Packaging method | Steel Strapping VCI Paper/Stretch Film Timber Skids |
1. C-Purlin (C-Section Steel Purlin)
Shape: Resembles the letter "C" with a single web and two flanges (one open side).
Common Dimensions:
Flange Width: 50-100mm
Web Height: 100-300mm
Thickness: 1.2-3.0mm (cold-formed steel)
Key Features:
Easy to fabricate and install.
Used for secondary structural framing (e.g., roof/wall supports).
Compatible with bolted or welded connections.
Applications:
Industrial buildings, warehouses, and metal roofs.
2. Z-Purlin (Z-Section Steel Purlin)
Shape: Zigzag ("Z") profile with asymmetric flanges.
Common Dimensions:
Flange Width: 60-120mm
Web Height: 100-400mm
Thickness: 1.5-4.0mm
Key Features:
Higher load-bearing capacity than C-purlins due to overlapping capability.
Optimized for long spans (e.g., 6-12m).
Often used in sloped roofs (nesting reduces joint gaps).
Applications:
Large-span structures (aircraft hangars, solar panel supports).
3. U-Purlin (U-Section Steel Purlin/Channel Purlin)
Shape: U-shaped channel with two parallel flanges.
Common Dimensions:
Flange Width: 40-80mm
Web Height: 50-200mm
Thickness: 1.5-5.0mm
Key Features:
Rigid structure, suitable for heavy loads.
Often hot-rolled (thicker than C/Z-purlins).
Applications:
Heavy-duty industrial roofs, bridge decks, and trailer frames.
Comparison Table
Feature | C-Purlin | Z-Purlin | U-Purlin |
---|---|---|---|
Profile | Open C-shape | Symmetric Z-shape | U-channel |
Strength | Moderate | High (overlaps) | Very High |
Span | Short-Medium (3-8m) | Medium-Long (6-12m) | Short-Medium (3-6m) |
Connection | Bolted/Welded | Nested/Bolted | Bolted/Welded |
Material & Coating
Steel Grade: ASTM A653 (Galvanized), Q235/Q345 (Chinese standards).
Corrosion Protection:
Hot-dip galvanized (HDG): 80-275 g/m² coating.
Painted/PVDF: For aesthetic or harsh environments.
Typical Standards
International: ASTM, EN 10346, JIS G 3302.
China: GB/T 6725 (cold-formed steel).


