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Translator #1: Safety Bypass with Visual Notification

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  • The Standard: 
    • ANSI B11 risk reduction principles recognize that certain operating modes—such as setup, maintenance, troubleshooting, or adjustment—may require a safety function to be intentionally bypassed under controlled conditions. When a bypass is permitted, it should be authorized, limited to the intended purpose, and accompanied by appropriate protective measures so personnel are aware the machine is operating differently than during normal production. (See the applicable ANSI B11 machine-specific standard and the general risk reduction principles in the ANSI B11 series.)
      • Note: Exact bypass requirements vary by machine type and the applicable ANSI B11 standard. Always consult the specific standard governing your equipment.
  • The Practical Translation:
    • A safety bypass should never become an invisible condition.
    • If a guard interlock, light curtain, scanner, or other safety device has been intentionally bypassed, anyone approaching the machine should have a clear indication that the machine is operating in a different mode. 
    • That indication may include a flashing beacon, HMI status message, illuminated bypass indicator, or another readily recognizable visual notification appropriate for the application. Visual indication does not eliminate the hazard—it helps communicate that normal safeguarding has been intentionally altered while other risk reduction measures are in effect.
    • Ask yourself:
      • Would maintenance immediately recognize the machine is in bypass mode?
      • Could an operator mistake the machine for normal production?
      • Is the bypass limited to authorized personnel and specific operating modes?
      • Is the bypass automatically removed before returning to normal operation?
  • The Takeaway:
    • A visual notification doesn't make a bypass safe—it makes the condition visible.
    • The goal is to reduce the likelihood that someone unknowingly interacts with a machine operating under different safeguarding conditions.
  • Applicable Standards (depending on machine type and application):
    • ANSI B11.0 – Safety of Machinery (general risk assessment and risk reduction principles)
    • Applicable ANSI B11 machine-specific standard (for example, B11.19 where relevant to safeguarding performance requirements and other B11 standards as applicable)
    • Other applicable standards such as NFPA 79 or ISO 13849 may also apply depending on the machine and control system.
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