Flumes and Pipe Slope

When it comes to managing and measuring flow, the best choice is a flume. However, depending on the needs of your operation, you may need to connect your flume to a pipe, which poses a wide range of difficulties. In particular, you need to make sure that the downstream or upstream slope of your pipe is not steep enough to affect the rate of your flow.

If you’ve never connected a flume to a pipe before, it’s important to get a few tips about pipe slope and to learn how it can impact your system. Learn more about pipe slopes for fiberglass flumes, and why you need to be certain that your operation has the right tools.

Upstream Conditions

To get the accuracy that you need out of your flume, you need to be certain that the upstream of your flow is subcritical. If the pipe upstream of your flume is too steep, it can massively increase the speed of your flow and impact the accuracy of your readings.

The appropriate pipe slope will largely depend on the length of the line. For instance, if the line size is 8 inches, then your upstream slope should be about 2 percent. Whatever the correct slope, any upstream pipe will need to include a straight run, meaning a section that is free from bends or elbows. Generally, you will need a straight run of 15 pipe diameters if you want to maintain a proper flow velocity.

If your pipe has a smaller capacity, your straight run can be slightly smaller. It may also be possible to use a flow conditioner if you’re having trouble with your slope or straight run, but it’s usually better to install everything correctly.


Making sure your upstream conditions are correct is the most important part of connecting your flumes to pipes, however, you also need to promote proper downstream conditions. Fortunately, the pipe slope conditions for the flow downstream of your flume are much simpler and more easily accomplished. Ideally, the downstream slope will be the same, or larger, as the upstream slope. Otherwise, you may experience flow backing up into your flume.

You also need to make sure that your downstream pipe is sized correctly. Just like with the slope, the size of your downstream pipe should be the same as your upstream pipe. Also, you will need a downstream straight run of at least 5 pipe diameters to prevent backup.

Pipe Slopes for Fiberglass Flumes Tools

Although it may take a little bit of effort, connecting a pipe to a flume and ensuring the right slope isn’t as difficult as you might think. However, you will need the right tools for the job, and the easiest way to get the right pipe slopes for fiberglass flumes is shopping with Tracom, FRP.

In the Tracom catalogue, you will find a huge selection of high-quality fiberglass flow measurement tools, including flumes with end adapters perfect for piped flows. With our products, your operation will have the level of success that you need. Request a quote from Tracom today and equip your operations with the right fiberglass products.