Why is hard temper tube not color marked?

Hard temper tubing is often subjected to processes that involve high temperatures, especially in applications such as gas distribution or industrial piping where it may be exposed to heat during installation or operation. When hard temper tubes are exposed to high temperatures, any color marking applied to identify them can deteriorate, fade, or become illegible. This degradation of color marking occurs because the inks or dyes used for coloring might not withstand the thermal conditions, potentially leading to confusion in identification.

In contrast, non-hardened or softer temper tubes are typically color-marked to denote specific material properties or sizes, which assists technicians and engineers during installation and maintenance. However, for hard temper tubes, maintaining clear identification through color markings becomes less practical due to the risk of destruction from high temperatures. Thus, the absence of color marking is rooted in practical considerations of durability and longevity in challenging environments rather than issues of compliance, cost, or necessity in general application.