API · ASME · DIN · EN standard industrial valves
Steam Safety Valves
Steam safety valves guard boilers and steam headers, venting overpressure flashes before they can lift a vessel rating — sized on the inlet-by-outlet paired flanges that let a small inlet serve a larger discharge. The range covers a spring-loaded execution with bodies in cast iron, WCB, SS304, SS316 or ductile iron, a nozzle, adjusting ring, disc, guide sleeve and stem set in SS304 or SS316, under a carbon-steel bonnet and cap with a steel spring and stainless adjusting bolt. Working pressure spans PN1.6 to PN4.0 and Class 150 to Class 300 with NPT, RF or RTJ ending. Design follows the API 520/521/526/527 relief series with ASME 25.3, face-to-face per ASME B16.10, EN 558-1 or DIN 3202, flanges per ASME B16.5, DIN 2543/2545 or EN 12627, and API 598 / DIN 3230 testing. Selection turns on boiler or header set pressure, stainless trim against wet or superheated steam, and the paired inlet/outlet flange sizes the connection table lists.
Part of the Safety Valves family
Last updated: 2026-11
Family specifications
| set pressure range | 0.1 to 1.6 MPa |
|---|---|
| pressure class | PN1.6, PN2.5, PN4.0, Class 150 to Class 300 |
| size range | DN32–DN150 |
| body materials | Cast Iron, WCB, SS304, SS316, Ductile Iron |
| body materials | Carbon Steel |
| nozzle materials | SS304, SS316 |
| disc materials | SS304, SS316 |
| end connections | NPT, RF, RTJ |
| temperature range | ≤350℃ |
| design standards | ASME 25.3, API 520, API 521, API 526, API 527 |
| testing standards | API 598, DIN 3230 |
| face to face | ASME B16.10, EN558-1, DIN 3202 |
| adjusting ring materials | SS304, SS316 |
| guide sleeve materials | SS304, SS316 |
| spring materials | Steel |
| stem materials | SS304, SS316 |
| adjusting bolt materials | Stainless Steel |
| cap materials | Carbon Steel |
| flange standards | ASME B16.5, DIN 2543, DIN 2545, EN 12627 |
| sv material grades | ASTM A216 WCB, ASTM A217 WC6, ASTM A217 WC9, ASTM A182 F11, ASTM A182 F22, ASTM A351 CF8M |
| sv applications | Boiler outlet lines, Main steam headers, Superheater circuits, Process steam systems, Steam pressure vessels |
| adjusting ring | SS304, SS316 |
| guide sleeve | SS304, SS316 |
| adjusting bolt | Stainless Steel |
| end connection | NPT, RF, RTJ |
| end connection dimension | ASME B16.5, DIN 2543, DIN 2545, EN 12627 |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of steam safety valves?
The published specification for this family lists ASME 25.3, API 520, API 521, API 526, API 527 as the design standards. Testing follows API 598, DIN 3230.
What sizes and pressure ratings are available for steam safety valves?
The published size range is DN32–DN150, and the published pressure ratings are PN1.6, PN2.5, PN4.0, Class 150 to Class 300. Availability of a specific size and rating is confirmed at quotation.
What materials are steam safety valves available in?
The published specification lists body materials: Cast Iron, WCB, SS304, SS316, Ductile Iron. Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do steam safety valves cover?
The published working temperature range is ≤350℃. For a medium at the edge of the range, confirm the suitability of the selected seat and body materials at quotation.
What end connections do steam safety valves support?
The published specification lists NPT, RF, RTJ as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for steam safety valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
Knowledge: selection guides
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Preparing a larger or non-standard requirement? The Steam Safety Valves quotation guide explains what to include, the standard ranges and custom options, and the documents to attach.
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