Alberto Sérgio Miguel

Thermal comfort assessment of a surgical room through computational fluid dynamics using local PMV index.

BACKGROUND Studies concerning indoor thermal conditions are very important in defining the satisfactory comfort range in health care facilities. OBJECTIVE This study focuses on the evaluation of the thermal comfort sensation felt by surgeons and nurses, in an orthopaedic surgical room of a Portuguese hospital. METHODS Two cases are assessed, with and without the presence of a person. Computational fluid dynamic (CFD) tools were applied for evaluating the predicted mean vote (PMV) index locally. RESULTS Using average ventilation values to calculate the PMV index does not provide a correct and enough descriptive evaluation of the surgical room thermal environment. As studied for both cases, surgeons feel the environment slightly hotter than nurses. The nurses feel a slightly cold sensation under the air supply diffuser and their neutral comfort zone is located in the air stagnation zones close to the walls, while the surgeons feel the opposite. It was observed that the presence of a person in the room leads to an increase of the PMV index for surgeons and nurses. That goes in line with the empirical knowledge that more persons in a room lead to an increased heat sensation. CONCLUSIONS The clothing used by both classes, as well as the ventilation conditions, should be revised accordingly to the amount of persons in the room and the type of activity performed.

Experimental Validation of a CFD Model in a Thermal Environment Characterization

Comfort has a great influence on work performance and productivity. Creating a comfortable environment can be achieved by various routes: a good selection of clothing and a proper design of equipment and technical facilities that can render an appropriate acclimatization of the occupational environment. There are several methods for solving problems of thermal comfort, including computer simulation of the thermal system comprising the Human Body - Clothing - Environment. With the evolution of computer technology and CFD (Computational Fluid Dynamics) techniques one can now develop complete analysis of HVAC systems, with regard to the fields of flow velocity, temperature distribution, particularly in the vicinity of the human body. In this way a complete interaction of the human body with the surrounding air can be descried. The difficulty in modeling the human body arises from the complex geometric shape and its thermo-physiological properties, being important to include all these factors in the numerical simulation of the human body in a closed environment. In the current study a CFD model was developed to describe the fluid flow, heat transfer and mass transfer between the ventilation air and a human manikin inside a room. The computational model solves the heat, mass and momentum conservation equations in the computation domain using a finite volume discretization method and the resulting equations are solved in the ANSYS

Evaluation of Occupational Exposure to Noise in Portuguese Industrial Companies

This study analyses the developments occurred with regard to occupational noise exposure in industrial companies, over a period of three years. Data has been gathered in a total of 121 companies, involving 1753 different workplaces from different industrial sectors. Results indicate a slight decrease on the number of operators exposed to Daily Exposure Levels above the maximum threshold set. A discussion is included on the type of measures implemented for noise control at the companies visited.