of course there is some clearance between the vertical sides of the rails of the rack and the outside edges of the pallet thus in another exemplary embodiment the lengths of beams 26 are sufficiently short to accommodate the resultant play or possible shifting from side to side of a pallet mounted in the rack thus in all cases with regard to this exemplary embodiment the end of a beam 26 will not be above the vertical extension of the innermost edge of the rail in other exemplary embodiments e g where one end may extend beyond said vertical extension and the other does not the length and or position of the beams may chosen accordingly to anticipate shifting within the rack in accordance with the above exemplary embodiments in the event of a fire the plastic of the pallet softens and loses strength and or burns away and cross beam 26 will no longer be supported at one or both of its ends as the plastic softens or disappears the one end of the pallet will fall from the rail and the pallet will collapse into the space between the rails referring now to fig6 in another exemplary embodiment at least one beam 26 a is offset although all beams may be from one lengthwise edge so that one end of the beam.