PaintSquare.com


The First Word in Protective & Marine Coatings

A Product of Technology Publishing / PaintSquare
JPCL | PaintSquare News | Durability + Design | Paint BidTracker

Download our FREE eBook on New Technology Coatings for Corrosion Control

Problem Solving Forum

| More

December 20, 2010 - January 2, 2011

What is the Cold Wall Effect? Can it cause premature coating failure and, if so, how do I prevent or minimize it?


Selected Answers

From Simon Hope of Bilfinger Salamis on December 29, 2010:
'Cold Wall Effect' is normally due to a temperature gradient being built up across a coating as described in the previous two answers. It is commonly encountered in ships' tanks where the contents are at a significantly higher temperature than the surrounding ambient, or it regularly occurs in process vessels where a process liquid is running significantly higher than the ambient. Classically with process vessels these have originally been insulated with heat conservation materials but have been selectively stripped (typically from 5 o'clock to 7 o'clock for belly inspection and corrosion monitoring as well as prevention of CUI (Corrosion Under Insulation). This lack of insulation creates the necessary thermal gradient that can lead to Cold Wall failures of the coating. Reinstatement of insulation using a syntactic material against the more common mineral wool insulations can help reduce Cold Wall failures due to lack of insulation and saturated areas of wool cooling the shell. The major drawback is the lack of ability to undertake shell inspections using conventional U/T methods externally, so removable panels need to be integrated into the design so that all parties are satisfied. Internal coatings need to be high density and low permeability with a coefficient of expansion closely in line with the substrate to avoid micro cracking when heat-cycled. Typically, solvent-free epoxy phenolic type coatings with carefully selected fillers (normally ceramics) will give the best resistance to this type of failure. As can be seen, it is not normally attributable to a single source, but a combination of problems leading to a situation where failure may occur. Careful design and a full understanding of the operation of the item can help considerably with mitigation and avoidance.

From David Grove of Shaw Nuclear Power Services on December 28, 2010:
The cold wall effect is where there is a temperature difference between one side of a sheet structure to the other side, which generally can cause condensation or blisters under the coating. The best way to eliminate this is to ensure that the surface is washed and rinsed with clean fresh potable water before final surface preparation with sufficient profile. For heavily rusted, chemically contaminated surfaces, I used to specify a commercial (or rough) blast to expose the steel, then a final wash followed by a near-white (SSPC-SP 10) blast. Since all coatings are some- what permeable, the key is to ensure that any moisture intrusion does not have a surface contaminant to react to and cause a blister. Contact your coating technical service for specifics.

From Craig Wallbank of W Abrasives on December 21, 2010:
Cold wall effect is a term commonly used when a structure, say a holding tank, has a lower atmospheric temperature on the outside than the product that is stored inside. This thermal difference can cause water vapour to build up between the substrate and the lining that was applied to the inside of the tank. As the water may hold soluble salts, this will have an effect of 'blistering' and therefore a failure. Although I am not a coating 'expert,' I understand that the lining system should have a low permabilty rating to help prevent this from happening.

Please sign in to submit your answer this question    

Tagged categories: Coating failure


Current PSF Question | Submit a PSF Question | Full PSF Archive

Sherwin-Williams
Heat-FLex® Hi-Temp 1200

Improved Corrosion
Resistance
Enhanced Durability
Faster Shop Throughput


Surface Prep Supply
Surface Prep Supply

Blast It! Coat It! We have you covered every step of the way. Supplier of:
• Abrasives
• Equipment
• Accessories
• Protective Coatings
888-331-7737(PREP)


Bullard

The Next Generation
of Blasting

• Lightest
• Coolest
• Most Comfortable
• Most Dependable


N.T. Ruddock Co.

Our Abrasives Hold Up Under Pressure

N. T. Ruddock focuses on abrasive selection, equipment evaluation, equipment maintenance & reduction of abrasive consumption. Other services include Screen Analysis & Background Radiation Testing.


Novatek Corporation
Dustless Coatings Removal

Strip it, clean it, and profile it,
all dust free! High production
rates and Blast like finishes.
Comply with new lead
standards.


BASF
New resins from BASF will have metals loving water:

Excellent corrosion resistance, low VOC, high gloss, thin films basf.us/industrialcoatings
polyorders@basf.com
800-231-7868


Absolute Equipment/Grand Rental Station
Portable Power from Absolute Equipment

•Compressors
•Lighting Systems
•Generators
•Light Compaction
Sales • Rental • Service
Call 1-866-931-6655
Over a century of
providing excellence.

 
 
 
Technology Publishing

The Technology Publishing Network

The Journal of Protective Coatings & Linings (JPCL) PaintSquare
Durability + Design Paint BidTracker JPCL Europe

 
EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
MORE:      About PaintSquare.com   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us
 

© Copyright 2000-2014, Technology Publishing / PaintSquare, All rights reserved
2100 Wharton Street, Suite 310, Pittsburgh PA 15203-1951; Tel 1-412-431-8300; Fax 1-412-431-5428; E-mail webmaster@paintsquare.com