Corrosion Under Insulation (CUI) Testing of Zerust® Inhibitor Fusion (ZIF) Tape

 

Background

Corrosion under insulation (CUI) is a prevalent problem affecting thermally insulated equipment across a wide variety of industries. CUI occurs through the penetration of water or moisture via condensation or external sources through the insulation to the underlying metal surface.

 

Fig. 1: Example of corrosion under insulation

 

A simple lab test was conducted to evaluate the effectiveness of Zerust® Inhibitor Fusion (ZIF) Tape for CUI. In the test described below, a comparison was made between the control panels (no corrosion protection) and the test panels (protected by ZIF Tape). To simulate CUI, the test approach was to age panels that had been sandwiched between two pieces of damp insulation. The panel assemblies were then sealed in quart jars and aged at 50°C.

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Experimental

A brief outline of the experimental procedure can be found below:

• Steel panels cleaned by solvent wipe
• Test panels were wrapped with ZIF Tape
• Panel was sandwiched between two pieces of damp insulation

Fig. 2: Test Panel Assembly

• Assembly was placed in quart jar
• Jar sealed and aged at 50°C
• Every week, water was spritzed on to the insulation to ensure continued dampness

 

Fig. 3: Test Assembly

 

The testing was performed on two different substrates:

• Standard smooth mill test panels
• Precorroded panels

Panels were pulled on a periodic basis and visually inspected for qualitative evaluation.

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Results & discussion

Comparison pictures of the panels at the one, two, four, six, and eight week pull dates are shown below.

1. Smooth Mill Panels

Fig. 4: Control panels

 

Fig. 5: Panels treated with ZIF Tape

 

 

2. Precorroded Panels

Prior to preforming the test, smooth mill panels were purposely corroded via exposure to an acidic environment for 24 hours.

Fig. 6: Precorroded control panels

 

Fig. 7: Precorroded panels stored with ZIF Tape

 

For the precorroded panels, new, large, corrosion products continued to become apparent on the control panels while minimal new corrosion products were apparent on the test panels.

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Conclusion

A clear benefit can be seen from the ZIF Tape for both the smooth mill and precorroded substrates. As can be seen from the photos shown above, the presence of ZIF Tape greatly inhibited the formation of corrosion products.

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