I was just curious how others handle vestibules in commercial spaces over 3,000SF. There is a big difference between the requirement for a vestibule in the IECC versus ASHRAE 90.1. IECC requires them in any space over 3,000SF while ASHRAE typically only in buildings 4 stories or more. I'll be honest in that I don't always enforce the vestibule requirement if someone is using the IECC for energy compliance. Someone will submit a COMcheck using IECC with their permit application for a project that technically needs a vestibule, but all they have to do is change it to ASHRAE 90.1 and they don't need one. Nothing will have changed on the doors, windows, insulation, etc. otherwise. It's just that one code requires it, and the other doesn't. I could have them resubmit their COMcheck under ASHRAE, but it's just a waste of time for basically what amounts to a technicality. So again, I was just curious -- how do you all handle vestibules?