As well as considering the materials used in
your premises you should also consider their
form. For example, wood in the form of solid
baulks of timber is not readily ignitable, but
chopped wood or kindling is (similarly with
paper). Cardboard stored flat would not
present a high fire risk, but rolls of cardboard
stored vertically present a vertical surface for
fire to spread rapidly upwards, corrugated
cardboard presents an even greater risk.