What bulb color is used for a very extra high temperature of 400'F?

The correct bulb color used for a very extra high temperature of 400°F is green. In fire protection systems, especially in sprinkler systems, different colors are assigned to various temperature ranges for glass bulb sprinklers. These colors indicate the temperature rating at which the sprinkler will activate.

A green bulb color is specifically designated for high-temperature environments and responds at 400°F, which is significantly higher than most standard temperature ratings used in typical sprinkler systems. Understanding the color coding helps ensure that the right type of sprinkler is selected for specific environmental conditions, thereby ensuring effective fire suppression.

In contrast, other bulb colors correspond to lower temperature activation points. For example, red and black are used for lower temperatures, and purple typically indicates an even higher rating than the green bulb but still not applicable for 400°F. Thus, recognizing the significance of the green bulb color is crucial in selecting the appropriate sprinkler that meets the demands of the environment.