A mattress suspended above a floor can create a so-called "slot fire" in which mutual radiation between the two surfaces and trapped smok radiation create rapid and severe damage to both surfaces. The term "slot fire" was coined by Dr. Larry Cranberg, a nuclear physicist who invented the "Texas Fire Frame," a cast-iron fire place rack designed to hold logs in two horizontal layers. The effect of the open slot in this assembly is to effectuate ignition by a single sheet of newspaper and then promote burning nd increased radiation into the room.

Even a non-combustible cover suspended above a fuel load can increase the burning rate by dynamically traping hot smoke which radiates downward.

The classic example of a mattress creating the illusion of the use of an accelerant is in the 1973 John Knapp case which became the subject of the book "Triple Jeopardy" by Roger Parloff. In this case, a child pulled one end of his mattress off the bed and started a fire under the (slanted) mattress.

Mr. Knapp spent many years on death row despite the work of an engineer who demonstrated the mutual radiation effect experimentally. The Parloff book is recommended reading for any fire investigator.