For many years, during DOT audits, customers are often asked to provide technical information regarding the prevention of the closure plug Back-Off. By definition, Back-Off refers to the potential loosening of a steel or synthetic drum plug (usually the 2” and the ¾” on the top head) after the required torque is reached when closing a drum. Currently, CFR 49, 173.227(b)(2)(ii) does state that the screw closures must be “physically held in place by any means capable of preventing back-off or loosening of the closure by impact or vibration during transportation.” Transport Canada still refers to this requirement as “closures that are threaded.” However, in a move to have Transport Canada harmonize with the US CFR, COSTHA (The Council on the Safe Transport of Hazardous Articles) has submitted a proposed revision to Transport Canada. The proposal expands the criteria so that the “inner packagings shall have closures with gaskets and which shall either be threaded or physically held in place by any means capable of preventing back-off or loosening of the closure by impact or vibration during transport.”
For information about meeting the Back Off requirement, Skolnik offers solutions to securing closures plugs.