Stop Control Pushbutton Guarding

C

Cranetb_Newell

Member
Location
Newville, PA
Occupation
Electrical Engineer
We currently have some Start/Stop control stations on our Sorter Downlane conveyors to start and stop each individual downlane. When the manufacturer installed the system, they used the AB 800FP-E4PX01 for the Stop pushbutton, which has the extended head.

Unfortunately, the employees have been hitting the Stop pushbutton accidentally when grabbing the cartons off the line, so we wanted to protect the Stop Pushbutton in some way, likely replacing with either the G4PX01 (Guarded) or F4PX01 (Flush) versions of the pushbutton.

However, we are now getting pushback from our Safety Department that “Stop” pushbuttons need to have an extended head, be continuously operable, and readily accessible. They are quoting the following:
  1. ANSI B11.19 Section 9.4.1: "Normal stop function. Stop functions shall meet the requirements of NFPA 79."
  2. NFPA 79 Section 10.2.1: "Pushbutton Actuators. Pushbutton actuators used to initiate a stop function shall be of the extended operator or mushroom-head type."
  3. NFPA 79 Section 10.7.1.1: "Stop and emergency stop pushbuttons shall be continuously operable and readily accessible."
I think they are misreading the standards, and applying the rules for Emergency Stops to the basic Control System Start/Stop functionality. Can anybody cite any ANSI/NEC/NFPA code sections that would allow for guarding or recessing Stop pushbutton controls at operator control stations?
 
I had a problem with that in the Chocolate plant's molding line at the wafer placing stations. The operators were hitting the E stops when they were loading wafers so someone put a little wire loop around them as a guard. I think it was OSHA that had a problem with it. I watched how the wafer handlers moved and they were hitting them with their leg. I moved the E stop buttons about 8 inches over and everyone was happy.

Personally I want them to be easy to hit. When someone is getting pulled into the equipment, it's a panic situation. Panic makes people behave in funny ways and their ability to think goes all wonky
 
Joethemechanic said:
I had a problem with that in the Chocolate plant's molding line at the wafer placing stations. The operators were hitting the E stops when they were loading wafers so someone put a little wire loop around them as a guard. I think it was OSHA that had a problem with it. I watched how the wafer handlers moved and they were hitting them with their leg. I moved the E stop buttons about 8 inches over and everyone was happy.

Personally I want them to be easy to hit. When someone is getting pulled into the equipment, it's a panic situation. Panic makes people behave in funny ways and their ability to think goes all wonky
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Yes, I agree completely for E-Stop Situations, and there is an adjacent E-Stop to the Start/Stop control station for just that reason. This Start/Stop is attached to an unpowered roller conveyor, and only controls whether the upstream divert powered conveyor is running or not, where no personnel are stationed.
 
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Cranetb_Newell said:
Yes, I agree completely for E-Stop Situations, and there is an adjacent E-Stop to the Start/Stop control station for just that reason. This Start/Stop is attached to an unpowered roller conveyor, and only controls whether the upstream divert powered conveyor is running or not, where no personnel are stationed.
Click to expand...
I agree they are making a misinterpretation.
But good luck changing their minds.
 
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