Hi Tim,
This is not a straight forward answer to your question.
You need to setup thickness in the database for your insulation. From there you create an insulation specification.
https://knowledge.autodesk.com/support/fabrication-products/learn-explore/caas/CloudHelp/cloudhelp/2...
https://knowledge.autodesk.com/support/fabrication-products/learn-explore/caas/CloudHelp/cloudhelp/2...
It sounds like you are also using the multi-route tool within revit? You can omit the fittings.
https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/CloudHelp/cloudhelp/2018/EN...
The fabrication database is a rabbit warren of settings. I suggest you learn cadmep before working with fabrication parts.
