Pressure Safety Valves


Protecting both plant assets and personnel are the cornerstones of all safety programs. Cox-Walker specializes in evaluating pressure relief systems (PRS) from both an equipment protection perspective and an employee safety perspective.


Protecting both plant assets and personnel are the cornerstones of all safety programs. Cox-Walker specializes in evaluating pressure relief systems (PRS) from both an equipment protection perspective and an employee safety perspective.

Equipment Protection


Freeing your process engineers to run your plant is one of our goals in any project. Cox-Walker can assist in all aspects of the pressure relief device validation and sizing process from gathering pertinent process safety information (PSI), developing all credible overpressure scenarios, and utilizing pressure relief software to get the most accurate validation/sizing calculations. We follow the American Petroleum Institute (API) Standards 520, 521 and 2000, as well as the Client’s Standards and Procedures. Here’s a detailed look at how we can help:

Validating the proper size of a relief device starts with the quality of the information gathered beforehand. Our staff has the field experience and training necessary to identify and gather this information for you such as vessel U-1 forms, vessel/PRD data plate information, pump curves, etc. We also field sketch relief device inlet and outlet piping diagrams, update P&IDs, etc. Our goal is to minimize the time your company has to spend gathering the information and ensure we have all the necessary data to validate and size the relief device correctly.
Once the information is gathered, our detailed analysis begins. Our process engineers utilize a step-by-step process to ensure all credible overpressure scenarios are analyzed. Identifying the causes of overpressure is the crucial step before any sizing calculations can be made. A detailed analysis of overpressure scenarios such as external fire, equipment failure, utilities failure or runaway reaction is performed. API, ASME, and specific industry standards such as ASHRAE are followed in this process to make sure your plant meets the required specifications in your pressure relief system.
Whether it’s an existing relief device requiring validation or a new installation requiring sizing calculations, Cox-Walker is here to help. After the overpressure scenarios are identified, our engineers can utilize pressure relief software or your company’s specific methods to validate whether the existing valve is sized correctly. We will make recommendations if a new size is required and also provide sizing calculations for new relief device installations.
At Cox-Walker, we realize the documentation is crucial to the Process Safety Information and Process Safety Management teams. We pay attention to the details. Our engineers create specification sheets, detail the overpressure scenarios, produce Visio or CAD drawings of the pressure relief system and package up a finished document that is project-ready. We will customize the finished product to satisfy any audit specifications that your safety teams may have. Meet with us and let us help you with all your pressure relief system needs.


Equipment Protection


Freeing your process engineers to run your plant is one of our goals in any project. Cox-Walker can assist in all aspects of the pressure relief device validation and sizing process from gathering pertinent process safety information (PSI), developing all credible overpressure scenarios, and utilizing pressure relief software to get the most accurate validation/sizing calculations. We follow the American Petroleum Institute (API) Standards 520, 521 and 2000, as well as the Client’s Standards and Procedures. Here’s a detailed look at how we can help:

Validating the proper size of a relief device starts with the quality of the information gathered beforehand. Our staff has the field experience and training necessary to identify and gather this information for you such as vessel U-1 forms, vessel/PRD data plate information, pump curves, etc. We also field sketch relief device inlet and outlet piping diagrams, update P&IDs, etc. Our goal is to minimize the time your company has to spend gathering the information and ensure we have all the necessary data to validate and size the relief device correctly.
Once the information is gathered, our detailed analysis begins. Our process engineers utilize a step-by-step process to ensure all credible overpressure scenarios are analyzed. Identifying the causes of overpressure is the crucial step before any sizing calculations can be made. A detailed analysis of overpressure scenarios such as external fire, equipment failure, utilities failure or runaway reaction is performed. API, ASME, and specific industry standards such as ASHRAE are followed in this process to make sure your plant meets the required specifications in your pressure relief system.
Whether it’s an existing relief device requiring validation or a new installation requiring sizing calculations, Cox-Walker is here to help. After the overpressure scenarios are identified, our engineers can utilize pressure relief software or your company’s specific methods to validate whether the existing valve is sized correctly. We will make recommendations if a new size is required and also provide sizing calculations for new relief device installations.
At Cox-Walker, we realize the documentation is crucial to the Process Safety Information and Process Safety Management teams. We pay attention to the details. Our engineers create specification sheets, detail the overpressure scenarios, produce Visio or CAD drawings of the pressure relief system and package up a finished document that is project-ready. We will customize the finished product to satisfy any audit specifications that your safety teams may have. Meet with us and let us help you with all your pressure relief system needs.


Employee and Community Safety


Dispersion modeling is crucial to analyzing the consequences of potential releases from pressure safety valves (PSVs). Our engineers are experienced in modeling both overpressure and spurious failure scenarios for toxicity, thermal radiation and vapor cloud explosion hazards. Each pressure relief system has unique discharge points and receptors that must be defined in order to protect your employees and the community. Let Cox-Walker assist you in all aspects of your modeling and consequence analysis.

Prior to dispersion modeling, it is important to identify who could be impacted in a release. Gathering information on release elevations, community boundaries, HVAC intake locations, and receptor distances for modeling are our first steps. Let us do the detailed work so you can focus on running the plant.
The quality of the results produced from modeling software is only as good as the information input into the system. At Cox-Walker, we pride ourselves on learning your process, understanding the hazardous materials being released, and familiarizing ourselves with Safety Data Sheets (SDS) sheets, Protective Action Criteria (PAC) values, risk rankings, and all threat potentials. Once the research is complete, our engineers simulate the effects of the release in your location by utilizing SAFER TRACE and/or PHAST modeling software. We can provide detailed consequence analysis specific to your company’s risk management plan to assist you in further protecting your personnel and the surrounding community.
Once the dispersion modeling is complete, documenting the findings and providing solutions to minimize risk are key. Cox-Walker will prepare final documentation packages highlighting the dispersion modeling results and recommendations for safe discharge locations (if necessary). We aren’t just information providers. We are solutions-driven….working with your team to provide the safest environment for your employees and the community nearby.

Employee and Community Safety


Dispersion modeling is crucial to analyzing the consequences of potential releases from pressure safety valves (PSVs). Our engineers are experienced in modeling both overpressure and spurious failure scenarios for toxicity, thermal radiation and vapor cloud explosion hazards. Each pressure relief system has unique discharge points and receptors that must be defined in order to protect your employees and the community. Let Cox-Walker assist you in all aspects of your modeling and consequence analysis.

Prior to dispersion modeling, it is important to identify who could be impacted in a release. Gathering information on release elevations, community boundaries, HVAC intake locations, and receptor distances for modeling are our first steps. Let us do the detailed work so you can focus on running the plant.
The quality of the results produced from modeling software is only as good as the information input into the system. At Cox-Walker, we pride ourselves on learning your process, understanding the hazardous materials being released, and familiarizing ourselves with Safety Data Sheets (SDS) sheets, Protective Action Criteria (PAC) values, risk rankings, and all threat potentials. Once the research is complete, our engineers simulate the effects of the release in your location by utilizing SAFER TRACE and/or PHAST modeling software. We can provide detailed consequence analysis specific to your company’s risk management plan to assist you in further protecting your personnel and the surrounding community.
Once the dispersion modeling is complete, documenting the findings and providing solutions to minimize risk are key. Cox-Walker will prepare final documentation packages highlighting the dispersion modeling results and recommendations for safe discharge locations (if necessary). We aren’t just information providers. We are solutions-driven….working with your team to provide the safest environment for your employees and the community nearby.