Journal of Health and Safety at Work

Introduction: Introduction: Thermal comforts are one of the most human concerns in working as was as living environments in the past half century. Thermal comfort is the condition in which people are satisfied with the thermal environment, mentally. One of the new heating system employed in individual units is radiant heating system .The purpose of this study was to investigate the performance of radiant ceiling heating system and its impact on thermal comfort of workers.

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Material and Method: In the present analytical-descriptive study, the designed radiant heating systems were investigated in two repair and maintenance units, in Hamadan gas pipeline operation center. Firstly, the environment parameters, witch impact thermal comfort, were measured before and after using radiant heating system, in both understudy units. Then, wind chill index, thermal comfort indices, PMV and PPD were calculated. In addition, PPD and PMV were determined, based on workers subjective feeling by a questionnaire distributed among 22 workers.

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Results: According to the results, the radiant heating system in unit 1, has reduced the wind chill index by 42.3 Kcal/ m2.h, witch is not considered to be significant. In unit 2, wind chill index has been decreased by 109.3 Kcal/ m2.h, witch mean that thermal comfort has been changed from cold to an optimum environment. PMV n unit 1 went up by 37% after turning the system on, witch is equal to 17.24% increase in workers satisfaction. However, in unit 2, the workers satisfaction was 14.3% higher in comparison with unit 1.

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Conclusion: Due to large space of these industrial units, producing appropriate heating by convection mechanism is too difficult and expensive. The results confirmed that if radiant heating system applied based on scientific design principles they could be effective in promotion of thermal comfort due to heating surrounding surface by radiant and also reducing fuel consumption.

Introduction: One of the factors influencing on indoor air quality of the buildings is performance of HVAC (heating, ventilation, and air conditioning) systems. These systems supply clean and odorless air, with temperature, humidity, and air velocity within comfort ranges for the residents. The aim of this study was to evaluate performance HVAC system in an administrative building in Tehran.

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Material and Method: A questionnaire, developed in their research was used to assess the building occupants’ perception about the performance of HVAC system. To evaluate the performance of HVAC systems, air velocities were measured in the diffusers using a thermal anemometer. Moreover, CO2 concentration, air temperature and relative humidity were measured in the whole floors of the building. Air distribution inside the building was evaluated using smoke test.

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Results: Most of the studied people complained about the direction of airflow, thermal conditions and cigarette odor. The highest level of carbon dioxide was measured at 930 ppm inside the restaurant. The maximum and minimum air temperatures and relative humidity were measured 28.3-13.8° C and 28.4-23% respectively. Smoke test showed that the air distribution/direction wasn’t suitable in one third of air diffusers.

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Conclusion: Improper air distribution / direction was the main problem with the studied HVAC system which could be corrected by adjusting and balancing of the system.