General Corrosion Information
Any steel product that is used in outdoor applications will be affected by corrosion. The rate at which a specific steel product corrodes will ultimately be determined by the environment and location in which it is being used. Since there are many variables inherent in the process of corrosion, it is difficult to predict at what rate a steel product will corrode. Areas, for example, with high levels of humidity, moisture, and precipitation will cause the rate of corrosion of a particular steel product to increase while decreasing its effectiveness and strength. Impeding this process would require using products with greater corrosion resistance (i.e. thicker zinc coatings). Almcan Manufacturing offers a full line of connectors with different corrosion preventative coatings to better serve your specific needs.

Corrosion Preventative Coatings
G90 Standard Connector Coating
Galvanized G90 steel is coated with .90 oz. of zinc per square foot of surface area. This coating offers the least amount of corrosion resistance amongst the different coatings available. Although G60 galvanization is the minimum coating standard, Almcan connectors are predominantly manufactured with G90 galvanized steel.

HOT DIP Galvanized Coating
Hot dip galvanized products are immersed in a bath of molten zinc after fabrication. The amount of coating required per product increases with material thickness. As a result, coatings will range between 1.0 – 2.0 oz. per square foot of surface area (as per CAN/CSA-G164-M92/ ASTM A123).

TRIPLE ZINC G185 Connector Coating
Triple Zinc products offer the most effective corrosion resistance due to a heavier zinc coating. Galvanized G185 steel is coated with 1.85 oz. of zinc per square foot of surface as per ASTM A653. Almcan offers a full line of Triple Zinc products to help protect against corrosion.

* ALL PRODUCTS WITH ABOVE PREVENTATIVE COATINGS REQUIRE HOT-DIP GALVANIZED FASTENERS AS PER ASTM A153.
* TO PROLONG THE SERVICE LIFE OF CONNECTORS USED IN ANY OUTDOOR APPLICATIONS IT IS IMPORTANT TO CONDUCT OCCASIONAL CORROSION INSPECTIONS.

Pressure Treated Wood and Connector Corrosion
When guarding against the corrosion of your connectors, it should be noted that the elements (i.e. precipitation and humidity) are not the only culprits potentially responsible. The different types of pressure treated wood introduced several years ago to replace the then common Chromated Copper Arsenate (CCA-C) wood are treated with chemicals that are corrosive to steel. Copper Azole Type A & B (CBA-A & CBA-B), Alkaline Copper Quaternary (ACQ), and Sodium Borate (SBX) are the new predominant types of pressure treated wood that, when used together with the standard G60 galvanized connectors, accelerate the process of corrosion. Corrosion can compromise the load carrying capacity of a particular connector while reducing its strength. As a result, it is strongly recommended that when using these types of pressure treated wood to use connectors that have a greater resistance to corrosion.

Although the standard G60 galvanized coating does offer some corrosion resistance to connectors used in environments less susceptible to corrosion, it is limited in its effectiveness when used in applications involving the new types of pressure treated wood and in environments more conducive to corrosion. Greater corrosion resistant coatings are available (HOT DIP Galvanized and TRIPLE ZINC G185) that are more compatible with the new types of pressure treated wood. Almcan offers a complete line of Hot Dip Galvanized and Triple Zinc G185 connectors that can be used in many different applications.


IMPORTANT NOTE:
Regardless of the coating of your connector, we cannot guarantee a corrosive-free product. Corrosion is inevitable and we can only recommend using connectors with the strongest corrosion resistance (i.e. those with the heaviest zinc coatings) to provide the utmost protection and to help increase the longevity of your connector.

The Corrosion Process (as described on the Institute for Research in Constuction IRC website)
Corrosion is the deterioration of a metal that occurs when it reacts to the environment. Metals revert to their stable, natural form through a process called oxidation, or rusting, in the case of steel. Corrosion is an electrochemical process that requires the presence of both oxygen and moisture in order to proceed at a significant rate. In this process, which can be compared to a battery, an electric current passes through a conducting solution, such as water, between two parts of the same metal or between different metals. The current flows from an anodic area (positive electrode), which corrodes, to a cathodic area (negative electrode), which does not corrode. Corrosion can occur uniformly over the whole surface or locally. This depends on various factors such as moisture distribution, local breakdown of protective layers and material composition.

Source: IRC Website: Corrosion of Metal Ties in Masonry Cladding by A.H.P. Maurenbrecher