For sedentary activities, the PMV equation, derived by Fanger, is mainly based on the research of Nevins et al. (720 test subjects). Nevins' experiments were later on repeated by Fanger, but with 128 college-age Danish subjects and 128 elderly Danish subjects, instead of American subjects. Rohles did the research from Nevins et al. again, but over a more extensive temperature range and more, namely 1600, test subjects. Rohles' research results have been partly included in the derivation of the PPD equation, but not in the derivation for the PMV equation. Rohles' experimental results are published at a later time than the publication of the thesis of Fanger. The question arises: ‘If Rohles' experimental results were included in the derivation of the PMV equation, instead of Nevins' experimental results, to what extent does that change the PMV equation and the application area of the PMV equation, with regard of validity, for sedentary activities?'. In the same way, as Fanger described in his thesis, and using the results of Rohles’ experiment, this study is limited to the derivation of a PMV equation with a wider PMV range than −2 to 2, for sedentary activities.@en

Er zijn aanwijzingen dat het Sars-Cov-2-virus zich door de lucht kan verspreiden en dat infectie via aerogene transmissie niet kan worden uitgesloten. In hoeverre is dan het gewenste waargenomen luchtkwaliteitsniveau, dat ten grondslag ligt aan de dimensionering van een ventilatiesysteem, van invloed op de kans van besmetting en de matevan verspreiding in een kantoorgebouw?@en

Met ingang van 30 september is door de Rijksoverheid dringend geadviseerd niet-medische mondneusmaskers te dragen bij verplaatsing in de publieke binnenruimte. Aangezien er sprake is van een dringend advies en (nog) geen verplichting, zijn er situaties denkbaar waarbij een geïnfecteerd persoon zonder symptomen en zonder mondneusmaskers zich in de publieke binnenruimte begeeft. De vraag die dan kan worden gesteld: aan welke aerosolfiltratie dient een niet-medisch mondneusmaskers te voldoen, opdat zich geen verspreiding in de populatie van een publieke binnenruimte voordoet?@en

One of the fundamental human requirements is a working environment that allows people to perform their work optimally under comfortable conditions. Given that buildings and air conditioning systems are designed on the basis of a certain level of discomfort, this raises the key question ‘What is the effect of the level of comfort on the productivity of people working in office environments?’ The purpose of this paper is to quantify this relationship as an aid to making choices regarding the working environment at strategic level within the facilities management process, with particular emphasis on thermal conditions.@en

The key question in this study is: ‘To which extent is the difference in thermal comfort mathematically to describe by temperature sensation and the percentage of dissatisfied, between the elderly and non-elderly, related to the Fanger model?’. This study proves that it is possible to mathematically describe the difference in thermal comfort between elderly and non-elderly by means of a comparison between the calculation results of a thermophysiological two-node model, adjusted for individual characteristics, and different experimental studies. Since the various subgroups of elderly are increasing in number disproportionately to other age groups, adapting the existing thermophysiological human models, for predicting the thermal response of people depending on age and sex, is important. In this way, useful insights can be realized from modelling the thermal behaviour and response patterns of the elderly for the future design of buildings and climate installations.@en

Purpose – The purpose of this paper is to show that it is advisable to evaluate draught in an operating theatre in a different manner than the method according to NEN-EN-ISO-7730. The NEN-EN-ISO-7730 is an international standard for the analytical determination and interpretation of the thermal comfort of the human body and the local thermal comfort like for instance draught. Design/methodology/approach – Using a CFD computer program, it is possible to evaluate draught in an operating theatre in the design stage, according to different mathematical draught models. Findings – It would seem advisable to begin with the draught model developed by Griefahn. The model does, however, need to be modified to include the effects of temperature sensation and the direction of the air stream, so that it becomes applicable to a thermally cool environment (PMV<0) and a vertical air stream, the air pattern prescribed for an operating theatre. Originality/value – It can be demonstrated that by implementing the proposal in this paper in a CFD program, the possibility exists to be able to evaluate, in a responsible fashion, the results for a much broader range of parameters than is currently possible by means of the NEN-EN-ISO-7730.@en

If the society has the opinion that older people should work longer and should take care for themselves than, in the built environment, and particularly in the housing process, we have to note that the elderly have different requirements of health than young people. In the law and regulations, as well as the standards and guidelines, for elderly, however, are not explicitly taken into account.Build with more care for health offers the possibility to reduce the chance of disease and (the feeling of) insecurity, to stimulate the physical and mental activity and to provide support in the daily work and life operations. It increases the possibility of self-care and informal care and increases the quality of professional care. Viewed from this perspective, the right performance requirements on the well-being of elderly are evident and the standards and guidelines are to be adapted as a matter of urgency.This literature study is a first translation into a guideline for the indoor environment for vital elderly.@en

This paper has the objective to initiate a discussion on potential improvements or extension of the validity of the original equation of the Predicted Percentage of Dissatisfied (PPD), according to (NEN-)EN-ISO 7730. This paper is to be regarded as a supplement to a paper on a re-derivation of the PMV equation in the Fanger model (Roelofsen, Jansen, and Vink 2021). In practice, in scientific research it regularly appears that the PMV (Predicted Mean Vote), and by extension the PPD, are applied outside the range based on which the PMV and the PPD equation are derived. In practice, this can occur, for example, in the evaluation of the measurement or calculation of temperature exceedances in a room, for sedentary activities. As it turns out, a PMV equation with an application of −3 to 3, for at least sedentary activities, would be useful in the different fields of study. For that reason, Roelofsen has adapted the PMV equation in the (NEN-)EN-ISO model. But to what extent should the PPD equation also be adjusted? After all, the PPD is also derived from and limited to a PMV of −2 to 2, according to (NEN-)EN-ISO 7730.@en

There are different thermal perception models linked to a mathematical thermophysiological human model, with which the thermal sensation under stationary and/or dynamic conditions can be evaluated. Each of these perception and thermophysiological models have their own field of application. Stolwijk developed a thermophysiological human model without an associated thermal perception model, which today is still the basis for other mathematical thermophysiological models. Fiala developed the FPC model, also based on the Stolwijk model, and is one of the latest developments in the field of thermophysiological human models. In the FPC model, an equation is included with which the thermal sensation under stationary and dynamic conditions can be assessed; the so-called Dynamic Thermal Sensation (DTS). The DTS equation is, however, specifically developed for use in combination with the FPC model. In contrast to the Stolwijk model, the source code of the computer programs of the later developed thermophysiological human models is not freely available, which limits the use and applicability of the models in practice. It is precise because of the availability of the source code that the Stolwijk model is still used in industry and the research world. The question, therefore, arises: ‘To what extent can a human transient thermal sensation equation be derived, combined with the Stolwijk model, in a similar way to that used for the DTS equation in the FPC model?’.@en

In this study, using construction activities as an example, a proposal is made for the time-dependent prediction of the thermal sensation and the performance loss using a cooling vest, under transient conditions. The approach presented here can, mutatis mutandis, be used for any work activity and the use of a cooling vest, whether or not in a building.@en

Purpose: The purpose of this study is to analyze the question “In what order of magnitude does the comfort and performance improvement lie with the use of a cooling vest for construction workers?”. Design/methodology/approach: The use of personal cooling systems, in the form of cooling vests, is not only intended to reduce the heat load, in order to prevent disruption of the thermoregulation system of the body, but also to improve work performance. A calculation study was carried out on the basis of four validated mathematical models, namely a cooling vest model, a thermophysiological human model, a dynamic thermal sensation model and a performance loss model for construction workers. Findings: The use of a cooling vest has a significant beneficial effect on the thermal sensation and the loss of performance, depending on the thermal load on the body. Research limitations/implications: Each cooling vest can be characterized on the basis of the maximum cooling power (Pmax; in W/m²), the cooling capacity (Auc; in Wh/m2) and the time (tc; in minutes) after which the cooling power is negligible. In order to objectively compare cooling vests, a (preferably International and/or European) standard/guideline must be compiled to determine the cooling power and the cooling capacity of cooling vests. Practical implications: It is recommended to implement the use of cooling vests in the construction process so that employees can use them if necessary or desired. Social implications: Climate change, resulting in global warming, is one of the biggest problems of present times. Rising outdoor temperatures will continue in the 21st century, with a greater frequency and duration of heat waves. Some regions of the world are more affected than others. Europe is one of the regions of the world where rising global temperatures will adversely affect public health, especially that of the labor force, resulting in a decline in labor productivity. It will be clear that in many situations air conditioning is not an option because it does not provide sufficient cooling or it is a very expensive investment; for example, in the situation of construction work. In such a situation, personal cooling systems, such as cooling vests, can be an efficient and financially attractive solution to the problem of discomfort and heat stress. Originality/value: The value of the study lies in the link between four validated mathematical models, namely a cooling vest model, a thermophysiological human model, a dynamic thermal sensation model and a performance loss model for construction workers.@en

In de utiliteitsbouw hebben duurzaam en energiezuinig bouwen een sterke invloed op het ontwerp van de gevel en de klimaatinstallatie. In bepaalde situaties kan het raadzaam zijn om een zogeheten tweedehuid façade toe te passen. Hierbij wordt de gevel niet – zoals bij de klimaatgevel – met binnenlucht, maar met buitenlucht geventileerd. Om na te gaan aan welke randvoorwaarden de belangrijkste bouwkundige en installatietechnische voorzieningen moeten voldoen bij een tweedehuid façade, is een rekenstudie uitgevoerd.@en

Door de coronapandemie is er weer volop aandacht voor de binnenluchtkwaliteit in scholen. Een grootschalige inventarisatie van de ventilatiesystemen in schoolgebouwen heeft de nodige manco’s aan het licht gebracht. Inmiddels zijn verschillende mogelijke oplossingen voorgesteld om de besmettingskans in lesruimten te verminderen. Een daarvan is met FAR-UV-C-licht. Reden genoeg om te kijken of deze voorgestelde oplossing ook echt zoden aan de dijk zet.@en

Stolwijk developed a thermophysiological human model which, to day, is still the basis and inspiration for many other thermophysiological human models. The Stolwijk model used in this study is improved with regard of the calculation of the skin temperature and equipped with clothing as well as thermal sensation. Fiala also developed a thermophysiological model, based on the Stolwijk model, and is currently considered to be the latest development in thermophysiological human models. The current version of the Fiala model is known in practice as the Fiala thermal Physiology and Comfort (FPC) model. In the FPC model an equation is included to predict the thermal sensation under dynamic conditions, the so called Dynamic Thermal Sensation (DTS), based on the simulated core temperature and the mean skin temperature. This DTS-model was developed based on the subjects’ votes in early studies, which did not involve physiological measurements; instead, Fiala used his physiology model to predict the skin and the core temperatures from environmental variables measured in the tests. The correlations are therefore specific to the Fiala physiology model. In order to find out to what extent the DTS calculation results of the modified Stolwijk model deviate from the FPC model (version 5.3), in this study a number of variant calculations were carried out. Three well described and known scientific experiments from the professional literature are used for this, for a homogenous step-change transient thermal environment and for sedentary activity.@en

For the sake of energy and cost savings, it is sometimes necessary to maintain the indoor climate in a room at conditions that deviate from optimal thermal comfort. More important than thermal sensation is how a change in conditions will affect the thermal acceptability of a space and whether the percentage of people who are (dis)satisfied with the environment will change with regard of the acceptability. The aim of this technical note and arithmetic study is to find out to what extent the thermal indoor climate can be assessed on the basis of thermal acceptability, in addition to the thermal (dis)satisfied, by making use of research that has already been carried out. In addition to the relationship between the percentage of (dis)satisfied and acceptability, attention is paid to how this result relates to current Dutch government building regulations. The paper concerns a proposal for the assessment of thermal indoor climate based on the thermal acceptability, in addition to the thermal (dis)satisfied.@en

Purpose – The purpose of this paper is to show how the performance of the personnel can be negatively affected by conversations, adjacent to the working space, in an open-plan office environment. Design/methodology/approach – Using two scientific mathematical models it is possible to quantify the performance losses, as a result of adjacent conversations, with various desk layouts in an open-plan office. Findings – The results obtained from the underlying Finnish study can be improved by applying a regression analysis to the recorded research results. The modified deviation formula not only corresponds more closely to the research results, but also produces a better translation of the speech intelligibility index to the intelligibility qualifications, as shown in the guideline NPR 3438. Originality/value – It is reasonable to conclude that performance loss, as a result of a poor acoustic situation, can be related to the speech intelligibility in a space. The relationship between the speech intelligibility index and performance loss makes it possible to design on the basis of productivity improvement, resulting in a comfortable acoustic working environment and a consistent financial advantage for the organisation.@en

BACKGROUND: The original Stolwijk model is not equipped with clothing, thermal sensation, comfort indices, individual characteristics and performance loss models. OBJECTIVE: This study attempts to modify the model to include clothing, thermal sensation as well as the calculation of the percentage of dissatisfied as a result of general discomfort. The model is useful for the evaluation of thermal comfort in the built environment by professionals. METHODS: Methods described in literature with regard of clothing, the research of Fiala as well as some in the literature recommended and validated adjustments, to improve the simulation of the skin temperature per body segment, are implemented in the here assembled Stolwijk computer model. Finally, for verification of the above adjustments, the model was compared with experiments conducted in the field of thermal sensation at various levels of temperature change. RESULTS: By improving the simulation of the skin temperature per body segment and by adding clothing and thermal sensation, suitable for the assessment of steady state and transient thermal conditions, and fixed with this the percentage of dissatisfied, the scope of the Stolwijk model has become larger than it was before. CONCLUSION: On the basis of the calculations and the experimental results, it was concluded that the adjusted Stolwijk model was suitable for the simulation of the thermal sensation under steady state and transient thermal conditions.@en

Purpose – The purpose of the paper is to demonstrate that it is completely rational to invest in climate installations for offices designed on the highest comfort category. Design/methodology/approach – By means of a study on a building model it is proved that the benefits of a higher comfort category outweigh the costs of the additional investment, with marginally higher energy costs for cooling. Findings – Depending on the type of climate installation and the comfort class, the additional investment costs can be recovered within six month to two years, due to a higher level of comfort and raised productivity. Originality/value – The relationship between the thermal environment and productivity makes it possible to design on the basis of productivity improvement, resulting in a comfortable working environment and a consistent financial advantage for the organisation. If the indoor environment is henceforth assessed in the context of comfort and productivity, the participants in the housing process who are generally less interested in the aspects mentioned above will eventually incorporate investments in the quality of the workplace in their objects (in connection with the ability to sell and lease real-estate).@en

Purpose – The purpose of the paper is to demonstrate that it is completely rational to invest in climate installations for offices designed on the highest comfort category. Design/methodology/approach – By means of a study on a building model it is proved that the benefits of a higher comfort category outweigh the costs of the additional investment, with marginally higher energy costs for cooling. Findings – Depending on the type of climate installation and the comfort class, the additional investment costs can be recovered within six month to two years, due to a higher level of comfort and raised productivity. Originality/value – The relationship between the thermal environment and productivity makes it possible to design on the basis of productivity improvement, resulting in a comfortable working environment and a consistent financial advantage for the organisation. If the indoor environment is henceforth assessed in the context of comfort and productivity, the participants in the housing process who are generally less interested in the aspects mentioned above will eventually incorporate investments in the quality of the workplace in their objects (in connection with the ability to sell and lease real-estate).@en

Purpose – This article is a proposal and aims to be a first step to develop a method to evaluate and classify environmental noise, according to EN-15251 and CR-1752, in the built environment based on the percentage of dissatisfied related to the equivalent background noise level. Design/methodology/approach – In the European guideline CR-1752 and the standard EN-15251 three categories of the indoor environment in buildings are prescribed (category A, B and C). In the recommendations, the limit whereby the percentage of dissatisfied should remain under varies in each category for both the thermal indoor environment and the air quality. The categories for noise and illumination criteria are not yet explicitly related to a percentage of dissatisfied. Findings – Using the percentage of dissatisfied as the evaluation criterion, when related to the equivalent background noise, produces a more refined evaluation of comfort than an evaluation based on the percentage of seriously disturbed or the effects of sleep deprivation in relation to external noise. Furthermore, this corresponds to the European standards and recommendations concerning quality classification of the indoor environment, based on the percentage of dissatisfied. Originality/value – Based on recent European undertakings concerning the development of categories for the indoor environment based on the percentage of dissatisfied, it is desirable to utilise these categories to noise aspects too, and to relate it to the equivalent background noise level.@en