You draw a run and there is no elbow at the turn, no tee at the branch, or the pipe comes out at the right diameter but with the wall thickness of American steel pipe. None of that is a drawing mistake. It is the pipe type.
Revit routing preferences is the table inside each pipe type that tells Revit which segment the pipe is made from and which elbow, tee and transition to use at which size. This article builds a pipe type from scratch in Revit 2027: a segment with a size catalog taken from a manufacturer, a duplicated type, the fittings, and a test run. Drawing and connecting is covered in how to draw pipes in Revit; to build a company template for water and drainage, the Institute runs a Revit MEP course.
What pipe types in revit are made of
A pipe type is not one wall thickness. It is three layers of information nested inside each other.
The pipe segment holds the material, the schedule or type designation, the roughness and the size catalog. The catalog is where nominal, inside and outside diameters live.
Routing preferences ties that segment to fitting families: elbow, tee, cross, transition, union, cap, each with the size range it applies to.
Identity data such as Type Mark, Manufacturer and Cost sits in the pipe type and feeds the schedules.
That is why pipe types are named after material and joint, for example PPR PN20 or uPVC drainage, rather than after a system. One system may run in several materials, and the take-off needs the material.
Where the size catalog comes from
Revit does not know Vietnamese pipe. The size catalog has to come from the catalogue of the manufacturer approved for the project, or from the standard that catalogue declares.
Take PPR. The PP-R catalogue from Tien Phong Plastic states the pipe to DIN 8077 & 8078:2008 and the fittings to DIN 16962. Its table runs from DN 20 to DN 250 with a wall thickness for each pressure class: SDR 11 for PN10, SDR 7.4 for PN16, SDR 6 for PN20 and SDR 5 for PN25. At DN 25 the wall is 2.8 mm at PN10 but 4.2 mm at PN20, so the bore is quite different. The catalogue also recommends PN16 or higher for hot water.
For uPVC the same catalogue splits into two families. Pressure pipe follows ISO 1452 in the metric series from DN 21 up, graded by pressure class. Soil and waste pipe inside buildings follows ISO 3633, with a 3.0 mm wall from DN 34 to 90 and 3.2 mm from DN 110 to 160. Drainage and supply are therefore two separate segments, never one shared catalog.
The Institute's sample file already carries segments built from local catalogues, their names starting with REDY_: PPR PN10, PN16 and PN20 to DIN 8077 – 8078, uPVC PN8, uPVC Sch 40, steel and copper.
Steps 1–4: a pipe segment and its sizes
Step 1. Open Mechanical Settings. Type MS, or click the small arrow at the corner of the Systems › Plumbing & Piping panel. In the tree choose Pipe Settings › Segments and Sizes.
Step 2. Create the segment. Click the create icon beside the Segment box. The New Segment dialog opens with the rule stated at the top: a new segment requires a new material, a new schedule/type, or both. Choose Material, Schedule/Type or both, name it, and pick an existing catalog to duplicate the sizes from.
Step 3. Edit the sizes. For each size click New Size and enter three numbers: Nominal Diameter, Inside Diameter, Outside Diameter. On Vietnamese plastic pipe the nominal size equals the outside diameter — PPR DN 25 is 25 mm outside — and the inside diameter is the outside less twice the catalogue wall. An existing size cannot be edited: delete it and add it again.
Step 4. Clear the sizes you never use. Used in Size Lists decides whether a size appears while drawing; Used in Sizing decides whether Revit's sizing algorithm may pick it. If the project stops at DN 110, clear everything above and the list while drawing gets much shorter.
Steps 5–7: duplicate the type and set revit routing preferences
Step 5. Duplicate the pipe type. Start the Pipe command and click Edit Type, or in the Project Browser open Families › Pipes › Pipe Types, right-click a type and choose Type Properties. Click Duplicate and name it after the material and pressure class, for example PPR PN20.
Step 6. Open Routing Preferences. In Type Properties, under Segments and Fittings, click Edit on the Routing Preferences row. The dialog has three columns — Content, Min. Size and Max. Size — grouped into Pipe Segment, Elbow, Preferred Junction Type, Junction, Cross, Transition, Union and Cap.
Step 7. Set the segment and its range. On the Pipe Segment row choose the segment you built, then set Min. Size and Max. Size for the range it serves. One type can use several segments: PPR up to DN 63 and steel from DN 75 up, for instance. Add a row and split the ranges so they do not overlap.
Autodesk's Specify Routing Preferences for Pipe page notes that when more than one row matches, the first one listed is used, so row order matters; a size range of None means the part is never used and All means it is always used.
Step 8–11: choose the pipe fittings
Step 8. Load the families first. The content list only shows families already in the project. If one is missing, click Load Family inside the Routing Preferences dialog, or use Insert › Load Family; Autodesk's online content is at Insert › Load Autodesk Family.
Step 9. Pick the elbow and the tee. Set Elbow to the elbow family of the right material and Junction to the tee. On drainage, the junction should be a 45° wye or a swept tee so the flow stays smooth.
Step 10. Pick the preferred junction type. This row has two values: Tee and Tap. Tee branches with a tee fitting, Tap taps straight into the body of the main. Whichever you choose is what Revit creates as you draw.
Step 11. Finish with transition, union and cap. Transition is the reducer, Union the coupling, Cap the end cap. Any row left as None simply means Revit has nothing to insert in that situation.
Test the type, then update older runs
Select the new type and draw a run with a turn and a branch. If the table is right, the elbow and the tee appear as you click, and they are the families you chose.
After editing the routing preferences, select the existing segments and fittings and click Reapply Type on the Modify tab to bring them up to date; use Change Type to swap a run to a different pipe type entirely. The run keeps its position and connections, only the fittings change.
Schedules read these parameters directly, so a properly built type gives the right material and size in the schedule without any typing.
From CAD to Revit
On CAD the pipe library is a block file: one block per fitting per size, named by size and inserted by hand. Change the material and you change the whole set of blocks and rewrite the notes.
| Task | On CAD | In Revit 2027 |
|---|---|---|
| Wall thickness | a note or a separate table | the segment's size catalog: nominal, ID, OD |
| Fittings per material | a folder of blocks | families loaded into the project and set in routing preferences |
| Picking a size | from memory, typed | a list drawn from the segment, trimmed to what you use |
| Changing material on a run | redraw | select the run and Change Type |
| Quantities by material | count blocks | schedules that read the pipe parameters |
Check the catalog in the file against the manufacturer before using it. The PP-R PN10 segment in the Institute's sample file gives bores of 15.4, 19.4, 26.2, 32.6, 40.8 and 51.4 mm at DN 20, 25, 32, 40, 50 and 63. That is exactly the outside diameter less twice the catalogue wall for SDR 11. One wrong number here and every flow, velocity and quantity downstream is wrong too.
When routing preferences will not let you edit
| Symptom | Cause | Fix |
|---|---|---|
| Add row, remove row and the move arrows are all greyed out | No row is selected in the table | Click a row in the section you want to edit and the add button lights up |
| Editing one type changes another | You are editing a shared type | Click Duplicate, name it, then edit |
| The family you need is not in the list | It is not loaded into the project | Load Family from inside the Routing Preferences dialog |
| No elbow or no tee appears when drawing | The row is set to None, or the size range does not cover the size | Set the family and fix Min. Size and Max. Size |
| The size you need is missing while drawing | It is not in the segment, or Used in Size Lists is cleared | Mechanical Settings › Segments and Sizes, add or tick the size |
| Old pipes still use the old fittings | New settings only apply to what you draw next | Select the old run and click Reapply Type |
Three things you often hear
| What you often hear | What Revit 2027 actually does |
|---|---|
| Downloading a pipe family set gives you local pipe | Fitting families are only half of it; sizes and wall thickness live in the segment in Mechanical Settings |
| Nominal size means the bore | On local plastic pipe the nominal size is the outside diameter; the bore depends on the pressure class |
| Setting routing preferences updates every pipe | Pipes already drawn keep their fittings until you use Reapply Type or Change Type |
In short, a pipe type fit for local documents needs three things: a segment whose size catalog is copied from the catalogue, the fitting families of that material loaded into the project, and revit routing preferences filled in for each size range. Do it once in the template and every later project simply picks the type. If the discipline is new to you, start with what Revit MEP is and what a family is.
Frequently asked questions
What is the difference between a segment and a pipe type?
The segment holds the material and the size catalog; the pipe type ties that segment to a set of fittings through routing preferences. One segment can serve several types.
Do I need a separate type for each PPR pressure class?
Yes, if the project uses more than one. PN10 and PN20 have different walls and therefore different bores; separate segments keep quantities and hydraulics honest.
Where do I get fitting families when the library is not installed?
Insert › Load Autodesk Family pulls Autodesk's online content, or load families from the project sample file with Load Family.
Why is the wall thickness wrong even though the diameter is right?
The type is pointing at another segment. Check the Pipe Segment row in Routing Preferences and the catalog of that segment.
Does changing the type of a drawn run break the connections?
No. Select the run and use Change Type: the pipes keep their position and connections, and only the fittings are replaced.