Hot rolled steel channel and cold formed steel channel are both widely used for purlins, girts and light structural framing. This guide compares the two on section properties, load capacity and cost, with selection guidance for warehouses, industrial buildings and light steel framing.
Steel channel is one of the most commonly used structural shapes for purlins, girts, door frames, equipment supports and light framing. Two distinct production routes supply the market: hot rolled channel (PFC, UPE, UPN depending on the standard) produced by passing heated steel through rolling stands; and cold formed channel (C-section, Z-section, sometimes called lipped channel) produced by roll-forming thin gauge cold rolled coil. The choice between them depends on span, load, and the building code being followed.
Section Properties and Load Capacity
Hot rolled channel has tapered inner flanges (a result of the rolling process), a thicker web and flanges (typically 5–15 mm), and uniform material properties throughout. The thicker section gives high load capacity and good resistance to local buckling, making hot rolled channel the right choice for heavy spans, high loads, and dynamic or cyclic loading. Cold formed channel has sharp 90° corners, parallel flanges, and much thinner material (typically 1.5–3.0 mm), with the strength enhanced by strain hardening during the cold forming process. Cold formed is lighter, easier to handle on site, and significantly cheaper per metre, but has lower load capacity per kilogramme.
When Hot Rolled Channel Is the Right Specification
Hot rolled steel channel is the right specification for heavy purlin spans (above about 8 m), for girts in industrial buildings with high wind loads, for crane runway supports, and for any structural member where the load is concentrated or dynamic. It is also the correct specification where the building code requires hot rolled steel for primary structural members, and where the section will see welding that could compromise the cold work hardening of a cold formed alternative.
When Cold Formed Channel Is the Right Choice
Cold formed steel channel is the right specification for light steel framing in residential and commercial buildings, for purlins and girts in warehouses with short spans (under about 6 m), for door and window frames, and for any application where the section is used as a secondary member with modest loading. Cold formed is also widely used for the top and bottom chords of light steel roof trusses, and for the framing members of partition walls. The per-metre cost is typically 40–60% lower than hot rolled channel of equivalent depth, which is the main reason for its dominance in light construction.
Standards, Coatings and Connection Detail
Hot rolled channel is produced to ASTM A36 or EN 10034 (PFC designation) or JIS G3192. Cold formed channel is produced to ASTM A653 (galvanized) or EN 10346 (DX51D or structural quality S350GD). For outdoor or corrosive environments, cold formed channel is often supplied galvanized (G60, G90, or Z275) for built-in corrosion protection. Connections for hot rolled channel use bolted or welded standard structural details; for cold formed, self-drilling screw connections are typical. For long-span cold formed purlins, bridging or sag rods are often required at mid-span to control twisting.
What to Specify on the Channel RFQ
State the production process (hot rolled to ASTM A36/EN 10034/JIS G3192, or cold formed to ASTM A653/EN 10346), the section designation (C 100x50x15x2.0, PFC 200x75x25, etc.), the steel grade, the length, the coating (mill finish, galvanized G60/G90, primer), and any special testing (Charpy, yield strength). For heavy spans, default to hot rolled; for light framing, default to cold formed galvanized. Confirm the mill supplies the test report per EN 10204 3.1 with the actual yield strength, since cold formed sections derive much of their strength from the cold work and the base metal yield alone is not sufficient.
Related Resources from Baobin Steel
- Steel sheet catalog – cold rolled and galvanized substrate
- Structural steel overview – grades and standards
- Request a quote – send your framing plan for channel pricing