• Pressure difference was growing for control valve.

How SAM GUARD Helped

  • SAM GUARD identified a discrepancy between the opening position of the sensor, the set point, and the level. While the opening position declined, the other two remained stable.
  • SAM GUARD alerted initially on Oct 20, 03:07 and then again on Oct 22, 15:39.
  • The shift manager investigated the first reported event and added a note on Oct 21, 2019 00:34 saying: “pressure difference is growing. Suggest to check column level sensors.”
  • The senior engineer was asked to further investigate the event which eventually was affirmed and classified as “bad sensor.”


  • Several years prior to implementing SAM GUARD, a similar occurrence generated a huge flare event.
  • Flare events are the main concern of the plant as they produce protests, demands to shut down the facility and very bad publicity which forces them into crisis communication mode in order to overcome it.
bad sensor petrochemical plant use case