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Stress Corrosion Cracking

What is Stress Corrosion Cracking

Stress Corrosion Cracking (SCC) occasionally occurs in brass components when they are simultaneously exposed to tensile stresses and a corrosive medium. In this way, it is nearly always introduced during installation through over-tightening or contamination by a Stress Cracking Agent.

What Causes It?

Ammonia or Ammoniacal Compounds are the most typical cause of SCC, which can be found in cleaning fluids, refrigeration gases, sewage waste products, building materials, insulating materials (especially foams) and flame and smoke retarding treatments.

Moisture is a big part of the SCC process. It acts a catalyst by allowing any corrosive substances to collect and become more concentrated. This can be a particular problem in chilled water installations, where insulating materials allow the condensed moisture to be retained and kept in close contact with the surface.

How Can I Avoid It?

Stress Corrosion Cracking can be easily avoided using good installation practice and closely following installation guidance from manufacturers and national bodies. Otherwise you can look for other solutions to your application, such as copper or bronze based fittings.

Overall SCC can be avoided with adherence to good installation practice and adherence to our instructions.

Compression Fittings
  • Follow our instructions closely for installation.
  • A few drops of light oil can be used on the threads to assist the turning, which will reduce the stress on the nut.
  • In applications where moisture or contaminants can not be avoided it is advisable to protect the fitting by securely binding a moisture barrier to prevent anything making contact with the surface.