IIoT, SCADA & Edge Connectivity worked example

Alarm Rationalization Workload at 25% documentation, moc, and operator validation allowance: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop documentation, moc, and operator validation allowance to 25%, then walk the calculation through step by step. Estimate alarm rationalization hours from the alarm count to review, the team rate (alarms reviewed per hour against ISA-18.2), and an allowance for documentation, MoC, and operator validation.

The inputs for this scenario

  • Alarms to rationalize: 3,500 alarms (held at the documented default)
  • Team review rate: 10 alarms / hr (held at the documented default)
  • Documentation, MoC, and operator validation allowance: 25 % (the input this scenario stresses; the baseline uses 35)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base alarm rationalization hours = alarm count รท team review rate.
  • Required alarm rationalization hours works out to 438 hr at these inputs, and this is the headline figure for the scenario.
  • Base alarm rationalization hours works out to 350 hr at these inputs.
  • Documentation, MoC, and validation allowance works out to 25 % at these inputs.
  • Team review rate works out to 10 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where documentation, moc, and operator validation allowance sits at 35% and the headline result is 473 hr, this scenario comes in 7.41% below the baseline at 438 hr.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to documentation, moc, and operator validation allowance, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. The team review rate is highly site-specific; complex interlocked alarms or units with no existing alarm philosophy can drop the rate well below 10 alarms/hr, so calibrate against a pilot batch before committing to a schedule.

Results at a glance

  • Required alarm rationalization hours: 438 hr (headline result)
  • Base alarm rationalization hours: 350 hr
  • Documentation, MoC, and validation allowance: 25 %
  • Team review rate: 10 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Alarm Rationalization Workload calculator, set documentation, moc, and operator validation allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.