Severe Service Valves (SSVs) vs General Purpose Valves (GPVs)
Does Your Application call for an SSV or a GPV?
Valves are really used for just two main functions – to either control a process or isolate a process. That’s it, control or isolate.
However, the conditions under which valves must perform can vary greatly – from harsh and caustic chemical environments to extremely high pressure processes. Valves that have to stand up under tough and corrosive applications are referred to as Severe Service Valves, or SSVs.
Unfortunately, there is very little global agreement on what type of applications call for SSVs versus GPVs (general purpose valves). SSVs can mean different things to different people, though they are usually identified by the applications they’re used for and the environments in which they must function.
Luckily, in 2017, the Manufacturers Standardization Society (MSS) began the process of standardizing the definition and requirements of SSVs by creating the Severe Service Valve Task Force, which is determined to set the minimum requirements a valve must perform to when faced with extreme conditions.
What is a Severe Service Valve as most people understand it today?
SSVs must be “high performance,” but of course that term can mean different things to different people. That’s why it’s important to define standards for when an application calls for a Severe Service Valve versus a General Purpose Valve.
All industries use SSVs, but some industries will have greater need for severe service valves, such as the chemical manufacturing industry, where valves often come into contact with harsh and corrosive chemicals. The challenge is for the valves to continue performing at the basic level required by the process, even within these caustic environments.
An SSV must deliver a minimum performance over a minimum period of time in a harsh environment. SSVs are often identified by their application and those applications are usually challenging to the valve’s ability to survive and perform to its highest standard over an extended period of time. A valve that can survive in the application for a defined duration performing a basic function (control or isolation) up and until the agreed upon duration is reached is considered an SSV.
The consequence of a failure or degradation of performance in an SSV can have a worse impact on the process within which it’s operating than a regular GPV. So generally, corrosion is a key element in determining the need for an SSV and whether a valve counts as an SSV – they need to be able to stand up to the corrosive atmospheres.
If they cannot, they are a general purpose valve, or GPV and should not be used in an application that calls for an SSV.
Defining & Standardizing the Need for SSVs
The MSS is still some ways off from producing a Standard Practice to define what applications need SSVs as opposed to GPVs as well as to what standards a valve must perform in order to be considered an SSV. But the fact that they are moving toward defining this is a big step in the right direction to helping end users choose the right valve for their process.
This helps to increase both the efficiency and safety of your plant operations avoiding expensive down time and safety hazards. It’s important to ensure you’re using the right parts in every step of your operations process and the right valve repair and maintenance company can also lend you’re their expertise in this area, as well.