What is HSS? Why Hollow Structural Sections are the Secret to Stronger Buildings

Walk past any data center, power generation facility, mission-critical building, or industrial facility, and you'll find something invisible holding it together. Behind the cladding, beneath the concrete, and inside the roof framing, Hollow Structural Sections (HSS) or Tubes are quietly carrying enormous loads while keeping material costs and dead weight in check. 

Often referred to as the "secret weapon" of modern architecture and industrial design, HSS is transforming how we approach Tube construction. But what is HSS in construction, and why is it becoming the go-to choice for project managers?

At Sintel, we have deep experience with HSS or “Tubes” and have spent years fabricating large, heavy weldments for Fortune 50 construction companies, industrial clients, and sectors where structural integrity is non-negotiable. 

To meet increasing demand, Sintel is building a second facility specifically designed to handle large weldments at scale, primarily tube structures. This guide pulls together what our metals engineering team knows about HSS, so your next project benefits from that experience before the first cut is made.

What is HSS? Understanding the Basics

To understand the meaning of HSS in construction, you have to look at its geometry. HSS refers to high-strength welded steel tubing used as structural elements in buildings and various manufactured products. They are typically available in three primary shapes:

• Square

• Rectangular

• Circular (Round)

Unlike traditional I-beams or C-channels, which are "open" shapes, HSS is a closed-loop system. This structural closed-loop offers unique benefits that open sections cannot match. Sintel possesses the design and engineering expertise to guide clients through the entire process, from initial concept to final weld.

Why Hollow Steel Beams are the Secret to Stronger Buildings

1. Superior Strength-to-Weight Ratio

The primary benefit of an HSS structure is its efficiency. Because the steel is concentrated at the perimeter of the section, it provides excellent resistance to bending (twisting) and compression. This means you can achieve the same structural integrity as solid or open beams while using significantly less steel.

• The Customer Benefit: Using hollow steel tubes reduces the overall weight of the structure, simplifying shipping logistics and lowering foundation costs—ensuring your project stays on schedule and within budget. Furthermore, Sintel maintains strategic relationships with the best Tube Mills to ensure the entire value chain is optimized for cost and availability.

2. Exceptional Torsional Resistance

Standard I-beams are excellent for one-way bending, but they struggle when subjected to twisting forces. Because HSS is a closed section, it is remarkably stiff and resistant to lateral-torsional buckling.

• The Customer Benefit: This makes HSS or Tubes ideal for "big heavy parts" and large-scale industrial frames in power generation facilities where multidirectional loading is a factor. You get a more stable, reliable build that passes even the most demanding audits.

3. Aesthetics and Surface Finish

For many modern data centers, the HSS framing is left exposed as an architectural feature. The smooth, rounded corners and flat faces of HSS are not only visually appealing but are also much easier to clean and maintain than the deep "nooks and crannies" of I-beams.

Sintel’s in-house, best-in-class Powder Coat services adhere perfectly to HSS's or Tubes' clean surfaces. By using a single supplier for both fabrication and finishing, you eliminate the hassle of coordinating multiple manufacturers and ensure a high-quality, durable finish that protects against corrosion.

4. Simplified Fabrication and Automation

HSS is a dream for modern HSS construction because its uniform cross-section enables highly efficient robotic and automated welding. At Sintel, we leverage automation and robotics to process HSS or Tubes with extreme consistency. This ensures every component is "best-in-class," reducing the need for on-site adjustments and shortening your total time-to-completion. Our upcoming second facility further expands this capability, allowing us to manage massive Tube-based weldments at an unprecedented scale.

A Quick Guide to Common HSS Steel Grades

Not all HSS is the same. Grade selection directly affects structural performance, weldability, and connection design. Here are the grades most commonly encountered in HSS construction:

• ASTM A500 Grade B: The most widely used grade for square and rectangular HSS in the United States. Reliable availability and well-understood weld characteristics make it the standard choice for general building framing.

• ASTM A500 Grade C: Higher minimum yield strength than Grade B, useful when member sizes need to be reduced or when design loads push the limits of Grade B sections.

FAQs

1. What is HSS in construction, and why is it used?

HSS stands for Hollow Structural Sections (often called Tubes). It is a type of metal profile with a hollow tubular cross-section. It is used in mission-critical buildings because it offers a high strength-to-weight ratio and excellent torsional load resistance, making it more efficient than traditional open-web steel beams.

2. What are the benefits of using hollow steel beams over I-beams?

Hollow steel Tubes provide better resistance to twisting (torsion) and are more aesthetically pleasing for exposed structures. Additionally, HSS has a lower surface area than I-beams, reducing the amount of fireproofing or powder-coating material required and lowering long-term maintenance costs.

3. How does HSS framing improve building safety?

HSS framing is exceptionally strong in compression and multi-directional loading. This makes it highly stable for data centers or power generation facilities during seismic events. Sintel’s engineering team provides the guidance necessary to ensure these structures meet the highest safety standards.

4. Can HSS be used for large-scale "big heavy parts"?

Yes, HSS is a preferred material for large-scale fabrication because it can support significant weight without adding unnecessary bulk. When combined with Sintel's robotic welding and automation, HSS can be fabricated into massive, high-precision components for industrial use.

5. Why is powder coating recommended for HSS structures?

Because HSS has smooth, continuous surfaces, it is an ideal candidate for a powder-coat finish. Powder coating provides a thick, durable protective layer that outlasts liquid paint, ensuring the HSS construction remains protected against the elements for decades.

6. Is HSS framing "Made in USA" available?

Yes. Sintel prides itself on providing "Made in USA" fabrication services. Using domestic HSS ensures the materials meet strict quality standards and support local supply chains, giving you peace of mind that your structural components will last.