What color must the labels be for copper tubing systems that convey fuel gas?

The color labeling for copper tubing systems that convey fuel gas is established to ensure clear identification and safety in plumbing and piping systems. Specifically, the use of black letters on a yellow field is a standardized practice within industry guidelines such as those outlined by the American National Standards Institute (ANSI) and the National Fire Protection Association (NFPA). This color combination helps to quickly and effectively indicate the presence of hazardous materials—in this case, fuel gas—thereby reducing the risk of accidents and promoting safety during installation, maintenance, and emergency situations.

By using black letters on a yellow background, the warning is highly visible and recognizable, allowing workers and emergency personnel to take appropriate actions if needed. This consistent labeling also aids in compliance with local codes and safety regulations that mandate clear marking of piping systems carrying specific substances.