Cranes are invaluable tools in the world of construction, saving time, effort, and helping to improve the safety of work sites. As with many specialist areas, cranes come with terms and abbreviations. Shortcuts in technical language help workers to better understand each other and to act faster.
When you are new to cranes, this unfamiliar language is confusing and can lead to misunderstandings among the crew. To make your life easier, Emerson cranes has assembled the most common words and acronyms that you will notice near, on, and around cranes.
Crane language made simple with our guide on:
Crane Terminology – Overhead Cranes & General Cranes
- SWL– Safe Working Load: Sometimes written as NWL or Normal Working Load. You may also see Maximum Rated Capacity MRC, instead of SWL.
- WLL– Working Load Limit: This is comparable to SWL and applies to anything below the crane hook. This reference should also be clear on the equipment and easy for all to see.
- HOL– Height of Lift: The safe vertical distance that a crane can lift a load. You can also say this is the maximum lifting height, from the ground to the hook of the crane.
- OTC– Overhead Travelling Crane: You may also see these cranes described as Bridge Cranes. Often the crane driver will sit in a cab of a large OTC beneath the bridge.
- EOTC– Electric Overhead Travelling Crane: Electric OTCs are good for indoor spaces since they do not create exhaust fumes.
- MPM– Meters Per Minute: This is the fastest rate of lift a crane can perform.
- S/G or D/G Single Girder or Double Girder: Relating to OTCs with either a single bridge or a double to support the hoist.
For safe and efficient crane usage, it is better to have a fuller understanding of the basic crane terms and how they apply to a lift. You can separate the terms into overhead (or bridge cranes) and for the general cranes that stand on a single platform.
The Hoist will have an electric motor to lift the load through a pulley system. The heavier the load, the slower the lifting speed of the hoist, in Metres per Minute. Slower lifting speeds will be due to the motor converting torque, through gearing, to give better control over the load. You may want a dual-speed hoist that can lift small loads fast, but you need a slower hoist with more control for heavy loads.
The hoist will have a Safe Working Load limit marked on it. The clear markings of SWL, NWL, or MRC are in obvious places on all cranes. These markings are a reminder not to exceed the safe lifting strength of the hoist. On the hooks, slings, and shackles hanging from the crane, you will tend to see Working Load Limit. WLL does not show the safe working load of the hoist.
Some cranes can extend the length of their reach by adding a Jib. The Jib is an add-on to the boom of the crane, increasing the operational radius. And to add stabilisation to the base, most mobile cranes have Outriggers that extend their footprints to spread the weight.
The lifting capability of overhead cranes makes them indispensable for shipping projects. You may see Overhead Cranes in docks for lifting boats and in harbours for loading cargo. You can operate many EOTCs or OHCs from the ground or a separate control room.
Cranes need hoists to raise and lower the loads on their hooks. For an overhead crane, it is more common for a Travelling Hoist to run along a Single or Double-Girder bridge. An overhead crane uses two or four End Carriages to support the weight of the bridge and hoist.
This carriage is often mobile, on a Trolley, running on a track in a straight line the length of a warehouse or the bay. And an overhead crane will also have a speed limit for the trolley. The speed of movement is also a concern for the bridge, where the hoist traverses from side to side.
The Crane Beam or the bridge Spans the lifting area that fits between the end carriages. The bridge needs to be strong to cope with the full weight of loads and the hoist at its centre position, so it is often the part that weighs the most. The bridge must also resist twisting when running along the trolley with heavy loads.
Emerson Cranes is one of the leading crane hire companies in the UK. Our staff has the best training and qualifications in the industry, with safety being our number one priority.
We carry out extreme lifting challenges on a day-to-day basis and have both the knowledge and the tools to lift your levels of success.
Contact us at Emerson Crane Hire limited today for guidance and a quote.