Understanding TEMA heat exchangers
The Tubular Exchanger Manufacturers Association, or TEMA, has developed standards that define the design, fabrication, tolerances, installation and maintenance of shell-and-tube type heat exchangers. The TEMA standard defines the main configuration of exchangers and the classification for usage in the industry. This standard and the ASME code are the main governance used to design and fabricate exchangers along with any customer specifications.
Sterling TT is an expert in designing and manufacturing TEMA heat exchangers. We comply with a range of international and national heat exchanger standards, including TEMA, which is widely used for shell and tube type heat exchangers. Find out what TEMA standards are and how they impact heat exchangers.
If you’re looking for a manufacturer who designs bespoke shell and tube heat exchangers to TEMA specifications, get in touch with us at Sterling TT. We work with clients across the globe and would love to discuss your requirements.
What are TEMA heat exchangers?
TEMA heat exchangers are shell and tube heat exchangers built to manufacturing standards laid out by the Tubular Exchanger Manufacturers Association (TEMA). TEMA regulations define the style of heat exchangers and the machining and assembly tolerances.
As the default, TEMA would be used in conjunction with the design industry code. When there’s no designated industry code, TEMA would be the first protocol called upon. Read more information on heat exchanger standards.
What is the purpose of TEMA?
The purpose of TEMA is to regulate shell and tube heat exchanger manufacturing through the TEMA standard, securing the safety and reliability of an end user’s equipment. TEMA standards are used internationally to ensure that a heat exchanger will be of high quality no matter where it’s manufactured.
The construction standards for shell and tube heat exchangers are laid out in the Standards of the Tubular Exchanger Manufacturers Association document. The most recent edition (the 10th) was published in 2019.
There are three major TEMA classifications:
- TEMA C (General commercial applications)
- TEMA B (Chemical applications)
- TEMA R (Refinery applications)
For the most part, the three are very similar.
TEMA C is the most commonly used and has the lowest requirements as it’s designed for heat exchangers for general service.
TEMA B and R are slightly more specialised to ensure the heat exchangers are suitable for more challenging environments. They typically require features such as confined gasket joints, increased minimum thickness or allowances for lighter materials.
Want to know more? Read: ‘Heat exchanger tube sheets for challenging operations’.
What’s covered in TEMA standards?
The TEMA Standard includes 10 sections, covering nomenclature through to the physical properties of fluids used in shell and tube heat exchangers.
- Fabrication Tolerances
- General Fabrication and Performance Information
- Installation, Operation, and Maintenance
- Mechanical Standards TEMA Class RCB Heat Exchangers
- Flow Induced Vibration
- Thermal Relations
- Physical Properties of Fluids
- General Information (for example: pipe, tube, fitting and flange dimensions; pressure-temperature ratings; conversion factors)
- Recommended Good Practice
Are there aspects not covered by the TEMA standard?
The TEMA standard is designed to be applicable to “shell and tube exchangers which do not exceed any of the following criteria:
- inside diameters of 100 in
- production of nominal diameter, in. and design pressure, psi of 100,000
- a design pressure of 3000 psi*
In theory, this means any shell and tube heat exchanger that falls outside these parameters is not fully covered by the standard. Although, the final section on Recommended Good Practice does provide information for units with larger diameters and the standard outlines that criteria “may be applied to units which exceed the above parameters.” *
The TEMA standard doesn’t cover thermal-hydraulic design methods for heat exchangers. Design and manufacturing companies, such as Sterling TT, use their own systems for this.
Finally, the TEMA standard is a manufacturing standard. This means it’s ideally used in conjunction with design codes, such as ASME.
* Standards of the Tubular Exchanger Manufacturers Association, 10th ed., 2019, TEMA, Inc., 25 North Broadway, Tarrytown, New York 10591, USA, Section 5:1.1.1
TEMA has specified not just a set of standards for heat exchanger manufacturing, but also designated a notation system. There are many mechanical design variations for front heads, rear heads and shells, so the notations identify the major varieties to create clarity.
The first letter corresponds to the front head, the second to the shell type and the third to the rear head type.
This image is the TEMA nomenclature. © 1988 by Tubular Exchanger Manufacturers Association. More recent editions contain a more modern image, but the nomenclature is the same:
For example, a ‘BEM’ type is a fixed tube sheet exchanger with bolted removable bonnets.
Find out more about tube sheet heat exchanger configurations.
Understanding TEMA designations could help you determine the best configuration for your shell and tube equipment.
At Sterling TT, we can work with you to design the best TEMA heat exchanger for your requirements. We can maximise efficiency while considering many other factors such as budget, upkeep and sustainability. Get in touch.