Chemitics’ pressure-relief system projects follow a proven methodology based on years of experience and thousands of relief device installation evaluations. Regardless of project size or complexity, our stepwise methodology ensures the most effective use of our and our clients’ resources to deliver quality evaluations and comprehensive documentation.

To ensure your relief system design and design basis documentation meets RAGAGEP, the Chemitics way consists of the following steps:

1. Develop project guidelines

Our first step is to develop project guidelines that form the framework of our evaluations. The project guidelines document incorporates internal client guidelines, industry standards and codes, relevant RAGAGEP, and state and local laws. The project guidelines are written to supplement the aforementioned documents with the purpose of clarifying gray areas.

2. Collect and manage mechanical and process information

During a pressure-relief system project, a significant amount of process safety information (PSI) is required. Select elements of PSI include: Process Flow Diagrams (PFD), Piping and Instrumentation Diagrams (P&ID), Piping isometric drawings, relief device and equipment specifications, U-1 forms, vessel drawings, etc. Chemitics works with our clients for the most effective means of data collection and organizes the knowledge in a manageable format as a supplemental deliverable.

3. Document overpressure scenarios

Along with client engineering guidelines, Chemitics’ procedures clearly define criteria for determining the credibility of potential overpressure scenarios based on the type of pressure-system under consideration. Our experts also review PHA results to incorporate the risk of overpressure in the design basis documentation.

4. Quantify relief requirements

For every overpressure scenario determined to be credible, Chemitics calculates the required relief rate. The relief requirement is based on industry recommended practices to ensure the documentation is aligned with performance-based consensus standards.

5. Quantify relief system performance

The relief system performance includes not only the relief device capacity, but the overall functionality of the system. In parallel with inlet pressure drop and built-up backpressure calculations, the API engineering analysis is performed to estimate the installation stability. For relief systems discharging to atmosphere, the safety of the discharge location is evaluated.

6. Quality Review

Ensuring the quality of our evaluations is critical to our self-discipline. We utilize third-party reviewers and software to ensure the accuracy of our assessments and calculations.

7. Document potential deviations

Ultimately a pressure-relief system analysis may result in potential deviations from RAGAGEP as clarified in the project guidelines. Potential deviations include items such as inadequate relief capacity, excessive inlet pressure drop, and unprotected systems. The Chemitics way provides a risk ranked list of potential deviations categorized based on severity for discussion with our client before issuing a report.

8. Mitigation of identified potential deviations from RAGAGEP

When the list of potential deviations is agreed upon, Chemitics works with client-side process safety professionals and relevant contractors to identify the most appropriate mitigation method. The mitigation phase considers risk criteria to ensure the final design meets As Low As Reasonably Practicable (ALARP) guidance.

We are committed to ensuring reliable, available, auditable, and maintainable pressure-relief system documentation and work with our clients preferred calculation and knowledge management software solutions. Where a preferred solution has not yet been identified, we provide our final deliverables in Microsoft compatible software formats to minimize future training and ensure future support. We have expertise in traditional process simulation software and in specialized relief system software such as: iOiQ Process Safety Office SuperChems/ioXpress, Curtiss-Wright iPRSM, Siemens PSPPM, Berwanger PPM, and the AIChE family of tools CCflow.

Effluent handling system projects can be executed standalone or following a pressure-relief system project.

To ensure your relief system design and design basis documentation meets RAGAGEP, the Chemitics way consists of the following steps:

1. Develop project guidelines

Our first step is to develop project guidelines that form the framework of our evaluations. The project guidelines document incorporates internal client guidelines, industry standards and codes, relevant RAGAGEP, and state and local laws. The project guidelines are written to supplement the aforementioned documents with the purpose of clarifying gray areas.

2. Collect and manage mechanical and process information

During a flare system project, a significant amount of process safety information (PSI) is required. Select elements of effluent handling system PSI include: electrical one-line diagrams, utility flow diagrams, facility plot plans, piping isometric drawings, network equipment specifications, flare tip specifications, etc. Chemitics works with our clients for the most effective means of data collection and organizes the knowledge in a manageable format as a supplemental deliverable.

3. Document common-cause overpressure scenarios

Based on the pressure-relief system documentation and the effluent handling system PSI, the common-cause scenarios are documented to capture the largest relief loads and those that may challenge the network.

4. Quantify hydraulic network performance

For every credible common-cause scenario, Chemitics estimates the performance of the piping network. Results from the network performance evaluation include the built-up backpressure on relief devices, and pressure, temperature, sound power level, and velocity profiles. The goal of the hydraulic evaluation is to ensure the profiles are aligned with RAGAGEP.

5. Quantify network equipment performance

The effluent handling equipment evaluations include the knockout drum separation efficiency and retention time, flare tip capacity, and toxic dispersion, thermal radiation, and flammability limit assessments. Ensuring the safety of the discharge location is a key element of relief system design and is also the subject of a recent CSB report.

6. Quality Review

Ensuring the quality of our evaluations is critical to our self-discipline. We utilize third-party reviewers and software to ensure the accuracy of our assessments and calculations.

7. Document potential deviations

Ultimately a flare system analysis may reveal potential deviations from RAGAGEP as clarified in the project guidelines. Potential deviations include considerations such as excess built-up backpressure on relief valves, vibration risk, low-temperature concerns, and excessive thermal radiation. The Chemitics way provides a risk ranked list of potential deviations categorized based on severity for discussion with our client before issuing a report.

8. Mitigation of identified potential deviations from RAGAGEP

When the list of potential deviations is agreed upon, Chemitics works with client-side process safety professionals and relevant contractors to identify the most appropriate mitigation method. The mitigation phase considers risk criteria to ensure the final design meets As Low As Reasonably Practicable (ALARP) guidance.

We are committed to ensuring reliable, available, auditable, and maintainable pressure-relief and effluent handling system documentation and work with our clients preferred calculation and knowledge management software solutions. Our experts have completed dozens of flare and vent header hydraulic analyses using a wide variety of industry standard software solutions including: SimSci Visual Flare, AspenTech FlareNet / Flare System Analyzer, Berwanger/Siemens PPM, and iOiQ Process Safety Office SuperChems. Where a preferred solution has not yet been identified, we provide our final deliverables in Microsoft compatible software formats to minimize future training and ensure future support.