Safety valves - SAFE SN ANSI | ARI

ARI-SAFE-SN ANSI Safety Relief Valve ASME

The ARI-SAFE-SN ANSI is a spring-loaded, direct-acting safety relief valve of semi-nozzle design, intended for the protection of pressure vessels, steam lines, gas, vapor, and liquid systems against overpressure. The valve is type-tested in accordance with ASME Section VIII Division 1 and is supplied with UV-stamp / NB-stamp certification.

Technical Specifications

• Design: Spring loaded, direct acting, semi-nozzle
• Flanges: ASME / ANSI B16.5
• Pressure Classes: ANSI 150/150 and ANSI 300/150
• Sizes: 1" x 2" up to 6" x 10"
• Body Materials: SA216 WCB (carbon steel) or SA351 CF8M (stainless steel)
• Temperature Range: SA216 WCB: -20°F to +800°F; SA351 CF8M: -75°F to +750°F
• Sizing: API 520 per ASME VIII
• Seat Tightness: API 527
• Center-to-Face Dimensions: API 526, per API orifice

Variants 901 / 902 / 911 / 912

• 901: Closed manual lift, closed spring cover
• 902: Open manual lift, open cover
• 911: Gas-tight cap, closed cover
• 912: Open manual lift, closed cover

No external actuator is used. The lever, where present, is intended for test lifting only.

Sealing and Backpressure

Available with metal-to-metal seat or soft seat disc, depending on process media and temperature. Optional EPDM bellows or stainless steel bellows for specific service conditions. Accumulated backpressure is typically limited to 10% of set pressure; higher values require engineering review and appropriate configuration.

Applications

Suitable for installations built to ASME/ANSI standards:

• ASME VIII pressure vessels
• Steam headers and lines
• Process gases and instrument air
• Liquids with sizing in gal/min
• Export skids with ANSI flanges

Selection Data

For gases: mass flow, molecular weight, temperature, set pressure, and backpressure are required. For liquids: volumetric flow, density, viscosity, temperature, set pressure, and backpressure are required. Valves with set pressure below 15 psi are not ASME Code stamped.