Controlling Humidity in Indoor Parking Lots

Increasing humidity levels in modern indoor parking garages is driving up maintenance costs for building owners and creating new problems.  Modern ventilation methods need to address this trend.

Carbon monoxide detectors take the guess work out of calculating ventilation rates in garages.  Demand-based ventilation saves heating dollars and improves the quality of the air.  But, since overall ventilation rates are lower, humidity is going up.

Here are some contributing factors:-

1. With demand based ventilation there is more ventilation during peak periods and little or no ventilation during off hours. The sources of high humidity, however, are constant, like melting snow.

2. Old style gas detectors widely used in the 1980s and 1990s were, so called, “multi-gas” type sensors which responded to many gases, carbon monoxide being just one.  Slow accumulation of gasoline vapours from parked automobiles would cause the ventilation system to cycle on from time to time during the night when no cars were moving.  This reduced the humidity levels.  Modern sensors are very specific to detect only carbon monoxide.  They are more precise, but humidity levels can go up.

3. Buildings are sealed better today.

4. More people wash their cars indoors and they wash them more often.

Enter Opera’s new humidity sensor module which simply plugs into the standard series 5002 carbon monoxide sensor.  It reads 0-100% relative humidity with a precision of 3% and displays it on the screen along with the gas levels.  The user can adjust the maximum level with the keypad.  The ventilation system attached to the gas sensor will, then, also control the humidity.  No additional field wiring required. When the garage floor is washed, the humidistat acts as an automatic dryer and eliminates the humidity without the worry of leaving the door open or ventilation on over-ride for too long.

Adding the humidity option is just another step by Opera to make their exhaust gas monitors specially suited to this market.  Each unit also has built in temperature monitoring and controls to evacuate excess heat in summer from air conditioners installed in garages, variable speed fan output to reduce fan noise and maintenance, the lowest profile of any sensor on the market, to avoid collisions, and, just in case, a robust collision resistant enclosure.

High garage humidity in the winter will cause wear and tear on the concrete floor as salty water will stand around longer.  It causes corrosion of metal components of mechanical and electrical systems and automobiles.  High humidity can also be dangerous, as the windshield of a cold car entering a humid garage will instantly fog up.