Hydrotest & Documentation: What EPCs Expect at Final Release
By Qiangbin Chu · Sales Manager & Operations Lead, Suzhou Lmart Energy Equipment
Key Takeaways
- A successful hydrotest alone does not authorize shipment — EPC teams require the complete documentation package before granting release.
- The final release gate has three pillars: hydrotest evidence, QA traceability pack, and document control closure (MDR/VDRL status).
- Projects commonly slip after hydrotest because "test performed" is not the same as "report issued and register closed."
- Lmart's standard final release package includes signed hydrotest report, calibrated gauge certificates, full MTR traceability, weld maps, NDE reports, and as-built drawings.
Why the Final Release Gate Matters More Than the Test Itself
Hydrotest is often the last big manufacturing gate — but EPC teams typically care even more about what happens after the test: report issuance, traceability, and final release package closure. A vessel that passes hydrotest but ships without complete documentation creates receiving problems, site quarantine delays, and potential re-inspection costs.
API 660 is a common reference for shell-and-tube heat exchangers in petroleum, petrochemical, and natural gas industries and includes testing and preparation for shipment in its scope. This guide maps out what EPC procurement teams should require before signing the release-to-ship authorization.
Hydrotest Evidence: The Minimum EPC Package
The hydrotest itself is governed by the applicable design code (ASME VIII Div.1 UG-99/UG-100, PED 2014/68/EU, or project-specific requirements). But beyond the test, EPC inspectors expect a complete evidence package that demonstrates the test was performed correctly and the results are traceable.
- Hydrotest procedure (approved by EPC/TPI if required by the purchase order)
- Calibrated pressure gauge and recorder certificates (valid calibration within the required window)
- Test pressure and hold time record — showing actual pressure, hold duration, and ambient temperature
- Witness sign-off by EPC inspector or Third Party Inspector (TPI) if required
- Leak and visual inspection results with disposition (accept/reject/repair)
Per ASME VIII Div.1 UG-99, the hydrostatic test pressure must be at least 1.3 times the MAWP (Maximum Allowable Working Pressure) multiplied by the lowest stress ratio. The test medium is typically water, and the hold time is generally 30 minutes minimum for pressure vessels. All readings must be recorded by calibrated instruments.
Traceability and QA Pack
Beyond the hydrotest report, EPC final release requires full traceability from raw material to finished equipment. This QA package forms the backbone of the Manufacturer's Data Report (MDR) and is critical for regulatory compliance, insurance, and future maintenance planning.
- Material Test Reports (MTRs) mapped to each pressure-retaining part — cross-referenced to heat numbers
- Weld map showing all production welds, welder identification, and WPS numbers
- Welder qualification records (WPQ) for all welders who performed pressure-retaining welds
- NDE reports: RT, UT, MT, PT as required by the design code and project specification
- NCR (Non-Conformance Report) register with all items closed and dispositioned
- Final dimensional check report (as specified in the purchase order or data sheet)
| Document | Purpose | Typical Requirement |
|---|---|---|
| MTR (Material Test Report) | Material traceability to heat/lot | EN 10204 3.1 or 3.2 per PO |
| Weld Map | Traceability of each weld joint | Welder ID + WPS number per joint |
| NDE Reports | Weld integrity verification | Per ASME V / project spec |
| Hydrotest Report | Pressure boundary verification | UG-99/UG-100 compliance |
| MDR (Form U-1) | ASME code compliance record | Signed by AI + manufacturer |
| NCR Register | Non-conformance closure evidence | All items closed before release |
Document Control Closure
The final piece of the release puzzle is document control — confirming that every required deliverable in the Vendor Document Requirements List (VDRL) or Master Document Register (MDR) has been issued, reviewed, and approved.
- Final document register (MDR/VDRL) showing status of all required deliverables
- As-built drawing issuance plan — confirming which drawings ship with equipment vs. follow later
- O&M manual (Operation & Maintenance) — required by most EPC contracts before release
"Test performed" is not the same as "report issued and register closed." EPC schedules need the paperwork gate as much as the shop gate.
Practical Release Gate Checklist
Before authorizing release to ship, EPC project engineers and inspectors should confirm the following four gates are cleared. This checklist can be copied directly into your project inspection plan.
- Do not release to ship until ALL four gates below are confirmed closed.
- Gate 1: Hydrotest completed and report issued — signed by manufacturer and witness (if required)
- Gate 2: NDE reports issued and any NCRs closed — no open non-conformances
- Gate 3: Document register shows all required items as "Issued / Approved / As-built"
- Gate 4: Packing and preservation evidence included for receiving inspection at site
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How Lmart Manages the Final Release Process
At Lmart, the final release process is managed through our ISO 9001-certified quality system. Each project has a dedicated document register established at kick-off, and all QA deliverables are tracked against the customer's VDRL throughout fabrication. Hydrotest reports are issued within 24 hours of successful test completion, and the full vendor data book is compiled and shipped with the equipment.
For projects requiring third-party inspection, Lmart coordinates directly with the customer's TPI or Authorized Inspector (AI) for ASME U-Stamp work. Our QA team maintains real-time document status tracking so customers can verify documentation completeness before the release-to-ship meeting.
Summary
A successful hydrotest is a necessary but not sufficient condition for final release. EPC teams must verify three pillars before authorizing shipment: complete hydrotest evidence with calibrated instrument records, full QA traceability (MTRs, weld maps, NDE, NCR closure), and document control closure showing all required deliverables issued and approved. Treating the documentation gate with the same rigor as the shop gate prevents the most common cause of post-hydrotest schedule slippage.
Lmart holds ASME U-Stamp, PED/CE, and 6 classification society approvals (DNV, BV, CCS, ABS, LR, NK).
103-mu campus in Zhangjiagang · 38,000 m² workshop · 300+ staff · 15,000 T/year capacity
Last reviewed: December 20, 2025 · Technical accuracy verified by Lmart Engineering Dept.
Frequently Asked Questions
Why do projects slip after a successful hydrotest?
Because "test performed" is not the same as "report issued and register closed." The most common cause of post-hydrotest delay is incomplete documentation — missing MTRs, unsigned NDE reports, or open NCRs. EPC schedules need the paperwork gate cleared with the same discipline as the shop gate. Establishing the document register at project kick-off and tracking it through fabrication prevents surprises at release.
What is the minimum hydrotest hold time per ASME VIII?
Per ASME VIII Div.1 UG-99(b), the minimum hold time for hydrostatic testing is 30 minutes for pressure vessels. During this period, the vessel is held at test pressure (minimum 1.3 times MAWP adjusted for stress ratio) while being visually inspected for leaks. The test pressure, hold duration, and ambient temperature must all be recorded using calibrated instruments with valid calibration certificates.
What documents should be included in the vendor data book?
A typical vendor data book for ASME pressure equipment includes: Manufacturer's Data Report (Form U-1), Material Test Reports (MTRs) per EN 10204 3.1/3.2, welding procedure specifications (WPS) and welder qualifications (WPQ), NDE reports, hydrotest report with gauge calibration certificates, dimensional inspection report, GA and as-built drawings, nameplate rubbing, and the O&M manual. The exact list is governed by the project VDRL.
Does Lmart support third-party inspection during hydrotest?
Yes. Lmart routinely coordinates hydrotest witness points with customer-appointed Third Party Inspectors (TPI) and ASME Authorized Inspectors (AI). Our facility in Zhangjiagang has dedicated inspection areas, calibrated test equipment, and on-site coordination staff. We issue formal hold/witness notification to inspectors per the approved ITP (Inspection and Test Plan) at least 5 working days before the scheduled test.
What happens if an NCR is still open at the time of hydrotest?
Open NCRs must be dispositioned and closed before final release authorization. If an NCR relates to a pressure-retaining component, it typically must be resolved before hydrotest. If the NCR is non-pressure-related (e.g., cosmetic or documentation), it may be accepted with a concession from the EPC project engineer, but this must be formally documented and agreed before release to ship.
What is the difference between MDR and VDRL?
The MDR (Manufacturer's Data Report, ASME Form U-1) is the code-required document certifying that the vessel was designed and fabricated in accordance with ASME VIII. The VDRL (Vendor Document Requirements List) is the project-specific document register that lists all deliverables the manufacturer must submit — including the MDR, drawings, calculations, test reports, and manuals. The VDRL is typically issued by the EPC at purchase order stage.
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