In addition to the problems of environmental comfort and the alarming energy issue associated to the dependency of building systems for space cooling and mechanical ventilation for 100% of occupational time, already widely discussed in the specialized literature, another problematic aspect of the environmental quality of the sealed glass-box building is the exposure of the occupants to contaminants present in the recirculated, with risks to health. As mentioned in the first text of this series (1), the concern with the air quality in buildings acquired unprecedented proportions in the scenario of the pandemic of the New Corona Virus (2).

Recapitulating a piece of information also mentioned previously, it is essential to underline the fact that air conditioning systems reuse a big portion of the internal air, recirculating it and adopting only a small fraction of fresh air pulled from outside. The technical recommendations for fresh-air requirements made in the Brazilian standard NBR 16401, which give parameters to the whole design of air-conditioned spaces (3), follow those from ANVISA (4), that establishes the minimum inlet of 27 m3of external air per person per hour. Based on this criterion, a typical office floor, with an occupation between 8 to 10 m2per person, would have approximately 10% of its air volume filled by fresh air, whilst the remaining 90% are from recirculated air, also commonly named in Portuguese as “vicious air”.

The artificial cooling systems tend to blow into the space air around 15oC, aiming to achieve internal average temperatures of around 22oC. In this way, the highest the targeted temperature and the volume of fresh air brought into the system, more energy is demanded in the process of cooling the environment. For this reason, the bigger the amount of fresh air, in other words, the bigger the introduction of external air in the cooling system, more energy is consumed in the cooling process, mainly in the warm days of the summer period, when the external air has higher temperatures (5).

Besides the temperatures, the relative humidity is another essential parameter for thermal comfort. In close environments (without natural ventilation), the increase of humidity levels is associated with the density of occupation that, when excessive (for example, with less than 10 m2per person), increases significantly the latent heating loads (original from human breathing), adding to the energy loads in the air-conditioning system (6).

In parallel to that, it should be considered that the filters of air conditioning systems do not retain viruses or gases, acting merely in the control of a certain amount of particles.

As already said here, the maintenance is of great importance to the health, comfort, well-being and productive of occupants. The dependency of air-conditioning can create environments subjected to health issues that characterize the syndrome called SBS, Sick Building Syndrome, originally identified in the 80s, with serious cases of health problems in Brazil and abroad (7). This illness encompasses various types of symptoms that get aggravated with long periods of permanence in sealed work environments and get better during holidays and weekends.

Various chemical agents are related to the worsening of air quality and the trigger of such syndrome, such as: volatile organic particles, nitrogen dioxide, carbon dioxide, carbon monoxide, ozone, suspended particles, fungus, acnes, bacteria, problems related to relative humidity and others. Among the main symptoms are: difficult to breath, tiredness, fatigue, irritation of the eyes, cough, sneezing, stress, headaches, lack of concentration. According to Peder Wolkoff (8), chemical agents can cause damage to health in concentrations that are not yet perceived by the smellt, justifying the importance of regular research about the air quality in office buildings in general, even when chemical agents are not perceived.

In addition, more recently, studies from Sheila Regina Sarra (9) in office buildings located in the city of São Paulo showed high incidence of SBS symptoms in a set of offices with exclusive dependency of artificial air-conditioning. When these results were compared with those obtained in work environments with natural ventilation, significant differences were verified in the health of occupants. The use of mixed-mode ventilation (alternating mechanical and natural ventilation) was associated with a reduced incidence of respiratory symptoms, dry-eyes, headaches and lack of concentration.

In this way, the design and operation of building systems are faced with the dilemma between better air quality, associated with higher fresh air rates (a strategy of great importance in the context of viruses and other contaminants), versus a higher energy efficiency of the system that, in one hand, lead to the adoption of minimum fresh air rates in the system. Adding to the energy issues, the polemic around air quality of spaces with air conditioning systems raises, once more, the question with regards the generalized and banal premise of the air conditioned space.

With respect to the control of internal environmental conditions, the design of office buildings count on energy-efficient alternatives of cooling systems and artificial lighting, allied to building automation. However, the fact is that with all the technological options currently available, the sealed environment continues to be reproduced, with an envelope that instead of protect the internal environment from solar radiation, works as a great heat collector.

In reality terms, the design practice of this type of building reveals that the conception and sizing of air conditioning systems use as design reference maximum annual values of external temperatures, instead of considering a more real/likely profile of thermal profiles throughout a typical warm month and, consequently, oversizing the cooling system.

In this way, besides promoting energy savings and the reduction of the associated environmental impacts in the building sector, design office buildings to the well calculated re-introduction of natural ventilation (as commonly done until the end of 60s in Brazil), contributes to the prevention of illness related to the workspace, adding human and social value to the discussion of energy efficiency.

However, the return of natural ventilation in office buildings in cities of warm climates such as São Paulo demands, on one hand, a change of cultural values about the notion of environmental comfort and, on the other, a technical knowledge from the perspective of the design team, about how to deal with climatic variables in the architectural strategies. Scenarios such as the one of the New Corona Virus pandemic raise a challenge against the conventional design standards, not just related to architecture, but also to the rules of climatization systems, including aspects of use and occupation of buildings, mainly office buildings, opening new possibilities for the architecture of better environmental performance in general and not only from the energy point of view. Besides questioning the design of the glass box and its technological systems, this architectural approach will promote a more significant intervention of the occupants upon their own environmental comfort and quality, reincorporating the simple act of opening a window when desirable and comfortable outside.

notes

NA – A série de oito artigos intitulada “O pobre desempenho ambiental dos escritórios por trás da caixa de vidro” conta com os seguintes colaboradores: Amanda Ferreira, Ana Silveira, Aparecida Ghosn, Bruna Luz, Carolina Leme, Claudia Ferrara Carunchio, Cristiane Sato, Eduardo Lima, Erica Umakoshi, Guilherme Cunha, Julia Galves, Juliana Trigo, Karen dos Santos, Laís Coutinho, Larissa Luiz, Monica Uzum, Nathalia Lorenzetti, Paula Abala, Sheila Sarra, Sylvia Segovia.

NE – Este é o terceiro de uma série de oito artigos sobre o tema do “desempenho ambiental”. A série completa é a seguinte:

GONÇALVES, Joana; et. al. The poor environmental performance of offices behind the glass-box. An overview (chapter 01/08). Drops, São Paulo, year 21, n. 158.08, Vitruvius, nov. 2020 <https://vitruvius.com.br/revistas/read/drops/21.158/7926/en_US>.

GONÇALVES, Joana; et. al. The poor environmental performance of offices behind the glass-box. Thermal comfort and energy demand (chapter 02/08). Drops, São Paulo, year 21, n. 160.02, Vitruvius, jan. 2021 <https://vitruvius.com.br/revistas/read/drops/21.160/7999/en_US>.

GONÇALVES, Joana; et. al. The poor environmental performance of offices behind the glass-box. The control of the thermal environment and air quality in times of pandemic (chapter 03/08). Drops, São Paulo, year 21, n. 161.02, Vitruvius, feb. 2021 <https://vitruvius.com.br/revistas/read/drops/21.161/8024/en_US>.

MICHALSKI, Ranny; et. al. The poor environmental performance of offices behind the glass-box. Acoustic comfort. Drops, São Paulo, year 21, n. 163.02, Vitruvius, apr. 2021 <https://vitruvius.com.br/revistas/read/drops/21.163/8073/en_US>.

GONÇALVES, Joana; et. al. The poor environmental performance of offices behind the glass-box. The transformation force of architectural strategies. Drops, São Paulo, year 21, n. 164.08, Vitruvius, may 2021 <https://vitruvius.com.br/revistas/read/drops/21.164/8186/en_US>.

1
Ver acima, na nota do editor, os demais artigos da série.

2
CLEMENTS-CROOME, Derek J. Creating the Productive Workplace, Spon-Routledge, 2000.

3
ABNT – Associação Brasileira de Normas Técnicas. ABNT NBR 16401: Instalações de ar-condicionado – Sistemas centrais e unitários. Parte 1: Projetos de instalações. Rio de Janeiro: ABNT, 2008.

4
ANVISA – Associação Nacional de Vigilância Sanitária. Resolução-RE n. 09, de 16 de janeiro de 2003 <https://bit.ly/2PMvQUz>.

5
Ver: KATS, Greg. Greening our built world: Costs, benefits and strategies. Island Press, Washington DC, 2010.

6
XU, Xiangguo; HUANG, Zhiyuan; ZHANG, Xiaobo; LI, Zhao. A novel humidity measuring method based on dry-bulb temperatures using artificial neural network. Building and Environment, v. 139, jul. 2018, p. 181-188 <https://bit.ly/3sXgxqo>.

7
STOLWIJK, Jan A. J. Sick-building syndrome. Environment Health Perspectives, v. 95, 1991, p. 99-100<https://bit.ly/33fbDZQ>.

8
WOLKOFF, Peder. Indoor air pollutants in office environments: Assessment of comfort, health, and performance. International Journal of Hygiene and Environmental Health, v. 216, n. 4, jul. 2013, p. 371-394 <https://bit.ly/30kHNTq>. Ver também: WARGOCKI, Pawel; SEPPÄNEN, Olli (Org.). Indoor climate and productivity in offices. REHVA Guidebook, 2006.

9
SARRA, Sheila Regina. A questão da saúde na avaliação pós-ocupação de escritórios: uma proposta metodológica. Orientadora Roberta Consentino Kronka Mülfarth. Tese de doutorado. São Paulo, FAU USP, 2020.

about the authors

Joana Carla Soares Gonçalves é arquiteta e urbanista pela UFRJ, mestre em Environment and Energy pela AA School of Architecture, doutora e livre-docente pela FAU USP. Orientadora dos programas de pós-graduação Arquitetura e Urbanismo da FAU USP e Architecture and Environmental Design, School of Architecture and Cities, University of Westminster, Londres. Profa. da AA School of Architecture, Londres. Diretora da Associação PLEA.

Roberta C. Kronka Mülfarth é arquiteta e urbanista pela FAU USP, mestre pelo Programa Interdisciplinar de Pós-Graduação em Energia da USP, doutora e livre-docente pela FAU USP. Orientadora de pós-graduação em Arquitetura e Urbanismo da FAU USP e no Programa de Educação Continuada – PECE, no curso de especialização de Gestão em Cidades, junto a POLI USP. Vice-coordenadora do USP Cidades. Chefe do Departamento de Tecnologia da FAU USP.

Marcelo de Andrade Roméro é professor titular da FAU USP. Arquiteto e urbanista pela UBC, mestre, doutor e livre docente pela FAU USP, Pós-Doc pela CUNY (USA). Orientador e professor dos programas de pós-graduação da USP, do Instituto de Pesquisas Tecnológicas do Estado de São Paulo – IPT, da Universidade de Brasília, do Centro Universitário Belas Artes de São Paulo e da Peter the Great St. Petersburg Polytechnic University.

Ranny Loureiro Xavier Nascimento Michalskié engenheira mecânica pela UFRJ, mestre e doutora em engenharia mecânica pela COPPE-UFRJ. Professora doutora da FAU USP, onde atua como docente no ensino e na pesquisa, na graduação e na pós-graduação. Coordenadora da Regional São Paulo da Sociedade Brasileira de Acústica – Sobrac. Participa da elaboração de normas técnicas brasileiras em acústica da Associação Brasileira de Normas Técnicas – ABNT.

Alessandra Rodrigues Prata Shimomura é arquiteta e urbanista pela PUC-Campinas, mestre pela Unicamp e doutora pela FAU USP. Professora pela Faculdade de Arquitetura e Urbanismo e Orientadora do programa de pós-graduação em Arquitetura e Urbanismo da FAUUSP. Advisor no Student Branch ArchTech Labaut da ASHRAE e Membro do Comitê PLEA (Passive and Low Energy Architecture) Chapter Latin America and the Caribbean (PLEA-LAC).

Eduardo Pimentel Pizarro é arquiteto e urbanista, mestre e doutor pela FAU USP. Professor da Universidade São Judas. É embaixador do LafargeHolcim Awards e já desenvolveu pesquisa na Architectural Association Graduate School, em Londres, e na ETH, em Zurique. Ganhador de prêmios como o Jovem Cientista (Brasília, 2012) e o LafargeHolcim Forum Student Poster Competition (Detroit, 2016).

Monica Marcondes-Cavaleri é arquiteta e urbanista, doutora e pós-doutora pela FAU USP. mestre pela AA Graduate School, Londres. Há 15 anos é consultora e pesquisadora em desempenho ambiental e eficiência energética da arquitetura. Especialista no uso de ferramentas avançadas de simulação computacional em avaliações dinâmicas e integradas de desempenho ambiental e eficiência energética. Auditora AQUA-HQE.

Marcelo Mello é engenheiro civil pela Politécnica USP, arquiteto e urbanista pela FAU Mackenzie, Mestre em Sustainable Environmental Design pela Architectural Association School of Architecture, Londres, e doutor pela FAU USP. Trabalhou com consultoria em sustentabilidade no Centro de Tecnologia de Edificações – CTE, e hoje atua como Diretor na Arqio Arquitetura e Consultoria.

João Pinto de Oliveira Cottaé arquiteto pela PUC-Campinas, mestre em Sustainable Environmental Design pela AA School of Architecture, Londres, e doutorando pela FAU USP. Sócio do escritório Oliveira Cotta Arquitetura. Em seu portfólio destacam-se o novo centro de P&D da empresa Siemens na Ilha do fundão, no Rio de Janeiro e a ampliação da estação de metrô Santo Amaro.

Juliana Pellegrini L. Trigo é arquiteta e urbanista pela FAU Mackenzie, pós-graduanda no programa de Arquitetura e Urbanismo da FAU USP, com foco em processo de projeto de edifício de alta desempenho. President Elect ASHRAE Brasil Chapter 2021/2022 e diretora do escritório Studio Symbios. Com mais de 20 anos de atuação, obteve publicações e premiações em concursos nacionais e internacionais.