# NACE SP0198

Source: https://coatmentor.com/standards/nace-sp0198/ · Updated 2026-10-14

Preventing corrosion under insulation and fireproofing (CUI) with coatings and design.

**Publisher**: AMPP (NACE)

**Area**: Systems, environments and degradation

SP0198 is the standard practice for corrosion under insulation (CUI): steel that corrodes where water is trapped under insulation or fireproofing. The current edition is 2017.

## The idea

Water under insulation does not dry out, so the steel lives in conditions close to immersion. SP0198 therefore treats the coating under insulation as an immersion-grade barrier and chooses it by the operating temperature. It also addresses equipment design, choice of insulation, and in-service inspection.

## Points exams test

- Carbon steel suffers general corrosion and pitting under wet insulation; austenitic stainless steel suffers external stress corrosion cracking.
- Inorganic zinc alone is not used under insulation in the warm range where CUI is worst: zinc does poorly in a closed wet space and can stop protecting the steel.
- Thermally sprayed aluminium and high-temperature epoxies are among the systems used.

**4** practice items in the members area mention NACE SP0198 (CIP 2: 2 · FROSIO written: 2).

## Related

- **Concepts:** [Corrosivity categories (ISO 12944-2)](https://coatmentor.com/learn/corrosivity-categories/) · [Zinc-rich primers](https://coatmentor.com/learn/zinc-rich-primers/)
- **Standards:** [ISO 12944](https://coatmentor.com/standards/iso-12944/) · [ISO 2063](https://coatmentor.com/standards/iso-2063/)

## About this page

This page describes the subject of NACE SP0198 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.