Spring Loaded Safety Valve

Technical Summary

Nominal Size: ½” to 12”

Pressure Class: Class 150 to Class 2500

Temperature Range: -29°C to 538°C

Design Standards: API 526, ASME Section VIII, ASME B16.34

Set Pressure Range: As per system requirement

Construction and Materials

Body and Pressure Retaining Parts

• ASTM A216 WCB
• ASTM A351 CF8M
• ASTM A217 WC6
• ASTM A217 WC9
• ASTM A182 F316

Internal Components

• Disc: ASTM A182 F316 / Hard faced (Stellite)
• Seat: Stainless Steel / Stellite faced
• Stem: ASTM A182 F6a / ASTM A182 F316
• Spring: Chrome silicon alloy steel / Inconel (for high temperature service)

Sealing System

• Seat Sealing: Metal to metal sealing with precision-machined seating surfaces
• Gasket: Spiral wound gasket with graphite filler

Functional Design

Spring Loaded Safety Valve is a self-actuated pressure relief device that uses spring force to hold the disc against the seat under normal operating conditions. When system pressure exceeds the set pressure, the force acting on the disc overcomes the spring load and the valve opens automatically to discharge excess pressure.

As the system pressure falls below the reseating value, the spring forces the disc back onto the seat to restore tight shut-off. This design provides dependable overpressure protection without the need for external power or pilot control, making it suitable for steam, gas, and vapour service across a wide range of industrial systems.

Material and Grade

Standard Materials

Component	Material	Grade	Typical Application
Body	Carbon Steel	ASTM A216 WCB	General steam and utility services
Body	Stainless Steel	ASTM A351 CF8M	Corrosive and process media
Body	Alloy Steel	ASTM A217 WC6 / WC9	High temperature pressure relief service
Disc & Seat	Stainless Steel with Stellite overlay	ASTM A182 F316	Wear resistance and tight sealing
Stem	Stainless Steel	ASTM A182 F6a / F316	Load transfer and corrosion resistance
Spring	Alloy Steel / Inconel	High strength spring material	Pressure set control and high temperature resistance

Extended Materials (On Request)

• Hastelloy C276 for aggressive chemical service
• Inconel 625 / 718 for high temperature and severe service
• Duplex Stainless Steel (F51) for chloride-rich environments

Additional Information

Valve Type	Spring Loaded Safety Valve
Pressure Function	Overpressure protection
Operation	Self-actuated spring loaded relief
Set Pressure Control	Factory set and adjustable within specified range
Back Pressure Performance	Suitable for installations with low and stable back pressure
Installation	Vertical installation required
Service Media	Steam, gas, vapour

End Connections

• Flanged as per ASME B16.5
• Butt weld as per ASME B16.25

Applications

• Oil and gas industry: overpressure protection in gas lines, separators, and process systems
• Power generation: steam boiler safety and auxiliary pressure protection
• Refining and petrochemical industry: pressure relief in utility and process service lines
• Chemical processing: safety protection in vapour and gas handling systems
• Pulp and paper industry: steam safety applications in process units
• General industrial systems: compressed gas, air, and utility pressure protection