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Subchapter 1. Unfired Pressure Vessel Safety Orders
Article 6. Anhydrous Ammonia

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§512. Repairs and Alterations.

(a) Field welding, where necessary, shall be made only on nonpressure parts that were installed by the manufacturer of the tank.

(b) No repairs or alterations involving flame, arc, or other method of welding shall be made to any tank until such tank has first been certified as free of anhydrous ammonia by competent personnel.

(c) No repair or alteration affecting the safety of the tank shall be made until the contemplated repair or alteration has been authorized by a qualified inspector. Nothing in this order shall prohibit the exchange or interchange of valves, fittings, and appurtenances intended for the same purpose.

(d) No tank that has been subjected to a fire shall be returned to service until it has been inspected by a qualified inspector and found to be safe.

(e) Any vessel requiring repair or alteration or that has been subjected to a fire shall be prepared for hydrostatic test by the owner when such test is deemed necessary by the qualified inspector.

(f) All repairs affecting the safety of the tank shall be reported to the Division within 21 days by the qualified inspector authorizing such repairs. The qualified inspector shall stamp his certificate of competency number adjacent to all welded repairs authorized by him, except that in the cased of repairs to quenched and tempered steels, this number need not be stamped. This exception shall be noted on the inspector's report.

(g) Any welding necessary when making repairs or alterations to tanks shall be done by welders and welding procedures qualified in accordance with Section IX of the ASME Code in the position or positions used in making the repair.


1. Amendment filed 12-8-72 as procedural and organizational; effective upon filing (Register 72, No. 50).

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