Technical Building Code Research Articles

Comparative analysis of thermal characterisation methodologies of a historical double leaf masonry wall

Energy consumption for heating and air conditioning is one of the main factors to consider in the energy efficiency of buildings. Correctly assessing thermal losses in the envelope is essential for decision making when it comes to minimising the cost of using thermal installations and improving the thermal comfort of a building. This paper presents a comparative analysis between different thermal transmittance characterisation methodologies. The comparison is carried out between different quantitative methodologies, including that which is described in the Spanish Technical Building Code CTE DB-HE, direct measurement methodologies through an analysis of materials, and in-situ measurements based on the recording of heat flux and temperature differentials as described in ISO 9869. The results of the application of these methodologies on a traditional Mediterranean wall reveal significant differences between each of them. Further, the discrepancies between the default transmittance values and the values obtained through direct measurement of the envelope are determined.

Indoor Radon Concentration Related to Different Radon Areas and Indoor Radon Prediction

Indoor radon has been observed in the buildings at areas with different radon risk potential. Preventive measures are based on control of main potential radon sources (soil gas, building material and supplied water) to avoid building of new houses above recommended indoor radon level 200 Bq/m3. Radon risk (index) estimation of individual building site bedrock in case of new house siting and building protection according technical building code are obligatory. Remedial actions in buildings built at high radon risk areas were carried out principally by unforced ventilation and anti-radon insulation. Significant differences were found in the level of radon concentration between rooms where radon reduction techniques were designed and those where it was not designed. The mathematical model based on radon exhalation from soil has been developed to describe the physical processes determining indoor radon concentration. The model is focused on combined radon diffusion through the slab and advection through the gap from sub-slab soil. In this model, radon emanated from building materials is considered not having a significant contribution to indoor radon concentration. Dimensional analysis and Gauss-Newton nonlinear least squares parametric regression were used to simplify the problem, identify essential input variables and find parameter values. The presented verification case study is introduced for real buildings with respect to various underground construction types. Presented paper gives picture of possible mathematical approach to indoor radon concentration prediction.

Design and analysis of an industrial steel building. Limit states, stability check

This work is focused on the design of a structural steel industrial building of double-T type section located in an industrial area of Valladolid (Spain). Firstly, a linear analysis is carried out to dimension the structure and check that it resists according to the established regulations, the Technical Building Code (CTE), the national adaptation of the Eurocodes (ECs). For the analysis of the structure, the 3D model of slender bar bending (Navier-Bernoulli bending theory) and the non-uniform twist or constrained warping model (Vlasov’s torsion theory) are considered. In the second place, a nonlinear analysis is performed with the objective of verifying the Ultimate Limit State of stability of the structural elements and of the industrial building as a whole. All this without the need to estimate buckling coefficients of each of the beams that make up the structure, and without the need for important simplifications. Finally, a linear analysis is once more performed to check the Service Limit State for the frequent combination of actions. The solution of the problem results from an iterative process of searching for the best solution, that is, the one that, with the least amount of steel used, fulfills all the requirements: resistance, stability and displacement limits established by the current regulation.

El Diseño Basado en Prestaciones frente al Incendio de las Estructuras de Edificación

En el presente trabajo se presentan las ventajas de utilizar el Diseño Basado en Prestaciones cuando se afronta la seguridad de las estructuras frente a la acción del incendio, se aporta una visión general del método y se muestran las ventajas de su aplicación en proyectos singulares de edificación a través de un caso real de estudio. Aunque el diseño prestacional tiene un amplio recorrido en países como el Reino Unido, Estados Unidos o Japón, con más de 30 años de evolución y desarrollo, en España hace apenas una década que la normativa ha abierto las puertas a utilizar el diseño prestacional. Sin embargo, aunque el Código Técnico de la Edificación anima a los diseñadores a llevar a cabo esta estrategia de trabajo, aún es poca la información que incorpora para tal fin.

Dynamic evaluation of the thermal inertia of a single-family house: Scope of the retrofitting requirements to comply with Spanish regulations

This paper presents a study of the thermal performance of a single-family house located in a coastal city in northern Spain that was built according to Spanish standards during the 1990s. The study estimates an annual energy demand of around 95kWh/m2 and a thermal power rating of the heating system of around 16kW. The potential energy savings that would be obtained by implementing different retrofitting measures frequently used nowadays are also quantified: installing a ventilation system with heat recovery, improving the insulation of opaque construction elements, replacing the existing windows with high-thermal performance windows, and reducing air infiltration rates. These integrated actions on the house would reduce the annual energy demand below the requirements of both the Technical Building Code (24.24kWh/m2year for this case of study), which is the regulation currently in force in Spain, and the well-known Passivhaus standard (15kWh/m2year), which is one of the most widespread building standards in Europe. Compliance with these requirements means that the annual energy demand and the size of the heating system would respectively be potentially reduced by 81% and 57% of the present values.

Environmental and energy impact of the EPBD in residential buildings in cold Mediterranean zones: The case of Spain

The residential sector in the European Union accounts for 27% of final energy consumption and 23% of CO2 emissions. Due to this situation, the European Union, in order to strive for greater energy efficiency and savings, has established the Energy Performance of Buildings Directive, which, in the case of Spain, takes the form of a Basic Document outlining Energy Saving in the Technical Building Code (CTE-DB-HE). The aim is to perform an energy and environmental analysis in a multi-family housing block, evaluating improvements that are the result of the implementation of the CTE-DB-HE and comparing them with the previous situation. For this purpose, five representative cases for 26 Spanish cities located in cold climate zones are analyzed. The results reveal that with the current rules, an energy demand reduction of over 60% is achieved. In addition, 65% higher reductions are obtained both in the non-renewable primary energy consumption and CO2 emissions, thereby achieving class B building status. These remarkable savings show that the right direction is being taken toward nearly zero-energy buildings (NZEBs).

Analysis of the influence of wood cladding on the thermal behavior of building façades; characterization through simulation by using different tools and comparative testing validation

New policies on energy efficiency in buildings aim to improve our environment. EU requirements on reduced energy demand to achieve Nearly Zero Energy Buildings are of equal importance to pollution and raw-material consumption. Addressing these parameters, building life-cycle analyses are needed, not only to reduce energy consumption, but also to encourage the use of renewable materials. Other priorities are building maintenance and construction material management at the end of the useful life of the building. The use of wooden façades is not very common in Spain. In this study, its energy efficiency is assessed against Spanish Government Regulations, through the Building Technical Code. Hence, this analysis of wooden façades examines their influence on the thermal behavior of the whole building, considering both material properties and structural design, focused on the exterior cladding or protective layer. These structures imply an optimized assembly design together with the application of a protective treatment, depending on its natural durability. “Radiata pine” was selected as one of the most common pine species in the Basque Country, suitable for cladding and grown in sustainable forestry programs. Several commercial simulation tools were used, such as: Therm, Wufi, and DesignBuilder aiming to a full thermal characterization of these particular enclosures, whereas the results obtained were finally validated through an experimental facility.

Rooftop analysis for solar flat plate collector assessment to achieving sustainability energy

The insufficiency of current energy sources, elevated costs and global climate worriment are distinctive factors making of renewable energy an issue of boosting consideration. In this concern, solar energy is viewed as being indefinitely environmental friendly, carbon-free, beneficial nature with appreciated cost potentials and is witnessing fast progressing. Following the Horizon 2020 climate and energy package, the volume of gases emitted by greenhouses has to be cut down by 20% by all the European Union (EU) member countries in order to enhance energy performance by 20% and raise the renewable energy rate to 20% by 2020. Solar energy on building roofs plays a crucial aspect in renewable and sustainable energy consumption of high-density human habitats. A merest energy should be allocated to provide hot water service from solar sources, as other European norms for new buildings by the Spanish Technical Building Code, similarly to other European regulation on achievement objectives. The climate zone and the overall demand of hot water in the building regulate this minimal amount needed. This manuscript use a new methodology for automatic detection of geometric patterns from aerial or space images using a Hierarchical Temporal Memory (HTM) algorithm. In this way, an automatic method for the identification of building roofs in order to assess the opportunities available to install solar thermal systems in small urban areas has been developed. As case of study: a village with 7000 inhabitants was analyzed in the South of Spain. The maximum overall accuracy obtained among the different classifications made was 98.05%, avoiding problems related to the use of images with high spatial resolution, as in the salt-and-pepper noise effect. This approach contributes reducing the generated carbon and GHG emissions and open new perspectives for energy savings strategies to optimize the energy efficiency of buildings. In the case study, implementing the solar thermal systems would come out with a saving of 1.4 tons of CO2 per inhabitant.

AJUSTE DE LA CONDUCTIVIDAD TÉRMICA DE DISEÑO FIJADA POR EL CÓDIGO TÉCNICO DE LA EDIFICACIÓN PARA MATERIALES DE FACHADA

The Spanish Technical Building Code establishes a temperature of 10°C and an equilibrium moisture content with a relative humidity of 50% and 23oC, 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, resulting in optimistic designs of the building thermal envelopes and higher energy consumptions than expected by design. This article analyses these differences, reviews the weaknesses of the Spanish Code in this area, and uses a recently developed procedure to determine the actual thermal conductivity of facade materials with similar precision and less calculation effort that the standard UNE-EN ISO 10456. All this would contribute to improve the thermal design currently defined for the Spanish buildings.

Urtarokobiltegiratze termikoko sistemen bideragarritasun tekno-ekonomikoaren azterketa

Gaur egun, Europako energiaren kontsumo osoaren %40 eraikinek eragiten dute.Kontsumo horren barnean, eraikinetako berokuntza eta ur bero sanitarioaren (UBS) erabilera nabarmentzen da, batik bat. Espainiaren kasuan, berokuntza %50 da, eta UBSa, berriz, %27. Proiektu honen bitartez, Espainia mailan Urtarokobiltegiratze termikoko sistemen (STES)bideragarritasun ekonomiko zein energetikoa aztertu da. Espainiako hainbat hiritako eskari termikoak simulatu dira, eta STESaren bitartez berogailuko eta UBSko eskari osoaren %45-60 artean asetzeko saiakera egin da. Beraz, ikusita eraikinetan kontsumo energetiko handia izaten dela, eta, gainera,jakinda Eraikuntzarako Kode Teknikoak (CTE) ur bero sanitariorako eguzki-energia termikoaren kontribuzio minimoa derrigortzen duela, sistema horien bideragarritasunaren azterketa ezinbestekoa da. Hala, energia berriztagarrien erabilera sustatzen da.

Update of energy performance certificates in the residential sector and scenarios that consider the impact of automation, control and management systems: A case study of La Rioja

Energy performance certificates are considered to be tools for knowledge and energy planning in the residential sector. Although energy performance certificates describe primary energy consumption and the associated emissions of a home or building, they do not consider the influence of building automation control systems (BACS) or technical building management (TBM) systems on these parameters. The European Standard EN 15232 remedies this shortcoming and evaluates the savings in primary energy and the reduction of CO2 emissions that can be achieved by these systems. This study investigates the energy performance certificates registered in the Autonomous Community of La Rioja and considers the policy changes in the Technical Building Code (Código Técnico de la Edificación) and, specifically, the Basic Document for Energy Saving (Documento Básico de Ahorro de Energía) (CTE-DB-HE). Due to this regulatory change, we corrected the certificates and outlined different scenarios based on the implementation of these systems in this study. These scenarios show the potential distribution of energy performance certificates and the improvements in the ratings obtained.

Climatic zoning for the calculation of the thermal demand of buildings in Extremadura (Spain)

The present work reports on a methodology to assess the climatic severity of a particular geographic region as compared to specific information available in the current regulations. The viability for each of the 387 municipalities in the Autonomous Community of Extremadura (Spain) is analysed, making a distinction between those with reliable climate reports and those for which no such information is available. In the case study, although the weather conditions in Extremadura are quite homogeneous according to the Spanish Technical Building Code (STBC 2015) classification and most areas are associated to zone C4 (soft winters and hot summers), the southern area in the region is associated to zone D1, similar to the north of Spain, where winters and summers are cool, which does not coincide with the actual climate in the south of Extremadura. The general climatic homogeneity in Extremadura was also highlighted with the new procedure, predominating zone C4, but unexpected or unreal climatic zoning was not generated, giving place to a consistent spatial distribution of zones throughout the region. Consequently, the proposed method allows a more accurate climatic zoning of any region in agreement with the Spanish legislation on energy efficiency in buildings, which would enhance the setting of thermal demand rates according to the actual climatic characterisation of the area in which a particular municipality is located.

Revisión y mejora de la caracterización del grado de impermeabilidad requerido por el CTE DB-HS1 para fachadas de edificación

The Spanish Technical Building Code published in 2006 regulates the basic requirements of building facades 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 facade. However, the parameters used by the Spanish Code can be improved, resulting in a more appropriate estimate of the required water tightness degree and thus in an improvable allocations of the necessary design conditions. This paper reviews these parameters, presenting other internationally applied, and analyses the moisture exposure in the Spanish territory, which would allow improving the subsequent performance of the basic requirements imposed to the facades.

New Plaster Composite with Mineral Wool Fibres from CDW Recycling

Over the last decade the intense activity of the building sector has generated large quantities of construction and demolition waste (CDW). In particular, in Europe around 890 million tons of CDW is generated every year; however, only 50% of them are recycled. In Spain, over the last years 40 millions of tons of construction and demolition waste have been generated. On the other hand, since the implementation of the Technical Building Code regulation the use of mineral wools as building insulation materials has become a widespread solution in both rehabilitation and new construction works, and because of that, this kind of insulation waste is increasing. This research analyzes the potential of a new composite (gypsum and fiber waste) including several mineral wools waste into a plaster matrix. For this purpose, an experimental plan, characterizing the physical and mechanical behaviour as well as the Shore C hardness of the new composite, was elaborated fulfilling UNE Standards.

Analysis of Cracking Moment of Flexural Elements Reinforced by Steel and FRP Reinforcement

The application of FRP reinforcement in concrete structures is quite popular nowadays. In this article the cracking moment of flexural concrete structures reinforced by steel and FRP reinforcement bars is investigated. There is estimated that the behaviour of tensile concrete is nonlinear when crack opens. The nonlinearity was estimated by two different cases. In the first one the coefficient of elastic and plastic strain of tensile concrete were applied and in the second the stress-strain relationship were expressed by polynomial function. That function prepared according to compressed concrete stress-strain diagram described in design standard EN 1992-1-1. Those two different stress-strain relationships were used for cracking moment calculation. Also the cracking moment calculations were performed using mentioned standard EN and Technical building code STR 2.05.05:2005. In all cases the calculations were performed in assumption that the behaviour of compressed concrete is elastic when crack opens. The obtained results were analysed and presented base conclusions. DOI: http://dx.doi.org/10.5755/j01.sace.9.4.7428

A proposed method based on approximation and interpolation for determining climatic zones and its effect on energy demand and CO2 emissions from buildings

The accuracy in assigning a climatic zone to a city is essential for studying the correct sizing of domestic hot water, heating, and cooling systems, as well as of construction materials. In Spain, the current system for allocating climate zones is one proposed by the Código Técnico de la Edificación (Technical Building Code) (CTE) and includes a method based on Royal Decree 235/2013, Procedimiento Básico para la Certificación de Eficiencia Energética de Edificios de los Edificios (Basic Procedure for Certification of Energy Efficiency of Buildings), as well as on the recognized document CERMA to calculate energy demands, CO2 emissions, and energy ratings. The climatic data of cities is not always available, so the CTE method has proposed some solutions, but they are not always precise enough. In this paper, we propose an alternative classification of climatic zones as a result of applying a new method based on approximation and interpolation functions, with a maximum error of 5.773e−15 in summer and 6.661e−16 in winter. This new method has been applied and tested in Andalusia in Southern Spain, a region with 772 municipalities. According to the climatic data available, the new proposed method has resulted in more precise climatic zones than the two versions of the CTE (2009 version and the 2013 update). The results are closer to reality, and the method is exportable to any region.

Analysis of wind action on unique structures with application to Seville Fair Gateways

The implementation of temporary large structures for different events such as large stages for concerts, advertising posters or symbolic accesses to public festival areas is threatened by the danger of collapse due to wind action. An analysis of the European code is necessary, using comparisons with other analysis tools such as wind tunnels, to establish whether such standards are secure for specific unconventional geometries.For the purposes of this comparison, a model corresponding to a particular structure is analyzed, the Gateway to the Seville Fair in Spain. This paper first establishes a comparison between the national and the European code for wind action: the Spanish Technical Building Code (CTE DB SE-AE 2006) and Eurocode 1 (EN 1991-1-4 2007), taking into account that the national code has been developed using the European one as a model. Both standards are analyzed to demonstrate that the national code is not fully adapted to the European one. Subsequently, the results obtained from the European code are compared with those derived from the development of an experimental test of the same model in a wind tunnel.The final objective of this paper is to demonstrate that neither national nor international codes are valid for structures with unique geometries, and therefore in this case it is necessary to perform an experimental test to determine wind action accurately.

APLICACIÓN AL CÓDIGO TÉCNICO DE LA EDIFICACIÓN DE AVANCES EN EL ESTUDIO DE LA EXPOSICIÓN A LA HUMEDAD DE FACHADAS

ABSTRACT: Assessing the water penetration exposure of building facades 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 into the Spanish framework were used. These results allow assessing the performance of the parameters that define the water tightness degree required by the Spanish Code in the building facades at each location. The findings presented here highlight the need to revise the parameters used to establish this degree, with the goal of achieving a higher design performance and improve the allocation of the required facade systems in each case. For this, new exposure maps that can be used for the improvement of the Spanish Code are presented.

Integral energy performance characterization of semi-transparent photovoltaic elements for building integration under real operation conditions

In this paper, a methodology for the integral energy performance characterization (thermal, daylighting and electrical behavior) of semi-transparent photovoltaic modules (STPV) under real operation conditions is presented. An outdoor testing facility to analyze simultaneously thermal, luminous and electrical performance of the devices has been designed, constructed and validated. The system, composed of three independent measurement subsystems, has been operated in Madrid with four prototypes of a-Si STPV modules, each one corresponding to a specific degree of transparency. The extensive experimental campaign, continued for a whole year rotating the modules under test, has validated the reliability of the testing facility under varying environmental conditions.The thermal analyses show that both the solar protection and insulating properties of the laminated prototypes are lower than those achieved by a reference glazing whose characteristics are in accordance with the Spanish Technical Building Code. Daylighting analysis shows that STPV elements have an important lighting energy saving potential that could be exploited through their integration with strategies focused to reduce illuminance values in sunny conditions. Finally, the electrical tests show that the degree of transparency is not the most determining factor that affects the conversion efficiency.

Analysis and Repercussions of the Updating of the Spanish Regulation Regarding Ventilation and Infiltration

The Spanish Technical Building Code is one of the three royal decrees that were approved in Spain as a consequence of the transposition of the European Directive on the energy performance of buildings (2002/91/EU, 2002). One basic document of the Technical Building Code deals with the limitations of building energy demands. Nowadays, due to the recast of the European Directive on the energy performance of buildings (2010/31/EU, 2010), a revision process of the current regulations has begun, starting with the Technical Building Code, with its first revision envisaged for 2012. In this paper we, as collaborators in this updating process, describe and analyse the main changes regarding ventilation and infiltration that the “new” Technical Building Code (TBC) is going to introduce. These main changes cover:1. The calculation methodology;2. The ventilation technologies that can be considered;3. The default values and the data that the user can supply to assess particular cases.Basically, these changes make it possible to move from a previous regulation that considered:1. One indoor pressure and one outdoor pressure, assuming all the indoor spaces as a single-zone (calculation methodology EN 13465 (2004));2. A constant extraction flow for 24 hours a day, without the possibility of using a control system;3. No possibilities of changing the sizing of vents, default behaviour curve of the vents and air permeability of opaque elements according to EN 13465 (2004).To a new regulation that considers:1. One indoor pressure and one outdoor pressure (calculation methodology EN 15242 (2007)) but keeping indoor zoning that allows calculating (using mass conservation) the airflow between zones;2. The possibility of using a control system allowing different flows each hour for a demand controlled ventilation scheme and pre-heating of supply air flow;3. The possibility of sizing vents, using self-regulating vents and changing the air permeability of opaque elements, for example if a blower-door test has been carried out.