ICC-ES AC358 establishes a rigorous, standardized framework for evaluating the structural adequacy, installation procedures, and durability of helical foundation products. It defines four primary requirement categories that must be met for a system to be considered code-compliant:

1. Design Capacity Verification: Per section 4.2, systems must use test piles or empirical methods to ensure load-bearing capacity matches project-specific requirements. This often involves site-specific geotechnical evaluations and field verification through load testing.
2. Corrosion Protection: AC358 mandates specific steel thicknesses and coating requirements based on soil corrosivity. For example, aggressive soils require a minimum steel thickness of 0.375 inches and hot-dip galvanizing per ASTM A123, while extremely aggressive soils require 0.5 inches of thickness plus additional protective layers.
3. Installation Torque Correlation: Per section 5.3, the criteria define the relationship between the rotational torque measured during installation and the pier’s ultimate axial capacity. This allows for real-time verification of capacity in the field.
4. Material Standards: The criteria reference specific standards like ASTM A500 for structural tubing and ASTM F1554 for anchor bolts to ensure consistency in the quality and fabrication of the steel components.

Adhering to these criteria ensures that helical piers provide predictable performance and meet independent, third-party verification for challenging geotechnical conditions, such as the expansive clay soils found in the Colorado Front Range.