Technology is everywhere these days, but understanding it is often difficult. Especially for a technophobe like me. So, let’s make your lives just a tiny bit easier.
You might often hear the words Rated Capacity Indicator (RCI) but not know what it means. You might even work with RCIs and not know what they’re called.
Well, this article is going to tell you exactly what an RCI is, and what it can be used for.
I’ll answer that in simple terms right now.
The primary aim of a Rated Capacity indicator (RCI) is to prevent machines – such as cranes, excavators, piling rigs, etc – from exceeding their limits. For example, an RCI will stop a crane from lifting more than its manufacturer’s guidelines. This helps to prevent a crane from tipping over.
Let’s get into a little more detail.
What is an RCI?
A Rated Capacity Indicator (RCI) is a system that’s made up of sensors, and a screen that provides digital information.
HSE regulations state that a machine that can lift more than 1 tonne should be fitted with an RCI. The types of machines that this would apply to are things like cranes, piling rigs, shovel loaders, lorries, road-rail vehicles, and excavators.
On cranes, RCI sensors can monitor things like:
- the weight of the load being lifted
- the height of the load
- depth of excavation or piles
- wind speed
- slew speed and angle
- hoist gear speed
- jib gear speed
- radius.
- lifting limit percentages
A lot of this information gets shown as readings on a monitor/screen so that the operator of the machine can carry out their work safely.
Why are Rated Capacity Indicators useful?
An RCI is useful in various machines. Not only does an RCI stop the machine from exceeding its limits, it also makes life much easier for the machine operator.
Let’s give you a couple of examples.
Here is some of the fundamental information a crane driver and piling rig driver will see on their monitor:
Cranes
Weight readings
Apart from stopping cranes from being overloaded, there are many reasons why a crane driver should always have an idea of what weight the load that they’re lifting is.
- To not overload lifting accessories
All lifting accessories, like chains, slings, clamps, etc, have a Safe Working Load (SWL) limit. If the load being lifted exceeds what the accessory can safely take, there is a risk of the accessory breaking.
This could be catastrophic if the accessory breaks while the load it is holding is in the air.
- To not overload the crane
If cranes lift more than they’re configured for, there is a high risk of damage to the crane.
Some cranes are also prone to tipping over if overloaded. Although, most modern cranes are fitted with motion cut technology. This cuts the machine’s motions before it exceeds its safe capabilities.
- Jib deflection
Heavy loads can cause jib deflection. This can make the load swing outwards when lifted, which can be dangerous. So, knowing how heavy a load is can help the driver to deal with the jib deflection.
Height readings
- To not smash into the ground
Depth perception can be difficult to assess, particularly on tower cranes. If the driver has a reading to show when the load or hook is approaching the ground, they can slow the hoist down to avoid smashing the block or load into the ground, or worse, people on the ground.
- To not slew into obstructions
If a crane driver knows the height of a certain obstruction, they can make sure the hoist is above that obstruction when slewing.
For example, the balcony or platform on a building might be two floors up from the ground. When the driver goes to that area and sees that it’s 8-10m up from the ground, they can make sure the hoist is above 10m when repeatedly going to the balcony from the ground.
This can be useful for very tall cranes, because depth perception can be difficult to assess for tower crane drivers.
Speed and power
- Various cranes, such as crawler cranes, for example, travel on the ground. They have gauges to show how fast they’re travelling, plus the revs per minute that they’re using while they’re both traveling and lifting.
Wind speed
- Wind has a huge factor in lifting operations. All lifting personnel should constantly monitor wind speed because certain loads are not permitted to be lifted in high winds. Operating cranes in high winds can be extremely dangerous.
Here are two screen options from the same tower crane.
Different crane models show different information.
Piling rigs
Speed and power
- Rpm
This can mean two things, depending on the model of the machine.
- Rotations per minute – As the rig drills, this feature indicates the speed at which it is spinning.
- Revs per minute – Shows the amount of engine revolutions per minute.
- m/min
When the rig drills down, this indicator shows the speed at which it goes down, in metres per minute.
- Torque and bar pressure readings
When drilling in hard ground, the torque and bar pressure increases.
Angles
- Inclinometer
This measures inclinations in ground level, as it will affect the angle at which the boom is when drilling.
- Boom angle
Indicates the angle of the boom, so that it can drill a pile at a true vertical.
Weight
- Crowd rope weight indicator
The amount of weight the crowd rope is holding.
- Main rope weight gauge
This measures how much weight the main rope is holding. The main rope holds the Kelly bar and auger. 10kN = 1T, 10kN = 2T, etc.
Height and depth
- Drive motor gauge
Indicates the height of the drive motor.
- Depth gauge
Shows the depth of the Kelly bar.
- Hole depth
This shows how deep the hole that has been drilled is. It’s useful for when different drivers take over drilling that specific hole.
Similarly to conventional cranes, piling rigs have limit switches to stop them operating outside of their capabilities.
Here are some examples:
- Sensors that stop the boom from going out too far. On uneven ground, the boom leaning forward too far could tip the machine over.
- Limit switches at the top and bottom of the mast to stop the drive motor.
- Anti-two block system to stop the equipment from running up into the sheeves.
What happens if an RCI doesn’t work?
If an RCI fails to work, measures that prevent incidents or injuries are reduced. For example, a crane’s hoist has an ‘upper limit’ that slows the hoist down when the hook approaches the jib. Without this feature in place, the hook block can smash into the jib when hoisting up at full speed, which could make the hook block detach from the ropes and crash down to the ground.
This is only one example of several potential catastrophes.
Also, if a monitor screen goes blank or gives faulty readings, the machine operator won’t have accurate figures to go by, which leads to guess work. Guess work should never be relied upon when operating heavy plant.
Conclusion
Technology is advancing at breakneck speed. This can only benefit all involved with using heavy machinery. Although, it’s important to not rely on the technology too much, in case it fails. As with most things, the more technology there is, the more that can go wrong.
Knowing the fundamentals, the basics, the old-school ways of operating machinery, will reduce the chances of incidents happening if the technology does fail. By the same token, it’s equally important to know what the technology is and how to use it, to get the best benefits. As well as knowing what to do when the RCI’s safety restrictions come into action.
Hopefully, this article has shed some light on that.
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