[sbaiddn]

"* Air change. I found out that commercial spaces (concert halls or airplanes etc) change the entire air several times an hour. "

With good reason - spaces that don't are terribly uncomfortable within ten minutes.

[MichaelZuo]

It sound's a bit odd this is even notable.

This is the minimum standard for any new construction commercial/institutional building according to recent building codes in Ontario, and probably many other jurisdictions.

Maybe it's unusual for these building code standards to actually be enforced without special exemptions where the writer lives?

[abdullahkhalids]

I was in a developing country where such things are rarely if ever enforced by law. Though, because many HVAC systems are imported, they automatically satisfy reasonable standards.

Our company had ethics enough to try and enforce such reasonable standards without any external pressure.

[MichaelZuo]

> Though, because many HVAC systems are imported, they automatically satisfy reasonable standards.

Not necessarily, because it's trivial to turn down HVAC systems to a smaller, code violating, number of air exchanges per hour.