Standard · Surface preparation and conditions
NACE SP0178
How tanks and vessels are built and ground smooth before an internal immersion lining goes on.
SP0178 tells designers and fabricators how to build a tank or vessel so that its internal lining can work. It is the 2007 revision of the older RP0178.
What it asks for
- Continuous welds, with butt welds preferred to lap welds.
- Weld spatter, arc strikes, slivers, gouges and other surface flaws removed.
- Sharp corners and edges rounded off to a radius of 3.2 mm (1/8 in.) or more, unless the specification agrees on another figure.
- Interior details that a blaster and a painter can reach.
Weld finish grades
An appendix describes grades of weld surface preparation, from welds left as they are to welds ground flush. A plastic weld comparator shows them. The written descriptions take precedence over the drawings and the comparator. SP0178 deals with the surface of a weld, not its strength: welding codes govern weld integrity.
3 practice items in the members area mention NACE SP0178 (CIP 1: 3).
Related
Try it in an exam-style question. The free readiness check shows the question style, explains every answer and gives you a dated study plan.
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This page describes the subject of NACE SP0178 in our own words; it does not reproduce the standard. For the full text, buy the current edition from AMPP. Checked on 2026-10-14; errors go in the corrections log. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.