PaintSquare.com
Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site

 

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

Advertisements
 
Safway Services
 
Safeguard Assets. Ensure Productivity. HAKI®
 
Protect assets and equipment. Keep facilities open and operational. Maintain schedules regardless of weather. Ensure smooth and continuous production. Easy to erect. Safway is the primary distributor of HAKI® products including HAKISPAN and HAKITEC® 750 – in North America.
 

 
Strategic Materials Inc.
 
Crushed Glass Abrasives
 
TruAbrasives™, a clean crushed glass abrasive superior to other abrasives for performance, health, and environmental benefits.
 

 
SEMicro Division, M.E. Taylor Engineering, Inc.
 
Coatings Adhesion Testers
 
The PATTI® accurately measures the bond strength between coating & substrate. Outfitted properly, the surface can be rough, porous, or curved & >10K psi strong!
 

 
SAFE Systems, Inc.
 
SAFE Systems'
Blast Lights &
Deadman Switches
 
Halogen or LED blast lights available with our NEW urethane bumper. Switches available in many colors for color coding your hoses.
 

 
Polygon
 
POLYGON - Temporary Humidity Control
 
We specialize in innovative climate control solutions for industrial painting, utilizing alternative energy sources and combining desiccants with heating or cooling.
 

 
Tarps manufacturing, Inc.
 
QUALITY MADE IN AMERICA —Available near you!
 
CLICK to get a behind-the-scenes look at how Tarps Manufacturing makes the highest-quality tarps right here in the USA — available nationwide.
 

 
DeFelsko Corporation
 
PosiTector SST Soluble Salt Tester
 
Measures the concentration of soluble salts on metal surfaces. Use with all Bresle patch types including the reusable, adhesive-free PosiPatch.
 

 
Monti Tools, Inc.
 
BRISTLE BLASTER® – THE ORIGINAL ONE
 
  • Abrasive blast with a power tool
  • Remove corrosion, mill scale and coatings
  • Cleans & roughens
  • Meets SSPC-SP 10 / NACE No. 2
  • Profile up to 4.7 mils
  • ATEX Zone 1
  •  

     
    Abrasives Inc.
     
    Discover the MAGIC.
     
    Black Magic® coal slag. It’s consistent, cleaner, cuts better, less dust. Get it where you need it, when you need it. Abrasives Inc. info@abrasivesinc.com
     

     
    W Abrasives
     
    New blast suction and recycling system!
     
    Phenics systems, made by W Abrasives, is a new way to transform traditional site blasting by enabling recovery and recycling of steel grit.
     

     
     
     

    Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

    TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL webmaster@paintsquare.com


    The Technology Publishing Network

    Durability + Design PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

     
    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