To our insulation industry corrosion under insulation is a financial burden. Millions of dollars are spent annually to remediate, replace, and re-insulate corroded systems. To compound these costs, plant shut-downs to repair and remediate far out-cost the actual remediation costs.

Metal corrosion begins when four ‘ingredients’ are present

• An Anode
• A Cathode
• An electrical path connecting the anode and cathode
• An Electrolyte

An anode, a cathode, and an electrical path connecting them; these ‘ingredients’ are inherent in all metals. The electrolyte; normally water, but it can be other liquids or solutions, or chemical compounds.

Where corrosion occurs, the anode sacrifices itself to protect the cathode, releasing positively charged metal ions into the electrolyte and electrons are left behind in the metal. These electrons flow through the metal to protect the cathode.

An electrolyte is a solution capable,which is in the form of ionic flow of conducting electrical current. The electrical path is a connection between the anode and cathode where current in the form of electrons can flow. Free electrons do not flow in the electrolyte, only in a metal path.

Anodic and cathodic areas develop where chemicals have been deposited, temperature differences, and in areas where moisture is present. Chlorides(Cl-) and other industrial contaminants in the electrolyte can also cause an area to become anodic. The contamination may be present on the metal surface before it is coated or insulated. Once these areas become wet, then corrosion begins.

Three of the four elements for corrosion to occur are inherent in all metals, it’s like the simplicity of a boxed cake mix; “just add water” and corrosion will occur. Corrosion can be accelerated by cyclic temperature changes or the presence of chlorides or other elements.