Following up from our June outdoor Air Quality blurb celebrating #Canada150 and Canadian air quality, we decided to move the party indoors and talk about indoor air quality. There are several elements of air quality and each is important.
First Runner Up – Temperature
None of us can function in an overly hot or cold environment and we do know the human body is sensitive to tiny fluctuations in temperature. So sensitive that so 1 or 2 degrees can make a big difference. Looking at industry standards like ASHRAE 55, 22°C or roughly 70°F is best. Any cooler or hotter and occupants will be cold or sweat.
Second Runner Up – Humidity
The amount of moisture in the air affects how much heat it holds and how well occupants breathe. Air that is too dry will cause dry throat and a raspy cough and more colds, while too much moisture and you encourage mold and vermin. ASHRAE 55 suggest Relative Humidity is best kept at 50%.
Thirdly – Carbon
Carbon Dioxide and Carbon Monoxide are both by products of human respiration but are harmful in large quantities. Our beloved ASHRAE 62 suggests more than 3500 parts per million (ppm) of carbon over an 8 hours will make occupants sleepy and lethargic. Yikes ..
Last and certainly not least – Air
Us Engineers think of how much air coming into a space as Air Changes per Minute (ACH). Now that varies by the type, size and use of the space but spaces like lobbies, coffee shops and living rooms are best at 5 cubic feet per meter (cfm) or 2.5 liters per second. Dancefloors, malls and gyms where activity is higher go as high as 20 cubic feet per meter (cfm) or 10 liters per second ACH.