What is the lowest allowable thickness for a tube steel column's SFRM application?

The correct answer is based on the standards and guidelines set for Spray-Applied Fire-Resistive Materials (SFRM) application. For tube steel columns, fireproofing requirements are determined by factors such as the intended fire resistance rating and the type of SFRM being used.

The minimum thickness of fireproofing is crucial because it ensures that the steel structure can withstand high temperatures for a specified duration during a fire event. This thickness is established through testing and engineering assessments that have been conducted to ensure adequate fire protection.

In this case, 1 inch is recognized as the lowest allowable thickness of SFRM application for tube steel columns, providing sufficient insulation and protection to maintain the structural integrity of the steel during exposure to fire. This thickness is in alignment with the fire resistance ratings typically specified in building codes and standards, which aim to ensure safety in fire situations.

Thinner applications would fail to achieve the necessary fire resistance, which could lead to structural failure in a fire scenario, while thicker applications may be excessive and unnecessarily increase material costs and application time without providing additional benefits in terms of fire protection.