The exact maximum flow rate for a copper pipe is not a single number; it depends directly on the size (diameter) of the pipe being used and the recommended maximum velocity of the water flowing through it. The flow rate (Q) is calculated using the formula:
*Q = v A**
Where:
- Q is the flow rate (e.g., in gallons per minute or cubic feet per second)
- v is the velocity of the water (e.g., in feet per second)
- A is the cross-sectional area of the pipe (e.g., in square feet)
The maximum velocity is the key limiting factor for water in copper pipes, as provided in the reference.
Recommended Water Velocities in Copper Pipe Systems
Maintaining water velocity below recommended limits is crucial to prevent issues such as erosion corrosion, particularly in hot water systems, and to minimize noise within the plumbing system.
Based on industry recommendations, the maximum advisable water velocities for copper tube systems vary with temperature:
| Water Temperature Condition | Recommended Maximum Velocity (feet per second - fps) |
|---|---|
| Cold Water Systems | 5 - 8 fps |
| Hot Water Systems (< 140º F) | 4 - 5 fps |
| Hot Water Systems (> 140º F) | 2 - 3 fps |
Reference Information Included: The recommended maximum velocity for water in a copper tube system is 5 - 8 feet per second (fps) for cold water systems, 4 - 5 fps for hot water systems < 140º F, and 2-3 fps for hot water systems with a temperature greater than 140º F.
Calculating Maximum Flow Rate for a Specific Copper Pipe Size
To determine the maximum flow rate for a specific size of copper pipe (such as 1/2-inch Type L, 3/4-inch Type M, etc.), you would need:
- The internal diameter of that specific pipe size (which determines the cross-sectional area A).
- The appropriate maximum velocity from the table above, based on the water temperature in the system.
Once you have the internal diameter, you can calculate the area using A = π (diameter/2)², and then use the formula Q = v A with the maximum recommended velocity for your system conditions.
Therefore, while the velocity limits are defined, the maximum flow rate is unique to each copper pipe size.
