The Complete Guide to Safety Valves: Types, Operation, Standards & Maintenance

What Is a Safety Valve?

A safety valve is a type of passive control valve that relies on the fluid's own pressure or action to open and close.Passive control means Safety valve is a critical safety device designed to automatically release pressure from a system when the internal pressure exceeds a preset limit. It serves as the last line of defense in pressurized systems, preventing equipment damage, system failure, or catastrophic explosions caused by overpressure.

Advantages of Safety Valves

A safety valve is a type of passive control valve that relies on the fluid's own pressure or action to open and close.It has many advantages as follows:

Overpressure Protection
Automatically releases pressure when it exceeds the set limit, preventing equipment damage or explosions.

Reliable and Autonomous Operation
Operates independently without requiring external power or control signals.

Simple and Robust Design
Fewer moving parts ensure high reliability and low maintenance requirements.

Fast Response Time
Instantaneous pressure relief minimizes system risks.

Cost-Effective Safety Solution
Prevents costly downtime, repairs, and safety incidents.

Applications of Safety Valves

A safety valve is a type of passive control valve that relies on the fluid's own pressure or action to open and close.It can demonstrate advantages in the following application scenarios:

Boilers and Pressure Vessels
Protects against overpressure in steam boilers, autoclaves, and storage tanks.

Oil and Gas Industry
Used in pipelines, separators, and compressors to prevent pressure buildup.

Chemical and Petrochemical Plants
Safeguards reactors, heat exchangers, and processing equipment.

Power Generation
Ensures turbine, boiler, and auxiliary system safety in power plants.

Water and Wastewater Systems
Prevents overpressure in pump systems, filtration units, and storage tanks.

Pharmaceutical and Food Industry
Ensures pressure stability in sanitary and hygienic systems.

Fire Protection Systems
Used to control pressure in fire suppression pipelines and systems.

How Does a Safety Valve Work?

A safety valve is a type of passive control valve that relies on the fluid's own pressure or action to open and close.Here is an introduction to its specific workflow：

P1 represents the system pressure entering the valve, acting on the lower surface area.

Working process

When the system pressure P1 is below the set value, the spring force Fr is greater than the fluid pressure force (P1 × 𝑆𝑎), and the valve disc is pressed tightly against the valve seat by the spring, keeping the valve closed and the system sealed.

As the system pressure P1 rises, when the fluid pressure force P1 × 𝑆𝑎 exceeds the spring force Fr, the valve disc begins to lift upward, moving away from the valve seat.

The valve opens, releasing excess pressure through the valve, thereby reducing the internal system pressure.

When the pressure drops below the set value, the spring force once again exceeds the fluid pressure force, and the valve disc is pressed back against the valve seat, closing the valve and stopping the discharge.

Types of Safety Valves

◆ Spring Loaded Safety Valve

◆ Lever Safety Valve

◆ Pilot Operated Safety Valve

◆ Boiler Safety Valve

◆ Pressure Vessel Safety Valve

◆ Gas Storage Tank Safety Valve

Safety valves are passive control valves that rely on the pressure or action of the fluid itself to open and close. Therefore, the quality of safety valves, which do not require manual operation, is extremely critical, and inspection standards serve as the criteria for measuring the quality of safety valves.

International standard

Before purchasing the product, you need to confirm whether the supplier has the following international certification standards:ASM,EPED,ISO.       

Safety valves with inspection standards have the following advantages compared to similar products:

◆ Ensure Safety

◆ Ensure Reliable Performance

◆ Standardize Quality

◆ Compliance with Regulations

◆ Enhance Market Recognition

Installation Guidelines for Safety Valves

Installation Position, Flow Direction, and Piping Length
Ensure the safety valve is installed in the correct position according to the system design. Always confirm the flow direction matches the arrow marked on the valve body. Keep the piping length between the safety valve and the pressure source as short and straight as possible to reduce pressure loss and avoid turbulence.

Avoid Resonance
Install the safety valve in a location that minimizes vibrations and resonance, which can affect valve performance and cause premature wear. Use appropriate supports and vibration dampeners if necessary.

Steam Discharge Direction
Pay attention to the direction of steam or fluid discharge from the safety valve. Ensure the discharge pipe directs the released medium safely away from personnel and equipment, preventing hazards or damage.

Safety Valve Maintenance

The safety valve is a critical pressure protection device. Regular maintenance is essential to ensure its reliability and the overall safety of the system. The following are the key aspects of safety valve maintenance:

◆ Routine Inspection

◆ Function Testing

◆ Cleaning and Lubrication

◆ Calibration & Reseating

◆ Replace Worn Parts

◆ Documentation