I am really confused here guys - I was pretty sure that RSC fell between B rate and C rate chests. Is that not true? B rated chests are not much metal at all.. I have a gardall one with a 1/8" plate door, it's B burglary rated, and 1 hour 350 degree fire rated, I don't have a lot of confidence in it. I also have an unlabeled Amsec, either a BLC or DDE, not completely sure - but it's massive, and very confidence inspiring. I thought RSC fell between those two.
It can get quite confusing for people who don't deal with safes on a regular basis. This also includes other professionals like locksmiths.
The RSC "Residential Security Container" rating, is an actual UL rating. I don't believe it means a lot, but it does undergo a test. The safe has to last 5 minutes against prying devices (not to exceed 18") and hammers (not to exceed 18" or 5 pounds). Clock starts, safe is attacked for 5 minutes, if it's still closed in 5 minutes it passes.
To compare that to another UL rating that does mean something, let's look at a TL-15. This is a 15 minute rating against all hand tools, power tools, and pressure applying devices. There are no restrictions on tool sizes or weights. Those attacking the safe are professionals, with advance knowledge of the safe's design. The clock only runs while a tool is in contact with the safe. Let's say the clock starts, they drill on it for a minute, and the bit breaks. The clock is stopped, the bit is changed, and the clock starts when they continue to drill. The safe will fail if opened within 15 minutes of running clock time, or a 6 square inch hole can be placed through the door.
Here's what confuses people:
B rate, C rate, E rate, and F rate are really not ratings at all. There is no test performed on these safes. These designations are definitions issued by the ISO, and has to do with construction methods. These in turn are used to determine the theft risk factor.
Without getting too in depth, a B rate safe will have 1/4" worth of steel in the body, and 1/2" worth in the door. A C rate would have 1/2" worth in the body, and 1" in the door. An E rate is very similar to a TL-15 in construction, using a 1" body, and 1.5" door. A F rate would have the same 1" body, but a 1.5" laminate door.
Composite safes have thrown a bit of a monkey wrench into these definitions, but there are still ways to determine an equivalent level of protection.