“CL” in plumbing is short for “close” or “closed”. This term is typically used to indicate the position of a valve or tap. For example, a valve with a “CL” designation might be used to control the flow of water to a fixture or appliance. When the valve is turned to the “CL” position, the water flow is stopped or restricted, effectively closing off the supply.

The term “CL” is used in plumbing because it is a clear and concise way to communicate the status of a valve or tap. In many cases, plumbing systems can be quite complex, with multiple valves, taps, and fixtures that all need to be controlled and monitored. By using clear and consistent labels and markings, plumbers can easily understand the status of different parts of a system, which can help reduce the risk of mistakes and increase the overall efficiency of the system.

In addition to the “CL” label, other common labels and symbols used in plumbing include “OP” for open, “H” for hot, “C” for cold, and “O” for overflow. These symbols are typically used to indicate the status of valves, taps, and other components, and they help plumbers quickly and easily understand the state of the system at a glance.

It’s also worth noting that the use of symbols and labels in plumbing is regulated by industry standards. For example, the American National Standards Institute (ANSI) provides guidelines for the use of symbols and labels in plumbing systems, which helps to ensure consistency and clarity across different systems. These standards can be particularly important in commercial and industrial settings, where large, complex plumbing systems are used.