- (a) The installation of magnesium sacrificial anodes in cargo tanks utilized for the carriage of flammable or combustible liquids in bulk is prohibited.
(b) A sacrificial anode using an aluminum alloy will be permitted in cargo tanks under the following criteria:
- (1) The maximum allowable energy that can be developed by a falling anode shall be 200 foot-pounds.
- (2) No anode shall be installed more than 6 feet above the bottom of the tank. Special consideration will be given when structural design prevents the anodes from falling in event of failure of the attachments.
- (3) Each anode shall have at least two welded or bolted connections to the supporting structure. Special consideration will be given to proprietary attachments which provide equally safe installations.
- (4) The plans of the anode installation and a chemical analysis of the alloy composition shall be submitted for approval. The anode should be magnesium free and the silicon content limited to trace amounts.
- (5) The recommended construction of the anode should utilize a mild steel core with necessary attachments. Other types may be used but will require special consideration.
- (c) Sacrificial anodes using materials other than those having aluminum and/or magnesium in whole or in part are permitted.
[CGFR 69-72, 34 FR 17482, Oct. 29, 1969]