I have given away my National Fire Code and NEC manuals since I took early retirement. I did not plan on ever using them again, So, I gave them to some associates for reference.
As for OSHA, They have a web site, but it is very difficult to zero in on anything particular. They tend to run one around in circles.
I do not remember which sections, sub-sections, etc. which related to machine tools. Sorry.
You might be able to reference something to the Emergency Stop regulations, as I think that they are related. The reason being that some robotic installations have secure perimeters in that if one breaks a security beam, or enters an area while the robot is in motion, that everything comes to a screeching halt. I am not sure, and have tried to forget everything about work, as I have been away from all systems for 25 months.
I think it doesn't really matter about the limits on a small stepper driven system as the stepper could be stalled easily, but when dealing with powerful commercial machines and equipment with servo's, it's a different ballgame. If an encoder fails to send pulses back to a 50 HP servo, then the system sees it as the system has not moved, and more voltage and/or current is supplied to the system so it will move. When an axis crashes at 500 IPM, I believe that the other axis would totally destroy the million dollar machine if they were still allowed to continue on with the machining program. I have seen a similar accident happen with the operator's hand on the E-stop pushbutton. He pressed the E-stop, but his reaction time was too slow. Just an observation.
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