nouvelles de l'entreprise How to Choose a Steel Space Frame for Large-Span Industrial and Commercial Buildings

Project Span Is the First Selection Factor

For most industrial and commercial projects, the decision to use a steel space frame begins with one number: the required span. A space frame carries load through a three-dimensional network of members joined at nodes, so it can cover long clear distances without intermediate columns. But "long span" is not a fixed threshold — what matters is what the building must do inside that span.

Before any structural comparison, confirm four span-related variables:

• Building width — the overall measurement across the short axis, which usually sets the governing span.
• Clear span — the unobstructed distance between supports that the client actually needs.
• Intermediate columns — whether columns are permitted inside, or whether the floor must remain fully open.
• Single-span or multi-span — one long span behaves very differently from a series of shorter spans sharing internal columns.

Roof geometry matters just as much. Flat, arched (cylindrical), and dome (spherical) space frames distribute load differently, so the same span may require different member sizes and node layouts. When a client says "we need 80 m clear", the next questions should be: flat or arched, and can any supports be placed along the way?

Within a single project, the pattern of supports often decides cost more than the headline span. A wide building split into several shorter spans that share internal columns can be lighter overall than one very long clear span, because member forces rise quickly as span increases. A client who needs a column-free floor for operations will accept a heavier structure as the price of clear space. The real task is to find where the functional need ends and structural economy begins — and to state that trade-off to the client before design starts.

Building Use Changes the Structural Requirement

The same span can serve very different purposes, and each purpose changes the load picture. Typical applications bring different demands:

• Stadium and arena roofs — long spans, high wind exposure, and suspended equipment such as lighting rigs and scoreboards.
• Exhibition halls — large column-free floors, moderate suspended loads, and flexibility for future displays or layout changes.
• Industrial plants — heavier roof dead load, possible equipment or crane loads, and an aggressive internal environment.
• Coal storage sheds — very large covers, dust and moisture, and concentrated bulk material loads.
• Airport canopies — wide or cantilevered spans, high wind, and visible architecture that shapes the node and member layout.
• Warehouses — often moderate span, but roof dead load and any future solar, HVAC, or conveyor loads must be planned from the start.

Matching the structure to the intended use early avoids late changes that are expensive and slow to reverse on site.

Loads That Must Be Confirmed

No space frame can be selected responsibly without the project loads. At minimum, the buyer and the supplier should agree on:

• Dead load — self-weight of the structure, roof panels, insulation, and finishes.
• Live load — maintenance access and any temporary loads during service.
• Wind load — based on the project location's wind speed, exposure, and terrain category.
• Snow load — based on the project location's ground snow level and the roof shape, including drift where relevant.
• Suspended equipment — lighting, HVAC, sprinkler lines, signage, or crane rails.
• Roofing load — the weight and fixing method of the actual metal roof panel system.

These values come from the project country's structural standard, not from a supplier's default assumption. Confirming them first keeps the selection grounded.

Steel Grade: Q235 / S235JR or Q345 / S355JR?

Space frame members and nodes are commonly produced from Q235 / S235JR or Q345 / S355JR steel. The higher grade offers greater yield strength, which can allow smaller member sections for a given load — but it also affects fabrication, welding procedure, and cost, and it must match the project's design standard. The grade should be confirmed against the engineer's calculation rather than chosen by habit.

Connections, Protection, and Roof System

Once the span and loads are fixed, three further choices shape the delivered product. First, the node type — bolt ball or welded ball — determines how the frame is fabricated and assembled, and it affects site tolerance. Second, the support condition at each column or wall defines the reactions the frame must transfer to the foundations. Third, the surface treatment — hot-dip galvanizing or painting — sets the corrosion protection for the project environment. Finally, the roof panel system, whether a metal panel with EPS, PU, or Rockwool insulation, adds dead load and fixes the panel detail. Planning these alongside the main structure avoids surprises in fabrication and on site.

Buyer Selection Checklist

The table below collects the inputs a supplier needs before a space frame can be quoted. Gathering them in one place shortens the design and pricing cycle considerably.

Work through these items with the client before requesting a quotation. A space frame chosen against real span, use, loads, and grade will perform as intended — and the conversation stays on engineering facts rather than assumptions.