Black steel

scaffman1

scaffman1

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We still have black steel in stock, can anyone tell me why it does not conform to TG20:08?
 
TG20 ? i could be wrong but seem to remember that black steel has basically albeit a small % the same qualities as galvanised tube , as the come off the same roll @ the mill, the qalvanisation process is done afterwards,and is only there to stop the rusting and purely asthestics, black tube can still be bought to order today but only a few pennies cheeper than galv, although once the black tube starts to badly pitt through rust it most be withdrawn from normal scaffolding use but can still be used for non loading jobs such as treepro/site handrails etc, we still have some we use for this purpose
 
When checked on the cads system that we use it states that black steel is not recommended by TG20

We have a job on the go,and there are a few black steel tubes in it and some inspector has been there and has put on his report that the scaffold is partly erected from black steel tube and that they should be changed immediately.
But having looked at our TG20 report (even if the whole job is black steel)it would not fail.

###***~~ is what I have to say.:(:nuts::nuts:
 
Section 39.5 & Table 17 of TG20:08 Vol. 2 give values for used tube with corrosion allowance, whereas galvanised tubes in good condition are considered "as new". Table 17 assumes a maximum reduction in wall thickness of 0.4mm (from 4.0mm down to 3.6mm) which gives a subsequent reduction in safe working bending moment of 12%.

'Black steel' tubes definitely conforms to TG20:08 provided they are in serviceable condition. However, the reduction of up to 12% in load-bearing capabilities (depending on corrosion) should be kept in mind when using the safe height tables etc, and calculations for design scaffolds should adhere to the lower values given in Table 17 as a worst-case scenario.
 
mark87 said:
Section 39.5 & Table 17 of TG20:08 Vol. 2 give values for used tube with corrosion allowance, whereas galvanised tubes in good condition are considered "as new". Table 17 assumes a maximum reduction in wall thickness of 0.4mm (from 4.0mm down to 3.6mm) which gives a subsequent reduction in safe working bending moment of 12%.

'Black steel' tubes definitely conforms to TG20:08 provided they are in serviceable condition. However, the reduction of up to 12% in load-bearing capabilities (depending on corrosion) should be kept in mind when using the safe height tables etc, and calculations for design scaffolds should adhere to the lower values given in Table 17 as a worst-case scenario.
Click to expand...

Cheers mark,we had some lads on site there today and I was told that there were around fifteen black steel tubes on the job,and most of them were as transoms. The job was only two lifts high in any case !!!
 
You would be surprised how many scarf don't know the difference from black blue and red apart from the obvious
 
It's fine but you're supposed to avoid mixing them and putting them under too much strain I believe.
 
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