The Tubular Exchanger Manufacturers Association (TEMA) is an association of manufacturers of shell and tube heat exchangers. TEMA has established a set of construction standards for Shell and Tube Heat Exchangers. The Standards are regularly updated and published; the most recent edition is the seventh, published in 1988. Most shell and tube exchangers ordered by the process industries and for other high-severity applications throughout the world are built to TEMA standards.
To quote from the Standards (p. 20), "the TEMA Mechanical Standards are applicable to shell and tube exchangers with inside diameters not exceeding 60 inches 1.52 m, a maximum product of nominal diameter (inches) and design pressure (psi) of 60,000 in. psi 10.5 m · MPa, or a maximum design pressure of 3,000 psi 20.7 MPa." However, a section on Recommended Good Practice is provided to extend the Standards to units with larger diameters.
The Standards recognize three classes of heat exchanger construction:
Class R for the severe requirements of petroleum processing (and usually including most large scale processing applications).
Class C for general commercial application.
Class B for chemical process service.
There is in fact relatively little difference between the Standards for the three classes; where there are differences, Class R calls for heavier and more conservative construction features, and Class B (since these are usually stainless steel or high alloy exchangers) gives some allowance for lighter (i.e., thinner metal) construction for noncritical components.
TEMA Standards are divided into ten sections:
General Fabrication and Performance Information
Installation, Operation, and Maintenance
Mechanical Standards TEMA Class RCB Heat Exchangers
Flow Induced Vibration
Thermal Relations (includes fouling and charts of the configuration correction factor on the Logarithmic Mean Temperature Difference)
Physical Properties of Fluids
General Information (e.g., dimensions of pipe, tubing, fittings and flanges; pressure-temperature ratings; conversion factors, etc.)
Recommended Good Practice
TEMA does not give or recommend thermal-hydraulic design methods, leaving it to the individual company to use their own methods or one of the published or commercially available computer-based methods.
Even though TEMA has only about 20 members (who must meet strict standards of in-house thermal-hydraulic and mechanical design capability, manufacturing accountability, and quality control to attain membership), practically all shell and tube heat exchangers for the process and related industries are specified to meet TEMA standards of construction. The Standards are set by members of the Technical Committee of TEMA.
Standards of the Tubular Exchanger Manufacturers Association, Seventh edn., 1988, TEMA, Inc., 25 North Broadway, Tarrytown, New York 10591, USA.