Marathon Petroleum / Garyville, LA
Marathon Refinery — Unit 10 Revamp
Revamp of crude unit 10 with new charge pumps and upgraded ICSS.
Systems
3
Subsystems
6
Open A
2
Open B
1
MC83%
RFSU53%
Comm.37%
Handover12%
Learn: Systemization
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Systemization
Showing 3 of 3
20-IAInstrument Air SystemCriticalMechanical
Plant and instrument air generation, drying and distribution.
Code
Subsystem
Discipline
MC
RFSU
Comm
Handover
20-IA-001
IA Compressor Package
K-2001A, K-2001B
Mechanical
mc
rfsu
comm
turnover
20-IA-002
IA Dryers
D-2010, D-2011
Mechanical
mc
rfsu
comm
turnover
20-IA-003
IA Distribution Network
L-200-IA
Piping
mc
rfsu
comm
turnover
10-PUMCrude Charge PumpsHighMechanical
Main crude feed pumps to the distillation column.
Code
Subsystem
Discipline
MC
RFSU
Comm
Handover
10-PUM-001
P-1001 A/B Train
P-1001A, P-1001B
Mechanical
mc
rfsu
comm
turnover
70-ICSSICSS / DCSCriticalInstrumentation
Integrated Control & Safety System cabinets, marshalling, network.
Code
Subsystem
Discipline
MC
RFSU
Comm
Handover
70-ICSS-001
ICSS Cabinet Room
UCP-01, UCP-02
Instrumentation
mc
rfsu
comm
turnover
70-ICSS-FG-10
F&G Loops Unit 10
FG-10-LOOPS
Fire & Gas
mc
rfsu
comm
turnover
All changes saved
Why this matters
Systems carve the plant into commissioning packages. Subsystems are the smallest units that can be walked down, energised, and turned over independently. The breakdown drives MC, RFSU, commissioning sequence, and operations acceptance.
Common field problems
Boundaries follow P&IDs only — ignoring constructibility; utilities not split first; ICSS loops span multiple subsystems creating turnover deadlocks; vendor packages lumped with field-erected scope.
Best practice
Split utilities (IA, N₂, cooling water, electrical) ahead of process; align subsystem boundaries with isolation valves and electrical breakers; lock the SBS in the project's Master Tag Register before walkdowns begin.