What do the colors of glass bulb sprinkler heads mean?

The colors of glass bulb sprinkler heads indicate the temperature at which the bulb will break, triggering the sprinkler system. Typically, the colors range from red for the lowest activation temperature (around 155°F or 68°C) to blue for higher temperatures (up to 286°F or 141°C). This color-coding helps ensure that the sprinkler activates appropriately based on the specific fire safety requirements of different environments.