When engaging a potential fabricator, have a discussion with that manufacturer to help them understand how your tank will be used, the conditions, lifespan expectations, preventive maintenance commitment, and other key operational details. We ask questions about our projects to ensure that the product each customer requests is the proper solution for their challenge.
Think about answering the 5 W’s and an H — Who, What, When, Where, Why, and How:
Because Rexarc does not provide pressure vessel design services, we sometimes see a disconnect between the drawings and specifications customers bring us and how their pressure vessel is going to be used, the conditions it will operate in, or the expectations for its lifespan.
This situation is not unusual. Procurement specialists are frequently buying multiple types of equipment and are not experts in everything they purchase. They don’t always know all the questions to ask.
Additionally, many companies use in-house or their preferred design houses. Many fabricators, like Rexarc, do not design pressure vessels so they can focus on the engineering and the fabrication.
However, these scenarios can create an unintentional disconnect that could lead to some potentially challenging — if not dangerous — situations.
If your ASME stainless steel pressure vessel fabricator is not asking a lot of questions, be sure to engage them in a conversation about your project needs and expectations.
At Rexarc, we take time to get to know our customers, especially our first-time customers. With generations of steel tank excellence, we look to build long-term relationships. That means we ask a lot of questions. One of the most important in our engineering review of each project is asking how the tank will be used. Though intent may seem clear, it is not always the case.
As we were processing the engineering documents for a new customer’s 1,500-PSI pressure vessel, the answer to that question changed the project drastically.
Turns out, the tank would be subjected to cyclic loading, which is a sustained fluctuation of pressures within a defined range. For example, this could be the repeated filling and draining of a pressure vessel in a manufacturing process. Sometimes, these pressure vessels are called pulse tanks.
That continual varied stress on the tank can decrease the lifespan of the tank especially when cyclic loading isn’t accounted for in the tank size and pressure. Because of the additional stresses on this tank, we worked with the buyer to have the tank redesigned for 3,000-PSI, which better matched performance and lifecycle expectations for the customer.
Sometimes, the solution is much simpler than re-engineering. An aerospace customer requested a fuel tank for testing small-scale rockets launching to sub-orbital space. After verifying this was a test tank, the addition of a stand made it more valuable to the customer who could use the tank repeatedly with greater ease.
Additionally, your fabricator can customize your tank with piping and electronics to be compatible with legacy systems in the event of a tank replacement. If you are replacing an existing tank within a system, it is important to talk with the fabricator about why the tank is being replaced. Factors that caused the original tank’s failures can possibly point to a change in the replacement tank’s design or the addition of sensors to monitor conditions and performance.
The environment in which the tank will be used can also impact fabrication.
Pressure vessels are fabricated from solid materials that contract and expand to temperature variations like all solid materials. Exposure to water, gases and other chemicals can attack the tank from the exterior and interior, causing degradation and decreasing lifespan.
Tanks operating outdoors and exposed to extreme weather conditions can be coated to better withstand temperature variances and precipitation or pollution damage. Those that are visible on the exterior can be painted to make them more aesthetically pleasing.
Even tanks operating indoors can be subjected to harsh environments. Sharing that information with your fabricator can help them suggest materials and welding processes to alleviate corrosion. Paint and other coatings also can extend product lifespan as well.
It also is possible that your tank will need to be mobile. Customization like skidding and palletizing make it easier to maneuver your pressure vessel.
So many factors affect the expected lifespan of a pressure vessel. While some may vary over time, knowing the existing conditions and expected capacity fluctuations can help produce a pressure vessel that will optimally perform as expected for as long as expected.
The environment, chemical exposure, operational use, cyclic loading, corrosion, and preventive maintenance can all dramatically alter a pressure vessel’s performance and its lifespan.
Take all of these factors into account when specifying your tank and working with your fabricator. Choices about materials and customization at the manufacturing stage can prolong a pressure vessel’s operation, increase your uptime, and maximize return on investment.
For ASME stainless steel pressure vessels under continual use, service and preventive maintenance is key to ensuring they meet lifespan expectations and maximizing uptime. Who will be responsible for maintaining the unit and what skills and resources do they have available to do so?
When steel tank maintenance falls to an individual with multiple maintenance responsibilities, consider partnering with a service provider who can develop a plan for your specific system and operating conditions. A solid maintenance partner can alleviate the stress of those maintenance responsibilities while ensuring optimal performance and safety.
Additionally, many pressure vessels and steel tanks can be outfitted with viewports, gauges and sensors that can help make maintenance easier. As a closed system, monitoring the interior of the tank can be difficult without taking a system offline. Tank customizations can help increase operating uptime.
Share the maintenance procedure and responsibility information with the manufacturer so they can tailor equipment training and operating instructions appropriately. Access points and service manifolds can be labeled with metal stamping for easy access.
Finding a pressure vessel fabrication partner who will work with you to ensure they are delivering on your expectations is worth the extra time and effort. Assuming your fabricator understands all your expectations from a set of drawings may deliver on your immediate needs, but ultimately will result in disappointment.
Fabricators work with many contacts to produce stainless steel vessels and tanks. Engineers, procurement specialists, technicians, and operators all have different skill sets, experience, and knowledge. And fabricators can offer different levels of support to their customers in the production process. By communicating all of the details of a vessel’s operation and ongoing maintenance, your fabricator can help you deliver a product that not only meet ASME guidelines but performs as needed each and every time.
Working with a fabricator should be more two-way conversation than hitting the order button on a website.
Summary – Discussions with your stainless steel ASME pressure vessel fabricator before manufacturing can result in a tank that performs better and lasts longer. Assuming specific details about how and where the tank will be used, maintenance options for the tank, and the design intent are obvious can lead to receiving the wrong tank for the customer’s expectations.
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