S. Mazzacane, University of Ferrara, Ferrara, Italy; G. Lupo, G. Cannistraro, A. Cusumano, University of Messina, Messina, Italy; C. Giaconia, University of Palermo, Palermo, Italy.
In the last 10 years it has become more important to provide a comfortable and healthy environment for both the patients and the surgical team in operating theatres. However this development is characterized by a multitude of factors that must be considered and analyzed in order to avoid many problems such as hypothermia, chemical and microbiological pollution and thermal discomfort. Comfort conditions are very difficult to guarantee in surgical theatres, due to differences between the clothing worn by the surgical team and the drapes worn by the patients. In the first case, the influence of anaesthetic infusion acting on the thermoregulation parameters of the patient’s body must be taken into account, and the rehabilitation time extension after the operation. Also relevant are the thermal stress phenomena for the personnel, which could reduce their work efficiency, depending on the level of their sweat index. Consequently the control of microclimatic parameters for satisfying everyone is difficult. To solve this problem, experimental studies have been carried out in two operating rooms located in Ferrara’s hospital. The results of this investigation are directed to the identification of a new index of thermal stress for this type of environments, useful to prevent the thermal stress condition for the surgeons and the patient. This article shows a relevant review about literature methods used for the environmental evaluation of the operating theatres and the actually used HVAC systems for achieving the best thermal comfort conditions.
D. Herron, Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC- CERL), Champaign, IL.
TEMF is used to rebuild and provide maintenance for Army tactical equipment and vehicles. These buildings include maintenance, repair, and warehouse bays as well as functional areas with office space. In 2004, ERDC-CERL conducted a study to evaluate different opportunities to improve energy performance, indoor air quality, and occupant thermal comfort in TEMF Standard Design. Technology options used in the study included: (1) Improved source capture vehicle exhaust systems resulting in reduced general ventilation; (2) building envelope design in accordance with applicable portions of the new ASHRAE “Advanced Energy Design Guide: Small Office Buildings” design guide; (3) cool roofs; (4) effective ventilation systems using a Solar Wall to preheat make-up air, and a reduced design capacity and variable air volume (VAV); (5) low intensity radiant floor hydronic heating systems; (6) vehicle entry/exit vestibules, and (7) evaporative cooling systems. Performance of each technology was studied through modeling and simulation of their performance using the EnergyPlus program for 12 representative U.S. Department of Energy (DOE) climate zones. This paper and conference presentation will describe simulation results for each selected technology and for combined best options. Based on the life-cycle cost analysis (LCCA), implementation of these options will reduce annual energy consumption in TEMF by 60-75% depending on location and will significantly improve indoor air quality (IAQ) and worker comfort at no or minimum additional first cost.
C. Saunders, P. Johnson, M. Coldwell, Health and Safety Laboratory, Buxton, United Kingdom; J. Wheeler, Health and Safety Executive, Bootle, United Kingdom.
Malaria is estimated to be responsible for 1 to 2 million deaths each year. There are a number of devices available to kill/repel malaria-carrying mosquitoes. The two types of device commonly available for use indoors are a mat and liquid plug-in vaporizer. Both these devices release synthetic pyrethroid pesticides when heated. They are usually used in hotel bedrooms during the night. A project was carried out to investigate the human exposure to these types of devices. The main route of exposure from these devices was identified as inhalation, although surface deposition on skin and ingestion were both possible. Room ventilation rates, room configuration, and emission rate of pesticide were identified as factors that would have a significant effect on exposure. A mock-up hotel bedroom was constructed, complete with furnishings. Both types of plug in devices were tested at three air change rates (ACRs); 0.5, 3 and a worst-case scenario of 0.05 ACR. These ACRs were selected based on tracer gas measurements in typical bedrooms of two hotels. In addition, three furniture layouts were selected. Air concentrations were measured at three different room heights: 1.6 m and 1.15 m to represent the breathing zone of a person standing and sitting, and 0.2 m above the bed as a position representative of the breathing zone of a recumbent person. Surface concentrations on the floor, bed, and table were also measured. In addition, the emission rates of pesticide from the two devices were measured. Results showed that the air change rate had a significant effect on both the airborne and surface pesticide concentration. However, room layout had no effect on the concentration distribution. Airborne concentration of pesticide did not vary with sample height or position. The results of this study will be used to review human exposure for risk assessment studies.
S. Mazzacane, University of Ferrara, Ferrara, Italy; G. Lupo, G. Cannistraro, A. Cusumano, University of Messina, Messina, Italy; C. Giaconia, University of Palermo, Palermo, Italy.
Thermal indices have been used historically in the assessment of potential heat stress situations. The selection of the correct index call for a comprehensive investigation of the situation and general environment. Factors such as temperature, radiant heat load, air velocity, humidity, clothing, metabolic load, posture and acclimatisation should be taken into account. Environmental data are part of the necessary means of ensuring, in the majority of routine work situations, that thermal conditions are unlikely to affect negatively the worker well being. Some studies have been carried out in Italy in order to define a program of prevention and reduction of the heat stress risk to health workers and patients using current thermal stress indices. However data acquired in field are scarce and they regard the study of the microbiological contamination conditions more than the thermo-hygrometrical comfort situations. The specific objectives of the research project exposed in the present paper are:
These objectives will be reached and carried out at least in the 4 operating rooms of S.S.Annunziata Hospital (Cento, Ferrara) and in laboratory of University of Ferrara, named CERTECA (Air Technology Research Centre), where is located an operating room in full scale (1:1), equipped with every kind of device able to reproduce artificially some types of ventilation and thermo-hygrometrical conditions.
J. Hollick, Conserval Engineering Inc., Toronto, ON, Canada.
Transpired solar collectors that use metal walls to heat outdoor ventilation air have been used in numerous retrofits of factories and are now gaining acceptance in commercial and government buildings. Projects have been installed in 20 countries and now several military bases have installed the transpired solar collector to heat their buildings. The U.S. Department of Energy has rated this transpired collector in the top 2% of energy inventions and has stated, “Transpired collectors provide the most reliable, best performing, and lowest cost solar heating for commercial and industrial buildings available on the market today.” Natural Resources Canada now offers software for designers to evaluate these savings. This paper will present the background on the technology, project examples, design considerations, software tools, building integration methods, colors, and typical savings. Designs also focus on the ability to improve indoor air quality by heating larger quantities of fresh air.
E. Sandberg, Satakunta Polytechnic, Pori, Finland; H. Koskela, P. Saarinen, Finnish Institute of Occupational Health, Turku, Finland.
When the stratification or zoning room air-conditioning strategy is applied to an industrial space, the convection flows, i.e., plumes created by the heat sources, are utilized to achieve the accumulation of heat and contaminants in the upper part of the room, where the extract devices are located. When aiming at certain target levels of indoor air conditions, the dimensioning of the needed supply airflow rate is greatly dependent on these buoyant flows. The return airflow from the upper part to the lower part of the room reduces the heat and contaminant removal efficiency. The hypothesis of this study was that the disturbance due to the air jets has an enlarging influence on the convection airflow rate. In order to prove the statement experimentally, a series of laboratory experiments were carried out. The studied jet was relatively weak in order to avoid large horizontal movement of the plume. The airflow rate, diameter, momentum flux, and temperature of the plume were all measured at three heights, first in undisturbed conditions and then with disturbance of four horizontal velocities 0.25-1.0 m/s of the jet. The heating power of the cylindrical heat source was varied from 150 W to 900 W. The location of the jet was varied vertically and horizontally. The basic equations for the airflow rate, diameter and momentum flux of the plume were determined using the undisturbed cases. The disturbed cases were then compared with the undisturbed ones. The relative strength of the disturbing air jet showed a quite linear dependence on the airflow rate and diameter of the plume. An increase of more than 50% in the plume airflow rate was measured, an indication that attention should be paid to it in dimensioning.
R. Niemelä, Finnish Institute of Occupational Health, Helsinki, Finland.
Productivity is one of the most important factors affecting the overall performance of any organization. A common allegation is that improving work environment results in productivity gain. The relationship between work environment and productivity, however, has been insufficiently explored. One reason for this may be the fact that productivity measurement is usually seen as rather complicated. The aim of this paper is to consider the study designs and measurement methods suitable for the measurement of productivity in the work environment. Two study design approaches are used. In the intervention approach, the indoor climate and the productivity are measured before and after the improvements of indoor climate of a work room. The values obtained are then compared. In the observational approach, the productivities obtained from two work rooms with similar production and work processes but with different indoor climates are compared. In this paper, the focus is devoted to employee productivity that was measured in terms of products or services produced per work hour. In addition to the productivity indicator, the concentrations of dominant air contaminants and thermal conditions were measured. Questionnaires on perceived work environment and symptoms were conducted at the same time with the measurements of the work environment parameters. The case studies on productivity measurements in metal industry as well as in office environments are given. Better work environments in the case study buildings were achieved by improving the performance of the HVAC systems.
Posted May 30, 2006