Wednesday, June 10, 2009

The identification and screening of scenarios has been identified as a source of error and variation in Layers of Protection Analysis (LOPA). This paper presents a simplified chemical process risk analysis as an effective means to minimize the overall time required relative to Hazard and Operability studies (HAZOP) while providing a semi-quantitative measure of consequence that may include human harm. The approach provides consistent results independent of the analyst and may be utilized in evaluation of Management of Change, inherently safer design decisions for capital projects, and LOPA revalidation. Conditional and relational logic may be captured through the use of simple spreadsheets to further improve overall efficiency.

The technique is based on simplification of established models that may be readily utilized by engineers engaged in the operation or design of a chemical manufacturing facility without special software and limited training. Results are realistic and may be directly compared with corporate or regulatory guidelines for risk of fatality or injury. At each step in the risk analysis process, more detailed or sophisticated methods may be used to refine the estimates. Furthermore, results from any step may indicate that the hazard from a specific scenario case is not sufficient to continue with subsequent analysis steps.

There are many potential ignition sources in a petrochemical plant; such as hot work, internal combustion engines (in vehicles and other equipment), improperly classified or maintained electrical equipment (including lighting), and adjacent fired equipment. These are typically controlled via measures such as hot work permits for welding/burning, hot work or vehicle entry permit requirements to operate engines inside posted areas, proper electrical classification along with programs to maintain it, and programs/practices to prevent/detect releases of flammable materials.

When a diesel engine is exposed to an external fuel source such as an airborne combustible hydrocarbon in the surrounding environment, it naturally ingests the mixture into the air intake system. Since diesel engines control fuel and not air, the engine can no longer maintain speed control.

Diesel engine runaway is a serious problem in an environment where hydrocarbon vapors or mist from gasoline, gas station vapors, condensates, aviation fuel, propane, and natural gas may be present. A runaway can be described as an engine running out of control on an external fuel source where the operator cannot shut down the engine using conventional methods. Turning off the engine ignition switch, fuel system, shutting off the solenoid or disengaging the engine’s load will not stop a diesel engine.

In a total runaway engine situation, the result can range from minor engine damage to engine explosion, causing catastrophic damage to the equipment and surrounding facilities and/or death or injuries to personnel. Fortunately, there is simple, inexpensive technology available which can prevent a diesel engine runaway.

The authors will present what companies are doing around the world to control ignition sources in general, and in particular to avoid explosions resulting from diesel engine runaway, in the oil and gas, chemical, petrochemical and mining industries.

Examining critical operating, engineering and field Process Safety Information (PSI) in parallel can help uncover hidden hazards and risks. This objective data analysis can then be used to define specific corrective actions, to create broad reaching solutions for preventing & mitigating risks, and to formulate comprehensive strategies for managing integrated PSI.

This session will illustrate how to develop a PSI Assessment toolset and implement a comprehensive PSI strategy to improve operability, reduce risk, and maintain compliance.

The OSHA Refinery National Emphasis Program (NEP) and OSHA Voluntary Protection Program (VPP) PSM Supplement ask specific questions relative to many recognized and generally accepted good engineering practices (RAGAGEP). Many of the same RAGAGEP can be expected in the planned OSHA Chemicals NEP as well, so chemical industry personnel should be aware of what RAGAGEP OSHA is recognizing and inspecting against and their key requirements, in order to comply with the OSHA PSM regulation and improve process safety at their sites.

This presentation will review the RAGAGEP referenced by OSHA in its Refinery NEP and VPP documents, highlight some of the key RAGAGEP which ABS Consulting often finds not fully implemented/followed at petrochemical sites, and discuss approaches for complying with the requirements of these RAGAGEP.