Best Way to Manage Unimportant Requests?

I'm now working two jobs out of one office. I will be spending most of my time on college ministry--brainstorming, planning, writing, studying, meeting with people.

But I also spend 15 hours a week taking care of facilities. The problem I'm facing is that I have people come by my office with urgent but unimportant requests while I'm studying and working on college ministry projects--things like coffee makers and locked doors.

So my question is What is the best way to manage requests and time so that I give most of my time and energy to my priorities? And not to requests to unlock a door at the back of the property.