analysis ◽  
Toxic Elements ◽  
Low Cost ◽  
Treatment Technique ◽  
Groundwater Treatment ◽  
Efficient Treatment ◽  
Treatment Techniques ◽  
Cost Treatment ◽  
Treatment Technologies ◽  
Microbial Contaminants

Abstract Purpose of Review This paper reviews various low-cost treatment techniques such as adsorption, permeable reactive barrier, and biological techniques for the simultaneous removal of chemical and microbial contaminants from groundwater and discusses treatment mechanisms of different treatment techniques. This paper also discusses the challenges of groundwater treatment, how to choose the appropriate treatment technique, and cost analysis of groundwater treatment. Recent Findings Various treatment technologies have been used for the treatment of groundwater: physical, chemical, and biological technologies with different success rates. In the literature, various adsorbents have been successfully synthesized from low-cost and environmentally friendly materials. Adsorption is considered an efficient treatment technique for the removal of both toxic elements and pathogens by utilizing different adsorbents. For example, the nanostructures of MgO with a BET surface area of up to 171 m2/g obtained a very high adsorption capacity of 29,131 mg/g for fluoride ions in water, while the incorporation of iron in activated carbon has improved its adsorption capacity to 51.3 mg/g for arsenic. Moreover, certain adsorbents have shown the capability to remove 99% of the rotavirus and adenovirus from groundwater. Summary Groundwater resources are contaminated with toxic metals and pathogens. Therefore, water treatment technologies should be evaluated for their efficiency to remove such contaminants. Determination of the most cost-effective and efficient treatment technique is not an easy task and requires the understanding of various aspects such as the contaminants present in water, the reuse options considered, and cost analysis of the treatment technique.

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