Sidewalls stay lowered and out of the way until they are needed. To some, a containment berm's sidewalls mean security. To others, they are a nuisance. After all, who needs sidewalls if there's no spill? One of the main advantages of the Rapid Rise Model is that the sidewalls stay out of the way until they are needed. Foam in the top, outer perimeter of this containment berm's sidewalls raise the walls with the level of the liquid should there be a spill while rigid struts provide added support. But the walls stay down and flat during normal, day-to-day, operations. Helps comply with SPCC and EPA spill containment regulations.