IAQ IN BASEMENT CARPARK STUDY OF CARBON MONOXIDE LEVELS IN BASEMENT CARPARK VENTILATION DESIGNS

Motor vehicle pollution is generally recognized as a source of pollution more than any other single human activity. It is one of the dominant sources of CO (89%). This thesis studies the levels of CO in basement car park with respect to the effectiveness mechanical ventilation systems designed in accordance to local design codes. The general requirement is to provide six air changes per hour in the space that fifty percent of the air exhausted must be from low level. Under these guidelines, the designers are to select and located the exhaust / supply air points. A total of twenty-six (26) cases representing six (6) basic mechanical ventilation designs were simulated. The results were compared and analyzed. The results showed that the showed that the location of the exhausting air points and its mounting height has only minor impact (-3%) on the performance of the ventilation system for the control of carbon monoxide levels. Thus, the local code requirement of 50% exhausts at low levels was found to have no significant impact on system performance. On the other hand, it was found that the control of location and height of the supply air points to have a major effect (-20%) in the control of carbon monoxide levels. In addition, the number of supply / exhaust air points was noted to have significant effect on the concentration pattern of carbon monoxide. Overall, the results have successfully identified several important design considerations for the design of a mechanical ventilation system for basement car parks as well as giving an overview on the differences in performance characteristics for six commonly used design configurations.

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• NG ENG SIN