Emerging risk in the construction industry: Recommendations for managing exposure to nanomaterials

Abstract Nanotechnology has aroused great interest in the construction industry because new materials with outstanding properties are being designed, and the features of traditional materials can be improved. However, exposure to nanomaterials is the most recent new emerging risk in the construction industry and the current knowledge about this topic is limited. This paper aims to identify the main aspects regarding the exposure to and use of nanomaterials in the construction sector from a risk prevention perspective. This starting point allows authors to establish a set of recommendations structured in order to identify how and where to act in order to manage the risk of exposure to nanomaterial on construction sites. Keywords: emerging risk; safety risks; health risk; engineering controls; organizational measures; personal protection equipment. Riesgo emergente en la industria de la construcción: Recomendaciones para controlar la exposición a nanomateriales Resumen La nanotecnología ha despertado un gran interés en la industria de la construcción por el diseño de nuevos materiales con propiedades extraordinarias y por la mejora de las prestaciones de los materiales tradicionales. Sin embargo, la exposición a nanomateriales es un nuevo riesgo emergente en la industria de la construcción y los conocimientos actuales sobre este tema son limitados. Este documento tiene como objetivo identificar los principales aspectos relacionados con la exposición y el uso de nanomateriales en el sector de la construcción desde la perspectiva de la prevención de riesgos. Este punto de partida permite a los autores establecer una serie de recomendaciones estructuradas para identificar cómo y dónde actuar con el fin de controlar el riesgo de exposición a los nanomateriales en las obras de construcción. Palabras clave: riesgo emergente; riesgos para la seguridad; riesgos para la salud; medidas de control técnicas; medidas de organización; equipos de protección personal

Thermal Perception in Naturally Ventilated University Buildings in Spain during the Cold Season

The indoor thermal environment has become a critical factor, due to its impact on the energy efficiency of a building and the health and performance of its occupants. It is particularly important for educational buildings, where students and teachers are exposed to these thermal conditions. This study assessed the impact of natural ventilation efficiency and university students’ thermal perception during the cold season. A field monitoring campaign and a questionnaire survey were conducted. A total of 989 students participated in this study. The results show that, although the CO2 concentration in 90% of the evaluated classrooms was below the European recommended value (i.e., 800 ppm), only 18% of the classrooms were within the thermal comfort zone defined by national regulations. These thermal conditions caused 55% of the students surveyed to report that they were dissatisfied, and that this environment interfered with their academic performance. Significant differences were found between thermal sensation votes from female and male students (p < 0.001). The obtained neutral temperature was one degree higher for female students than for males. Our results suggest that ventilation protocols need to be modified by adjusting the window opening strategy, and these findings should be used as guidelines during their redesign.Consejo General de la Arquitectura Tecnica (CGATE)State Research Agency (SRA) of SpainEuropean Commission PID2019-108761RB-I0

Development of a BIM-Based Framework Using Reverberation Time (BFRT) as a Tool for Assessing and Improving Building Acoustic Environment

This research was funded by the Consejo General de la Arquitectura Tecnica (CGATE), the "Junta de Andalucia" (Spain) under project B-TEP-362-UGR18 and the State Research Agency (SRA) of Spain and European Regional Development Funds (ERDF) under project PID2019-108761RB-I00.Both the building design and the construction process determine the indoor acoustic quality of enclosures. A suitable indoor acoustic environment is crucial for the productivity and well-being of users. For this purpose, Reverberation Time (RT) is often calculated or measured in situ. Recently, Building Information Modelling (BIM) has provided a new paradigm to face building projects. Nevertheless, little research has been conducted on the optimisation of indoor acoustics using BIM methodology. In this context, the objective of this work is to propose and develop a BIM-based framework for the analysis, evaluation and optimization of the RT. The proposed procedure allows designers to explore alternatives in order to achieve an adequate acoustic performance without any further needs of specific software. This proposal is devised to consider some important characteristics of the project, such as its location, applicable regulations, room uses, materials and costs. This framework calculates the solution set that meets the requirements, showing the set of optimal solutions according to the minimization of both the cost and the optimum absorbent surface area. BFRT contributes by offering a tool to support the decision making process of designers during the initial design phase in the field of acoustic conditioning of buildings.Consejo General de la Arquitectura Tecnica (CGATE) Junta de AndaluciaEuropean Commission B-TEP-362-UGR18State Research Agency (SRA) of SpainEuropean Commission PID2019-108761RB-I0

Predictive Model of Clothing Insulation in Naturally Ventilated Educational Buildings

This publication is part of the I + D + i project PID2019-108761RB-I00, funded by MCIN/ AEI/10.13039/501100011033Providing suitable indoor thermal conditions in educational buildings is crucial to ensuring the performance and well-being of students. International standards and building codes state that thermal conditions should be considered during the indoor design process and sizing of heating, ventilation and air conditioning systems. Clothing insulation is one of the main factors influencing the occupants' thermal perception. In this context, a field survey was conducted in higher education buildings to analyse and evaluate the clothing insulation of university students. The results showed that the mean clothing insulation values were 0.60 clo and 0.72 clo for male and female students, respectively. Significant differences were found between seasons. Correlations were found between indoor and outdoor air temperature, radiant temperature, the temperature measured at 6 a.m., and running mean temperature. Based on the collected data, a predictive clothing insulation model, based on an artificial neural network (ANN) algorithm, was developed using indoor and outdoor air temperature, radiant temperature, the temperature measured at 6 a.m. and running mean temperature, gender, and season as input parameters. The ANN model showed a performance of R-2 = 0.60 and r = 0.80. Fifty percent of the predicted values differed by less than 0.1 clo from the actual value, whereas this percentage only amounted to 32% if the model defined in the ASHRAE-55 Standard was applied.MCIN/AEI PID2019-108761RB-I0

Monitoring and Assessment of Indoor Environmental Conditions in Educational Building Using Building Information Modelling Methodology

Managing indoor environmental quality (IEQ) is a challenge in educational buildings in the wake of the COVID-19 pandemic. Adequate indoor air quality is essential to ensure that indoor spaces are safe for students and teachers. In fact, poor IEQ can affect academic performance and student comfort. This study proposes a framework for integrating occupants’ feedback into the building information modelling (BIM) methodology to assess indoor environmental conditions (thermal, acoustic and lighting) and the individual airborne virus transmission risk during teaching activities. The information contained in the parametric 3D BIM model and the algorithmic environment of Dynamo were used to develop the framework. The IEQ evaluation is based on sensor monitoring and a daily schedule, so the results show real problems of occupants’ dissatisfaction. The output of the framework shows in which range the indoor environmental variables were (optimal, acceptable and unacceptable) and the probability of infection during each lecture class (whether or not 1% is exceeded). A case study was proposed to illustrate its application and validate it. The outcomes provide key information to support the decision-making process for managing IEQ and controlling individual airborne virus transmission risks. Long-term application could provide data that support the management of ventilation strategies and protocol redesign.Consejo General de la Arquitectura Tecnica (CGATE) (2018)State Research Agency (SRA) of SpainEuropean Commission PID2019-108761RB-I0

Monitoring and Assessment of Indoor Environmental Conditions after the Implementation of COVID-19-Based Ventilation Strategies in an Educational Building in Southern Spain

Since students and teachers spend much of their time in educational buildings, it is critical to provide good levels of indoor environmental quality (IEQ). The current COVID-19 pandemic has shown that maintaining a good indoor air quality level is an effective measure to control the transmission of the SARS-CoV-2 virus. This study used sensors to monitor key IEQ factors and assess several natural ventilation scenarios in a classroom of the University of Granada. Subsequently, the IEQ factors (temperature, relative humidity, CO2 concentration, acoustic environment, and air velocity) were evaluated for the selected ventilation scenarios in the occupied classroom, and the field monitoring was carried out in two different assessment periods, winter and summer. The obtained results show that the CO2 concentration levels were well below the recommended limits. However, the maintenance of the recommended thermal and acoustic IEQ factors was significantly affected by the natural ventilation strategies (temperature and relative humidity values were very close to the outside values, and the background sound pressure level was over 35 dBA during the entire assessment). The proper measurements and careful selection of the appropriate ventilation scenarios become of utmost importance to ensure that the ventilation rates required by the health authorities are achieved.Consejo General de la Arquitectura Técnica (CGATE)State Research Agency (SRA) of Spain and European Regional Development Funds (ERDF) under project PID2019-108761RB-I00.Junta de Andalucía and European Regional Development Funds under project B-TEP-362-UGR1

Analysis of Impact of Natural Ventilation Strategies in Ventilation Rates and Indoor Environmental Acoustics Using Sensor Measurement Data in Educational Buildings

Indoor environmental conditions can significantly affect occupants’ health and comfort. These conditions are especially important in educational buildings, where students, teachers and staff spend long periods of the day and are vulnerable to these factors. Recently, indoor air quality has been a focus of attention to ensure that disease transmission in these spaces is minimised. In order to increase the knowledge in this field, experimental tests have been carried out to characterise the impact of natural ventilation strategies on indoor air quality and the acoustic environment. This study has evaluated three ventilation scenarios in four different classrooms in buildings of the University of Granada, considering different window and door opening configurations. Ventilation rates were estimated using the CO2 Decay Method, and background noise recordings were made in each classroom for acoustic tests. Results show that specific natural ventilation strategies have a relevant impact that is worth considering on the background noise in indoor spaces. In this sense ventilation rates provided by the different configurations varied between 3.7 and 39.8 air changes per hour (ACH) and the acoustic tests show a background noise ranging from 43 to 54 dBA in these scenarios. Consequently, managers and teachers should take into account not only the ACH, but also other collateral impacts on the indoor environmental conditions such as the thermal comfort or the acoustic environment.Consejo General de la Arquitectura Técnica (CGATE)State Research Agency (SRA) of Spain and European Regional Development Funds (ERDF) under project PID2019-108761RB-I00

Whole Body Vibration Exposure Transmitted to Drivers of Heavy Equipment Vehicles: A Comparative Case According to the Short- and Long-Term Exposure Assessment Methodologies Defined in ISO 2631-1 and ISO 2631-5

This research was funded by the Consejo General de la Arquitectura Tecnica (CGATE), Junta de Andalucia and European Regional Development Funds under project B-TEP-362-UGR18, and the State Research Agency (SRA) of Spain and European Regional Development Funds (ERDF) under project PID2019-108761RB-I00.The construction and transport sectors are the industries with the highest proportions of workers exposed to vibrations in the European Union. Heavy equipment vehicle (HEV) drivers often perform operations on different uneven surfaces and are exposed to whole body vibration (WBV) on a daily basis. Recently, a new version of ISO 2631-5 was published. However, since this new method required as input the individual exposure profile and the acceleration signals recorded on more surfaces, limited studies have been carried out to evaluate HEV operations according to this standard. The objectives of this study were to assess the WBV exposure using the methods defined in ISO 2631-1:1997 and ISO 2631-5:2018 and to compare the obtained health risk assessments between drivers with different anthropometric characteristics. For this purpose, two drivers were selected and a field measurement campaign was conducted. Regarding short-term assessment, results showed that VDV was the most restrictive method with exposure levels above the exposure action limit value, while SAd indicated that the same exposures were safe for the worker. With respect to long-term assessment, Risk Factor RA showed that the driver with the highest body mass index was the only one who exceeded the low probability limit of adverse health effects.Consejo General de la Arquitectura Tecnica (CGATE), Junta de AndaluciaEuropean Commission B-TEP-362-UGR18State Research Agency (SRA) of SpainEuropean Commission PID2019-108761RB-I0

Proposal of Combined Noise and Hand-Arm Vibration Index for Occupational Exposure: Application to a Study Case in the Olive Sector

In many production and industrial sectors, workers are exposed to noise and hand-arm vibrations (HAV). European directives have established the maximum limit values or exposure action values for noise and vibration independently. However, in many cases, workers who endure hand-arm vibration also receive high noise levels. This research suggests a procedure to aid the establishment of precautionary measures for workers with simultaneous exposure to both physical agents. This procedure defines a combined index based on the energy doses for both noise and HAV. From this combined index, the suggested methodology allows a recommended exposure time for workers with simultaneous noise and HAV exposure to be calculated. This methodology can be adapted to tackle the relative importance assigned to both agents according to the safety manager and new knowledge on combined health effects. To test this method, a measurement campaign under real working conditions was conducted with workers from the olive fruit-harvesting sector, where a variety of hand-held machinery is used. The results of the study case show that the suggested procedure can obtain reliable exposure time recommendations for simultaneous noise and HAV exposures and is therefore a useful tool for establishing prevention measures.State Research Agency (SRA) of SpainEuropean Commission PID2019-108761RB-I0

Reopening higher education buildings in post-epidemic COVID-19 scenario: monitoring and assessment of indoor environmental quality after implementing ventilation protocols in Spain and Portugal

Post-epidemic protocols have been implemented in public buildings to keep indoor environments safe. However, indoor environmental conditions are affected by this decision, which also affect the occupants of buildings. This fact has major implications in educational buildings, where the satisfaction and learning performance of students may also be affected. This study investigates the impact of post-epidemic protocols on indoor environmental conditions in higher education buildings of one Portuguese and one Spanish university. A sensor monitoring campaign combined with a simultaneous questionnaire was conducted during the reopening of the educational buildings. Results showed that although renewal air protocols were effective and the mean CO2 concentration levels remained low (742 ppm and 519 ppm in Portugal and Spain universities, respectively), students were dissatisfied with the current indoor environmental conditions. Significant differences were also found between the responses of Portuguese and Spanish students. Indeed, Spanish students showed warmer preferences (thermal neutrality = 23.3℃) than Portuguese students (thermal neutrality = 20.7℃). In terms of involved indoor factors, the obtained data showed significant correlations (p < 0.001) between acoustic factors and overall satisfaction in the Portuguese students (ρ = 0.540) and between thermal factors and overall satisfaction in the Spanish students (ρ = 0.522). Therefore, indoor environmental conditions should be improved by keeping spaces safe while minimizing the impact of post-epidemic protocols on student learning performance.The first two authors wish to thank the support of the Ministerio de Ciencia, Innovación y Universidades of Spain, under an FPU grant. This research was funded by the Consejo General de la Arquitectura Técnica (CGATE), and the State Research Agency (AEI) of Spain and European Regional Development Funds (ERDF) under project PID2019-108761RB-I00. Funding for open access charge: Universidad de Granada/CBUA