According to ISO 7730:2005, classification is a mandatory precondition for thermal comfort assessment since the appropriate criterion depends on which category the specific work situation (SWS) investigated belongs to. Unfortunately, while the standard does include three different comfort criteria, it does not indicate how the appropriate criterion should be selected. This paper presents a classification scheme that allows thermal comfort assessment to be reliably performed in any environment. The model is based on an algorithm that calculates a score by means of a weighted product of three quantities, each one taking care of a specific, highly relevant element: the subject's thermal sensitivity, the accuracy required for carrying out the task and the practicality of thermal control. The scheme's simple modular structure can easily accommodate both changes and additions, should other hypothetical elements be identified to be as relevant to the classification scheme. The model presented allows a modulation of comfort levels across different social groups. It is so possible to provide extra care for children, elderly, pregnant women, disabled and other ‘weak’ categories, as required by ISO/TS 14415:2005, by setting the highest comfort level. Finally, it also widens the options for simultaneously establishing comfort conditions for different individuals performing different tasks in the same area and clarifies whose comfort should be pursued with the highest priority.

Purpose: This paper investigates the thermal conditions inside a passenger car driven after it was left a few hours in a shade-less parking lot, and the related implications for the driving performance. Materials and methods: Experimental results for twelve tests carried out in four different vehicles are presented and discussed. Each test is characterized by means of the predicted core temperature t_core of the driver after 60 minutes, as calculated by a heat stress model. The fractional performance loss is calculated by adjusting existing algorithms for office tasks to accommodate literature data on driving-related tasks, and then re-casting the algorithm as a function of t_core instead of the air temperature t_a. Results: Based on measured temperatures and humidities, fractional performance losses up to 50% are predicted even for relatively simple tasks such as keeping the vehicle on a straight course. Performance losses in excess of 75% are predicted, under the most extreme thermal conditions, for demanding tasks, such as correctly identifying a signal and reacting in due time. Conclusions: The implementation in technical standards on heat stress assessment of two new thresholds is recommended. The lower threshold, to be set at t_core ≅ 37.1 °C, is aimed at ensuring that the subject is able to carry out demanding mental tasks without appreciable performance loss, while the higher threshold, to be set at t_core ≅ 37.2 °C applies to simpler tasks.

As a part of their very wide range of applications, international standards also represent an excellent technical support to the legislation on comfort and health at the workplace. The existing standards on thermal comfort and on indoor air quality both include limits of acceptability which strongly depend on the category chosen for the investigated work environment. Therefore, the same situation can easily meet compliant or largely exceed specified limits depending on which category is applied. Unfortunately, no clue is currently provided on how to select the appropriate category, and the end-user is left uninformed. In this paper, we present a method to assign limits of acceptability to any work situation whose thermal comfort and indoor air quality must be assessed. The method extends previous work developed specifically for thermal comfort and is based on an algorithm which takes into account three quantities that provide a comprehensive description of the work environment, the activity which is carried out and the sensitivity of individuals. The scheme’s simple modular structure can easily accommodate both changes and additions, should other hypothetical elements be identified to be as relevant to the classification scheme.

This paper's main issue is a strong advocacy in favour of an a priori classification of thermal environments that can be really functional to comfort assessment: Class 1, environments where comfort conditions can be established (comfort-prone environments), and Class 2, environments where this is not practically feasible. The former, which are also identified here as ‘thermally unconstrained’ environments, because of the absence of elements preventing comfort from being pursued, are the subject of a novel classification scheme. In assembling such a scheme, the four standardized synthetic indexes (Predicted Mean Vote, Insulation REQuired, Predicted Heat Strain, Wet-Bulb Globe Temperature) have been carefully scrutinized, with special emphasis on the regions of overlap. Additional data from national technical documents and legislation have been used to help in assembling the discomfort assessment scheme. All available information has been reprocessed and cast in a form specific for use in comfort-prone environments. Classification takes place through placement in a four-level and in a six-level discomfort scale for cold and warm environments, respectively; for each area, a recommended descriptor as well as a time frame for intervention are specified. The new scheme also eliminates a few glitches and inconsistencies existing in the ISO 15265 scheme, mostly in the area of cold discomfort. Being solely concerned with comfort-prone environments and keeping an open mind with respect to all available information, the new classification scheme represents a simple and robust all-round tool, tackling issues related to both comfort assessment and to action planning for an optimized allocation of available resources.

Introduction: Due to the COVID-19 pandemic, healthcare workers are now required to use additional personal protective equipment (PPEs) to protect themselves against the virus. That led to an increased clothing insulation which is negatively affecting the perceived healthcare workers’ thermal sensation. Objectives: While demonstrating through software simulations the potential level of thermal discomfort healthcare workers involved in the COVID-19 emergency can be subjected to, this work aims at identifying measures to improve thermal sensation perception and acceptable thermal conditions for medical personnel. Methods: After having obtained the insulation values of individual clothing used by staff during COVID-19 emergency through the use of a thermal well-being evaluation software, the Fanger indexes (PMV - Predicted Mean Vote and PPD - Predicted Percentage of Dissatisfied) were calculated in order to estimate staff satisfaction to microclimatic conditions. Results: The use of COVID-19 additional PPEs with an air temperature equal to 22 °C (normally considered optimal) brings the PMV index equal to 0.6, which corresponds to 11.8 % being unsatisfied (PPD) due to perceived heat. Discussion: The use of additional protective devices significantly increases the clothing insulation level, facilitating the onset of conditions of thermal discomfort in the health workers. Workers engaged in the execution of nasopharyngeal swabs were most affected by the summer weather conditions and certainly represent the most critical category, for which it would be recommended to implement a higher turnover of service to reduce individual exposure time and consequent discomfort.

The correlation between heat exposure in outdoor working environments and adverse effects to the health of workers has been widely investigated. Recent epidemiological studies, combined with direct observations, highlight an increase in work-related risks and hazards, which in turn leads to an increase in accidents at work. In this research, we investigated the tendencies and variability of such hazards in the Italian cities of Cagliari, Genoa, Lamezia Terme, Lecce, and Venice, as well as other cities overlooking the Mediterranean Basin, namely Beirut, Cairo, Gibraltar, Istanbul, Larnaca, Tunis, and Valencia.Specifically, we evaluated the Heat Index (HI), which is not considered the most accurate and reliable heat stress indicator, but can be applied on a wide scale as it depends entirely on temperature (Ta) and relative humidity (RH) data.Data products released by NOAA and based on local measurements across the Mediterranean Basin, performed between 2000 and 2024, were collected and analyzed with Jamovi 2.6.19, R v. 4.4.2 and MATLAB v. 2023. The HI provides two threshold values, Danger and Extreme Danger, which correspond to specific combinations of relative humidity and temperature considered hazardous for human health. We calculated the number of hours that, every year between May and October, exceed these thresholds. All trends lines show an increase over time, compatible with anthropogenic climate change. From this, we infer a percentage increase in the order of 60% with respect to productivity hour loss over the time span of two decades. The analysis also showed an extension of the boreal summer to September. Data confirm a constant increase in the number of HI-Danger which, in Tunis for example, increased from 49 days in 2000 to 156 days in 2024.Furthermore, the threshold of 35 °C as a limit for work activities often used in absence of national regulations does not appear to be conservative in more than one third of the studied locations. Despite the limitations of this methodology, this work is intended to set up new mitigation policies, at various scales, in the absence of more detailed methods accounting for additional parameters such as clothing and specific body acclimatation.