Choosing between a single girder and a double girder overhead crane comes down to five things: the load, the span, the hook height you need, the duty of the crane and the building it will run in.
This guide explains how the two designs differ, where each one fits and what to check before you ask for a quotation.
The basic difference
A single girder overhead crane carries its hoist trolley on the lower flange of one main girder. A double girder crane carries its trolley on rails fixed to the top of two girders.
That one change affects capacity, lifting height, weight on the runway and the equipment you can fit.
Hook position and headroom
On a single girder crane the hoist hangs below the girder, so the hook sits lower in the bay. On a double girder crane the trolley runs on top of the girders, so the hook can travel higher for the same building height.
If the roof structure leaves little room above the load, headroom often decides the design before capacity does. Measure from the top of the runway rail to the lowest roof member, and from the floor to the highest point you need to lift.
Capacity range
CESAN builds single girder overhead cranes up to 32 t and double girder overhead cranes up to 250 t. Below about 10 t a single girder design is common. For heavy loads or wide spans, a double girder crane is usually the practical choice.
Single girder: where it fits
- Light to medium loads in workshops, warehouses and assembly halls.
- Lower crane weight, so lighter runway beams and building columns.
- Simpler structure and a lower purchase price.
- Typical hoist: an electric wire rope hoist or an electric chain hoist.
- Maintenance lifts, machine feeding and general material handling.
Double girder: where it fits
- Heavy loads, long spans and frequent lifting.
- Higher hook position, because the trolley runs on top of the girders.
- Room for walkways, cabin control, magnets, grabs and other attachments.
- Two girders give a stiffer structure for wide spans.
- Applications such as steel handling, precast plants, power stations and machine shops.
Duty class: how hard the crane works
Two cranes with the same capacity can work very differently. One lifts a heavy part a few times a day. The other lifts near full load every few minutes across two shifts.
The duty class, set to FEM or ISO 4301, describes this. A higher duty class needs stronger structure, gears, brakes and wheels. Give us the number of lifts per hour, the typical load and the hours of operation per day.
Runway and building
The crane transfers its weight to the runway beams and the building columns. A lighter single girder crane puts less load on an existing building. A double girder crane may need stronger runway beams or new ones.
If the runway already exists, send its profile, span and the loads it was designed for. If it is new, we can give the wheel loads so your structural engineer can size the supports.
Hoist, control and attachments
- Hoist: wire rope or chain, standard or low headroom, one hoist or two.
- Control: pendant, radio remote control or cabin.
- Drives: inverter (VFD) control for smooth starts and accurate positioning.
- Attachments: hooks, lifting beams, magnets, grabs and other below-the-hook devices.
Cost beyond the crane price
A single girder crane costs less to buy. But if a heavier load or a busier shift appears later, an undersized crane becomes expensive to replace. Check the runway, the power supply and the access for maintenance as well as the crane itself.
A quick way to decide
- Choose single girder when the load is light to medium, the duty is moderate and the building should carry as little extra weight as possible.
- Choose double girder when the load is heavy, the span is wide, headroom is tight or the crane will work hard every day.
- Ask an engineer when the two options look close. The difference is often in duty class and headroom.
Standards
CESAN designs overhead cranes to recognized standards such as FEM 1.001, EN 13001 and ISO 4301. Tell us which standard your specification requires. See also our guide to CE, FEM and DIN for crane buyers.
Send us your requirements
To prepare an accurate offer, we need the capacity, span, lifting height, duty class or operating hours per day, runway details, power supply and control method. Send them through the enquiry form and our engineers will reply with a technical and budgetary assessment.
You can also read about our overhead cranes and the price guide.