1. (i) When an AST system is out-of-service, the facility must continue operation and maintenance of corrosion protection in accordance with section 613-4.2(b) of this Subpart, and inspections and leak detection in accordance with section 613-4.3(a) of this Subpart. Subpart 613-6 of this Part must be complied with if a release is confirmed.
2. (ii) Inspections and leak detection required under section 613-4.3(a) of this Subpart are not required as long as the AST system is empty. (The AST system is considered empty when all materials have been removed using commonly employed practices so that no more than 2.5 centimeters [one inch] of residue remain in the system.) However, inspections and leak detection required under section 613-4.3(a) of this Subpart must resume consistent with the original schedule or upon resumption of delivery of petroleum into the AST system, whichever is later.

3. (2) When an AST system is out-of-service for more than three months, the facility must also comply with the following requirements:

   1. (i) leave vent lines open and functioning; and
   2. (ii) cap and secure all other piping, ancillary equipment, and manways.

4. (3) When an AST system is out-of-service for more than 12 months, the facility must permanently close the AST system in accordance with subdivision (b) of this section, unless the AST system is located at a facility where one or more other tank systems are not out-of-service.

   (b) Permanent closure.

5. (1) At least 30 days before beginning permanent closure, a facility must notify the department of its intent to permanently close, unless such action is in response to corrective action. Within 30 days after permanent closure, a facility must submit a registration application to the department, in accordance with section 613-1.9(f) of this Part, indicating that the AST system has been permanently closed.

6. (2) To permanently close an AST system, the facility must empty and clean it by removing all liquids, vapors, and accumulated sludge. One of the following codes of practice (refer to section 613-1.10 of this Part for complete citation of references) must be adhered to in order to comply with this paragraph:

   1. (i) API RP 2016, August 2001; or
   2. (ii) NFPA 326, 2010 edition.
7. (3) Every tank that is part of an AST system that is permanently closed must, if not removed, be stenciled with the date of permanent closure.
8. (4) ASTs that are permanently closed that remain at the facility must be protected from flotation.

9. (5) AST systems that have been permanently closed may not be returned to service unless the entire AST system meets the requirements for category 3 AST systems.

   (c) Records for permanent closure.

   The facility must maintain for three years records that are capable of demonstrating compliance with closure requirements under this Subpart. In addition, the facility must transmit a copy of the records to the department within 30 days after permanent closure.

(a) Out-of-service AST systems.

(1)