Mateja Dovjak

Challenging the assumptions for thermal sensation scales

ABSTRACT Scales are widely used to assess the personal experience of thermal conditions in built environments. Most commonly, thermal sensation is assessed, mainly to determine whether a particular thermal condition is comfortable for individuals. A seven-point thermal sensation scale has been used extensively, which is suitable for describing a one-dimensional relationship between physical parameters of indoor environments and subjective thermal sensation. However, human thermal comfort is not merely a physiological but also a psychological phenomenon. Thus, it should be investigated how scales for its assessment could benefit from a multidimensional conceptualization. The common assumptions related to the usage of thermal sensation scales are challenged, empirically supported by two analyses. These analyses show that the relationship between temperature and subjective thermal sensation is non-linear and depends on the type of scale used. Moreover, the results signify that most people do not perceive the categories of the thermal sensation scale as equidistant and that the range of sensations regarded as ‘comfortable’ varies largely. Therefore, challenges known from experimental psychology (describing the complex relationships between physical parameters, subjective perceptions and measurement-related issues) need to be addressed by the field of thermal comfort and new approaches developed.

Integral Control of Health Hazards in Hospital Environment

Hospitals present complex indoor environment with various users, health hazards and specific activities. This paper classifies health hazards specific to the hospital environment (HE), defines their interactions and possible impacts on human health and summarizes recommendations for biological and chemical hazards. A detailed literature review clearly shows that there is no developed system or method for integral control of health hazards in HE. There is no appropriate technology available that would allow development of optimal thermal comfort conditions for individual users in HE. For integral control of physical hazards, an innovative low exergy (LowEx) system was designed and tested. The system enables individual control of thermal comfort parameters to meet the needs of various users in the same room. It enables the design of optional conditions for healthcare and treatment considering the different requirements of individual patients and thermally neutral zones for other users. The system application is presented in a model room for burns patient. The measured energy use was lower by 11–27% for space heating and by 32–73% for cooling, when using LowEx system as compared to the conventional system. Owning to its flexibility, the system can also be used for other potential users.

Individualisation of personal space in hospital environment

The purpose of the paper is to test a Low Exergy heating and cooling system (LowEx system) that enables the creation of healing and comfort conditions for individual user with minimal possible energy use. The LowEx system was tested in a model room for burn patient and compared with the conventional one. Thermal comfort conditions were simulated for three individual users (burn patient, healthcare worker and visitor) energy use was measured. In a simulation, users were exposed to the required conditions for burn patient created with both systems. The LowEx system creates optimal conditions for burn patient with lower human body exergy consumption (hbExC) rate valid for thermoregulation, minimal evaporation, radiation and convection. For healthcare worker and visitor, the LowEx system creates individual thermal comfort zones. For the LowEx system, the measured energy use for heating was 11-27% lower and for cooling 32-73% lower than for the conventional system.

Integral control of hospital environment

Hospital presents a complex indoor environment. Patients, healthcare workers/staff and visitors can not be treated as uniform group with the same needs, demands and conditions for thermal comfort. There is no method or system to provide optimal thermal comfort for everyone besides rational energy use for heating and cooling. The paper presents a design of a smart patient room in which thermal comfort conditions are highly controlled and energy use for heating and cooling minimized. Control system is based on the concept of individualization of personal space. With this respect two systems for heating and cooling are compared on the basis of thermal comfort calculations for two patients and measured energy use for heating and cooling. Human body exergy balance model is used together with building energy model. To control HE a smart system on the basis of fuzzy logic is applied. An individualized personal zone is designed.

User-Centred Healing-Oriented Conditions in the Design of Hospital Environments

Design approaches towards energy efficient hospitals often result in a deteriorated indoor environmental quality, adverse health and comfort outcomes, and is a public health concern. This research presents an advanced approach to the design of a hospital environment based on a stimulative paradigm of healing to achieve not only healthy but also comforting conditions. A hospital room for severely burn patient was considered as one of the most demanding spaces. The healing environment was designed as a multi-levelled, dynamic process including the characteristics of users, building and systems. The developed integral user-centred cyber-physical system (UCCPS) was tested in a test room and compared to the conventional system. The thermodynamic responses of burn patients, health care worker and visitor were simulated by using modified human body exergy models. In a healing environment, UCCPS enables optimal thermal balance, individually regulated according to the user specifics. For burn patient it creates optimal healing-oriented conditions with the lowest possible human body exergy consumption (hbExC), lower metabolic thermal exergy, lower sweat exhalation, evaporation, lower radiation and convection. For healthcare workers and visitors, thermally comfortable conditions are attained with minimal hbExC and neutral thermal load on their bodies. The information on this is an aid in integral hospital design, especially for future extensive renovations and environmental health actions.

Identification and Control of Health Risks in Hospital Environment from the Aspect of Users, Buildings and Systems

Izvleček Izhodišča: Bolnišnice predstavljajo kompleksno notranje okolje, v katerem so bolniki, zaposleni in obiskovalci izpostavljeni številnim dejavnikom tveganja za zdravje. Raziskav, ki bi obravnavale več dejavnikov tveganja hkrati, je danes malo. Ne izhajajo iz povezave med uporabniki, stavbo in sistemi. Namen metaanalize je prepoznati fizikalne, biološke in kemične dejavnike tveganja za zdravje v bolnišničnem okolju ter izdelati izhodišča za pripravo priporočil za njihovo preprečevanje in obvladovanje. Pri tem bomo upoštevali uporabnike ter življenjski cikel stavbe in sistemov. Metode: Opravili smo metaanalizo raziskav na področju fizikalnih, bioloških in kemičnih dejavnikov tveganj za zdravje v bolnišničnem okolju. Zajeli smo dve bibliografski bazi (Pub Med in Science Direct). V analizo je bilo vključenih 634 virov literature, ki so bili objavljeni med letoma 1934 in 2012. Izhodišča za pripravo priporočil smo izdelali po nadgrajeni metodi inženirskega načrtovanja. Rezultati: Na podlagi izsledkov metaanalize smo pripravili izhodišča za pripravo priporočil, ki vključujejo sistematične ukrepe, specifične za bolnišnično okolje. Preprečevanje fizikalnih dejavnikov tveganja za zdravje vključuje ukrepe s področja zakonodaje, načrtovanja stavbe in sistemov ter usposabljanja zaposlenih. Najpomembnejši ukrepi s področja bioloških in kemičnih dejavnikov tveganja za zdravje so: preprečevanje in obvladovanje poti prenosa povzročiteljev bolezni ter nadzor kemičnih onesnaževal v notranjem in zunanjem zraku. Zaključki: Metaanaliza predstavlja nov pristop k preprečevanju in obvladovanju fizikalnih, bioloških in kemičnih dejavnikov tveganja za zdravje v kompleksnem bolnišničnem okolju - od načrtovanja stavbe do njene uporabe in vzdrževanja. Učinkovitost stavbe in sistemov se doseže s celostnim upoštevanjem značilnosti uporabnikov, bolnišničnega okolja in rabe energije. Uporabljen pristop je tudi pogoj za načrtovanje stavb in sistemov; je temelj uspešnih prenov. Abstract Background: Hospitals represent a very complex indoor environment where patients, staff and visitors are exposed to numerous health risk factors. Studies where health risk factors specific to the hospital environment are represented together are for the moment scarce, and they do not arise based on the relationship between users, buildings and systems. The purpose of this study is to identify physical, biological and chemical health risk factors and to prepare starting points for elaboration of recommendations for their prevention and control. In doing so, we took into account users, life cycle of buildings and building systems. Methods: Meta-analysis was carried out studying physical, chemical and biological health risk factors in the hospital environment. We searched Pub Med and Science Direct for peer-reviewed publications from 1934 to 2012. 634 sources of literature were included. The starting points for the preparation of recommendations were made through an upgraded method of engineering design. Results: On the basis of meta-analysis, the starting points for the preparation of recommendations were made. They include systematically defined actions specific for the hospital environment. For the prevention of physical health risk factors, actions are defined on the level of legislation, building and system design as well as worker qualifications. For the prevention of biological health risk factors, actions in the chain of infection are included and control of outdoor and indoor air pollution is provided. Conclusions: This study presents a new approach to the prevention of physical, biological and chemical health risk factors in the complex hospital environment, from the design stages to the stage of usage and maintenance. Efficiency of buildings and systems is attained through a holistic approach, taking into account the characteristics of users, hospital environment and energy use. The presented approach is necessary for the design of buildings and building systems and a basis for successful renovations.