Denver, just because it's federal doesn't automatically rule out cameras. I just sort of threw it out there as an idea, but if it's something you want to try, don't just disregard it- it's all a matter of asking the right person. Especially if the area you want to set the camera up at is unclassified! Ask your sponsor, they can talk to the security manager on your behalf. Heck, they might already have the info you need on the security cameras!
Really, if this is a secure area, you'd have to go through the same security procedures with anything capable of data logging. It would be harder to get permission to set it up in a secure area, but since you don't really need the tape, you could view it right there under the supervision of your escort and have the tape destroyed when you've gleaned what you need from it.
Oh, a possibly easier idea- do you have an ammeter with a min/max setting and an AC/DC adapter? You could clamp an emergency cable, set it on min, and see if it reads 0 the next morning. Or if the batteries in your ammeter are dead when you come in, that's probably a good indication, too!
Edit: idea2: splice a wall clock onto one of the emergency light circuits
Won't tell you when the outage happened, but will tell you exactly how long it was!
[This message has been edited by SteveFehr (edited 10-21-2006).]