14 Jan How Safe Are Your Emergency Shutdown Valves?
If you work with petrochemicals at your plant, safety is constantly at the top of your list of everyday concerns. But how do you know just how safe your emergency shutdown valves are? In this post, you’ll learn how you can tell if your emergency shutdown valves are safe at your plant or whether you should reassess what you’re using to process dangerous chemicals.
What Are Emergency Shutdown Valves?
Emergency shutdown valves (ESDs) serve the purpose of stopping the flow of hazardous chemicals when it detects a dangerous event, whether an earthquake, pressure change or otherwise. They’re integrated into the makeup of a processing system as an automated safety mechanism, or fail-safe. ESDs are fail-safe in the sense that they close immediately upon any sort of control system failure. If a temperature or pressure controller, for example, fails or cuts off, the emergency shutdown valve will close.
ESDs can be installed in-line to any location upstream, midstream or downstream, in order to effectively stop the flow of hazardous chemicals. Sometimes controllers fail or cut off in the event of a natural disaster like an earthquake or storm, which throws off the air pressure reading and other readings in the processing system. It causes the system to malfunction, which could result in the unintended, uncontrolled release of processing chemicals in the system. Clearly, if there’s a fire at the plant, you would want to prevent the release of petrochemicals from fueling the fire.
The Safety Importance of Emergency Shutdown Valves
By preventing the release of any petrochemicals during a natural disaster or system failure, the plant can minimize safety-related risks. This safeguards the plant’s staff, the environment, as well as the plant’s equipment.
ESDs are legally required on any processing equipment that is placed on an offshore oil drilling rig. The BP Horizon explosion in the Gulf of Mexico in 2010 was a catastrophic event that potentially could have been prevented with safer equipment. Nonetheless, oil leaked into the Gulf of Mexico for a total of 87 days of agony for the oil company, as the media followed the effects of the leak on the surrounding natural habitats and local businesses.
New petrochemical regulations have since been rolled out at the federal level. Emergency shutdown valves that prevent the uncontrolled release of oil or other material are now required. This safeguards everything from the safety of personnel and surrounding wildlife to the company’s image and profits.
Emergency Shutdown Valve Types
Ball valves are a common type of valve used for emergency shutdowns. Ball valves are typically used to stop the flow of fluids traveling in a straight line through a system. If you need an emergency shutdown valve to stop the flow of air, you need a butterfly valve or a swing gate valve as your emergency shutdown valve. In this way, emergency shutdown valves are tailored to the application, because the type of emergency shutdown valve depends on what you’re processing.
Functional Safety and Certifications
Safety standards and certifications for functional safety are becoming more pervasive in recent years within petrochemical process industries. Automated safety protection features like ESDs in a processing plant make up the functional safety of a processing plant. The ESDs and other automated safety elements in the plant are rated for their level of safety based on their probability of failure.
The International Electrotechnical Commission (IEC) sets safety standards for valves and how to comply with them. A SIL certificate describes the safety level of a valve, on a scale of 1 to 5. A SIL-1 valve is the least safe, while the SIL-4 is extremely safe. Many industry-standard valves are SIL-3 certified because getting this certificate is a cost-effective option that is still extremely safe. While SIL certification is not necessary for your valves, it serves as valuable information about the valves you have, which can be particularly useful if a third party comes in to work on redesigning.
If you’re not sure how safe your emergency shutdown valves are, you can have a team follow functional safety instructions and audit your plant’s safety features.
Integration of Emergency Shutdown Valves
Emergency shutdown valves are integrated into the makeup of a processing system as an automated safety mechanism. ESDs can be installed in-line to any location, whether the flow is upstream, midstream or downstream. You need to ensure the emergency shutdown valve you choose is well-suited for your application. Once in place, your ESDs will vastly improve the safety of your petrochemical plant.
Bottom Line: How Safe Are Your Emergency Shutdown Valves?
At the end of the day, it’s up to you to check and assess the safety level of your emergency shutdown valves. Doing so can help ensure you have a very low probability of failure, as reflected in the SIL level of the emergency shutdown valves. Considering their role in keeping personnel safe, they’re probably the most important equipment in the plant to focus on and keep up-to-date.