Shell and tube heat exchangers are important instruments in a wide variety of industries. They are used in refining oil, preparing pharmaceutical products for market, ensuring that food and dairy products are safe to eat and helping breweries create the perfect pint of beer, among other use cases.
While these industries are widely diverse, they all encounter the same concern: which shell and tube heat exchanger to purchase for their operations. Heat exchangers have a long lifespan, especially when they are made with the highest-quality standards and materials. But, when it comes time to make a new purchase, it's crucial that it is done right.
Not only does the configuration matter, but so do the codes and standards the equipment meets. Industry standards help ensure all products are built in the best way possible for customers. It prevents companies from buying subpar products. The American Society of Mechanical Engineers also pointed out that costs and training time are lowered when everyone adheres to the same standards and methods of design.
"Industry standards help ensure all products are built in the best way possible."
Ensuring your shell and tube heat exchanger is designed and built in accordance to the correct industry standards is of the utmost importance for a business. If an exchanger does not meet the right criteria, the products may not be suitable for distribution, and a new exchanger or an upgrade may need to be purchased.
One of the most widely used industry standards comes from the Tubular Exchanger Manufacturers Association. This group updates its set of standards as needed, the most recent being from 1988, according to Thermopedia.
Under TEMA's standards, there are three subcategories:
- Class B, used for chemical processes
- Class C, used in general commercial applications
- Class R, generally used in petroleum processing, but can also be used for large-scale processing applications
The differences between the classes are subtle but important. For instance, the nature of working with petroleum creates a need for heavier and more durable construction, while chemical processing is better done with stainless steel and lighter equipment.
Other common standards shell and tube heat exchangers are built to adhere to are those set by the American Society of Mechanical Engineers. The ASME VIII code refers to the pressurized parts of a shell and tube heat exchanger, according to Thermopedia. These parts are the ones inside the shell, primarily the tubes.
Section VIII is the one most often applied to shell and tube heat exchangers, though Thermopedia explained sections II and V are also used occasionally. These refer to materials and nondestructive testing, respectively. There are a total of 11 sections in ASME's standards.
"Different countries have varying rules regarding standards."
ASME was designed to be applied to many different types of equipment, not just shell and tube heat exchangers. Many exchangers will be certified by both ASME and TEMA, as the latter was in part designed to be a supplemental level of criteria for the machines.
As heat exchangers are an important piece of equipment for many industries, they are used all over the world. Different countries have varying rules about what standards equipment need to meet to be legal. Because of this, it's crucial that equipment manufacturers and purchasers know where an exchanger is going, and what the rules are there. It's also important that anyone buying or using an exchanger be fully aware of the regulations in the country the exchanger will be used.
The Pressure Equipment Directive is one such international standard that is required in the European Union. PED covers a wide scope of equipment, from boilers to piping to pressurized storage vessels. It also applies to shell and tube heat exchangers.
PED includes rules about:
- Harmonised standards
- Essential requirements
- Market surveillance
- Conformity assessment
Each of these rules is put into place to ensure workplace safety, and that products that are processed with a particular piece of equipment are safe for the public.
Another international standard is the Canadian Registration Number. This is required for any boiler, pressure vessel or fitting that will be in operation in Canada. Acquiring one ensures that the equipment is certified to be used in a specific province or territory.
The CRN is written with a multi-digit number, a decimal, and one or more numbers or letters that represent a specific territory or province. For instance, "1" indicates British Columbia, while "T" represents the Northwest Territories.
When purchasing a shell and tube heat exchanger, getting the right certifications is crucial. Enerquip's team of engineers will know what your industry requires and will work with you to meet your needs.