Q: “My question is in regards to the turning barrel of a “tumbler”. Does this need to have a shroud or guard to keep people from making contact with it? We have the shafts, ends and transmission parts completely covered.”
A: “Revolving barrels, containers, and drums must be guarded by an enclosure interlocked with the drive mechanism, so the barrel, gun, or container cannot revolve unless the guard enclosure is in place.”
Barrels, Containers, and Drums - 29 CFR 1910.212(a)(4)
Now, here’s how this may look in practice...