The Importance of Certification for Pressure Vessels

Air tank with pressure gauge.

Do you work in an industry where the use of pressure vessels is common?

Then, explosions may be something you worry about. You want to stay safe at work and go home at the end of the day in one piece. Have you ever looked at a vessel and wondered how it can keep its pressurized contents safely in place? Who makes sure that these vessels are safe? Have you ever noticed the stamp or plate on a vessel and wondered what it means?

Let's find out!

What are Pressure Vessels?

If you don't work in a field that routinely uses pressure vessels, you may not know what they are. Simply put, they are containers that hold pressurized contents.

This means that the container holds its contents, either a gas or a liquid, at a different pressure than the atmosphere. It is critical that this vessel maintains its seal. Otherwise, the sudden pressure change will cause an explosion.

The vessels were originally invented to handle the steam needed to operate a steam engine back in the day. But now these vessels are very useful for a variety of applications. Everything on the following list uses these vessels in some manner:

  • Recompression chambers
  • Mining operations
  • Nuclear reactor vessels
  • Distillation towers
  • Submarines
  • Spaceship habitats
  • Petrochemical plants
  • CO2 extraction systems

These vessels are also routinely used for storing liquefied gases like propane, butane, LPG, chlorine, or ammonia.

Safety

As you can imagine, safety is a huge concern with these vessels. If you've ever popped a balloon with a pin, you have an idea of what would happen if a pressure vessel suddenly lost its seal.

Safety is the number one reason why proper certification is so important. The American Society of Mechanical Engineers (ASME) put into place their rather stringent standards in 1914. Before this, working with these vessels was very dangerous.

The vessels often failed and exploded. These explosions often severely injured or even killed anyone that was nearby. Obviously, this was not ideal. So the ASME put into place inspections and certifications that these vessels had to pass.

It didn't start out this big, but now the ASME's code encompasses 28 books and over 14,000 pages. It covers residential and industrial boilers and every pressure vessel imaginable.

It is an international code that everyone should adhere to. After all, it doesn't matter where you are on the planet. Physics is still physics, and a vessel will still explode under the same miserable conditions.

ASME Certification

Not all these vessels are created equally. They can handle a wide range of PSI. Thus the ASME construction code has different standards that apply to the vessels. Regardless, though, any vessel that will handle more than 15 PSI is subject to the ASME code.

The vessels are divided into three groups. Those that handle up to 3,000 PSI, up to 10,000 PSI, and those that handle pressures over 10,000 PSI.

The ASME has guidelines for the types of materials that can be used to build these vessels. Some requirements apply to all vessels. Others only apply according to how much pressure the vessel will handle.

Once the vessel has been approved, it gets a stamp or plate that boasts ASME certification. Many insurance companies will only cover a company that uses pressure vessels if every vessel has this ASME certification.

Of course, it's possible that any pressure vessel can fail. Don't assume that a vessel is foolproof just because it has been certified. But, meeting the certification standards greatly reduces the risk of failure and a potentially serious tragedy.

Good Design

In addition to the materials that can be used, the code also covers how the vessel should be designed. The ASME clearly lays out design standards that a vessel must meet or exceed to get certification. Even the shape of the vessel is essential for proper construction.

This also extends to the fabrication process. Manufacturers should follow certain procedures during fabrication that will help ensure the integrity of the vessel. Manufacturers must also follow a quality control regimen to ensure that the vessels they produce are solid.

The ASME also keeps an eye on the manufacturer's track record. The vessels that a manufacturer produces must consistently meet the ASME standards.

Transportation

While a pressure vessel can explode at any time, they are particularly dangerous during transport. The vibrations and jostling about that happen during transport can be just enough to cause the vessel to fail.

Imagine the devastation if a vessel explodes on a public roadway.

For this reason, the Department of Transportation also gets involved here. They issue an R-stamp that is very important. If a vessel needs repairs, the welder must have this R-stamp certification.

The welder (and the shop) have to undergo strict testing to receive this certification. Once they obtain it, they have to stay in good standing with the National Board of Boiler and Pressure Vessel Inspectors.

Improper repair of these vessels is a hazard to the public that is taken very seriously. This certification ensures that everybody stays safe.

Stay Safe

Who knows how many lives have been saved because of the ASME standards. But the only way to ensure that they keep saving lives is by following them.

Now that you know what ASME certification is and why it's so important, it helps to ensure that your vessels meet all the codes and standards. If you see a pressure vessel in use that doesn't have the proper certification, say something. You could potentially save someone's life.

Would you like to learn more interesting tidbits about chemical or mechanical engineering? Be sure to check out our education page. We've got great bits of interesting information about the exciting world of engineering.

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