Hub Specifications

Inside Diameter .840- .845”
Outside Diameter 1.080”
Pipe Requiremements – Schedule 40 ½” Pipe .084” outside diameter.

What are the Metric equivalents of the pipe sizes? Why is it so hard to figure out which pipe matches which hubs? You’re right. This is confusing!

In the USA, PVC pipe is measured based on the inside diameter. This is logical, because engineers need to know how much airflow or liquid flows through the pipes.  n Europe, PVC pipe is measured by the outside diameter. This is also logical, because the outside diameter determines the overall size of the pipe.

When choosing the pipe to match to the Sonostar hubs, it is always best to have a hub on hand to make sure the pipe fits. Why? Because there are tolerance ranges for manufacturing PVC pipe whereby two manufacturers producing 40 mm pipe could have either thinner or thicker walls in the pipe, or the inside or outside diameter could be different from factory to factory. When you go to the market to buy PVC, you should always take a hub with you to make sure you’re getting what you need.

For Sonostar’s Standard (1/2”) hubs, we fit the pipe inside the hub arms, so it is the outside diameter of the pipe that is significant. In the USA, that outside diameter is .84”. In Europe, that is equivalent to 21.33mm, but most pipe is sold as 20 mm. It works just fine.

Sonostar’s Megahubs can use either 1” pipe on the inside of the hub arms, or 1 ½” pipe on the outside of the hub arms. This is equivalent to 32 mm pipe on the inside of the hubs, and 48.3 mm on the outside of the hubs. Therefore, to use the inside of the hubs, it is the outside diameter of the pipe that must be less than 32 mm. To use the outside of the hub arms, you need to have a pipe with an Inside diameter of more than 40.1 mm. In most of Europe, that would be a 50 mm pipe. Remember, 50 mm usually refers to the outside diameter of PVC pipe sold in the metric world.