January 2015

Welcome to ‘Stainless Solutions’ from IMOA. Each month, we will cover a different stainless steel issue with tips on design and specification, and links to technical resources.  This month we are providing resources to help assess the corrosiveness of coastal environments.
Assessing the Corrosiveness of Coastal Environments

It is not uncommon to apply general rules to the specification of materials, such as proximity to the coast. This type of guidance can be very helpful but there are exceptions to every rule.  The ‘typical’ coastal construction site where Type 316 stainless steel is used successfully has these characteristics:

  • at least 0.2 km and up to 16 km (0.12 miles to 10 miles) from a large saltwater body (ocean or harbor)
  • low to moderate salt, pollution and particulate level exposure
  • none of the exterior surfaces are sheltered
  • surfaces are regularly subjected to heavy rain cleaning which minimizes the accumulation of corrosive substances

Severe coastal environments  where precautions should be taken may meet the requirements above but there are additional site conditions which make them more corrosive:

  • close proximity to salt water
  • rocky shorelines
  • salt combined with heavy industrial pollution
  • hot, low-rain environments with high surface salt accumulations where evening humidity or salt fog dampens surfaces
  • volcanic fume exposure
  • sheltered areas in hot humid environments that cannot be rain washed
  • regular light, misty, high-salt-content rain and/or salt fog that dampens but does not clean surfaces

Without finish specification or design changes, at least light superficial “tea staining” corrosion of Type 316 can occur in more severe locations.  In such cases, a more corrosion resistant stainless steel such as 2205 duplex will be needed, particularly if there is an aesthetic expectation of a pristine appearance. The corrosiveness of the site, aesthetic requirements, and expected maintenance frequency determine effective solutions.  IMOA has a website page to provide guidance on identifying and selecting materials in coastal climates.  It includes links to two articles with guidelines for typical and severe locations.

Our selection system can help you determine whether the site is more severe and our case studies show how it is used.  Case studies 3 (New York and Miami), 4 (Singapore), 5 (Hong Kong), 6 (Canary Islands), 7 (Barcelona), 9 (Australia), 10 (New York), 11 (Thames Barrier) and 14 (New Zealand) illustrate a variety of applications and site conditions.

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Continuing Education – American Institute of Architects (AIA)

IMOA is an AIA continuing education system approved provider with eight 1-hour programs that are registered for both live face-to-face and distance learning credit.

1. Stainless Steel Sustainable Design
2. Bioclimatic Design With Stainless Steel Weather Screens
3. Stainless Steel Structural Design
4. Stainless Steel Specification For Corrosive Applications
5. Deicing Salt: Stainless Steel Selection to Avoid Corrosion
6. Stainless Steel Finish Specification
7. Advanced Stainless Steel Specification and Problem Avoidance
8. Specification of Stainless Steel Finishes and Grades For Corrosive Applications

For more information or to schedule a workshop contact Catherine Houska, 412-369-0377 or email chouska@tmr-inc.com.

What is IMOA?

IMOA (International Molybdenum Association) is a non-profit industry association, which provides technical information to assist with successful specification of molybdenum-containing materials. Molybdenum is an element. When it is added to stainless steel, molybdenum increases its resistance to corrosion caused by deicing salts, coastal atmosphere and pollution.

If you have a topic suggestion for a future issue of Stainless Solutions or need additional technical advice on stainless steel specification and selection, please get in touch here.

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In providing consultation or other assistance with respect to technical issues, any consultation, assistance or material is provided for the general information of the recipient and should not be used or relied upon for any specific application without first securing competent advice. IMOA and their respective employees, consultants and members (i) make no representation or warranty, express or implied, of any kind with regard to such consultation, assistance or material including no representation or warranty of  suitability for any general or specific use; (ii) assume no liability or responsibility of any kind in connection  therewith; and (iii) disclaim any and all liability for any claim that arises therefrom. 

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