SHS, RHS and CHS Hollow Sections: A Complete Guide
Square, rectangular and circular hollow sections explained: EN 10219 vs EN 10210, ASTM A500, sizes, wall thickness, grades, weight formula, galvanizing and uses.
Saudi Steel Work Editorial Team · · 3 min read
Short answer: SHS (square), RHS (rectangular) and CHS (circular) hollow sections are closed steel tubes used as structural members. Cold-formed sections to EN 10219 or ASTM A500 are most common; hot-finished sections to EN 10210 offer more uniform properties and tighter corners. They are efficient in compression and torsion and give a clean appearance.
Hollow structural sections combine strength, light weight and clean lines. They're used everywhere from building columns to canopies, handrails and solar structures.
Shapes
- SHS — square, e.g. 100 × 100 × 5
- RHS — rectangular, e.g. 150 × 100 × 6
- CHS — circular, e.g. 114.3 × 6.0
Cold-formed vs hot-finished
| Factor | Cold-formed (EN 10219, ASTM A500) | Hot-finished (EN 10210) |
|---|---|---|
| Process | Formed cold from strip, welded | Formed or finished hot |
| Corner radius | Larger | Tighter |
| Residual stress | Higher | Lower |
| Cost | Lower | Higher |
| Availability | Very common | Less common regionally |
Design codes assign different properties to each; don't substitute without approval.
Grades
- EN: S235JRH, S275J0H, S355J2H
- ASTM A500: Grade B, Grade C (and newer Grade D/E)
Weight estimate
SHS/RHS: kg/m ≈ (2 × (B + H) − 4t) × t × 0.00785 CHS: kg/m = (OD − t) × t × 0.02466
| Section | Approx. kg/m |
|---|---|
| SHS 50 × 50 × 3 | 4.5 |
| SHS 100 × 100 × 5 | 15.0 |
| RHS 150 × 100 × 6 | 22.4 |
| CHS 114.3 × 6.0 | 16.0 |
Published tables are slightly lower for SHS/RHS due to corner radii. Use our steel weight calculator.
Why hollow sections perform well
- Equal stiffness in both axes (SHS, CHS) suits columns
- High torsional stiffness
- Less surface area to paint than open sections of similar capacity
- Smooth, modern appearance
Connections
Connections are often welded; bolted connections need end plates or special blind bolts. Detailing matters — involve your fabricator early (fabrication process).
Corrosion protection
Seal ends or galvanize with proper venting. For exterior steel, see hot-dip galvanizing explained.
Browse our hollow sections.