A common question that arises during the material specification process is the functional difference between ASTM A500 and ASTM A513 steel tubing. Customers and design teams sometimes assume these specifications are interchangeable. However, when we delve deeper into the material properties and manufacturing standards, multiple differences emerge. 

As a structural engineer, your mandate is to create efficient, constructible designs that meet structural integrity requirements while managing cost constraints. Specifying the wrong tubing can lead to compromised load-bearing capacities, budget overruns, or delayed project timelines. 

This guide breaks down the core differences between A500 and A513 tubing, outlines their distinct applications, and provides the technical context you need to optimize material selection for your projects. 

What is A500 Tubing?

ASTM A500 tubing goes by several names in the industry. Engineers most commonly refer to it as Hollow Structural Sections (HSS), although structural tubing and tube steel (TS) are sometimes used. 

Manufacturers produce A500 tubing specifically for structural load-bearing applications. Due to its high strength-to-weight ratio and efficient characteristics, A500 HSS frequently serves as the structural backbone for large commercial projects like factories, stadiums, warehouses and data centers. It can be used as structural framing for server racks, cooling towers, MEP skids, architecturally exposed canopies and much more. 

When you order A500 tubing from a mill, each bundle will have a Mill Test Report (MTR) available. The MTR details the chemical composition of the steel coil used to manufacture the tube and verifies the physical properties, including yield strength, tensile strength, and elongation. This documented proof of physical capability is one of the most vital distinctions between A500 and A513 material. 

Atlas Tube offers a full size range of domestic ASTM A500 HSS. This includes Jumbo HSS™, with sizes reaching up to 22 inch square, 28 inch round, and 34×10 inch rectangle, all with wall thicknesses up to 1 inch. In addition to MTRs for every bundle shipped, Atlas also offers factory-specific EPDs to help engineers precisely calculate GWP and optimize LEED credits when working with HSS. With full material traceability and the shortest lead times in the industry, our HSS allows engineers to push the boundaries of structural design while maintaining efficient supply chains and delivering projects on compressed timelines. 

ASTM A500 Jumbo HSS enables teams to increase efficiency on large projects.

What is A513 Tubing?

A513 is classified as mechanical tubing. Manufacturers produce this material for consumer-based and industrial applications where tight dimensional tolerances are necessary, but load-bearing capacity is not a primary concern. 

A513 tubing does not support structural loads, and so the manufacturing standard does not require the reporting of yield, tensile, or elongation properties. Instead, material reporting focuses on dimensional accuracy and surface finish. 

You will typically find A513 tubing in products like lawnmower handles, recreational vehicle components, furniture frames, and heavy machinery enclosures. A513 may also be used in shelving units, sporting equipment, and other areas where weldability and precise dimensional tolerances are required. While it excels in these mechanical applications, A513 lacks the verified structural properties required for building infrastructure frameworks.

ASTM A513 mechanical tubing has the tight tolerances required for equipment like weightlifting machines.

Key Differences Between A500 and A513

When specifying material for your next project, understanding the precise differences between these two specifications ensures structural reliability and code compliance. 

1. Physical and Structural Requirements

A500 mandates rigorous testing and reporting of physical properties. Structural engineers rely on these documented yield and tensile strengths to perform accurate load calculations. A513 carries no such requirements. Using A513 in a structural capacity introduces significant risk, as the material lacks documented load-bearing capabilities. 

2. Dimensional Tolerances

A513 mechanical tubing offers tighter dimensional tolerances compared to A500. Because A513 serves in mechanical assemblies where parts must fit together precisely, the manufacturing process restricts variations in outer dimensions and corner radii. 

For example, on a 2×2-0.083 tube: 

A513: The corner radius ranges tightly from 5/64 inches to 1/8 inches. 

A500: The maximum corner radius is 0.249 inches, allowing for greater corner radius variability while maintaining structural mass. 

3. Stenciling and Identification

Tracking materials on a busy job site requires clear identification. For A500 tubing, industry standards require stenciling for any tube with a side measuring 5 inches or larger. This stenciling helps fabricators and contractors verify they are using the correct structural grade material for specific connections and load-bearing columns. A513 material requires no such stenciling. 

A500 vs. A513 Specification Comparison Table

Feature	ASTM A500 (Structural / HSS)	ASTM A513 (Mechanical)
Primary Application	Load-bearing structures, buildings, bridges, data centers	Consumer goods, machinery parts, furniture, shelving racks
Dimensional Tolerances	Looser (e.g., 2×2–0.083 max corner radius is 0.249“)	Tighter (e.g., 2x2x0.083 corner radius is 5/64″ to 0.125″)
Physical Requirements	Strict verification of yield, tensile strength, and elongation	No physical requirements or structural verification
Documentation	Material Test Report (MTR) provided	No MTR provided

Moving Foward With Confidence

Understanding the difference between structural and mechanical tubing protects your project from engineering failures and specification errors. Always specify ASTM A500 for any application requiring load-bearing capabilities. Leverage the documented MTRs and factory-specific EPDs from a domestic manufacturer like Atlas to ensure code compliance and create efficient, cost-effective structures. 

By capitalizing on the largest domestic range of HSS sizes and utilizing new connection technology from Atlas Tube like the HSS Connections Hub™ or the Shuriken Structural Nut Keeper®, you can navigate design changes swiftly and deliver highly functional spaces that meet all stakeholder expectations. 

For additional technical support, connection design resources, or general HSS assistance, contact a sales representative or one of our HSS experts.