Temporary Instrumentation and Controls Bypass - Fundamental Intent | AIChE

Temporary Instrumentation and Controls Bypass - Fundamental Intent

Last updated May 18, 2021 | Element: Fundamental Intent

To identify and manage bypassing of instrumented safeguards on process equipment, which are designed to pre-vent fires, explosions, or toxic releases that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts. 

Instrumented safeguards execute many types of functions, such as reactive or permissive inter-locks, operator response to alarms, fire and gas systems, and safety instrumented functions. Bypassing (also referred to as “impairing”, “suppression” in the case of alarms, or “jumpering” for electronic circuit bypassing of field devices) the safeguard’s function or a device used by the safeguard may impair or eliminate the safeguard’s ability to prevent or mitigate the hazardous event.

Example activities that might require use of a Temporary Bypass or Jumpering of Instrument-ed Safeguard SWP, a pre-authorized bypass procedure, or a temporary MOC: 

Process Start-up Activities

  1. Bypassing low flow pump safeguard     
  2. Bypassing low level safeguards on tank inlet valves     

Automation Asset Integrity Activities

  1. Bypassing safeguard device to investigate poor performance and repair if necessary
  2. Bypassing safeguard device for scheduled testing

Other Bypassing Activities

  1. Any other bypassing of safeguard functions or devices while protected equipment is not in an inherently safe state
  2. Operating with a failed instrument
  3. Operating with degraded functionality