Keep in mind that Epic likes to make their characters all slightly larger than the average person, so you might not want to use IronGuard as a realistic example.
I found that 1UU = 1 3DS Unit = 1,8cm For example, standar guy (IronGuard) in UDK at 1UU=2cm is 1,96m tall, using 1UU=1,8cm is 1,76m tall (for me 1UU=1,8cm looks more real).