Complex sentence: The best grades of linoleum were called "battleship linoleum", as a common use of this material was in warships, albeit fire-retardant versions, as battle experience showed that standard linoleum was an inappropriate material due to its flammability.
Split into simpler sentences: The best grades of linoleum were called "battleship linoleum", as a common use of this material was in warships. Actual battle experience showed this was an inappropriate material due to its flammability.