(a) The valve that is closed to prevent the flow of gas to the customer must be of tamper-proof construction and be provided with a locking device or other means designed to prevent the opening of the valve by persons other than those authorized by the operator.

(b) A mechanical device or fitting that will prevent the flow of gas must be installed in the service line or in the meter assembly. The mechanical device or fitting shall be of a type that cannot be removed except by properly authorized employees of the operator.

(c) The customer's piping must be physically disconnected from the gas supply and the open pipe ends sealed.