Basically ASTM creates the material specifications and standard test methods to determine compliance. ASME selects those ASTM materials which will perform adequately in boiler or pressure vessel service and accepts them with stated limitations.
Even though most of the time the ASTM and ASME materials are nearly identical, there may be differences. There are many ASTM materials that are not acceptable by the ASME Code. Both of these American standards have specific meanings and usage which sometimes makes them different.
Basically, ASTM creates the material specifications and standard test methods to determine compliance. The ASME codes select those ASTM materials that work perfectly in boiler or pressure vessel service and then accept them within the service range of limitations.
The main difference between ASTM and ASME materials is that ASTM materials are applicable for a range of different uses. Whereas ASME materials are specifically developed for use in pressurized equipment. ASTM materials can be used in non-pressurized equipment services like machinery and equipment. But ASME materials are suitable for pressurized equipment like boilers, heat exchangers, pipes, fittings, piping spools, tanks, pressure vessels, large liquid, and oil and gas storage containers.
Also, ASTM is not a code. It only issues properties of materials through its standards. On the other hand, ASME is a code that may use ASTM materials for its applications.
Comparing ASME and ASTM Codes
As you likely understand from the quick overview of the two codes above, ASME and ASTM standards are related yet separate. The two entities have often cooperated to create material specifications that apply to the industrial heating industry.
Equipment built to ASME standards is often built using the materials designated by ASTM code (though it’s also important to note that there are also many ASTM materials that are not appropriate for use in ASME code stamped equipment manufacturing).
These are just two of the various codes that apply to industrial heaters and heating systems. As you’re shopping your equipment options, they are two important standards to keep in mind.