As a restaurant owner, you face many challenges that are unexpected, and require some quick education, and the latest one is negative air pressure.
We noticed in this very cold and wet San Francisco weather that we had very heavy drafts in our restaurant.  We noticed high velocity drafts that were literary pouring out of every opening (including electrical sockets) and make our restaurant, customers and food cold! In fact, this was causing our furnace to shut off, since the exhaust was receiving too much air in.
This happens because our hood for our kitchen is taking was taking in so much air and not being replaced with enough “make-up” air. So after some engineering calculations, a fix to our make-up air system, we are finally back on track!  Happy to report, we now have a warm and non-windy environment.
For those interested in more, this a great article: Â https://aristair.com/blog/8-reasons-restaurants-need-a-make-up-air-unit-for-the-kitchen/
So if you are a restaurant owner, or a customer and notice heavy drafts, mention air pressurization 🙂