- Representative OEM workflow only; no customer identity or unsupported performance claim is included.
- The vessel relief basis comes before valve model selection.
- Final acceptance requires the applicable code edition, verified calculation and approved project specification.
- The deliverable package links the vessel tag, valve tag, datasheet, sizing basis, drawings, MTC and test reports.
››› Case Scope
The OEM needs one traceable chain from vessel design data to valve release
Pressure-vessel manufacturers often receive process data, relief calculations, client specifications and documentation requirements from different parties. The safety valve package must reconcile these inputs before the vessel is completed, nameplated, inspected or shipped.
This example uses a generic process or utility vessel and focuses on the review method rather than a specific capacity, pressure or material. The same structure can be adapted to receivers, separators, surge drums, accumulators, filter housings, storage vessels and packaged skid vessels.
Project-control principle
A safety valve should not be approved from nominal inlet size or set pressure alone. The governing relief case, required relieving rate, certified capacity, inlet pressure loss, outlet back pressure, materials, pressure-temperature rating and documentation scope must agree with the vessel design basis.
››› OEM Input Package
Information required before technical selection begins
The fastest OEM review begins with a controlled input package rather than a model-number request.
01
Vessel Datasheet
Tag, service, volume, MAWP or design pressure, design temperature, nozzle details, code basis and materials.
02
Relief Scenario and Load
Blocked outlet, fire, regulator failure, compressor or pump upset, tube rupture, thermal expansion or reaction case with required capacity.
03
Process Conditions
Medium composition, phase, molecular weight or density, relieving temperature, relieving pressure and viscosity where applicable.
04
Installation Conditions
Inlet piping, outlet piping, discharge destination, superimposed and built-up back pressure, support and drainage.
05
Mechanical Specification
Inlet and outlet size, flange or thread standard, pressure class, facing, body, trim, seat, spring and bellows requirements.
06
Documentation and Inspection
Applicable standards, ITP, witness points, MTC type, test reports, drawings, certificates and final dossier index.
››› Relief Case Review
The largest credible case controls capacity, but other cases can control design details
An OEM review should retain all credible cases, identify the governing capacity case and record any secondary case that changes temperature, phase, material or discharge requirements.
01
Blocked Outlet or Closed Valve
Maximum upstream inflow enters the vessel while the downstream route is restricted. Confirm source capacity, fluid phase and downstream pressure.
02
External Fire Exposure
For applicable liquid-containing vessels, review wetted area, insulation, drainage, fluid properties and flare or vent-system capacity.
03
Regulator, Compressor or Pump Failure
Protect the lowest-rated downstream boundary against credible maximum source pressure and flow.
04
Heat Exchanger Tube Rupture
Review the high-pressure source, low-pressure side, transient flow, phase change and downstream disposal path.
05
Thermal Expansion
Small blocked-in liquid volumes can develop very high pressure; verify whether a separate thermal relief device is required.
06
Reaction or Gas Generation
For reactive vessels, define gas generation, vaporization, foaming, two-phase flow and emergency cooling assumptions.
››› Selection Basis
Convert the approved relief basis into a reviewable valve specification
After the governing load is approved, the OEM can evaluate required area, selected orifice, certified capacity, valve type, materials, pressure class and installation conditions. The valve datasheet should show the assumptions used for that selection.
Selection checkpoints
- Set pressure and allowable overpressure match the vessel code basis
- Required relieving load and calculated area are documented
- Selected orifice and certified capacity exceed the requirement
- Valve design is suitable for constant and variable back pressure
- Body, trim, seat and bellows materials suit the medium and temperature
- Inlet and outlet connections match nozzle and piping specifications
- Pressure-temperature ratings are valid at relieving conditions
- Inlet pressure loss and outlet piping are included in the installation review
- Required test, certificate and inspection records are listed before purchase
››› Valve Design Review
Typical design choices considered during an OEM project
The correct choice depends on the actual pressure profile, operating margin, medium and project specification.
01
Conventional Spring-Loaded
Suitable when back pressure is low and stable within verified valve limits. Simpler construction and documentation.
02
Balanced Bellows
Consider when superimposed or built-up back pressure can affect a conventional valve, or when the spring chamber should be isolated from outlet fluid.
03
Pilot-Operated
May support higher operating-pressure margins or different back-pressure conditions, subject to pilot cleanliness, sensing and service compatibility.
››› Project Documentation
The valve package should be ready for OEM review, client review and final handover
Document titles and scope should be agreed before order release so the final dossier is not assembled from incomplete or unrelated files.
01
Approved Valve Datasheet
Tag, service, set pressure, size, class, orifice, capacity, materials, accessories and standards.
02
Sizing and Capacity Record
Relief case, required capacity, calculated area, selected orifice, certified capacity and correction factors.
03
General Arrangement Drawing
Dimensions, center-to-face, flow direction, lifting and vent details, connection data and weight.
04
Material Certificates
Component material grade, heat or batch traceability and the required EN 10204 document type.
05
Routine Test Reports
Set-pressure calibration, shell pressure test, seat-tightness test and inspection release records.
06
Certificate and Compliance Index
Applicable certificate scope, product documents, revisions and final manufacturing-record-book index.
››› Inspection and Release
Release the valve against the agreed ITP and document index
The OEM should identify hold, witness and review points before manufacture. Final release confirms that the supplied valve, nameplate, seals, reports and drawings match the approved vessel item.
Where ASME certification or another conformity route is specified, the responsible parties must confirm the exact scope and marking requirements. A generic ASME reference should not be used as a substitute for the applicable certification status.
Release checklist
- Valve tag and serial number match the vessel document index
- Nameplate data match the approved datasheet
- Set-pressure and test reports identify the supplied valve
- Material certificates trace specified components
- Flanges, facings and dimensions match the vessel nozzle and piping class
- Accessories, seals, lever, bellows vent or pilot tubing match the drawing
- Open punch items and deviations are formally closed
- Final approved revisions are included in the handover package
››› OEM Project Workflow
Eight steps from vessel data to final valve dossier
The workflow creates a traceable approval path and reduces late changes during vessel inspection or shipment.
01
Confirm vessel design basis
Lock the tag, MAWP, temperature, code, nozzle and client specification.
02
Approve relief scenarios
Document all credible cases and identify the governing required capacity.
03
Complete sizing review
Calculate area and select an orifice using the approved fluid and pressure data.
04
Select valve construction
Choose conventional, bellows or pilot design plus seat, materials and connections.
05
Review installation
Confirm inlet loss, outlet back pressure, discharge route, support and drainage.
06
Approve drawings and documents
Close datasheet, GA, calculations, certificates and ITP comments.
07
Witness or review tests
Complete the required calibration, pressure, seat-leakage and inspection activities.
08
Release the final dossier
Link the delivered valve to the vessel tag and approved document index.
››› OEM RFQ Package
Send the vessel data and document requirements before requesting a quotation
A complete enquiry lets the supplier include the correct engineering, testing, inspection and documentation scope in the quotation. Late additions can change cost, lead time and the feasibility of third-party witness requirements.
Recommended enquiry documents
- Vessel datasheet and equipment tag list
- Relief calculation or required relieving rate
- P&ID and inlet/outlet piping information
- Client valve datasheet or project specification
- Connection, material and pressure-class requirements
- Applicable ASME, API, ISO, EN or local code edition
- Inspection and test plan
- Certificate and manufacturing-record-book index
- Quantity, destination and required delivery date
- Existing valve data for replacement or standardization projects
››› Related Engineering Resources
Continue the pressure-vessel safety valve review
These links use current ZOBAI pages that support the case workflow.
01
Pressure Vessel Applications
Review vessel types, relief cases and typical RFQ data.
02
API 520 Safety Valve Sizing
Connect the required relief load to area, orifice and certified capacity.
03
ASME Safety Valve Standards
Review the ASME BPVC and overpressure-protection context.
05
Type Test Certificates
Review design-validation evidence and certificate scope.
››› FAQ
Common questions about pressure-vessel OEM safety valve projects
No. It is an anonymized representative OEM workflow showing how pressure-vessel safety valve inputs, selection and documentation can be organized. It does not claim a specific customer, order quantity or project result.
The review normally requires the vessel datasheet, MAWP or design pressure, temperature, credible relief scenarios, required capacity, fluid properties, back pressure, connection requirements, materials, code basis and document list.
No. Nozzle size confirms only part of the mechanical connection. The valve must also satisfy the required relieving capacity, set pressure, fluid and temperature conditions, certified capacity, back pressure and applicable code.
Typical documents include the approved datasheet, sizing and capacity record, general arrangement drawing, material certificates, set-pressure report, shell pressure test, seat-tightness report, inspection release and final document index.
They should be agreed before manufacture or purchase-order release. Third-party witness, EN 10204 3.2 validation or special testing may not be recoverable after production is complete.
Yes. Send the vessel datasheet, relief basis, valve specification, piping information and required documents. The review can identify missing inputs and the next sizing, selection or quotation step.
Need an OEM safety valve package for a pressure-vessel project?
Send the vessel datasheet, relief calculation, valve specification, piping conditions and document list. ZOBAI can identify missing inputs and define the next engineering, inspection or quotation step.