What is the maximum depth of a column web beneath which primer is used on an SFRM?

The correct depth for applying primer on a sprayed fire-resistant material (SFRM) typically aligns with the need to ensure proper adhesion and effectiveness of the fireproofing system. For structural columns, the maximum depth below which a primer is recommended is 16 inches. This depth is significant because applying primer helps improve the bonding of the fire-resistive material to the steel substrate, particularly when dealing with larger cross-sections of structural steel.

When assessing fireproofing on columns, the application of primer is crucial for depths greater than this threshold. It may be less necessary for shallower configurations, as there is usually adequate contact and adhesion without additional surface preparation. Understanding the depth limits is vital for ensuring compliance with fire protection standards and achieving optimal performance of fireproofing systems in protecting underlying structural elements from fire exposure. This helps eliminate potential vulnerabilities in structural integrity due to inadequate fireproofing application.