Shop Versus Field Fabrication

There are special considerations for field fabrication. Field fabrication is needed for large diameter tanks, or where the removal of a vessel from a plant to line/reline is impractical. 

All construction involving pockets or crevices that will not drain or that cannot be properly abrasive-blasted and lined must be avoided. 

AM joints must be continuous solid welded. All welds must be smooth with no porosity holes, high spots, lumps, or pockets. Grinding is required to eliminate porosity, sharp edges, and high spots. 

AM Sharp edges must be ground to a minimum 1/8 radius. 

The outlets must be flanged or pad-type rather than threaded. 

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