ASTM G189-07 (2021)e1 PDF

Full title and description

ASTM G189-07(2021)e1 — Standard Guide for Laboratory Simulation of Corrosion Under Insulation. This guide describes laboratory apparatus (a CUI‑Cell), specimen preparation, and procedures to simulate corrosion under insulation (CUI) on insulated pipe specimens under controlled isothermal or cyclic temperature and wet/dry conditions to assess general and localized attack and compare insulation or protection systems.

Abstract

This guide provides a reproducible laboratory simulation for corrosion under insulation (CUI). It defines the CUI‑Cell exposure apparatus, test specimen preparation, controlled cyclic or isothermal temperature schedules, wet/dry cycling and monitoring parameters, and common evaluation metrics (mass loss, electrochemical measurements such as polarization resistance, and visual/ metallographic assessment). The goal is to accelerate and reproduce field‑relevant CUI mechanisms so materials, insulation systems, and inhibitors can be comparatively evaluated.

General information

• Status: Active (original designation G189‑07, reapproved and issued as G189‑07(2021)e1; the 2007 text was reapproved and amended to the 2021 editorial designation).
• Publication date: 01 January 2021 (reapproval/editorial version G189‑07(2021)e1); original approval Feb 15, 2007 (G189‑07).
• Publisher: ASTM International.
• ICS / categories: ICS 23.040.99 (Other pipeline components); categories: Corrosion of metals, wear and erosion; CUI testing and laboratory corrosion simulation.
• Edition / version: G189‑07(2021)e1 (original 2007 guide, reapproved/issued with 2021 editorial change notation e1).
• Number of pages: 11 pages (standard short guide).

Scope

The guide covers laboratory simulation methods for corrosion that occurs beneath thermal insulation on piping and similar components (CUI), addressing both general and localized corrosion phenomena. It specifies the simulated exposure environment (including water ingress, chemistry, temperature, and cyclic wet/dry regimes), the CUI‑Cell apparatus configuration, specimen mounting and insulation placement, and recommended measurements and reporting to allow comparative evaluation of insulation systems, coatings, inhibitors and materials. It is intended for comparative, accelerated laboratory evaluation rather than to reproduce every site‑specific field condition.

Key topics and requirements

• Definition and construction of a laboratory CUI‑Cell to simulate insulated pipe sections.
• Specimen preparation and mounting representative of insulated piping geometries.
• Test schedules for isothermal and cyclic temperature profiles and controlled wet/dry cycling to emulate condensation, ingress and drying phases.
• Control and monitoring of key parameters: temperature, injected water volume and chemistry, drainage, humidity and exposure timing.
• Evaluation methods: mass‑loss measurements, electrochemical techniques (polarization resistance, impedance), visual inspection and microscopic examination.
• Classification of simulation types and reporting requirements to support comparative performance assessment of insulation materials, inhibitors and protective systems.
• Guidance on safety, test repeatability, and limitations — the guide notes laboratory results are comparative and may differ from field CUI rates.

Typical use and users

Used by materials and corrosion test laboratories, insulation and coating manufacturers, plant maintenance and reliability engineers in chemical processing, petroleum refining, power generation and other industries with insulated piping and equipment. Also used by R&D teams developing corrosion inhibitors, protective linings, or improved insulation systems to compare performance under accelerated CUI conditions.

Related standards

Related ASTM corrosion practice and test methods such as ASTM G31 (laboratory immersion corrosion testing), G102 (calculation of corrosion rates from electrochemical measurements), G59 (polarization resistance), and other guidance from ASTM Committee G01 on Corrosion of Metals. NACE/AMPP standards and other industry guidance on CUI management and inspection are commonly used alongside G189 simulations for a comprehensive approach.

Keywords

corrosion under insulation; CUI; CUI‑Cell; insulation testing; wet/dry cycling; thermal cycling; mass loss; polarization resistance; laboratory simulation; accelerated CUI testing.

FAQ

Q: What is this standard?

A: ASTM G189‑07(2021)e1 is a Standard Guide for Laboratory Simulation of Corrosion Under Insulation that defines a laboratory exposure apparatus, procedures and evaluation methods to reproduce and compare CUI‑type corrosion on insulated pipe specimens.

Q: What does it cover?

A: It covers the design and use of the CUI‑Cell, specimen preparation, test schedules (isothermal and cyclic temperatures, wet/dry cycles), monitoring of exposure parameters, and common measurement techniques (mass loss, electrochemical tests, visual and microscopic examination) for comparative laboratory evaluation.

Q: Who typically uses it?

A: Corrosion test labs, insulation and coating manufacturers, plant maintenance and integrity engineers, and R&D groups in industries where insulated piping and vessels are subject to CUI (petrochemical, refining, power generation, process industries).

Q: Is it current or superseded?

A: The original guide was approved in 2007 (G189‑07). It appears in the ASTM catalog as reapproved/issued with the 2021 editorial designation G189‑07(2021)e1; users should confirm the latest status through ASTM or their standards provider if they require the most current administrative status.

Q: Is it part of a series?

A: It is maintained under ASTM Committee G01 (Corrosion of Metals) and is commonly used together with other G01/G-series corrosion test methods and guides (for example, G31, G59, G102) when evaluating corrosion rates and protective measures.

Q: What are the key keywords?

A: Corrosion under insulation (CUI), CUI‑Cell, insulation testing, wet/dry cycling, thermal cycling, mass loss, polarization resistance, accelerated laboratory simulation.