Common Steel Grades for Cold-Formed Steel Framing in Canada

For structural cold-formed steel framing in Canada, galvanized steel should conform to the requirements of the CSA S136 standard and the relevant ASTM specifications, such as ASTM A653 for coating designations like G90 (Z275) or higher for enhanced corrosion protection. The grade is determined by the steel's minimum yield strength (e.g., Grade 33/230 or 50/340) and the zinc coating weight, with higher coatings providing better durability. 

Key Standards & Specifications

 CSA S136

As the cornerstone for cold-formed steel design in Canada, CSA S136 delivers guidance on material properties and structural performance criteria that manufacturers and designers must follow to ensure consistent quality and safety. This specification aligns closely with similar North American standards, streamlining design practices across borders.

 ASTM A653/A653M

ASTM A653 focuses on the sheet steel itself, detailing zinc coating options and weights that are crucial for corrosion resistance in structural applications. By specifying these coatings, it ensures the steel remains durable in various environmental conditions.

 Breaking Down Steel Grades

 1. Yield Strength

The grade of cold-formed steel is often determined by its yield strength—how much stress it can withstand before permanently deforming. Two common grades used in Canada include:

- Grade 33 (230 MPa): Suitable for lighter-duty structural applications.

- Grade 50 (340 MPa): Offers higher strength for heavier loads and demanding applications.

 2. Zinc Coating Designation

When it comes to resisting corrosion and environmental wear, zinc coatings play a pivotal role. The designation reflects the coating’s thickness and weight:

- G90 (Z275): A highly robust option providing exceptional corrosion protection, typically recommended for structural framing.

- G60 (Z180): Offers moderate resistance to wear, though its application may be limited in harsher conditions.

- G275: Commonly associated with European standards and known for its long-term durability—some claim it can last up to 100 years in specific applications.

 Key Considerations When Specifying Steel

Choosing the right steel grade for your project involves referencing both Canadian and ASTM standards to align with structural demands and environmental factors. For instance, a typical recommendation might look like this: ASTM A653, Grade 50 (340), G90 (Z275) or higher. This formula ensures your chosen material can meet both strength requirements and deliver adequate protection against corrosion over the long term.

 Final Thoughts

Cold-formed steel framing offers unmatched reliability when specified correctly according to CSA S136 and ASTM A653 standards. By considering factors like yield strength and zinc coating designation, you can confidently select materials tailored to both the structural demands of your project and its environmental setting. Whether using Grade 33 with moderate coatings or Grade 50 with enhanced protection, thoughtful planning leads to optimal performance and durability in construction applications.