If attempting to create a Viking Pipe Type, such as the Viking Threaded Pipe, results in the following warning:

Revit could not find a matching Pipe Segment in "Pipe Types: Viking Threaded Pipe". Please check the routing preferences of "Pipe Types: Viking Threaded Pipe".

This is an indication that a default Schedule 40 pipe profile could not be found in your project. Most default templates include a definition of Schedule 40 pipe, but in the event the template you are working on is missing this, you can remediate through the following steps:

1. Manage tab on Revit ribbon
2. MEP settings -> Mechanical Settings
3. Under Pipe Settings -> Segments and Sizes
4. Create a new Segment named "Carbon Steel - Schedule 40", or "Steel, Carbon - Schedule 40"
5. Fill in the size catalog for for all desired sizes

(Note: CAA calculations do not rely on these parameters for internal diameters, but if you desire accurate dimensions they can be found by Googling "Schedule 40 Standard Pipe Sizes")