HYGROTHERMAL PERFORMANCE OF MASONRY WALLS IN RESIDENTIAL BUILDING IN A HUMID SUBTROPICAL CLIMATE DESEMPENHO HIGROTÉRMICO DE PAREDES DE ALVENARIA EM EDIFICAÇÃO RESIDENCIAL EM CLIMA SUBTROPICAL ÚMIDO

1 Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil, libbonadimam@gmail.com 2 Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil, maritzadarochamacarthy@gmail.com 3 Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil, luizacber@gmail.com 4 Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil, rodrigokarinileitzke@gmail.com 5 Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil, giane.c.grigoletti@ufsm.br 6 Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil, eduardogralacunha@yahoo.com.br Abstract


Introduction
Since the end of the 1990s in Brazil, the civil construction sector has drawn more attention to building sustainability, aiming to combine new technologies and constructive solutions to reduce energy consumption and improve building performance (TRINDADE; COELHO;HENRIQUES, 2021). This includes evaluating materials and construction techniques used for greater temperature control and humidity both in the building envelope and the indoor environment (JORNE, 2010).
Humidity problems can affect energy consumption, environmental conditions and indoor air quality, leading to mold growth (filamentous fungi) that are harmful to user health. In addition, wall durability and maintenance of the building envelope can be affected by humidity (GUERRA et al., 2012;BERGER et al., 2015;NASCIMENTO et al., 2019).
According to Mendes (1997), hygrothermal simulations evaluate the degradation and deterioration risks of a building´s constructive elements, in addition to estimating the internal conditions of thermal comfort as the presence of water inside a wall can also cause condensation in the building elements. Many of these anomalies arise from the lack of preliminary studies on the influence of the surrounding environment on the buildings (SOUZA et al., 2018). Thus, it is important to be knowledgeable about the complexity of the physical phenomena involved in the condensation process, as well as the influence of variables that affect the hygrothermal behavior of the construction system, such as indoor air humidity, material porosity, among others (RIBEIRO, 2013).
The hygrothermal behavior of a material depends on various parameters, especially local climate conditions, such as relative humidity, temperature, wind speed, among other climate factors, which vary depending on the location. Therefore, constructive solutions cannot be established without knowing the climate characteristics of each location (JORNE, 2010).
However, building construction is carried out in a similar way in several regions of Brazil, predominantly of masonry walls and ceramic tile roofs, disregarding the effect of the location on building performance (MORISHITA et al., 2016). Thus, it is essential to consider the climatic parameters that influence the hygrothermal behavior of buildings and materials, and how they vary according to location, to predict their durability and the quality of the indoor environment.
Due to the complexity of the variables involved in the heat, air and moisture transfer phenomena in buildings, computer simulation programs are important tools in hygrothermal behavior evaluation of construction systems exposed to different climate conditions (BUSSER et al., 2019). One of the most used simulation programs for this purpose is the computational calculation program called WUFI (Wärme-und Feuchtetransport Instationär -Transient Heat and Moisture Transport) developed by the Fraunhofer Institute for Building Physics (IBP) WUFI is a computational calculation tool for simulating the hygrothermal behavior of the building envelope, which allows simulations in a dynamic regime and sensitivity studies on composition, hygrothermal properties of materials and climate conditions (SANTOS, 2017). Based on the initial conditions and the interior and exterior boundary conditions of this system, the program can determine the thermal and hygrothermal integrity of building envelope assemblies in different climates (SETTER et al., 2019;ECS, 2007;DELGADO et al., 2013).
The program is governed by differential equilibrium equations, adopting a unidirectional heat and mass transfer model (CHO et al., 2019;IBRAHIM et al., 2014;PARK et al., 2019). WUFI meets the requirements and criteria established by EN 15026 (ECS, 2007), a European standard that presents procedures for evaluating the hygrothermal performance of building components and elements.
Another widely used program for calculating thermal loads and the energy analysis of buildings is EnergyPlus, a free computer program for energy simulation developed by the US Department of Energy (DOE). The program allows for the insertion of building volumetry data, the construction system, climate data, the definition of ventilation, as well as heating and cooling systems (DOE, 2018).
In recent years, there has been an advance in studies related to the thermal performance of buildings, especially after publishing the NBR 15220 (ABNT, 2005a) and NBR 15575 Brazilian standards (ABNT, 2013). However, in Brazil, there is still a lack of aspects that must be analyzed and reviewed to control mold growth and humidity in buildings (CUNHA; VAUPEL; LUKING, 2008). In addition, Brazil also has a lack of databases regarding hygrothermal properties of materials, which leads to limitations in terms of investigations and hygrothermal simulations. Morishita, Berger and Mendes (2020) observed that studies evaluating vapor transport and humidity in buildings in Brazil mostly address case study approaches, not evaluating the potential risk of humidity from a more comprehensive point of view, considering the climate, building standardization, thermal performance and indoor air quality. Mendes et al. (2003) found that, in porous building walls, the study of humidity is extremely important, both in humid and dry climates, as it can significantly affect the energy performance of the building. When the moisture analysis is overlooked, the air conditioning system may be overloaded, contributing to an increase in electric energy consumption.
Studies on the moisture risk in Brazilian buildings are currently underway in the ABNT/CB-02 -Brazilian Civil Construction Committee, to understand hygrothermal performance, improve construction systems and create evaluation criteria for Brazilian standards. It can be observed that the hygrothermal simulation can be an important way to understand the heat and moisture transfer phenomena in buildings, in addition to contributing with design, maintenance, durability and energy efficiency solutions for designers.
Considering the context, this study aims to present a contribution to the lack of literature in Brazil on this topic associated with moisture transfer, condensation risks on surfaces, and filamentous fungi mold risks in external vertical sealing systems (EVSS). The present article analyzed the hygrothermal behavior of four EVSS configurations in mortar-coated solid brick masonry compared to an expanded polystyrene (EPS) insulated wall, with different levels of water tightness (with and without a waterproof membrane) for the humid subtropical climate of the city of Pelotas, Rio Grande do Sul state (RS), classified as Bioclimatic Zone 2.

Method
The work was carried out in three steps, as shown in Figure 1. Initially, the typology and EVSS were chosen for the analyses, in which two boundary conditions were considered: the building envelope based on NBR 15575 (ABNT, 2013) and with a thermal insulation layer on the building envelope, adopted by Dalbem (2018).
In the second step, building simulations were conducted in two parts, firstly using the EnergyPlus (version 8.7) and WUFI Pro 6.5 programs, considering the building as naturally ventilated, and later, the WUFI Pro 6.5 program was used for air-conditioned buildings.
Finally, in the third and last step the evaluation criteria were defined, and the results were analyzed, based on the total moisture content, vapor condensation risk and filamentous fungi mold.

Characterization of weather conditions
Pelotas is located in the extreme south of Brazil, in the state of Rio Grande Sul, with latitude of 31º46'19" S, longitude of 52º20'33" W, and altitude sea level of 17m. The city is located in Bioclimatic Zone 2, according to the Building Thermal Performance Standard Part: 3 NBR 15220-3 (ABNT, 2005b). The city has a humid subtropical climate (Cfa), with no dry months, and significant precipitation according to the Köppen climate classification (KUINTCHER; BURIOL, 2001). It has an average annual temperature of 17.6 ºC and relative humidity of around 80.7% (EMBRAPA, 2001). The average annual precipitation is 1,402.7 mm and the highest precipitation rate is in February and the lowest in October, 187.8 and 87.1 mm, respectively. Figure 2 presents the climatological norms of the city of Pelotas -RS, based on 30 years of data from INMET meteorological stations (1981INMET meteorological stations ( -2010 for precipitation and air temperature.

Step 1: constructive typology
The constructive typology adopted was based on the model proposed by Sorgato, Melo and Lamberts (2016), with dimensions of 7.0m x 9.0m x 2.8m, totaling 63m² of built area, as shown in Figure 3. The building has 2 bedrooms, 1 bathroom, 1 living room and 1 kitchen, with north and east orientation for the bedrooms and living room, and a roof pitch of 27° in the north-south direction. The thermal properties of the building envelope components followed the constructive guidelines of NBR 15220-3 (ABNT, 2005b) for Bioclimatic Zone 2 (ZB2), thus having a thermal transmittance of 2.5 [W/ (m²K)].

Building envelope
For the building envelope characterization, the NBR 15575 (ABNT, 2013) and NBR 15220 standards (ABNT, 2005a) were used, adopting an EVVS in solid brick masonry and variations from adding the waterproof blanket, and thermal insulation layer in EPS, as shown in Figure 4. In the first condition, the constructive elements were configured as recommended by NBR 15575 (ABNT, 2013) regarding the minimum thermal transmittance for ZB2 of 2.5 [W/ (m²K)]. The walls were made of solid bricks with 8 holes and 2.5 cm plaster on both sides, with a variation of the envelope, using a waterproof membrane.
The second condition was based on Dalbem (2018), using a brick wall with 8 holes, 2.5 cm plaster on the inside and 1 cm on the outside, and EPS insulation. In this constructive element, there is also a variation after adding a waterproof membrane in one of the  For both conditions, the following were considered: ceramic tile roof that was 1 cm thick, air layer with thermal resistance of 21m².K/W and a 15 cm slab; ceramic tile floor; single-glazed windows and wooden doors, with a thermal transmittance of 2.3 W/ (m²K). Figure 4 shows the walls and roof used in this study. The thermal conductivity values, specific heat and material thicknesses are specified in Table 1.

Step 2: Energy Plus simulation
In this study, the EnergyPlus program (version 8.7) was adopted to create the indoor environment files with the relative humidity and indoor temperature data, needed for the hygrothermal simulation in the WUFI Pro 6.5 program, in the naturally ventilated situation. Figure 5 shows the infographic and the steps performed using EnergyPlus.
The house was modeled in six thermal zones (living room, kitchen, bedrooms 1 and 2, bathroom and attic roof) using the SketchUp Make 2017 program using the Euclid plugin (version 9.3). The roof was modeled with a thermal zone, considering the air layer with a thermal resistance of 0.21 (m².K)/W according to NBR 15220 (ABNT, 2005a).
The model configuration for the use and occupation conditions of the lighting systems and equipment followed the Technical Quality Regulation guidelines for the Level of Energy Efficiency in Residential Buildings -RTQ-R (INMETRO, 2012), considering the naturally ventilated environment.
The climate file used in the simulation refers to the city of Pelotas-RS, developed by Leitzke et al. (2018). After the simulation, the output data of the indoor temperature and relative humidity of the air were obtained, to create a file with data of the internal temperature for the WUFI Pro program.

Occupancy and lighting schedules
For the occupancy schedule, the living room and bedroom areas were considered. The dormitory has an occupancy of two people per room, and the living room, four people, which were used by all users. The occupant pattern was configured for weekdays and weekends according to the RTQ-R (INMETRO, 2012). Table 2 presents the occupant patterns and artificial lighting for the simulation. Table 3 presents the values of the metabolic rate, lighting power density and internal equipment loads, which were configured only for the living room area, with a 24-hour period using a power density of 1.5 W/m².

Soil temperature
The soil temperature was set using the Slab processor (version 8.7), in the EnergyPlus program, which considers the average values of the indoor and outdoor temperatures of the building to calculate the monthly average temperature of the soil. Thus, the building geometry, the data on the thermal properties of the materials and other model configurations are considered in the calculation (INMETRO, 2012;DOE, 2018). Table 4 shows the soil temperatures considered for the model simulation.

Natural ventilation
Natural ventilation was configured in the AirflowNetwork object, which considers the building geometry, characteristics and door and window opening control. The window opening operation routine was configured for the period of 24 hours a day, the occupation period of the rooms was not considered.
The window opening control was configured when the indoor air temperature in the room was greater than or equal to the thermostat temperature, 25°C (Tint≥Tsetpoint), considering Reckziegel et al. (2009), and when there were favorable conditions, that is, when the outside air temperature was lower than the inside air temperature by up to 5ºC (Text≤Tint).

Output data
The indoor temperature and relative humidity data of the internal air of the two typologies were exported, to create the internal file from the thermal zone of the room. This file was used in the simulation step with the WUFI Pro 6.5 program to define the boundary conditions of the inside environment in naturally ventilated buildings.

Step 2b: hygrothermal simulation
The hygrothermal simulations were carried out in the WUFI Pro 6.5 program. The aim was to identify the phenomena on the walls regarding the moisture conductivity and retention, vapor condensation risk and filamentous fungi mold. Figure 6 presents the configuration parameters and procedures adopted in the hygrothermal simulations. For the simulation, the following parameters were defined in the program: solar orientation to the south and to the north; small building with a height of up to 10 m; external and internal walls with latex type 1 paint, and absorption (short wave radiation) of 0.8 (dark). The ground reflectivity value (short wave) was 0.2, which was the default value of the program. The initial humidity and temperature conditions were considered constant throughout the constructive element.
The incident rain was calculated according to the ANSI/ASHRAE Standard 160 -Design criteria for humidity control in buildings (ASHRAE, 2016), considering the rain exposure factor (RE) 0.7 (facade protected by the surroundings) and rain deposition (RD) of 0.5 (facade not protected by eaves). The simulation analysis period was three years with a time interval of 1 hour. For the external climate input data, the TRY weather file data referring to the city of Pelotas, RS, from the EMBRAPA agrometeorological database, developed by Leitzke et al. (2018).
For the simulation, monitoring points were placed on the external and internal surface of the external wall so that moisture, temperature, moisture content, and filamentous fungi mold risk data could be monitored. Figure 7 and Table 5 show the data concerning solar radiation, incident rain, air temperature and relative air humidity, based on the climate file used in the analysis with the WUFI Pro program.
The internal hygrothermal conditions were defined for two simulation conditions, considering the naturally ventilated environment and air conditioning. For the first case, a file was created with relative humidity and indoor temperature data resulting from the thermal simulation in the Energy Plus program. As for the artificial conditioning situation, the internal conditions were defined according to ASHRAE 160 (ASHRAE, 2016), considering air conditioning, change to a floating internal temperature of 2.0 ºC, heating setpoint of 21.5 ºC and cooling setpoint of 23.5 ºC, for the two bedrooms considering the hourly renewal rate every hour.

WUFI Pro building system
For the WUFI Pro simulation, four configurations were adopted for the EVSS (Table 6), originating from the two models previously presented ( Figure 4). They are: MW, masonry wall described by NBR 15575 (ABNT, 2013) with thermal transmittance of 2.5 W/(m²K); MW-WM, masonry wall with waterproof membrane; MW-EPS, wall with EPS insulation layer and MW-EPS-WM, wall with EPS insulation layer and waterproof membrane. Table 7 presents the properties of the simulated materials, taken from the WUFI program library.

Total moisture content
The total moisture content indicates the building system's ability to dry out or accumulate water over time. This analysis is performed by comparing the final moisture content with the initial moisture content and is related to several factors such as: the time the element will take to dry, the characteristics of the material, the amount of water in the material production, the rain incident on the wall, the solar radiation incidence, and the location, among others.
According to Jorne (2010), there may be moisture accumulation in the constructive system if the moisture content at the end of the simulation is greater than the initial moisture content. In this case, the use of a waterproof membrane can help to control the flow of moisture, as it prevents the infiltration of rainwater incident on the facade, and that it passes to the other layers, which allows the vapor to leave the constructive system (SILVA; OLIVEIRA, 2019). In this study, the total moisture content was analyzed over an interval corresponding to three years, the minimum time for the stabilization of the EVSS system.

Vapor condensation risk
The vapor condensation risk can be assessed from the relative humidity indices of the EVSS layers to identify layers with extended periods of high relative humidity. According to França (2013), the occurrence of internal condensation in a constructive element can be analyzed by the relative humidity graph when reaching 100% at any point of the interfaces, and the existence of these points reflects the occurrence of internal condensation. Condensation risk is an important factor to be analyzed, as it indicates whether there is a possibility of the occurrence of liquid water somewhere in the system, whose factor can cause the filamentous fungi mold and degradation (RECKZIEGEL et al., 2013).
Considering the uncertainty regarding the relative humidity value for which the presence of filamentous fungi mold may exist, the regulation on which the WUFI formulation is based, DIN 4108-02 (DIN, 2003;ZIRKELBACH et al., 2007) considers that there is a fungi mold risk for relative humidity values above 80% for hygroscopic materials (JORNE, 2010).

Filamentous fungi mold
The filamentous fungi mold risk on the internal surface was evaluated considering the bio-hygrothermal model, using the WUFI-Bio plug-in, and the isopleth model, using the LIM curves (Lowest Isopleth for Mold). The points above the curves present temperature and relative humidity conditions favorable to filamentous fungi mold. For risk analysis, it is preferable that most points lie below this curve. The LIM curves are classified according to the substrate category (0, I and II), and are shown in Table 8 (SEDLBAUER, 2001). Ideal culture medium (Category 0) Complete biological medium (example: pine and spruce).

Biousable substrates (Category I)
This includes all biologically recyclable building materials, including wallpaper, plasterboard and materials from biologically degradable raw materials that can come from renewable natural sources, for example, cellulose.
Substrates with porous structure (Category II) This includes all building materials not considered in the previous category, e.g., plaster, mineral building materials, some species of wood and insulation materials not belonging to group I.
This study adopted the German standard DIN 4108-2 (DIN, 2003) as an analysis parameter, which considers relative humidity close to 80% as a limiting factor in a maximum exposure time of 6 hours per day. Filamentous fungi mold risk limit curves in which the level of humidity is critical are generated considering a temperature of 20 °C, however, some filamentous fungi start with lower temperatures and relative humidity levels. On the other hand, according to Sedlbauer et al. (2010), most filamentous fungi need relative humidity close to or above 80% to develop. Guerra et al. (2012) identified, from samples sent to a microbiology laboratory, five different genera of filamentous fungi, Penicillium, Paecilomyces, Cladosporium, Fusarium and Trichoderma, in three buildings in the city of Pelotas, RS, which belongs to Bioclimatic Zone 2 These fungi are common in southern Brazil and develop at 80% relative humidity (SEDLBAUER, 2001)

Total moisture content
In Figure 8, the total moisture content of the MW, MW-WM, MW-EPS and MW-EPS-WM systems for north and south orientations, considering the two cases studies: naturally ventilated (VN) and artificially conditioned (AC), over three years. Table 9 shows the initial and final values and the minimum and maximum values of total moisture content.  It can be observed that all the simulated systems presented a final total moisture content higher than the initial one, indicating the accumulation of water inside. The contents also increased with the orientation, which was already expected as the south orientation represents the facade with the lowest incident solar radiation. It is also observed that, for the MW system, there was little variation between the naturally ventilated and artificially conditioned conditions regarding the drying rate.
The addition of the waterproof blanket contributed to the reduction of the total moisture content by 76.81% in the naturally ventilated system, and by 80.47% for the artificially conditioned system, facing north. Regarding the addition of EPS, and the consequent increase in the thermal resistance of the wall, a reduction of 86.53% was observed in the moisture content in the north orientation and 84.69% in the south orientation under natural ventilation.
Only two systems presented final total moisture contents lower than the initial one, both systems with EPS (thermal insulation in the wall), under artificial conditioning and north orientation. These systems had a drying rate of 7.00% (MW-EPS, AC, north) and 7.75% (MW-EPS-WM, AC, north). All other analyzed systems showed negative drying rates, presenting a risk of water accumulation inside the wall. In other words, the best performances occurred with a thermally insulated wall and also thermally insulated with a waterproof membrane.

Vapor condensation risk
Figures 9 and 10 present the graphs corresponding to the temperature and relative humidity of the internal surface of the analyzed systems, for the north and south orientations, considering the two case studies (naturally ventilated and artificially conditioned) over the course of three years.
The environments corresponding to the system with only solid brick (Figure 9 -MW) presented relative humidity of 100%, indicating condensation risk in the construction system in all simulated situations, even in the artificially conditioned conditions. In the waterproof membrane system with (Figure 9 -MW-WM), when naturally ventilated, it can be observed that the highest relative humidity corresponded to the winter months (June, July and August), with values that exceed 90%. This same wall, under artificial conditioning conditions, the relative humidity on the internal surface presents values around 80% throughout the year, demonstrating condensation risk, except in the summer months, which presents values up to 65% of relative humidity. values, occurred largely during the winter, coinciding with the months of lower air temperatures and more favorable conditions for filamentous fungi mold.
On the other hand, the insulated and artificially conditioned walls (Figure 10 -WM-EPS), for both orientations, presented values of up to 70% of relative humidity in the most critical months, which ensures an adequate performance to the systems in this regard, minimizing the amount of moisture on the internal surfaces. The EPS layer has a great contribution to the humidity control in the other internal layers and in the system as a whole. Due to the physical characteristics and its high resistance to water vapor diffusion, the moisture content and relative humidity are considerably reduced before reaching the waterproof membrane, and consequently along the other internal layers, which have a lower moisture content and relative humidity, resulting in less condensation risk. Figures 11 and 12 show the filamentous fungi mold risk graphs on the internal surface of the analyzed constructive systems. The points represent the hygrothermal conditions on the internal surface of the building component at a given time. The color of each point indicates when that point occurred during the simulation, the yellow ones occur at the beginning of the hygrothermal calculation, followed by shades of green and the last points, in black, which represent the end of the calculation. This cloud of points analyzes the long-term trend of the simulation, for the filamentous fungi. proliferation The limiting curves represent the types of construction materials, LIM B I (bio-usable materials, plasterboard, etc.) and LIM B II (materials with a porous structure, such as plaster, mineral construction materials and some types of wood).

Filamentous fungi mold
For residential environments with walls meeting the requirements of NBR 15575 (ABNT, 2013), represented by Figure 11 (PA), there was a risk of filamentous fungi mold in all analyzed conditions, even for environments with artificial air conditioning. Since the standard NBR 15575 (ABNT, 2013) sets limits regarding thermal performance, and not hygrothermal performance, the walls did not guarantee the minimization of humidity on the internal surfaces, nor did they prevent filamentous fungi mold. When evaluated from the bio-hygrothermal model (WUFI Bio 4.0), the system showed unacceptable results and does not recommend using the system because it has mold with values greater than 239 mm/year. In order to comply with this evaluation methodology, and the system to be considered acceptable, the surface of the innermost layer, in contact with the air, must have mold (gm) of less than 129 mm/year, according to the WUFI Pro manufacturer's manual (ZIRKELBACH et al., 2007).
This behavior may be due to adsorption (wetting) and moisture absorption (a material's ability to absorb moisture) due to external conditions, but it can also occur due to the internal conditions of the environment, the water vapor condensation generated by the occupation, and by the low temperature of the internal surface of the external walls and consequent high level of relative humidity near the internal surfaces. It can be observed in the masonry wall with waterproof membrane (MW-WM system) that the membrane was not able to avoid the filamentous fungi mold risk when the environment was under natural ventilation. However, in environments with artificial air conditioning, the cloud of points is concentrated close to the critical mold risk, with the end points (darker) exceeding 80% RH, indicating the possibility of mold in this system. From the analysis of this last condition, with the bio-hygrothermal model, the system is considered acceptable, with filamentous fungi mold values below 129 mm/a. It can be observed in Figure 12 that the masonry walls with the EPS insulation system (MW-EPS), with natural ventilation, present a cloud of points above the LIM B II curve with points exceeding 80% of RH in the range of temperature of 20°C, indicating mold in this system. Observing the latter, with the bio-hygrothermal model, in the system indicates filamentous fungi mold values between 129 mm/a and 176 mm/a, showing the need for additional investigations to assess the acceptability of the system. In the PA-EPS system under artificial conditioning, the point cloud was found below the LIM B II, which means that the system under this condition does not present a filamentous fungi mold risk.
The same behavior was observed in the MW-EPS-WM system, in which the addition of the waterproof blanket did not present major changes in the filamentous fungi mold. It can be observed that the systems with controlled internal temperature, presented better behavior regarding filamentous fungi mold.

Conclusions
The present work evaluated the hygrothermal behavior of four construction systems with different levels of insulation and watertightness, considering the naturally ventilated and artificially conditioned environment. The analyses also considered the north, south orientations for the Bioclimatic Zone 2. The computer simulations used the WUFI Pro (version 6.5) and EnergyPlus (version 8.7) programs for the city of Pelotas-RS. The systems were evaluated for total moisture content, vapor condensation and filamentous fungi mold risks.
The hygrothermal performance analyses carried out in this work show that for the analyzed context, the masonry wall based on the limits of the NBR 15575 standard (ABNT, 2013), MW system, did not obtain satisfactory results in any of the evaluated items, regarding moisture, filamentous fungi risk, and condensation on the interior surfaces of the walls as the standard NBR 15575 (ABNT, 2013) sets limits regarding thermal performance, not hygrothermal performance. The wall presented a high moisture risk in the natural ventilation condition. This system obtained improvements only when simulated in the artificially conditioned situation. The results indicate that, for the analyzed conditions, this wall does not have a satisfactory hygrothermal performance for the humid subtropical climate of the city of Pelotas-RS in Bioclimatic Zone 2, presenting a predisposition to accumulate moisture in its interior, running the risk of contributing to the degradation of materials, the need for more frequent maintenance, and a risk to the health of residents.
In the simulated orientations, referring to north and south, the results showed that the facade orientation had a significant impact on the hygrothermal behavior of the wall that meets the requirements of NBR 15575 (ABNT, 2013), as the wall accumulated moisture over time, increasing the filamentous fungi mold risk on the interior surface of the outer wall of the environment. For future work, the other facades will be considered, as a more accurate way of comparing the impact of solar orientation on the hygrothermal behavior of this system.
Regarding the thermally insulated walls, based on Dalbem (2018), WM-EPS and WM-EPS-MW, only the systems under artificial conditioning did not present vapor condensation and filamentous fungi mold risksw. Aspects relateall d to durability, maintainability and costs analyzed were not considered in this study, which were presented in the study by Dalbem (2018) in a critical and in-depth way. These aspects will be considered in future studies.
Concerning the moisture content, the wall with EPS insulation had less moisture accumulation on the interior wall surface, compared to the MW system. However, only in the solutions MW-EPS and MW-EPS-WM, under artificial conditioning conditions and orientation to the north, presented a final moisture content lower than the initial one at the end of the simulation, with no accumulation of moisture inside the constructive system.
Overall, the EPS-insulated system tends to guarantee adequate performance for most of the year, which minimizes the amount of moisture on the interior surfaces of the walls. This would explain the smaller patches of filamentous fungi in these systems, especially in temperature-controlled environments.
From the results found, the importance of evaluating the hygrothermal performance in defining the characteristics of the building envelope is highlighted, in order to contribute to Brazilian standards, mainly taking into account the condensation risk in construction systems and the imminent filamentous fungi mold that can affect the performance of the entire building.
As the main limitation of the work, there is the need to build a database with the hygrothermal properties of the materials used in the simulation for the Brazilian context. In addition, the article was developed in accordance with the RTQ-R (INMETRO, 2012) and with the NBR 15575 (ABNT, 2013), in their old versions, in order to be the versions in force during the development of this work. For future work, updates to the standards will be reviewed.