A pressure vessel is a specially designed container which holds liquids, vapors, or gases at substantially high pressures. These vessels are often used in the petroleum refining and chemical processing industries, but can also be used in the private sector. The term pressure vessel applies to anything subjected to a notable amount of pressure, and includes everything from massive industrial chemical storage tanks, to home hot water tanks, and individual diving cylinders such as scuba tanks, among other things. Some pressure vessels are exposed to external heat sources, either directly or indirectly, and are known as fired pressure vessels. Those not exposed to external heat are known as unfired pressure vessels. However, no matter the size, type, or use, safety regulation is a critical feature in the production and maintenance of a pressure vessel.
Pressure vessels are usually subjected to pressures of at least 15 psig, and often significantly higher, with many vessels exceeding 1000 psig.
Because of this, the vessels must be designed to withstand intense internal pressure without failure, as failure could result in fatal or otherwise costly accidents, including poison gas leaks, fires, suffocations, and even shrapnel-generating explosions. Additionally, failure can cause massive loss of product and affect profits and a company’s ability to operate. In order to better withstand high pressure, coded pressure vessels are often spherical or cylindrical in nature with rounded edges to avoid focusing pressure at any one point. Many vessels are made of steel, and depending on the conditions in the area the vessel will be operating, some are made of composite materials or polymers.
Most pressure vessels are designed to include safety features. Smaller vessels are often created with a “yield before break” design, which allows them to bend or flex before any crack forms or grows in size. Larger vessels are often created with a “leak before burst” which allows for a crack in the vessel to grow and allow the contained substance to escape slowly rather than in one violent, explosive failure. While ideally neither of these situations would occur, having a plan in place to mitigate damages in cases when they cannot be completely prevented is an invaluable safety tool.
Pressure vessels must be constructed and inspected in accordance with any applicable regulatory codes and standards. For the industrial sector, The American Society of Mechanical Engineers, ASME, publishes and maintains an International Boiler and Pressure Vessel Code that establishes acceptable margins of safety for this equipment. The ASME Section VIII documents explain in detail the guidelines recommended for ensuring safety. Another important code for ensuring the safety of pressure vessels is API 510, which is a code for the inspection, rating, repair, and alteration of in-service pressure vessels.
Encorus Group offers both design and inspection of pressure vessels. Contact Dana Pezzimenti, PE, for matters pertaining to pressure design at 716.592.3980, ext. 128 or email@example.com. If you have inspection needs for a pressure vessel, contact Keith Taylor, Encorus’s Director of Mechanical Integrity, at 716.592.3980, ext. 143 or firstname.lastname@example.org.
A special thank you goes out to our summer intern, Mara Gilmartin, for contributing this article.
Encorus is proud to offer guaranteed reliability through our established American Society of Mechanical Engineers (ASME) Nuclear Quality Assurance Program (NQA-1).
Lindse Runge, one of Encorus’s Quality Assurance Technicians, gives some insight regarding what the NQA-1 Program is, what she does, and what type of clients would benefit from the program. NQA-1 is a nuclear quality assurance standard for nuclear facilities in the U.S. It relates to the design, construction and operation of such sites, and is a highly-regarded industry standard. ASME NQA-1 was created and is maintained by the American Society of Mechanical Engineers (ASME). This standard provides requirements and guidelines for the establishment and execution of quality assurance programs during siting, design, construction, operation and decommissioning of nuclear facilities. This standard reflects industry experience and current understanding of the quality assurance requirements necessary to achieve safe, reliable, and efficient utilization of nuclear energy, and management and processing of radioactive materials. The standard focuses on the achievement of results, emphasizes the role of the individual and line management in the achievement of quality, and fosters the application of these requirements in a manner consistent with the relative importance of the item or activity.
Lindse’s responsibilities include enforcing and implementing the requirements of Encorus’s QA program, developing / revising documents as required to comply with customer QA requirements and ASME NQA-1 requirements, reviewing customer purchase orders for QA requirements in order to develop plans to implement requirements throughout the project, reviewing Encorus purchase orders for QA requirements to ensure flow-down of customer requirements, participating in audits and surveys, and maintaining project files and documentation to ensure legibility, revision control, and traceability of records.
Encorus has a Quality Assurance Program that conforms to NQA-1 requirements to allow us to supply items and services to nuclear facilities. Clients that would benefit from an NQA-1 Program include the Department of Energy, Department of Defense, nuclear constructors, nuclear fabricators, and nuclear power plants.
If you think you would benefit from Encorus Group’s NQA-1 Program, please contact Quality Assurance Technician Lindse Runge at (716) 592-3980 ext 137 or email@example.com.
Please join us in welcoming Sindy Tang to Encorus’s Design Group! Sindy recently graduated with her Bachelor’s Degree in Electrical Engineering from University at Buffalo, and will be joining Encorus Group as an Electrical Engineer. Welcome, Sindy!
Encorus is in Leeds! Massachusetts, that is.
Employees traveled to the Northampton VA Medical Center in Leeds, MA to assess the condition of masonry, exterior walls, and roofs. The objective of this project is to design for the correction of deficiencies in order to prevent safety issues or service interruptions, and to stop any structural deficiencies from becoming more severe. Vince Roberts and Dan Sullivan are pictured here performing inspections.
Vince Roberts gives a thumbs up as he and Dan Sullivan perform inspections of the roof, masonry, and exterior walls at the Northampton VA Medical Center in Leeds, MA.
Encorus Group’s John Allan has had an article published in American City & County magazine. The article talks about the importance of automatic fire detection and suppression systems for the protection of municipal assets such as trucks, snowplows, emergency vehicles, and other equipment.
You can read the article by clicking here.
The concepts of structural engineering can be observed in many things that people commonly deal with on a daily basis, including buildings, bridges, and other structures, but did you know that structural engineering theories can be seen in the popular balancing game, Jenga? According to the How Stuff Works website, Jenga displays 5 major structural engineering principles.
The first concept that Jenga portrays is loading, which is the idea that a part of a structure supports the weight of another part or the rest of the structure. In Jenga, no two blocks are the exact same dimensions, therefore it is possible to remove loose blocks that do not rest evenly on each other. These blocks do not hold any of the weight of the rest of the structure, meaning that they are not load bearing. Structural engineers need to determine a load path so that the entire structure supports the weight from the pressure being exerted downward. The How Stuff works website tells us that there are three types of loads: dead loads, which are the “forces applied by all of the static components of the structure, like beams, columns, rivets, concrete, and drywall”; live loads, which are “the forces applied by all of the ‘moving’ elements that can affect a structure, including people, furniture, cars, and normal weather events like rain, snow, and wind”; and dynamic loads, which are “live loads that occur suddenly with great force. Examples are earthquakes, tornados, hurricanes, and airplane crashes”. When designing a structure, structural engineers need to perform calculations to ensure that all of the load bearing elements can support all three types of loads.
Jenga also portrays concepts relating to foundations. When setting up the game of Jenga, one should consider the surface upon which they want to build the tower. Unstable or uneven surfaces are a poor choice that would lead to the eventual collapse of the tower. Sturdy surfaces, such as a flat table or a hard, level floor, would be a much better choice to ensure the tower will not fall unprompted. This same concept applies to buildings and other structures. Structural engineers must be mindful of the foundation where the structure will be built. Foundations that are too fluid or too hard will lead to damage or collapse of the structure. Sufficient foundations should transfer the load into the ground, relieving the pressure from the bottom tier of the structure.
Tension and compression are two structural engineering concepts that can be observed in Jenga. According to the How Stuff Works website, compression is the “force applied when two objects are pushed together”, and tension is the “force applied when an object is pulled or stretched”. In Jenga, once a wooden piece is removed from the middle, it essentially becomes two columns with a beam across them. The beam experiences both tension from the from the columns below and compression from the pressure of the other blocks on top of the beam at the same time. When considering compression and tension, structural engineers must also consider what materials would have the appropriate tensile strength to effectively support the structure. Tensile strength is “the maximum force that can be applied to a material without pulling it apart”. Jenga uses wood for the pieces instead of rubber or a different material because it has the appropriate tensile strength and characteristics to support the tower structure for the game.
Rotational force can be found in the game of Jenga through the concept of maintaining rotational equilibrium. This is the idea that the taller the structure, the wider the supports at the bottom should be to reduce movement. In Jenga, once a bottom support is removed, leaving only a single piece rather than two, the tower becomes increasingly unbalanced and susceptible to falling due to small movements or changes in pressure. The same applies to buildings and other structures. If a tall structure relies on a narrow base, it will not be as stable as a tall structure that sits on a wide base.
Jenga also displays concepts that occur from earthquake forces, which is something that structural engineers need to consider if they are designing a structure in a seismically active area. When seismic activity occurs, structures can experience lateral and vertical vibrations, which could cause the structure to move. The stability of structures throughout seismic vibrations can be attributed to even weight distribution throughout the entire area. In Jenga, if you have more blocks toward the top of the tower and you bump the surface it sits on, the tower is more likely to move than if there were more blocks at the bottom rather than the top.
Next time you’re playing a game of Jenga, remember to look for these structural engineering concepts. If you have any questions or require any structural engineering services, contact Senior Structural Engineer Dan Sarata at (716) 592-3980, ext. 138 or firstname.lastname@example.org.
If you want to play a lively game of Jenga, call Client Relationship Manager Mike O’Neill at (716) 592-3980, ext. 155 or email@example.com.