Optimizing FOX and SOX

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FOX and SOX Infographic

If you wander into a CAP maintenance and reliability meeting, for a moment you may think you’re in a Dr. Seuss discussion group as you hear water professionals speaking in serious tones about FOX and SOX. But if you listen closely, you’ll quickly realize that these are two critical metrics in CAP’s award-winning maintenance program.

To explain, we’ll start at the beginning, with operational availability…OA for short. OA is the amount of time that CAP’s pumps are available to operate. There are 109 pumps in the system; each has 8760 available hours per year (24 hours a day x 365 days in a year). All annual statistics are percentages of that baseline OA number of 8760 hours.

SOX, or Scheduled Outage Factor, is a percentage of time that a pump unit is unavailable due to planned and scheduled maintenance. CAP works to achieve a SOX rate of 10%-15%.

FOX, or Forced Outage Factor, is the amount of time a pump unit is unavailable due to unanticipated breakdown or other emergency reason.  CAP works to achieve a FOX less than 2%.

“In a perfect world, there would be no forced outages and minimal scheduled outages, but that’s not how it works,” said Brian Buzard, Centralized Maintenance & Reliability Director. “Conventional wisdom is that if you back off scheduled maintenance, then you’ll see rise in forced outages and if you do too much maintenance, you risk inducing a failure.”

Obviously, not all pumps are scheduled to run all the time, even if they’re available. So, we also watch Service Factor (SF), which is the amount of time the unit was in service and running during the measurement period. This number is variable and dependent on water demand, power demand, SOX and FOX. Although we track OA and SF, they are not metrics that have goals attached to them; they are indicators of the effectiveness of our SOX and FOX. 

All of this data and corresponding metrics are used to help CAP’s maintenance achieve balance, combining technology with traditional work in the field.

OA data is collected electronically by use of Programmable Logic Controllers (PLCs), a small electronic computer that monitors various pieces of equipment in the field to ensure that all pumping unit shutdown events are captured. The PLC is programmed to identify changing conditions of the equipment and automatically send commands to the equipment that is being monitored.  

Preventive maintenance (PM) and condition assessments are completed by expert craftsmen, making sure that all work is completed within the carefully scheduled time. 

Why so much focus on FOX and SOX? It measures how effectively the Maintenance Department is keeping the equipment available to operations. This group produces one of CAP’s most valuable commodities.

“In the reliability group, operational availability is our product, our widget,” said Buzard. “We produce capacity and reliability within the CAP system.”

Here are a few terms to have at the ready the next time you find yourself discussing FOX and SOX:

  • FOX (Forced Outage Factor): the percent of time a pump unit is unavailable due to unanticipated breakdown or other emergency reason, based on 8760 hours per year
  • SOX (Scheduled Outage Factor): the percent of time that a pump unit is unavailable due to planned and scheduled maintenance, based on 8760 hours per year
  • OA (Operational Availability): the percent of time that CAP’s pumps are available to operate, based on 8760 hours per year
  • SF (Service Factor): the percent of time a pump unit actually ran, based on 8760 hours per year
  • PLCs (Programmable Logic Controllers): a small electronic computer that monitors various pieces of equipment in the field to ensure that all pumping unit shutdown events are captured.

PM (Preventive Maintenance): the regular and routine maintenance of equipment and to ensure reliability and prevent unplanned downtime from unexpected equipment failure