Single Girder vs Double Girder Crane: What’s the Difference and Which Should You Choose?
Short answer: a single girder crane has one load-bearing girder with the hoist running underneath; it handles 0.5-20 tons over spans up to about 20 m and costs less. A double girder crane has two girders with the hoist running on top; it handles 5-500+ tons, wider spans and higher duty cycles, so it suits heavy industry.
Structure
- Single girder: one girder between two end carriages; the hoist sits on an under-running trolley. Compact, lighter, cheaper.
- Double girder: two parallel girders; the hoist sits on a top-running trolley. Much stiffer, with greater capacity and span.
Comparison
| Feature | Single girder | Double girder |
|---|---|---|
| Capacity | 0.5-20 t | 5-500+ t |
| Typical max span | Up to 20 m | 35+ m (special up to 50+ m) |
| Hook height | Lower | Higher |
| Duty cycle (FEM) | M3-M5 | M5-M8 |
| Operator cabin | No | Yes |
| Approximate price | 30-50% lower | Higher |
| Structural weight | Lighter | Heavier, needs a stronger building |
| Maintenance | Easier, accessible from the floor | Needs a platform or cabin |
| Standards | FEM, ISO, DIN | FEM, ISO, DIN plus CMAA Class D-F |
Best applications
- Single girder: assembly plants, maintenance workshops, medium warehouses, food and pharmaceutical plants (stainless option), buildings with limited structural capacity.
- Double girder: steel mills and foundries, shipyards, heavy fabrication, power plants, ports, and any job over 20 t or 20 m span.
Five-step selection guide
- Maximum load: add a 25-33% safety factor (10 t actual means a 12.5-13.3 t crane). Above 20 t, choose double girder.
- Span: under 15 m, single is enough; 15-20 m depends on load and duty; over 20 m, double is recommended.
- Duty cycle: 1-4 h/day M3-M4 (single); 4-8 h/day M4-M5 (either); 2-3 shifts or 24 h M6-M8 (double only).
- Hook height: for maximum lift height, double girder has the advantage.
- Building structure: a double girder crane weighs 2-3 times more; have a structural engineer confirm the columns and beams.
Frequently Asked Questions
Can a single girder crane really lift 20 tons?
Yes, but span matters. A 20 m span at 20 t needs a special design with a very large H-beam, so a double girder crane may be better value.
Can I upgrade from single to double girder later?
It is possible but difficult and expensive because the runway rails must also change. Plan correctly from the start.
How much more does a double girder crane cost?
On average about 40-80% more at the same capacity.
Can ALLA build both?
Yes. ALLA designs, manufactures, installs and maintains both types to each plant’s specification. Talk to us about cranes.
