With so many factors to consider in choosing a material for your shell and tube heat exchanger, you may have a lot of questions. To start, you’ll need to decide which criteria are most critical to your operation. Criteria like:
thermal efficiency
cost
availability
corrosion resistance
cleanability
durability
You can then weigh the pros and cons of the options that best meet your priorities, since there is typically more than one good alternative. For example, the best material for heat transfer may not be sanitary enough for your application; or the most corrosion-resistant option may far exceed your budget. In most cases, there is a heat exchanger material option that can balance most of your priorities.
Here are a few tips and suggestions for evaluating the heat exchanger material options based on these common criteria.
No matter what industry you operate in, standards matter. They are the measuring stick against which companies and consumers can measure products and choose which ones best suit their needs. They are a way of demonstrating precision and care in the manufacturing of each model of a product.
There are some industries in which meeting standards is crucial to ensuring product safety and quality. The food, beverage and dairy industries must meet guidelines set by the Food and Drug Administration to ensure products are safe for human consumption. The pharmaceutical industry must also meet these requirements so that each medicine is not only safe, but effective.
What these industries have in common is more than consumer-facing products and FDA regulations; they also rely on shell and tube heat exchangers to help make their products as safe, effective and consistent as possible. In order for these industries to produce food, beverages and medicines that are of high quality, they must use equipment that meets specific guidelines as well.
There are a wide range of standards a shell and tube heat exchanger can adhere to. Knowing what they mean and which ones apply to your industry and area of operation are important for successfully moving forward.
ANSI
The American National Standards Institute has been coordinating the voluntary standardization system in the U.S. private sector for nearly a century. Groups called standards developing organizations work together to develop and improve upon standards.
ANSI publishes Standards Actions every week, which include calls for comments on standards proposals. In it, suggestions are made along with what machinery the standard changes would apply to. As of last year, more than 240 SDOs were accredited by ANSI, and more than 1,100 American National Standards were in place.
3-A Sanitary Standards Inc.
Standards for equipment design used in the dairy industry first came about in the 1920s. There were three interest groups, or associations, that worked to develop the standards: equipment fabricators, regulatory sanitarians and processors. To highlight the three associations’ collaboration, the standards became known as 3-A.
3-A Sanitary Standards were created and are maintained to ensure that all equipment used in the food, dairy and pharmaceutical industry is kept clean so that all products coming from them are safe for consumption. According to 3-A, the ideal equipment can be mechanically cleaned through a clean-in-place or CIP system, or can be easily taken apart for thorough manual cleaning.
API 660
The oil and gas industry is another area in which standards are crucial. Petroleum is used in nearly every aspect of today’s world. It fuels vehicles and heats buildings, but it is also used in textiles, health and beauty essentials, cleaning products and many more applications.
In the oil and gas industry, there are several standards companies must adhere to. Often, it is the end user or consultant who creates demand for refineries to follow these standards. The American Petroleum Institute designed standards called API Standard 660.
A newsletter from the CoDesign Engineering Skills Academy noted that these standards were drafted based on industry experience and practical considerations. They provide specifications for the design of a shell and tube heat exchanger for use in the petroleum industry, such as how thick the tubes can be, the type of exchangers allowed in refineries and how thick the tubesheet joints can be.
As demonstrated in the newsletter’s chart, API 660 has some similar standards as TEMA, though not always. For instance, under API 660, TEMA type P and W exchangers, which have outside packed floating heads and a floating tubesheet that is externally sealed, respectively, are not allowed to be used in a refinery. However, under TEMA’s standards, these can be used in certain situations.
It’s important to note the differences in standards when working in an industry where meeting regulations can help define the quality of a product. Knowing your customer base and what they value is also critical, as this will help manufacturers determine which equipment and which standards are right for them.
If you are looking for a shell and tube heat exchanger for your operations, talk to the experts at Enerquip. Their in-house engineering team will understand your needs and be able to determine which standards your equipment needs to meet.
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 loweredwhen 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.
TEMA
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.
ASME
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.
PED
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:
Materials
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.
CRN
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.
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