The Quality of the air you breathe is paramount to your health.

On the lower risk of the spectrum effecting your health is the buildup of Carbon Dioxide (CO2) in the space you occupy; you may feel tired and lazy.   On the higher end of risk is Carbon Monoxide (CO) entering the space as it may cause death as was the potential in our last post: Smoky Kitchen.

In this particular case the base building installed make-up air louvres in the rear of the building.  Normally this would be ok however in this particular case the rear of the building is a loading bay.

The issue here is in a typical loading bay the transport trucks back-up to unload their produce.  During this time the driver may leave the vehicle idling thus allowing for the build-up of Carbon Monoxide.  Having the make-up air louvre installed in the loading bay Carbon Monoxide may be introduced into the office space.



As Per AHRAE Standard 62.1, section 5.5.1 the location of any make-up air intake in a loading bay scenario is to be located a minimum of 25 feet away from the tailpipe:


5.5.1 Location. Outdoor air intakes (including openings that are required as part of a natural ventilation system) shall be located such that the shortest distance from the intake to any specific potential outdoor contaminant source shall be equal to or greater than the separation distance listed in Table 5-1.



Further to the Carbon Monoxide issue there was a second problem:

The make-up air intake for the office is installed behind the outdoor heat pump.  In summer the Heatpump is rejecting heat to the outside in order to cool the office.

The issue here is that when we pull in fresh outdoor air (Blue) the heat from the Heatpump (Red) may get sucked back into the office space!



Clearly we are not close to meeting the code in the Carbon Monoxide scenario and we are not achieving good engineering practice in the second example.

In the second part of this blog we will provide the Engineered Solutions to mitigate these challenges so stay tuned!

James Hicks P.Eng.

Evolve Mechanical Solutions