CONCEPT DEMONSTRATION
66Phillips 66Vessel Integrity Intelligence
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V-1158 — Steam Drum V-1158

Sulfur Recovery Unit · Steam service · Installed Aug 31, 1988 (38 yrs in service)

High
Current Min. Thickness
0.062 in
t-min 0.130 in
Measured Corrosion Rate
5.06 mpy
ML-predicted: 5.47 mpy
Remaining Life
0.0 yrs
Next Inspection Due
Feb 20, 2027
Interval: 0.5 yrs (API 510)

UT Thickness Trend

Minimum CML reading per inspection vs. ASME Sec. VIII t-min

Vessel Specification

MaterialSA-240-304L Stainless
Design CodeASME BPVC Section VIII, Div. 1
Joint Efficiency1.00
Design Pressure60 psig
Design Temperature462 °F
Operating Pressure43 psig
Operating Temperature372 °F
Diameter72 in
Nominal Thickness0.254 in
Corrosion Allowance0.0938 in
H2S / Chloride20 / 148 ppm
Flow Velocity17.2 ft/s
Process pH6.56
InsulatedYes

Corrosion & Remaining-Life What-If

Adjust operating conditions to see the live model-predicted corrosion rate and implied remaining life

Live Prediction — What-If Model
5.70 mpy
Predicted corrosion rate under these conditions (+0.64 mpy vs. current measured rate)
Implied Remaining Life
0.0 yrs
Implied Reinspection Interval
0.5 yrs

What-if model: standardized Ridge regression, R² 0.56 on held-out fleet data (3.25 mpy MAE). Runs entirely client-side for instant feedback — see Model Insights for the full fleet-scale ensemble model used for official predictions.

Governing Damage Mechanism — Corrosion Under Insulation (CUI)

API 571 §4.3.5

Localized external corrosion beneath insulation where moisture is trapped, most severe in the 140–250°F operating band.

Recommended inspection approach: Insulation removal at high-risk locations (nozzles, low points), profile radiography, or guided-wave UT screening per API 570/RP 583.

Inspection History

UT thickness readings, most recent first

DateMethodCML CountAvg ThicknessMin CML Thickness
Aug 22, 2026UT Spot40.0657 in0.0624 in
Jan 4, 2026UT Grid (API 572)40.0671 in0.0563 in
Mar 12, 2023UT Grid + RT40.0798 in0.0770 in
Feb 1, 2021UT Grid (API 572)40.0913 in0.0789 in
Sep 7, 2019UT Grid (API 572)40.0962 in0.0847 in
May 21, 2017UT Grid (API 572)40.1090 in0.1076 in
Mar 25, 2015UT Grid (API 572)40.1218 in0.1150 in
Feb 10, 2013UT Spot40.1302 in0.1154 in
Aug 29, 2010UT Spot40.1480 in0.1284 in
Jun 26, 2007UT Grid (API 572)40.1603 in0.1590 in
Nov 29, 2005UT Grid (API 572)40.1674 in0.1664 in
Mar 26, 2004UT Grid + RT40.1763 in0.1743 in
Jun 10, 2001UT Spot40.1908 in0.1821 in
Apr 7, 1998UT Spot40.2075 in0.1878 in
May 1, 1996UT Grid + RT40.2196 in0.2186 in
Nov 15, 1994UT Spot40.2238 in0.2204 in
Nov 24, 1991UT Grid + RT40.2398 in0.2203 in