(123c) Evaluating Tanks for Non-Normal Operating Modes

Tank conservation vents and emergency vents are installed for overpressure and overvacuum scenarios that may occur during normal operation on low pressure tanks. However, during maintenance events such as repair and cleaning there are scenarios that can occur that are specific to the maintenance event. These maintenance events will include inventorying, purging and steaming using equipment that may not have been considered for normal venting and operation. This topic will cover the types of equipment that will be used during these events and the special venting study that will be needed to mitigate any of the unique scenarios that may occur during these events. These unique scenarios include the use of solvents that are not normally stored in the tank being serviced or high volumes of purge gases used to inert or ventilate the tank. These studies typically review the written procedure and how equipment will be used. Any concerns identified will lead to recommendations for changes in the procedure or equipment to be used in the maintenance event.