HSS Tubing vs. Structural Angles: PEMB Framing Spec Guide

Choosing between HSS tubing and structural angle for metal building framing is not simply a matter of selecting the stronger section. For secondary and supplemental PEMB framing, the correct choice depends on load direction, torsional demand, connection design, fabrication requirements, and installed cost. For engineers and PEMB designers, the objective is to match the section geometry to the actual load case.

What Are HSS Tubing and Structural Angles?

HSS, or hollow structural sections, are closed structural members manufactured in square, rectangular, and round configurations. Structural HSS used in metal building applications is commonly manufactured to ASTM A500, including Grade C for applications requiring higher yield strength.

Structural angles are open, L-shaped members available with equal or unequal legs. Common structural specifications include ASTM A36 and ASTM A529.

Typical applications where these components are used include bracing, wind columns, canopy framing, mezzanine framing, equipment supports, cable tray supports, connection clips, and other supplemental steel components. 

Both shapes are widely used as structural steel for PEMB projects. Their geometry, however, gives the two shapes very different structural characteristics. 

Strength and Load Comparison

HSS generally provides more efficient load distribution when a member is exposed to bending or compression in multiple directions.

HSS has a closed cross-section, which means that material is distributed around both principal axes. That geometry can provide greater structural efficiency than an angle of comparable nominal weight in applications where loads are not confined to a single predictable axis.

Structural angles perform efficiently when loads align with their intended axis, but their asymmetrical, open cross-section creates an inherent ‘weak-axis’ condition. Engineers therefore need to account carefully for orientation, eccentricity, unsupported length, and connection geometry.

In the appropriate load case, the higher strength-to-weight efficiency of HSS can allow a lighter section to perform the work of a heavier open shape. On larger PEMB packages, reductions in member weight can affect material quantities, shipping, handling, and erection loads.

That does not make HSS automatically preferable. When axial loading is predictable and torsion is minimal, structural angle can remain the more economical solution.

Torsional Resistance: Where HSS Pulls Ahead

When meaningful torsion is present, HSS is generally the stronger specification choice.

Closed structural sections resist twisting far more efficiently than open sections. Steel Tube Institute guidance cited for this comparison indicates that closed sections such as HSS can provide roughly 200% to 300% greater torsional resistance than comparable open shapes.

That distinction becomes important in framing members subjected to eccentric or multidirectional loads.

Typical PEMB applications where HSS may provide an advantage include:

• Canopy outriggers
• Cantilevered framing
• Wind bracing subjected to eccentric loading
• Equipment supports
• Frames receiving loads from multiple directions

An open structural angle can experience considerably more rotation when torque is introduced because its cross-section does not form a closed torsional path.

The practical specification rule is straightforward: if twisting is a meaningful part of the load case, HSS should receive serious consideration.

Where Structural Angles Still Make Sense

Structural angles remain highly effective where torsion is not the controlling design condition and fabrication or connection simplicity is important.

Common applications include X-bracing, knee bracing, stair framing, clips, stiffeners, and other lighter secondary members.

Angles can offer several practical advantages:

• Lower installed cost for many lighter-duty bracing applications
• Simple gusset connections using conventional bolting or welding
• No end caps or slotting required for many connection details
• Broad availability in smaller, commonly specified sizes
• Straightforward fabrication for repetitive clips and bracing assemblies

This is also why channels, angles, and tubing sourcing should be considered alongside structural performance when developing a PEMB framing package.

Angle is often selected because it accomplishes the required structural task with a simpler connection and lower fabrication burden—not because it inherently outperforms HSS.

Cost, Availability, and Fabrication Considerations

Structural efficiency does not always translate directly into lower installed cost.

Structural angle is often less expensive per pound and readily available in smaller sizes. Its open geometry can also simplify connections to gusset plates, frames, and other members.

HSS may require additional fabrication depending on the connection. Potential requirements include slotting for gusset plates, end caps, specialized weld details, and more involved moment connections. That additional shop labor can offset some of the savings created by a lighter section.

Availability can also influence specification decisions. When both HSS and angle are available from inventory, designers have more flexibility to select the section based on engineering requirements rather than allowing material lead times to drive the choice.

Coating requirements should be addressed early as well. Both shapes can be galvanized or otherwise coated, but hot-dip galvanized HSS requires properly located vent and drain holes.

PEMB Framing Spec Guide by Application

The following guide provides a useful starting point for HSS tubing vs. structural angle PEMB framing decisions. Final section selection should always be based on project-specific engineering calculations and connection requirements.

The table should be treated as a specification framework—not a substitute for structural analysis.

Sourcing HSS Tubing and Structural Angles for Your PEMB Project

Once the framing design is established, material availability and processing capability become part of the procurement equation.

Brown Strauss supplies both HSS tubing and structural angles for pre-engineered metal building projects, including ASTM A500 HSS tubing and ASTM A36 structural angles. In-house cutting and processing can help align material deliveries with project bills of material and fabrication requirements.

Planning a PEMB framing package? Request a Quote from Brown Strauss.

Frequently Asked Questions

Is HSS tubing stronger than structural angle?

For a comparable weight, HSS can provide greater structural efficiency in many compression, bending, and torsional applications because its closed cross-section distributes material around multiple axes. The final comparison depends on section dimensions, unsupported length, loading, and connection conditions.

When should structural angle be used instead of HSS in a metal building?

Structural angle is well suited to X-bracing, knee bracing, clips, stiffeners, stair framing, and other applications where torsion is not the governing load and simple bolted or welded connections provide an advantage.

What ASTM grade is typically used for HSS tubing in PEMB framing?

Structural HSS used in PEMB framing is commonly manufactured to ASTM A500, with Grade C frequently specified for structural applications.

Can structural angle be used for PEMB wind bracing?

Yes. Structural angle is commonly used for wind and X-bracing when loads are primarily axial and torsional demand is limited. Its open profile also allows relatively simple connections to gusset plates and surrounding framing.