Dear 100 Hour Board,
Say there was a particular lab on BYU campus that would benefit greatly from having a microwave. Who would I contact to ask for one?
Dear Hungry Hungry Hippo,
My short answer is the punchline to this joke by Louis C.K.'s daughter: "Just the people who are in charge of that decision."
There are two types of labs that come to mind when I read your question: labs akin to the tutorial labs in the ESC or writing labs in the library, where students can go to receive help with homework. I doubt you'd be able to get a microwave into one of these labs; they're usually pretty anti-food. The other kind of lab is more like a research lab, used only by a very small percentage of the BYU faculty and student populations. These labs are generally more flexible in their rules, though if you're using specialty equipment, they may not want a lot of food there, either.
In either case, just find out who's responsible for the lab and talk to them about the possibility of installing a microwave. If they're okay with the idea, you'll probably have to go out and find a microwave yourself: most of the microwaves I've seen in ESC study rooms or other non-food preparation areas seem like they were plucked straight out of a Goodwill or D.I.
That's probably the most information I can give you with the level of detail you provided in the question. Good luck!