Ok, so the headline is a bit off-putting to anyone who operates a crane. But during our time showing companies how to better use their knuckle boom HIAB crane, we have seen many “interesting” outrigger pads that we will not allow to be used during our training.
In Alberta, this is what OH&S says:
“Despite section 88, an employer must ensure that a mobile crane equipped with outriggers is set up with the outriggers on load-bearing floats or pads that are of adequate size, strength and rigidity.”
What we see:
- 2×4 lumber with long bolts holding it all together – WRONG (bolts will bend and 2×4’s will deteriorate quickly)
- 18″ x 18″ x 1″ plastic pads that are now “cupped” – WRONG (plastic is fine but you MUST turn the pad each time)
- 10″ diameter x 3″ thick pads – WRONG (places too much ground pressure beneath outrigger shoe (float)
So, how do you know how much weight is being placed on your outrigger pad? This artcile – click HERE, sumarizes how to do the math and you SHOULD do the math.
On a knuckle picker (HIAB, Palfinger, etc), you typically have a smaller crane lets say a HIAB 144 series crane, mounted on an international chassis with a 16′ flat deck, lets break it down for the owner of this truck who just bought that nice crane and got a set of spanky new black plastic outrigger pads on it this is what you sholud be using:
A reasonable approximation for maximum ground pressure (worst case) applied by the outrigger is:
Pressure (tons per ft2) applied by outrigger =
0.85 x total crane mass + maximum crane capacity
individual outrigger area
So…add your own numbers and then do the math, chances are, your outrigger pad is likely NOT up to the task of holding your crane upright, on smaller pickers that only have one set of outriggers, this can clearly be a game changer. When a company offers you a stability package that makes the crane truck more expensive, that is something you want, not removed!
Why not give us a call, we can do the math for you for free, then supply you with the correct outrigger pads for your requirements based on a series of questions you need to answer…simple! To look at our outrigger pads, click HERE.