We are a small intermodal depot for empty containers. As do many other depots in our city, we stack containers 2 - 3 high for empty storage. Recently there was a wind storm which blew a container into a neighboring business parking lot. While there was minimal damage and no one was injured...the question was raised...is there a manufacturers regulation or suggestion as to how high empty containers should be stacked without locking mechanisms? Could you possibly offer any documentation which would clear up this issue? Sincerely, Debbie Schindler RJK GROUP INC.