Parking garages require ventilation because the exhaust fumes produced by the vehicles have to be discharged. This can be achieved with a mechanical or a natural ventilation system. A natural ventilation system has several important advantages compared with a mechanical system. As a rule natural ventilation systems arc simpler, cheaper and have fewer breakdowns, furthermore a natural system requires less maintenance and uses no energy (for air transfer).

A rapid method for employing personal exposure monitors (PEMs) to measure carbon monoxide (CO) concentrations in high-rise buildings is described. The purpose is to determine whether or not a CO problem exists in a building, and, if so, what corrective actions should be taken. The methodology was applied to a 15-story building in Palo Alto, CA, where elevated CO concentrations were discovered on the first 11 floors . The source appeared to be an underground parking garage.

After numerous tests and experiments on the best way to overcome the problems associated with Bus Garage Ventilation, a simple solution was arrived at - being the most effective and economic.

This paper presents the results of a research program that was conducted for ASHRAE by TRC- Environmental Consultants, Inc. The purpose of the study was to provide information on the effectiveness of existing ASHRAE ventilation guidelines for maintaining acceptable air pollutant levels and to develop a methodology for including economic utilization of energy in the consideration of future guidelines.

The ventilation requirements for decontamination are normally determined with a static calculation method. In some cases, the pollutant emission is intermittent, for example in the car park of an office building, where all the cars enter and leave the place nearly at the same time. Generally, in such a case, the volume of the garage is large, consequently the time constant of the system has a high value. So a static approach would no longer stay accurate and a dynamic evaluation is needed.

When an underground parking place is not ventilated frequently enough, it is natural that the concentration of contaminated air cannot be lowered to less than the safety limit. Further, when the supply or exhaust air is not of laminar flow, the contaminated air concentration will increase locally due to stagnation of contaminated air or due to vorticies generated in that place, even with a sufficient number of times of ventilation per unit time.