Section R. 408.14269 - Tumbling barrels and shot blastsRule 4269.
(1) A tumbling barrel shall have all of the following: (a) Have fittings to the barrel dust-tight or the barrel enclosed in a booth with an exhaust system as approved by the state department of licensing and regulatory affairs.(b) Be locked in place while being loaded or unloaded.(c) Have an interlocked barrier across the front before it can be started.(2) A shot blast cleaning chamber shall have doors, curtains including silhouettes, or guards to protect the operator.Mich. Admin. Code R. 408.14269