Modeling Plumbing Systems

Modeling Plumbing Systems


In this lesson, you will learn how to model plumbing fixtures and link them together to create hot water, cold water, sanitary waste, and fire sprinkler systems. You will start by placing sanitary fixtures in the architectural model, and then copy those placeholder fixtures into an Autodesk® Revit® MEP model. They will model pipe layouts to complete the sanitary waste system and create an example of a wet fire protection system. The endpoint of the lesson will be a plumbing model that can be used for analysis and shared with the other members of the design team and disciplines affected by the plumbing design decisions.

Placing Plumbing Fixtures in the Architectural Model

Designers typically place plumbing fixtures in their models as part of their preliminary design work to indicate the types and locations of fixtures, the required clearances, and their design intent. You can use a similar approach, placing plumbing fixture components in an architectural model to act as placeholders for items that will be connected into plumbing systems in a later step by others on the design team. Be sure to consider the clearances required by all applicable building codes as you place the fixtures. Make sure that the plumbing fixture components you load into your project and place are MEP-friendly (include connectors for the hot water, cold water, and sanitary systems in their definition). All of the plumbing fixtures included in the libraries installed by the 2011 versions of Autodesk® Revit® products are MEP-friendly, but older components may not be. To be certain, edit the component and look for the special system connector parts in its definition.

Copying Shared Elements into a Plumbing Model

Link the preliminary architectural model to your Revit MEP host project and use the Copy/Monitor tool to copy the placeholder elements to use as the starting point for the plumbing design tasks. {slider Modeling Sanitary Systems} Use tools in the Plumbing Panel of the Home tab to connect these fixtures and create several types of plumbing systems:

  • Sanitary
  • Domestic cold and hot water
  • Fire protection

The essential steps include:

  • Add pipes to model vertical risers.
  • Add horizontal branch pipes and connecting them to the riser.
  • Connect plumbing fixtures to the branch pipes.

You can place these pipes individually, or use Revit software’s auto-routing tools to generate recommended pipe layouts based on the fixture connections, pipe sizes, and connectors required. You view the plumbing systems defined and the devices assigned to each system in the System Browser.

Modeling Fire Protection Systems

Another essential plumbing system in many buildings is the fire protection system. You can use Revit software to model both wet and dry fire protection systems.

Fire sprinklers and their piping are typically located at the ceiling level. You place sprinkler components using the Sprinkler tool in the in the Plumbing and Piping panel of the Home tab. You can place the pipes that supply the sprinkler components manually or by using Revit software’s auto-routing tool to generate potential layouts. These pipes can be concealed in the ceiling or left exposed. 

Because sprinkler piping typically shares the ceiling space with many other building systems—structural elements, electrical wiring and lighting fixtures, and mechanical ductwork—it is important to check for interferences and adjust the routing as needed to avoid conflicts.

Learning Objectives

After completing this lesson, you will be able to:

  • Understand the importance of copying the model levels, grids, and fixtures into the MEP host model.
  • Explore modeling pipe systems between fixtures to create specific plumbing systems.
  • Appreciate the logic for sanitary pipe routing options in a multistory building.
  • Devise simple fire protection systems in ceilings.


Placing Plumbing Fixtures in the Architectural Model

In this exercise, you will learn how to:

  • Place plumbing fixture components in restrooms.
  • Copy plumbing fixtures to similar locations on other levels.

Figure 4.4.1 - Placing a lavatory plumbing fixture component

Video Tutorial
Student Exercise
  • Place toilet and urinal fixtures in the restrooms on level 1 of the building as shown in Figure 4.4.2.
  • Copy the plumbing fixtures to similar locations on levels 2, 3, and 4.

Figure 4.4.2 - Plumbing fixtures placed in the restrooms

Copying Shared Elements into a Plumbing Model

In this exercise, students will learn how to:

  • Copy shared levels and grids into a Revit MEP host project.
  • Create working views for plumbing design in Revit MEP.
  • Copy plumbing fixtures from the architectural model into Revit MEP.

Figure 4.4.3.Copying plumbing fixtures to the Revit MEP host project

Video Tutorial
  • Copy the plumbing fixtures from the architectural model into the Revit MEP plumbing model using the Batch Copy option to copy all of them.
  • Open the 3D Plumbing view to verify that the fixtures are copied into the Revit MEP plumbing model.

Figure 4.4.4 -  Plumbing fixtures copied into the Revit MEP host project

Modeling Sanitary Systems

In this exercise, students will learn how to:

  • Create a vertical riser.
  • Place horizontal branch pipes.
  • Connect branch pipes to the riser.
  • Connect plumbing fixtures to branch pipes.
  • View sanitary systems in the System Browser.

Figure 4.4.5. Creating a branch pipe to a vertical riser

Video Tutorial
Student Exercise
  • Copy the horizontal branch pipe on level 2 to similar locations on levels 3 and 4.
  • Connect the toilet fixtures on level 2 to the horizontal branch pipe with the Connect Into tool.
  • Connect the sanitary connector of the sink and urinal fixtures to the horizontal branch pipe using similar steps.

Figure 4.4.6 -  Plan and 3D views showing plumbing fixtures connected to horizontal branch pipe

Modeling Fire Protection Systems

In this exercise, students will learn how to:

  • Place sprinklers.
  • Create a wet fire protection system.

Figure 4.4.7. Placing sprinkler components on the face of a ceiling

Video Tutorial
Student Exercise
  • Place pendant sprinklers for a wet fire protection system in the ceiling of the large office at the northeast corner of level 2.
  • Create a wet fire protection system for the sprinklers placed in the previous step.
  • Open the 3D Plumbing view to display the sprinklers and the piping layout

Figure 4.4.8. Sprinkler piping layout created with the Generate Layout tool


Placing Plumbing Fixtures in the Architectural Model

  • What are the required clearances for restroom fixtures per your applicable building code?

The requirements vary per the local building code. The requirements per the Uniform Building Code include, for example:

Toilets: 30" (0.76 m) -wide clearance side to side, 26" (0.66 m) clearance in front

Showers: Minimum 34" by 34" (0.86 m) square

ADA requirements are more stringent still.

Toilets: 60" (1.52 m) -wide minimum clearance located 16" to 18" (0.40 m to 0.46 m) from the wall.

Sinks: A 30" (0.76 m) -minimum clearance floor space in front of lavatories that extend 17" (0.43 m) minimum from the wall.

  • What are the advantages and disadvantages of using wall-mounted plumbing fixtures versus floor-mounted?

Wall-mounted plumbing fixtures keep the floor area clear, allowing easier access when cleaning floors. The disadvantage is that space must be provided for the supply and sanitary piping in the wall behind the fixture. And the wall must be reinforced to carry the structural loads.

  • How does the mounting location affect the routing of the sanitary and water piping?

On the supply side, there is no difference. For sanitary piping, mounting location determines where space must be provided; for sanitary piping, either below the floor or in the wall behind the fixture.

Copying Shared Elements into a Plumbing Model

  • How can you control the types of fixtures copied during a batch copy?

You can select the fixture types to be batch copied within the Copy Monitor dialog box.

  • What are the advantages and disadvantages of mapping fixtures to new types?
  • In general it is better to copy the original types. The exception is if you have a plumbing fixture that is not MEP-friendly (does not have connectors and other MEP properties).

Modeling Sanitary Systems

  • How are the horizontal branch pipes that run below a floor typically concealed?

If the pipes will not be covered by a ceiling, then a soffit can be provided to enclose and conceal them.

  • Can you use multiple vertical risers to reduce the length of the branch pipes and the vertical clearance required to provide the minimum slope?

Yes, this is an effective strategy when vertical clearance is limited.

  • What are the biggest challenges when trying to find auto-routing solutions?

The biggest challenge is whether the required space is available to allow the connections (elbows, tees, and so forth) between the pipe sections to be made. If space is not available based on the settings specified, an auto-routing solution cannot be found.

  • Do the types and sizes of connector elements loaded in the project affect the auto-routing solutions available?

Yes, the auto-routing solutions will only have access to those elements loaded in the project. Loading more types and sizes of connectors can increase the number of solutions found.

  • If an auto-routing solution cannot be found, what strategies can you use to assist with finding an acceptable routing?

If an auto-routing solution cannot be found, you can manually place some of the major pipes and rely on auto-routing to determine layouts for specific smaller regions of your system.

Modeling Fire Protection Systems

  • What factors influence the design of a wet fire protection system?

The factors considered include: the usage of the space, the hazard classification of the building, the coverage area, the water flow, and the water pressure.

  • What is a typical spacing between sprinklers?

The sprinkler spacing will depend on the flow rate required and the water pressure available. Typical spacing can range from 12' x 12' (3.6 m x 3.6 m) to 20' x 20' (6.1 m x 6.1 m).

  • What factors need to be considered when determining the elevations of the main and branch pipes?

The biggest consideration is going to be the height of the ceiling plane, whether the sprinklers will be located on or below the ceiling, and the elevations of potential obstructions in the ceiling plane, such as ductwork or structural elements.

Key Terms

Key Term
Supply System
Piping systems that convey hot and cold water to supply the needs of plumbing fixtures in the building design.
Sanitary System
Piping systems that convey the used water away from sanitary fixtures and toward the sewage systems.
A vertical pipe.
Main Pipe
A larger horizontal pipe that supplies water to smaller branch pipes.
Branch Pipe
A smaller horizontal pipe that conveys water from the main pipe to an endpoint fixture.