What is an "edge rack" rated capacity for plastic pallets? for what type of industrial racking does this apply?

Plastic pallets are molded and designed to be rigid to hold heavy weights, yet pliable enough to handle forklift impacts or drops without shattering. This "give" or flexibility may cause the pallet to bend or creep under load depending on the product weight and type of racking. An edge rack rating is the load capacity where the pallet is minimally supported on two edges, typically found with drive in or push back racking.