# NACE SP0178

Source: https://coatmentor.com/standards/nace-sp0178/ · Updated 2026-10-14

How tanks and vessels are built and ground smooth before an internal immersion lining goes on.

**Publisher**: AMPP (NACE)

**Area**: Surface preparation and conditions

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

- **Concepts:** [Stripe coats](https://coatmentor.com/learn/stripe-coat/) · [Surface cleanliness grades](https://coatmentor.com/learn/surface-cleanliness/)
- **Standards:** [ISO 8501](https://coatmentor.com/standards/iso-8501/) · [NACE SP0892](https://coatmentor.com/standards/nace-sp0892/)
- **Defects:** [Edge corrosion (thin film at edges)](https://coatmentor.com/defects/edge-corrosion/) · [Steel surface imperfections](https://coatmentor.com/defects/steel-surface-imperfections/)

## About this page

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](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.