Oil-Injected Screw Gas Compressor Package: EPC-Ready Delivery Guide
Key Takeaways
- Battery limits must be frozen at kickoff — scope boundary drift on compressor packages cascades into rework across mechanical, E&I, and controls.
- Gas data is not optional input — composition envelope, dew point, and operating cases drive auxiliaries, protections, and material selection. No TBDs past purchase order.
- FAT is a schedule gate, not a factory tour — issue the FAT procedure and witness plan at M4, and ship only after the Vendor Data Book is closed with traceable evidence.
Overview: Why Compressor Packages Require Early Lock-In
The schedule risk on oil-injected screw compressor packages usually is not welding steel — it is scope boundary drift, datasheet TBDs, and FAT evidence arriving late. Unlike static equipment, a compressor package integrates mechanical, electrical, instrumentation, controls, and process disciplines within a single skid boundary. A TBD in any one area propagates through the others.
This guide helps EPC teams lock interfaces early and release shipment with traceable evidence. The structure follows the standard gate-based delivery sequence used on petroleum, petrochemical, and gas industry projects.
Applicable Standards
Correct standard selection prevents scope drift and specification mismatches at the RFQ stage.
| Standard | Scope | Notes |
|---|---|---|
| ISO 10440-1 | Directly scoped for dry and oil-flooded helical-lobe rotary compressors in petroleum, petrochemical, and gas industry services (special-purpose applications) | Primary reference for process gas services |
| API Std 619 | Rotary-type positive displacement compressors for similar services | Commonly referenced alongside ISO 10440-1 in EPC specifications |
| ISO 13631 | Packaged reciprocating gas compressors — not screw | Do not specify for screw compressor packages |
| API 617 | Axial and centrifugal compressors — not positive displacement | Do not specify for screw compressor packages |
Standard selection matters at RFQ: Specifying the wrong code basis (e.g., ISO 13631 for a screw machine) creates exceptions lists, clarification rounds, and re-quotation cycles before technical alignment is even reached.
Typical Package Scope
Final scope boundary is defined per RFQ and kickoff minutes. The following reflects a standard skid-mounted oil-injected screw compressor package.
- Compressor + driver: Motor and VFD/starter boundary defined. Coupling guard, alignment plan, vibration monitoring included.
- Oil system: Oil separator, oil cooler, filters, oil piping and instruments. Cleanliness and flushing scope documented.
- Gas cooling and separation: Aftercooler, suction scrubber, discharge separator — skid-mounted or standalone per project scope.
- Controls and safety: PLC/HMI, alarms, trips, interlocks. ESD interface definition and protocol mapping per project.
- Skid frame and handling: Structural steel base with lifting lugs, COG marking, transport restraints. Ready for site crane lift.
Why These Packages Slip Schedule
EPC delays on screw compressor packages are caused by the same few root causes, project after project.
| Root Cause | Impact | Prevention |
|---|---|---|
| Battery limits not frozen | Tie-ins, cabling, vent routing change late — rework cascades across disciplines | Freeze at kickoff with signed boundary table |
| Gas data TBD | Auxiliaries and protections get redesigned mid-fabrication | Lock composition envelope + dew point before PO |
| FAT not treated as a schedule gate | “Tested” but not closable; witness windows missed | Issue FAT procedure + witness plan at M4 |
| Data book cannot close | Shipment or site receiving blocked by missing records | Agree document register at kickoff; track weekly |
The schedule risk on oil-injected screw compressor packages usually is not welding steel — it is scope boundary drift, datasheet TBDs, and FAT evidence arriving late.
Datasheet Inputs EPC Must Freeze
These inputs drive scope stability more than most teams expect. No TBDs are allowed past the purchase order gate.
- Gas composition: Normal + upset envelope, contaminants, liquids carryover assumptions. Not one “nominal” number — define the range.
- Dew point / condensation: Define the condensation risk envelope. Drives material selection and separator sizing.
- Operating cases: Min / normal / max, recycle, standby, hot restart assumptions. Each case affects valve sizing and control logic.
- Noise and vibration: Include measurement point location and boundary expectation. Often missed until site commissioning.
- Site constraints: Area classification, ambient conditions, utilities (power / cooling / drains / vent destination).
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Scope Boundary Table (Battery Limits)
Use this in your RFQ and kickoff minutes. Lock vendor vs EPC/site responsibilities before fabrication begins.
| Scope Item | Vendor (Skid) | EPC / Site | Lock Early Notes |
|---|---|---|---|
| Compressor + driver + skid base | VFD/starter boundary, voltage/frequency | ||
| Oil system (separator / cooler / filters) | Cleanliness/flushing scope and evidence | ||
| Gas cooling (aftercooler) | / Opt | / Opt | Cooling medium + fouling allowance |
| Suction scrubber / discharge separator | / Opt | / Opt | Decide skid vs standalone early |
| On-skid piping to tie-ins | Tie-in coordinates, flange rating, orientation | ||
| Instruments and tags | Ranges + calibration evidence | ||
| Control panel / PLC / HMI | Protocol, remote I/O, ESD ownership | ||
| Vent / flare header routing | Vendor provides loads; EPC routes | ||
| Electrical feeder to skid | Termination and cable responsibility | ||
| Foundations / civil | Vendor provides loads / COG / lifting plan |
FAT Plan — What We Test Before Shipment
A useful FAT is evidence-based and aligned to ship-release criteria. The FAT procedure is issued at milestone M4 with a witness plan. Third-party witness windows are scheduled in advance.
| FAT Area | What Is Verified | Evidence Required |
|---|---|---|
| Controls | Start/stop sequences, alarms, trips, interlocks, reset rules | Full loop test with documented records |
| E&I verification | I/O mapping, terminal schedule, point-to-point checks, communications tests | Signed I/O loop records |
| Instruments | Calibration verification for all tested loops | Traceable calibration certificates with serial numbers |
| Oil system | Level / temp / DP protections verified; cooler functional checks | Cleanliness evidence documented |
| Closeout | Punch list rules agreed; Category A items closed before release | FAT report with all evidence referenced |
Vendor Data Book (Turnover Package)
If EPC document control cannot close the register, the project schedule pays the price. Agree the index at kickoff and track it weekly.
| Vol. | Contents |
|---|---|
| 1 | Final document register (status + revision history + transmittals) |
| 2 | Scope boundary + tie-in list + responsibilities matrix |
| 3 | Approved datasheet / basis of design (gas envelope + cases + unit system) |
| 4 | GA + loads + COG / lifting plan + access clearances |
| 5 | P&ID / schematic + line / valve lists |
| 6 | Compressor and driver docs (boundary, coupling/guard, alignment plan) |
| 7 | Oil system docs (schematic, specs, cleanliness / flushing notes) |
| 8 | Electrical: SLD / wiring / terminal schedule |
| 9 | Controls: I/O list, C&E, interlock list, comms mapping |
| 10 | ITP + hold/witness records + NCR disposition |
| 11 | FAT procedure + FAT report + calibration records |
| 12 | Preservation / packing + photo record + indicators / transport locks |
| 13 | O&M manual + spares + special tools |
| 14 | As-built drawings + redline log + final tag verification |
Delivery Milestones Map (EPC View)
Gate-based delivery keeps ship release predictable and document control closeable.
| Gate | Milestone | Output |
|---|---|---|
| M0 | Kickoff | Battery limits + document register agreed |
| M1 | Datasheet Freeze | Gas envelope + interfaces locked. No TBDs allowed past this gate. |
| M2 | IFA Issue | GA / schematic / I/O issued for EPC review |
| M3 | AFC Release | Approved drawings released for fabrication / procurement |
| M4 | FAT Readiness | Pre-FAT pack issued + witness plan locked |
| M5 | FAT Complete | FAT report issued + punch close plan agreed |
| M6 | Ship Release | Preservation/packing evidence + final register complete + release note issued |
Shipping Readiness (Dynamic Equipment Focus)
Rotating equipment is damaged or delayed at receiving when shipping evidence is missing or incomplete. The following are required before ship release.
- Transport restraints: Transport locks installed and documented. Shaft locking devices in place with removal instructions tagged.
- Shock / tilt indicators: Applied with photo record. Threshold values documented. Provides evidence chain for insurance claims.
- Corrosion protection: Sealed openings + desiccant + VCI wrapping as applicable. Preservation procedure referenced in data book.
- COG and lifting points: Centre of gravity marked. Lifting points clearly identified with rated capacity. Lifting plan in ship-release package.
Summary
Oil-injected screw compressor packages are integration-intensive. The mechanical, electrical, controls, and process disciplines all share the same skid boundary — which means one unresolved TBD can freeze multiple work fronts simultaneously. The mitigation is not difficult: freeze battery limits at kickoff, lock the gas datasheet before purchase order, issue the FAT procedure at M4 with a real witness plan, and release shipment only when the Vendor Data Book is complete. Everything else follows from those four disciplines.
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Last reviewed: March 24, 2026 · Technical accuracy verified by Lmart Engineering Dept.
Frequently Asked Questions
What standards apply to oil-injected screw gas compressors?
ISO 10440-1 and API Std 619 are the primary references for oil-flooded helical-lobe rotary compressors in petroleum, petrochemical, and gas industry services. Do not confuse with ISO 13631 (packaged reciprocating) or API 617 (axial and centrifugal) — these are distinct machine types with different code requirements.
What is included in skid scope vs site scope for a compressor package?
Scope is defined in a battery limits table and tie-in list covering mechanical, E&I, and utility boundaries. The vendor typically supplies the compressor, driver, oil system, on-skid piping, instruments, and control panel. EPC/site handles vent/flare header routing, electrical feeder to the skid, and foundations. Agreeing this table at kickoff is the single most effective way to prevent mid-fabrication rework.
What gas data must be frozen to avoid redesign loops?
Gas composition envelope (normal and upset), contaminants, liquids carryover assumptions, dew point/condensation envelope, and all operating cases (min / normal / max, recycle, standby, hot restart) must be locked before purchase order. These inputs drive auxiliary equipment sizing, protection setpoints, and material selection. A single “TBD” in the composition envelope can require re-sizing the suction scrubber, re-selecting separator internals, and revising the control logic — all mid-fabrication.
What must be complete before ship release of a compressor package?
The FAT report must be issued with all evidence referenced. Punch list Category A items must be closed before release. Preservation and packing evidence must be complete with photo records. Transport restraints and shock/tilt indicators must be applied and documented. The final document register must show all required deliverables as issued, approved, and as-built. A Release-to-Ship statement is then issued referencing “documentation complete” criteria.
How does Lmart handle FAT for compressor packages?
Lmart issues a FAT procedure at milestone M4 together with a witness plan that schedules third-party witness windows in advance. FAT covers: controls testing (start/stop/trips/interlocks), E&I verification (I/O mapping, point-to-point), instrument calibration (traceable certificates), oil system protections (level/temp/DP), and closeout with a referenced evidence FAT report. Category A punch items are closed before ship release is authorized.
How is the Vendor Data Book structured for a compressor package?
Lmart’s standard data book is indexed in 14 volumes covering: document register, scope boundary and tie-in list, approved datasheet / basis of design, GA and lifting plan, P&ID and schematic, compressor and driver documents, oil system documents, electrical and controls documents, ITP records, FAT procedure and report, preservation and packing record, as-built drawings, and O&M manual. The index is agreed with EPC document control at kickoff.
Ready to Discuss Your Compressor Package Project?
Lmart delivers oil-injected screw compressor packages to ISO 10440-1 / API 619 with complete FAT evidence, EPC-ready Vendor Data Books, and ASME / PED dual-coded pressure components where required. Our engineering team responds within 24 hours and delivers budget proposals within 48 hours.