Hydro-Fluoric (HF) Alky Unit Monitoring


Customer was sending NDT technicians to inspect the top of the HF Alky unit daily to monitor specific low spots to ensure wall loss did not exceed minimum required rate before outage planned in 6 mo. Now using system to correlate corrosion data to integrity operating windows (IOWs)


HF Alky Unit (HF Isostripper OVHD elbow), ~150F

  • 24” Sch. 40 … most piping is < ½” nominal wall but measured at ~0.300” with pitting and general “low spots”

Product Used

smartPIMS Cellular

  • smartPIMS LT Cellular w/ 8 dual element probes temporarily attached, managed by refinery maintenance
  • Monitoring interval: 12 hours
  • Data is monitored & trended daily using webPIMS
  • Installation time: 4 hours


Objectives achieved:

  • Safety – kept personnel from climbing & cumbersome inspection positions on tower
  • Economic – saved >$365K in inspection cost
  • Easy to install/monitor, accurate & semi-permanent solution