The indices of thermal comfort that constitute international standards, such as ISO 7730 and norms suggested by technical publications such as ASHRAE Fundamentals, are PMV, PPD, and T{sub oc}. The aim of this paper is to present similar indices developed from field studies. The studies were made at a school in Florianopolis, Brazil, and consist of more than 1,200 data points. The environmental variables were measured, and the metabolic rate and the thermal insulation of the clothing were estimated from existing tables. Thermal sensation votes were collected for all the students by means of specific questionnaires. The main conclusions are: There is good agreement between the sensations related by the subjects and those obtained from predictions determined by regression analysis; the studies provide one with a different understanding of dissatisfaction with a thermal environment; and when determined from the votes of dissatisfied people, the comfort temperature offers the advantage of showing one the percentage of people who are not comfortable.

Este trabalho discute os limites dados para a velocidade do ar pelas normas ASHRAE 55 (2004) e ISO 7730 (2005). Para tal, realizou-se uma análise comparativa entre os valores-limite para a velocidade do ar definidos por essas normas e as respostas dos usuários em relação à preferência e aceitabilidade do movimento do ar obtidas em experimentos de campo realizados em Maceió/AL. Resultados indicam que ambas as normas especificam valores para a velocidade do ar inferiores aos desejados pelos usuários. Os resultados da preferência do movimento do ar indicam que significativa percentagem dos usuários demanda “maior movimento do ar”. Quando associada às respostas da aceitabilidade do movimento do ar, a insatisfação dos usuários ficou mais evidente, assim como a demanda por maior velocidade do ar. O mesmo movimento de ar, considerado como inaceitável em climas frios e temperados, é desejado pelos usuários em climas úmidos. Nesse contexto, a aplicabilidade de limites máximos para a velocidade do ar provenientes de estudos com características climáticas diferentes deve ser evitada. Tais limites devem vir de resultados de experimentos de campo em ambientes naturalmente ventilados, onde os usuários possam utilizar de oportunidades adaptativas para reestabelecer o conforto térmico. Futuras normas brasileiras devem focar em tais questões, visando limites de velocidade que correspondam à expectativa dos usuários em climas quentes e úmidos.

According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), it is clear that the buildings sector presents the biggest potential for deep and fast CO₂ emission reductions on a cost-effective basis. Interestingly, this assessment was premised exclusively on technical (engineering) measures, but ignored completely the behavioural and lifestyle dimensions of energy consumption in the buildings sector. Behavioural change in buildings, however, can deliver even faster and zero-cost improvements in energy efficiency and greenhouse gas (ghg) emission reductions. With this in mind, designers are beginning to shift their attention to how they can widen the range of opportunities available in a building to provide comfort for the occupants, both in new-build and retrofit contexts. This in turn has re-awakened an interest in the role of natural ventilation in the provision of comfort. This discussion about adaptive comfort raises several questions, including the following: How can we shift occupants' comfort expectations away from the static indoor climates of the past towards the more variable thermal regimes found in naturally ventilated buildings? Are building occupants ‘addicted’ to static environments, i.e. air-conditioning (AC)? If so, how tolerant or compliant will they be when the thermally constant conditions provided by AC are replaced by the thermally variable conditions that characterize naturally ventilated spaces? Does the frequency of prior exposure to AC bias building occupants' thermal expectations and, if so, what are the implications of this bias for their acceptance of naturally ventilated indoor climates? Does prior exposure to AC lead building occupants to actually prefer AC over natural ventilation? This article addresses these questions in the context of a large field study of building occupants in a hot and humid climate zone in Brazil (Maceio). The temperature preferences registered on 975 questionnaires in naturally ventilated buildings are statistically analysed in relation to occupants' prior exposure to AC in their workplaces.

The objective of this paper was to perform an analysis on thermal acceptability in naturally ventilated (NVB) and air-conditioned buildings (ACB) located in hot and humid climates in Brazil. Experiments were carried out in April and November 2005 with 1.301 questionnaires based on ISO 10551:1995(E). Indoor and outdoor climatic variables were monitored simultaneously. The results revealed that 53% of the occupants of NVB and 78% of ACB were thermally satisfied. However, some restrictions were observed with the applications of the following methodologies: ISO/FDIS 7730:2005(E); ANSI/ASHRAE Standard 55:2004; Adaptive Temperature Limits (ATG) and prEN15251: 2005(E). Differences were observed between thermal sensation (TSV) and predicted mean vote (PMV) and between the subject's percentages expressing thermal unacceptability of the environment and the PPD calculated according to ISO/FDIS 7730:2005(E).