GM Material Specification: EMS-99 Steel Tubing – Copper Brazed

1. Standard & Practices: To comply with all requirements of ASTM A254

2. Hardness: (On ID 90 degree from Seam) Rockwell 30T 55 Maximum.

3. Flatten & Bend Test: A section of the tubing 2-1/2″ minimum long shall stand being flattened between parallel plates until the inside walls are in contact. The flattened section shall then be bent once through 90 degree around a pin having a diameter three times the wall thickness of the tubing, and shall be subsequently straightened once without cracking or showing flaws.

4. Tolerances:

Permissible Variation
OD 3/16″.002″.002″
OD 1/4″ & Over.002″.003″
Wall Thickness1.002″.003″

1For .020″ to .049″ thick walls.

5. Hydro-static Test: To withstand, without leaking, an internal hydro-static pressure sufficient to subject the material to a minimum fiber stress of 16000 psi. Hydro static pressure shall be determined by the following equation:



P = hydrostatic pressure in psi
S = alloable fiber stress, 16000 psi
t = wall thickness of tubing in inches
D = outside diameter of tubing in inches.

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