Fairings are the moldings at the end of a joint of pipe that joins two sections together. They may be larger or smaller than the diameter of the pipe itself, depending on the pipe specification, whether a step down or step up is needed at the joint. They may also be of a male design or female design. Some fairings may have a “key” in the form of a bump or notch to prevent incorrect pipe orientation.
Trenchlesspedia Explains Fairings
Without fairings, pipe joints would blend together via end-to-end. This would mean a substantial leak risk between the joints. Without the fairings, it would be difficult to mass-produce pipe joints, because the end of the joint would have to include any 45 or 90-degree turns. For example, the 45 and 90-degree turns that are easily assembled in a PVC pipe would then be a single piece of pipe with a 45 or 90-degree end.
On top of that, the ends would still be butted together and still leak. The fairing at each end of the pipe allows change to the pipe direction and the size of the outfall of the pipe, as well as an option to assemble multiple points of pipe to form one long, continuous pipeline.