José M. Pérez-Bella

• Ms. Eng, Ph.D.
• University of Zaragoza

Rainwater penetration into building facades results in multiple issues, including material and structural degradation, reduced energy efficiency, and health-related concerns among occupants. Currently, the watertightness performance of building facades is assessed based on standardized tests, which simulate generic water supplies and pressure diffe...

A wide variety of engineering applications requires the use of maximum values of rainfall intensity and wind speed related to short recording intervals, which can often only be estimated from available less exhaustive records. Given that many locations lack exhaustive climatic records that would allow accurate empirical correlations between differe...

Rainwater penetration on building façades has a significant impact on the durability, hygrothermal performance, and habitability of buildings. This research characterises the directional exposure of Mexican façades to rainwater penetration by identifying wind-driven rain (WDR) and driving rain wind pressure (DRWP) throughout the country. For this p...

The thermo-hygrometric conditions to which construction materials are subjected cause their thermal performance to vary by location. These variations must be characterised in order to design building envelopes adjusted to the requirements of each situation, thus contributing to improve their energy efficiency under actual operating conditions. To t...

The damaging effects caused by the penetration of rainwater into building façades require considering for their design the exposure to the two main climatic factors inducing this penetration: wind-driven rain and the simultaneous wind pressure. The characterisation of these exposures for each possible façade orientation of a building requires analy...

ISO standard 15927-3 establishes two calculation methods to characterise wind-driven rain exposure on building façades, with different approximations according to the available climatic data: (i) a reference method, using hourly wind and rain data, and (ii) an alternative method using average wind records and the present weather code for rain in ha...

The joint action of wind-driven rain and wind pressure is the main cause of water penetration in building facades, which causes various habitability and durability problems. The most widespread characterisation of both climate factors is based on exposure indices calculated in free-field conditions from records of precipitation—wind speed (scalar i...

Both semi-empirical methods and CFD simulations use real climate datasets as a basis for determining the building facade exposure to wind-driven rain and simultaneous wind pressure. The time resolution of these datasets and the number of variables considered (commonly rainfall intensity, wind speed and wind direction) determine the required calcula...

The Spanish Technical Building Code establishes a temperature of 10°C and an equilibrium moisture content with a relative humidity of 50% and 23°C, respectively, as reference to determine the design thermal values of construction materials. However, these reference values are not consistent with the actual climatic conditions of the country, result...

La caracterización higrotérmica de los cerramientos influye decisivamente en la precisión del diseño térmico de los edificios, afectando a su ahorro energético, costes de utilización y sostenibilidad. El trabajo analiza las incertidumbres que la normativa actual alberga para esta adecuada caracterización en los materiales de fachada, y proporciona...

The penetration of atmospheric water (rain) into facades creates problems for building habitability and the durability of construction materials. This study analyses the exposure of Brazilian facades to the two main climate factors responsible for this penetration: wind-driven rain and driving rain wind pressure. Daily weather records (spanning 200...

The accurate determination of a facade's watertightness performance is important for optimizing design. Different micro-climatic conditions can affect water penetration. The recently developed Bayesian method allows this performance to be estimated for any operating condition and location, based on the results of standardized watertightness tests....

There is currently a lack of international harmonization on the insulation requirements for the buildings. Given that this parameter defines the maximum energy losses allowed through a thermal envelope, building energy consumptions can vary considerably between countries. Both the United States of America (US) and the European Union (EU) should add...

The hygrothermal performance of building envelopes varies based on the temperature and moisture content of their materials. However, multiple building codes adopt constant conductivity values for construction materials based on standardised conditions that do not represent real operating conditions. Currently, a new procedure allows for correcting...

The Spanish Technical Building Code published in 2006 regulates the basic requirements of building façades to prevent the inadequate presence of atmospheric water inside Spanish buildings. The moisture exposure estimate, based on several climate parameters, allows adjusting these requirements for every location and façade. However, the parameters u...

The thermal conductivity of building envelope materials varies according to the conditions of temperature and moisture content. Precisely determining the thermal conductivity is a primary challenge in developing more appropriate, realistic thermal designs for buildings. However, a detailed implementation of environmental conditions requires either...

Watertightness tests allow evaluating the performance of building façades using standardised parameters that simulate real weather conditions, i.e., a combination of wind-driven rain and driving rain wind pressure. It has been a challenge for researchers to experimentally test simultaneous wind and rain conditions in a rigorous manner. However, two...

Assessing the water penetration exposure of building façades is a key task to guarantee the water tightness requirement included in the Spanish Building Technical Code since 2006. Recent studies have analysed the most relevant climate parameters that characterise this exposure at 80 Spanish locations. For this, international standards transposed in...

There is currently a lack of harmonization in the building energy efficiency requirements that are mandated by different countries. Energy efficiency is defined by the energy yield of the facilities and by the envelope energy losses. These energy losses are mainly conditioned by the thermal envelope transmittance, the compactness factor, and the in...

Wind-driven rain and the simultaneous action of wind pressure contribute to water penetration into building façades. Therefore, both climatic parameters must be considered in the design of building enclosures to manage the effects of water intrusion. This article presents a procedure for determining both parameters in a geographic area, by combinin...

In this paper, the response surface methodology (RSM) and finite element method (FEM) have been used to develop predictive models for the simulation and optimization of heat transfer process. The input variables were the material conductivity as well as the radiation emissivity, length and width of the recesses. The response variable considered was...

La penetración de humedad atmosférica en los cerramientos tiene gran influencia en el sector de la construcción y es responsable de múltiples problemas constructivos con una importante repercusión económica. El trabajo proporciona una introducción didáctica a los factores que intervienen en esta penetración y analiza la problemática desde el prisma...

Water tightness tests for building façades attempt to simulate the most relevant climatic exposures for water penetration by reproducing standard conditions. Because such conditions do not represent all possible climatic exposures for such enclosures, a new method was presented in a previous work that relates test severity to water tightness perfor...

Wind-driven rain and wind pressure are two fundamental climatic parameters affecting the penetration of wáter through building facades. Water tightness tests attempt to reproduce exposure extremes in order to evaluate the resistance to the passage of water through a facade. However, the exposure conditions for a given return period in a real situat...

This article defines a new index to characterise the risk of atmospheric water penetration into building enclosures. This risk index integrates the two most relevant exposure parameters for this phenomenon into a single value, combining the water supply presented by driving rain and simultaneous wind pressure on the surface of the enclosure. Compar...

This paper presents an experimental research work in order to obtain the main hygrothermal properties of different mixes of lightweight concrete (LWC) produced from expanded clay. Nowadays, the current state of art assumes an exponential relationship between the moisture content and the thermal properties for this kind of building material. The pri...

In this article, the annual directional exposure to driving rain and its characteristics are analysed and discussed at four Spanish sites that are characterised by different rainfall levels and topographical and wind conditions. For this study, the present weather observation method is used, which is based on average annual rainfall data and synopt...

This article presents a plan of action composed of various initiatives for including sustainable development education (SDE) transversally within university degree programs. The most important initiative is that of introducing sustainable development (SD) as a basic transversal skill for each thematic unit of the class, thereby completely modifying...

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In this study, the severity of the exposure of buildings in Spain to driving rain is estimated. The anual driving rain index (aDRI) is determined at 80 sites spread across Spain, based on wind and rain data recorded daily over 30 years. The comparison among the driving rain indices based on daily, monthly and annual climatic data, allows assessing...

The Spanish Building Technical Code, named CTE standard rule, establishes the present safety and habitability requirements in the building projects. This standard has been implemented in several phases since the year 2006. The CTE has adopted recent international approaches to other building standard rules, such as the performance-based codes or ob...

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