Richard Tully gives practical advice on ventilation requirements for underground car parks, emphasizing the need to remove fumes quickly from exit ramps where vehicles emit up to half as much carbon monoxide again as on the level.
The inventory of organics in the air of a ten year old office building shows a wide variety of natural and synthetical volatile organic compounds (VOCs). Although 240 employees consume 1200 - 1500 cigarettes per day, the effective ventilation system reduces the ETS rapidly, however, aromatic hydrocarbons and some natural compounds still remain in the air in the higher μg/m3-range. Systematic analyses of volatile compounds of all cleansers used shows that they are sources of higher limonene amounts. Aromatics entered by way of "fresh air'' intake near the parking entrance at street level.
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.
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).
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