Good day all-
Most info above is correct. The Federal Protective Service is the federal law enforcement agency that provides protection for the majority of federal buildings in the country (not just SSA, but IRS, US Courthouses along with the USMS, FBI buildings, FAA control towers, and so many more). FPS has responsibility for approx 9000 federal buildings or pieces of federal property, but they only have about a thousand or so police officers (or Inspectors) to protect everything. They rely on a massive Contract Guard (hereafter CG) program to help them provide protection/security at all of these places. The vast majority of posts for these CG's are at SSA's, since there are so many of them across the country. I would say that most of these posts are single guard locations, although there is a move happening right now where SSA is closing some offices and posting 2 or more guards at the remaining offices that stay open. Part of the reason is because of the increase in traffic that will happen, and party due to the fact that many SSA's are starting to employ metal detectors and x-ray machines (things that are sorely needed unfortunately). Per FPS (actually Homeland Security, which FPS is under) policy is that there will be one CG per screening device.
The vast majority of these CG's are not from local, little mom and pop security companies, but rather from massive government security companies. Securitas, Vendtech, Master Security, etc., but there are many others. Very few posts in the past have had radios, although that is starting to change. Relatively speaking, there are very few posts that have radios that go to an FPS dispatcher of some sort. Some multi-guard posts have radios that each guard is issued for shift communications. Some SSA posts have a set of FRS radios where the supervisor of that office can get a hold of the CG during his/her shift. The above poster who suggests utilizing Close Call (or Signal Stalker in the case of GRE radios) is probably giving the best advice. If I were to do that, however, I would do that JUST off the federal property you are interested in listening to. An over-eager CG (there are many of them) might get a little anxious if he/she sees someone with a scanner on actual federal property. Even if you are off property, a professional, alert CG (and there are many of them too) would call it in to the local PD/SO or even the FPS Mega Center for investigation. Just my opinion....