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What are the differences: Single vs. Double Girder Overhead Cranes

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Granada Cranes
Semi Goliath Crane

Choosing between a single girder and double girder overhead crane is one of the most fundamental decisions when specifying a new crane system. Each design has distinct advantages depending on your lifting capacity, building constraints, and budget. This guide explains the key differences to help you make the right choice for your operation.

Single Girder vs Double Girder: Quick Comparison

The main difference lies in the bridge construction: single girder cranes use one main beam with the hoist running underneath, while double girder cranes use two parallel beams with the hoist running on top.

Specification Single Girder Double Girder
Typical Capacity Up to 10-15 tonnes 10 to 60+ tonnes
Maximum Span Up to ~25 metres 30+ metres
Hook Height Better in limited headroom Requires more headroom
Initial Cost Lower Higher
Building Load Lighter – less structural demand Heavier – needs stronger structure
Maintenance Access From below or platform Walkway on bridge possible
Best For Light-medium duty, cost-sensitive Heavy duty, long spans

Single Girder Overhead Cranes

Single girder cranes feature one main bridge beam, with the hoist and trolley running along the bottom flange of the girder. This design makes them lighter, more compact, and more economical than their double girder counterparts.

Advantages

  • Lower initial purchase cost
  • Lighter weight – less demand on building structure
  • Better hook height in buildings with limited headroom
  • Faster and simpler installation
  • Lower running costs
  • Ideal for light to medium duty cycles

Limitations

  • Capacity typically limited to 10-15 tonnes
  • Span limited to around 20-25 metres
  • Less rigid at longer spans
  • Not suitable for heavy duty cycles
  • Fewer options for auxiliary equipment

Single girder cranes are the most popular choice for general industrial applications. For capacities up to 10 tonnes, they offer excellent value and performance. They’re particularly well-suited to workshops, warehouses, and manufacturing facilities where headroom is limited and loads are moderate.

Double Girder Overhead Cranes

Double girder cranes use two parallel bridge beams with the hoist and trolley mounted on rails on top of the girders. This configuration provides greater strength and rigidity, making them suitable for heavier loads and longer spans.

Advantages

  • Higher lifting capacities (up to 60+ tonnes)
  • Longer spans possible (30+ metres)
  • Greater rigidity and stability
  • Better for heavy duty cycles
  • More options for accessories and auxiliary hoists
  • Maintenance walkways can be fitted on the bridge

Limitations

  • Higher initial cost
  • Heavier – requires stronger building structure
  • Needs more headroom (hoist sits on top of girders)
  • More complex installation
  • Higher long-term maintenance costs

Double girder cranes are essential for heavy industrial applications. For capacities of 15 tonnes, 20 tonnes, or 30+ tonnes, double girder construction is typically required to handle the loads safely and efficiently.

How to Choose: Decision Guide

Which Girder Type Do You Need?

Choose Single Girder If:

Your maximum load is under 10 tonnes, span is under 20m, headroom is limited, budget is a priority, or duty cycle is light to medium.

Choose Double Girder If:

You need to lift over 15 tonnes, span exceeds 25m, heavy duty cycle is required, you need maintenance walkways, or auxiliary hoists are needed.

The “Grey Area” – 10 to 15 Tonnes

In the 10-15 tonne range, either configuration may work. The choice often comes down to:

  • Span length – longer spans favour double girder for rigidity
  • Duty cycle – frequent heavy use favours double girder
  • Headroom – limited headroom favours single girder
  • Budget – cost constraints favour single girder
  • Building structure – weaker structures favour lighter single girder

Our team can advise on the best option for your specific situation. Often a site survey is the best way to determine which design suits your building and operational requirements.

Applications by Industry

Industry Typical Girder Type Why
Warehousing Single girder Lighter loads, cost-effective, good hook height
Steel Fabrication Both Single for lighter work, double for heavy plate/beams
Automotive Single girder Component handling, moderate loads, production lines
Aerospace Both Precision work often single; large assemblies need double
Steelworks Double girder Heavy coils, high duty cycle, demanding environment
General Engineering Single girder Versatile, cost-effective for most workshop tasks
Power Generation Double girder Heavy turbines, transformers, long spans

Cost Comparison

Single girder cranes are typically 20-30% less expensive than equivalent double girder cranes. However, the total cost difference depends on several factors:

  • Crane cost – single girder uses less steel and simpler construction
  • Building modifications – double girder may require structural reinforcement
  • Installation time – single girder is faster to install
  • Running costs – lighter single girder uses less power
  • Maintenance – simpler single girder design means lower maintenance costs

Important: Don’t Under-Specify to Save Money

While single girder cranes are more economical, choosing one purely to reduce costs when a double girder is needed will lead to problems. Under-specified cranes suffer premature wear, reduced lifespan, and potential safety issues. Always specify based on your actual requirements, not just budget.

Hoist Position: Under-Running vs Top-Running

The girder type determines how the hoist travels:

  • Single girder (under-running) – hoist hangs below the girder, trolley runs on the bottom flange. This maximises hook height but limits capacity.
  • Double girder (top-running) – hoist sits on top of the girders, trolley runs on rails mounted on the beams. This allows higher capacities and better load stability but requires more headroom.

In buildings with restricted headroom, single girder cranes often provide better hook height because the hoist sits below the beam rather than on top of it.

Safety and Compliance

Both single and double girder cranes must comply with the same safety standards and regulations. All overhead cranes we supply are:

  • Designed and manufactured to British and European standards
  • Supplied with EC Declaration of Conformity and CE marking
  • Subject to LOLER thorough examination before handover
  • Equipped with safety features including overload protection, limit switches, and emergency stops

We also provide ongoing servicing and maintenance for both crane types, including LOLER inspections at the required intervals.

Need Help Choosing?

Our team can advise whether a single or double girder crane is right for your application. We’ll consider your loads, building, duty cycle, and budget to recommend the best solution.

Get Expert Advice

Or call 0800 376 27 27

Summary

Key Takeaways

  • Single girder – best for capacities up to 10t, spans under 20m, limited headroom, and cost-sensitive projects
  • Double girder – best for capacities over 15t, spans over 25m, heavy duty cycles, and demanding industrial applications
  • 10-15 tonne range – either may work; consider span, duty cycle, headroom, and budget
  • Cost – single girder is 20-30% cheaper, but don’t under-specify to save money
  • Hook height – single girder often better in restricted headroom
  • Both types – must meet the same safety standards and LOLER requirements

The right choice depends on your specific requirements. For most general industrial applications with moderate loads, a single girder crane offers the best combination of performance and value. For heavy lifting, long spans, or demanding duty cycles, double girder construction provides the strength and capability you need.

Explore our full range of overhead gantry cranes from 1 tonne to 60+ tonnes, or contact our team to discuss your requirements.

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