1.1 This Standard covers requirements for external corrosion protection systems on steel non-pressure tanks that are used for the underground storage of flammable liquids and combustible liquids. The requirements are structured as follows:

1. A Section 5, Cathodically Protected Tanks, covers external corrosion protection using sacrificial magnesium and zinc anodes, low profile nylon isolating bushings with internal and external threads and component thread sealant, electrical isolation and thin film dielectric coating (cathodically protected tank);

2. NOTE: Informative material on zinc reference electrodes is included in Appendix B, Methods For Monitoring Cathodically Protected Tanks.

3. B Section 6, Composite Tanks (Clad), covers external corrosion protection using dielectric fibre reinforced plastics or resins that are bonded to the tank (composite tank — clad);

4. C Section 7, Jacketed Tanks, covers external corrosion protection and secondary containment using dielectric jackets (jacketed tanks); and

5. NOTE: Jacketed tanks as described in this Standard are also considered to be double walled.

6. D Section 8, Coated Tanks, covers external corrosion protection using polyurethane (coated tanks).

1.1.1 These external corrosion protection systems are intended to be installed, operated and maintained in accordance with the manufacturer's instructions.

1.1.2 In addition to this Standard’s traditional safety requirements for underground steel tanks with nonmetallic protection systems that primarily evaluate structural integrity, material compatibility, corrosion resistance and mitigate environmental hazards from loss of liquid containment under expected normal conditions; optional construction and/or performance requirements, and associated ratings intended to address more severe conditions associated with the effects of Climate Change are included in Appendix F.

1.2 These requirements cover external corrosion protection systems for steel tanks manufactured in accordance with the applicable requirements of CAN/ULC-S603, Standard for Steel Underground Tanks for Flammable and Combustible Liquids, which are used for the underground storage of flammable liquids and combustible liquids that are compatible with the materials of construction.

1.3 This Standard does not cover requirements for the installation, maintenance and use of the tank. Tanks covered by these requirements are intended for installation and use in accordance with the authority having jurisdiction and other documents including but not limited to:

1. A CCME PN 1326 Environmental Code of Practice for Aboveground and Underground Storage Tank Systems Containing Petroleum Products and Allied Petroleum Products;

2. B The National Fire Code of Canada; and

3. C CSA B139, Installation Code for Oil-burning Equipment.

1.4 Except for optional Climate Change Adaptation requirements in Appendix F, these requirements do not cover special evaluations for resistance to, or use after, earthquakes, floods, high wind events, or other natural disasters.

NOTE 1: See the Note at the beginning of Appendix F for further information on the terms “Adaptation” and “Mitigation”, as they pertain to Climate Change.