7. Exposure Classes for Connectors and Fasteners

Corrosion exposure types for metal connectors and fasteners in most buildings can be grouped into five classes, which are discussed in this section. The five classes and their locations in a building are shown in Figure 6.

Exposure classes should be considered when determining which connectors and fasteners are appropriate for a given application. The use of corrosionresistant fasteners and connectors, such as those that are made of stainless steel or incorporate thicker zinc galvanizing (G185 or thicker), will reduce corrosion rates or extend the period that the zinc coating protects the base metal. Using corrosion-resistant fasteners and connectors will maintain the designed load path longer than nominally galvanized connectors and fasteners. In areas where corrosion is the most problematic, the most corrosion-resistant metal connectors and fasteners, such as Type 304 or Type 316 stainless steel, should be used.