Are you one of those who are getting confused between the pressure safety valve and the pressure relief valve? You aren’t the only one. It is usual for people to get confused between these two valves, particularly if you don’t have any experience in valve installations.

We will discuss everything you need to know about these two valves. Explain their functions, why you need to install them, and information about which one you need.

What is a pressure safety valve?

A pressure safety valve, also known as a PSV, is designed to prevent failure in your plumbing system. You can find them in boilers, power services, and water heater systems. They stop the pressure when the pressure goes above the determined limit. This is done by releasing pressure. Once the pressure reaches the maximum setpoint, it opens until the pressure drops to where the system can be used again without any danger.

In other words, the safety valve (PSV) prevents pressure from causing a burst in the system. When a PSV fails, it can be catastrophic and cause serious injury because of the steam and heat. Safety valves are designed to protect people and property by having these valves installed in the plumbing system.

What is a pressure relief valve?

Unlike the PSV, the pressure relief valve protects the equipment from damage caused by overpressure. The relief valve is also known as the PRV. However, it works before the pressure reaches dangerous levels, like the pressure safety valve.

It is slowing the pressure increases down. There is a setpoint on the pressure relief valve, and once the pressure reaches that point, the valve will be fully open. There is a lot more PRV equipment than PSV equipment, especially when it comes to the residential industry.

Different types of pressure relief valves versus pressure safety valve types

You will see that there are three different types of PRV and PSV. Even if they might sound similar, there are a couple of differences.

Pressure safety valve types

There are three different types of safety valves to choose from. It’s essential to make sure you choose the right one for the proper purpose if you need to replace or install a PSV.

• Direct-acting PSV What makes the direct-acting PSV different is its spring-supported closing mechanism. The spring can be adjustable or non-adjustable. The primary function of these spring-closing mechanisms is to control the pressure setpoint better.
• Pilot-operated PSVAs: The name says the pilot-operated PSV has a pilot that controls the pressure setpoint. It allows for a response pressure that is much closer to the working pressure.
• Bellows PSVThe Bellows PSV has some bellows above the poppet. The reason for this is that it diffuses and reduces back pressure. Backpressure is when the pressure might flow back into the valve.

Pressure relief valves

Pressure relief valves also have a couple of different types, like the pressure safety valve. Knowing the different valves will make it easier to choose the right PRV to purchase.

• Pilot-operated PRV The pilot-operated relief valve is similar to the PPSV’s pilot-operated valve. The main difference is that the cracking pressure and setpoint of the pressure are lower.
• Direct-acting PRVThe direct-acting PRV has the same spring support that popped to relieve system pressure. It is also adjustable or non-adjustable.
• Remote control PRV The remote-controlled relief valve controls the adjustable pressure with a distant direct-acting valve. This is done by connecting two valves with a narrow tube.

Applications of a PRV vs the PSV

Like the pressure safety valve, the PRV has crucial applications protecting humans and equipment. It is essential to know and understand these applications. These different applications are making it easier to know the differences.

Applications of the Pressure relief valve

• Sanitary pressure relief valve application is in high-rise buildings with higher water pressure in urban water supply networks.
• Mines and conveyance systems to ensure that the water supply obtains the proper service water and pressure flow.
• It is known that PRV can have a water-saving effect of more than 30%.

Applications of a Pressure safety valve

There are a couple of applications of a pressure safety valve. Some are in residential areas, while other uses are in the commercial industry. To understand PSV completely, you need to know the different applications of a PSV.

• The PSV is used in the oil, petroleum, and gas industry. The safety valve can shut off when the equipment malfunctions and prevent pressure from reaching damaging levels.
• Another industry where PSV is essential is industries that require sanitary conditions. Examples of these sanitary industries are Food, beverages, and pharmaceutical buildings.
• These include industrial and residential HVAC systems. The PSV is designed to relieve pressure when there might be damage done to one of the components.
• In Powerplants. The PSV is essential in power plants to compress gasses like steam and air. To make the working environment safe.

Advantages differences of these two valves

You are choosing the correct pressure relief valve. And to understand the difference between this and the PRV, you need to know more about their advantages.

• This is one of the most important safety features in many systems.
• They assist with relieving excess pressure. This is getting done before the pressure levels reach dangerously high levels.
• PRV can also improve the efficiency of the systems. With a PRV installed, it can help prevent severe damage or explosions to the system.
• Many people are using PRV as a safety device in an over-pressurization system to prevent accidents and injuries.

With the pressure safety valve, there are some advantages that you will not get with the PRV.

• Over-pressurized devices are dangerous if there isn’t a PSV installed. It will prevent over-pressurization from happening.
• It isn’t just to protect against injury to humans. But it also protects equipment from getting damaged when pressure gets too high.
• The safety valve is designed to relieve pressure automatically. There is no reason why human interference is needed. I am making it helpful in case of an emergency.

Disadvantages between the PRV and PSV

Knowing the disadvantages of each of these valves will make it easier to know which one you need to install.

Pressure relief valve disadvantages

• Just like pressure safety valves, it can be the cause of leaks. Leaks that can damage the equipment. It can also be dangerous if a gas system has a leaking valve.
• Valves might have problems like not opening or closing properly. The result will be safety issues and a disruption in the system.

Pressure safety valve disadvantages

• Worn PSV can cause leaks around the valve.
• There is always a chance that a safety valve can fail. This can cause over-pressurization and damage to the equipment.

Are the safety valve and relief valve the same?

It is important to understand if the pressure safety valve and the PRV are the same and have the same function. The one thing they both have in common is the pressure they release once it over-presses. But this is where the similarities end.

Safety valves open when the highest pressure has been reached. The PSV will wait until the pressure reaches critical stages. It will open the system to relieve the pressure immediately.

Pressure relief valves relieve pressure as it happens. It doesn’t wait till it reaches dangerous levels before the valve opens to relieve pressure.

Comparison between PSV and PRV

These are some comparisons between a PRV and the pressure safety valves. This will make it easier to understand the difference.

Purpose

The purpose of the pressure safety valve is known as a fail-safe valve, which aims to protect people and property. It releases pressure once the pressure levels have been reached.

A pressure relief valve keeps pressure in a system to a specific limit. This is to prevent overpressure in the first place. It dodoesn’tait till pressure is dangerously high before pressure is relieved.

Design

This is where the confusion starts. The design of the SV and PRV is similar. It is nearly identical. Both have spring-supported disks that keep the valve closed until pressure becomes high. The difference lies in the disk within the valve. The relief valve has a simple dish that rests on the valve seat. It will lie there until pressure builds enough to lift the disc.

The safety valve has a lop that the pressure cannot interact with. This cannot interact while the valve is closed. Once the safety valve cracks, the pressure will reach the lip. The force of the disc will increase, causing the disc to open and relieve pressure.

Operation differences

The operation between the pressure safety valve and the relief valve is different. With the safety valve, it will open immediately when the pressure has reached the set point. It will open completely.

The relief valve will not open at once. It will open slowly and increase when the setpoint has been reached. It also closes slowly when the pressure decreases.

Conclusion

Even if the pressure safety valve and the pressure relief valve are similar, there is a vast difference between them. The one keeps the pressure safe, only releasing it once it reaches dangerously high levels. The other valve opens slowly to ensure that pressure stays at a safe level.

With all this information, deciding which pressure valve you need to install will be easier. If you don’t know the differences in the valves, it is recommended that you talk to an expert about these valves. They might look and sound similar, but they do have different applications.