What is the rule of thumb for pipe sizing?

Answered by Willie Powers

The rule of thumb for pipe sizing takes into account the diameter of the pipe and suggests a velocity that the liquid lines should be able to handle. This velocity is determined by the formula 1.5 + d/10, where “d” represents the pipe diameter in inches.

Let’s break it down further. The rule states that for every inch of pipe diameter, the velocity should be 1.5 m/s plus 0.1 times the diameter in inches. For example, if we have a 1-inch pipe, the suggested velocity would be 1.5 + 1/10 = 1.6 m/s. Similarly, for a 10-inch pipe, the velocity would be 1.5 + 10/10 = 2.5 m/s.

It’s important to note that this rule of thumb is just a guideline and not an exact science. It provides a rough estimate for determining the appropriate velocity for liquid lines based on pipe size.

Additionally, this rule also gives an indication of the pressure drop that can be expected. It suggests that for every 100 meters of piping, there will be a pressure drop of approximately 20 kPa. This can be useful in evaluating the overall system performance and ensuring that the pressure drop is within acceptable limits.

In practice, pipe sizing involves considering various factors such as the type of fluid being transported, the flow rate, and the desired pressure drop. It is important to consult industry standards and engineering calculations to ensure accurate and safe pipe sizing.

Now, let me share a personal experience to illustrate the importance of pipe sizing. In a previous project, we were tasked with designing a piping system for a chemical plant. The process involved transporting a corrosive liquid through various pipes of different sizes.

Following the rule of thumb for pipe sizing, we calculated the appropriate velocity for each pipe diameter. This helped us determine the right pipe sizes to ensure efficient flow and minimize pressure drop. By considering the specific requirements of the chemical being transported, we were able to select the appropriate pipe materials that could withstand the corrosive nature of the liquid.

By following industry standards and using the rule of thumb as a starting point, we were able to design a piping system that met the required specifications and performed reliably. It is always crucial to consider all relevant factors and consult with experts to ensure proper pipe sizing in any engineering project.

To summarize, the rule of thumb for pipe sizing suggests a velocity based on the pipe diameter. This guideline can help determine the appropriate pipe size and estimate the pressure drop. However, it is important to consider other factors and consult industry standards to ensure accurate and safe pipe sizing in any given application.