Bones1, When I finished my floor and sealed it with a urethane sealer it looked great a worked ok if you cleaned up drips quickly.... But a few times more than I liked to see the sealer was eaten through buy mostly gasoline drips from a leaky bowl seal...So I really am not very impressed with it..So I don't think I would leave anything sit on it for long... My sealer was $100 for 5gals, took two coats... Hope this helps...
Like DP(above) says a two part will work better and longer both and it will best if done before anything can contaminate the fresh concrete...
Not real sure about what the fire dept. uses but I think its similar to what is used on commercial tile floors... But my floors were very shiny at first as well...
Remember shiny = slippery..