Stop treating alarms like advice

Spent my night chasing a low-flow alarm on a cooling loop that ping-ponged every 30 seconds. Everyone wanted a dashboard, I wanted a plug and a wrench. We found a partially collapsed suction hose and a clogged Y-strainer. The HMI logged 400 events. The pump logged 2 trips. Neither protected the asset. Well, there's your problem.

If an alarm requires an SOP, a reminder, and a hero, it is not an alarm problem. It is a design problem. Interlock it. Put a real differential pressure switch across the strainer, add a start permissive on minimum NPSHa, and give the pump a clean shutdown on low suction for 10 seconds, not 1. Add deadband and latching where it matters. Then you stop training operators to ignore noise.

We burn hours triaging nuisance faults instead of fixing the two-mechanical-things-per-line that always fail: loose mounts and dirty strainers. Anyone actually using ISA 18.2 style rationalization in brownfield plants, or do you just gut the alarm list during outage and move on? What simple interlocks have saved you the most grief?

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dee

Jul 9 at 11:00 AM

Same pain here: we killed 70% of cooling-loop chatter by adding a DP transmitter across the Y (latched at ~5 psid for 10 s), a start permissive on NPSHa (suction P + margin), and a low-flow recirc that opens before the pump cooks itself. Our ISA 18.2-lite in brownfield is a monthly bad-actor review - if an alarm lacks a defined operator action/time, it becomes an interlock or just an event. Gotcha to avoid: put DP taps on the strainer body and interlock the bypass closed, or maintenance isolations will trip you all night.

Stop treating alarms like advice

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