Chapter 11

Mechanical Piping

Mechanical piping is the lifeblood of a heating/cooling system. Incorrect piping can lead to problems in the field, and locating the pipes may take months. There are simple two-pipe systems and more-complex multipipe systems. When using Autodesk® Revit® MEP 2013 to lay out your systems, you will be able to easily see your routing options and even calculate the total volume of fluid in your system.

In this chapter, you will learn to do the following:

• Adjust the mechanical pipe settings
• Select the best pipe routing options for your project
• Adjust pipe fittings
• Adjust the visibility of pipes

Mechanical Pipe Settings

When setting up the mechanical piping to route, you will want to apply the proper pipe material. The purpose of this is to provide a more accurate layout by showing the correct pipe sizes and fittings for that system. You will have to adjust several areas to set this up properly. Most important are the Piping Systems and Pipe Types settings. You can also adjust pipe segments and sizes, as well as the fluids table as needed. Each is described here in more detail. After you set up these areas, you can then concentrate on the autorouting or manual routing of pipe.

Creating Piping Systems

Piping systems are essential part of designing piping layouts in Revit MEP 2013. They allow you to separate pipes from one another based on the function they are serving, the color and line pattern they should be displayed with, the fluid type they carry, and so on. The Piping Systems Properties can be accessed and customized from Project Browser ⇒ Families ⇒ Piping Systems (see Figure 11.1). You can see the piping systems required in all projects in the Project Browser:

• Domestic piping systems (covered in other chapters):
  • Domestic Cold Water
  • Domestic Hot Water
  • Sanitary
  • Vent
• Fire protection piping systems (covered in other chapters):
  • Fire Protection Dry
  • Fire Protection Other
  • Fire Protection Pre-Action
  • Fire Protection Wet
• Other (You can't use any calculations for this option, therefore this option is appropriate only for systems that don't require calculations.)
• Mechanical piping systems:
  • Hydronic Return
  • Hydronic Supply

Figure 11.1 Renaming pipe types

Each of these items is what we call a system classification. System classifications are hard-coded in Revit and you can't create new ones. However, you can create additional system types by right-clicking any of the existing piping systems and selecting Duplicate. When duplicating piping systems, it is important to determine what the system classification should be and select an existing piping system that is already assigned to that system classification. Once you create your piping system and realize that the system classification is incorrect, there is nothing you can do but delete it and start over with another one that has the correct system classification. There are a number of limitations with the system classifications; you are not allowed to change the system classification of piping systems or create or delete any system classifications. In addition, you must have at least one piping system for each of the 11 system classifications, and you cannot delete any of them even if you don't need them for your project.

Each piping system can be assigned its own project-wide graphic override. This, combined with the ability to assign a segment of pipe to any of these piping systems without attaching it to a fixture or equipment, lets you improve the documentation produced earlier in the design process, when equipment families have not been yet been built.

Benefit of Piping System Graphic Overrides

Ann is working on the early schematic of a mechanical piping design for a large convention center. The architect has already boxed out some space for the mechanical room containing chillers and pumps as well as the general location of the remote air-handling equipment. Now they need to begin coordinating piping chases throughout the structure.

Because the mechanical equipment has not yet been selected, Ann hasn't built the equipment families, but she still wants to be able to show both 2D and 3D plans of the proposed piping sizes and locations with the appropriate line types and colors. All that is required is for her to duplicate the existing piping-system hydronic supply and create chilling water supply and heating water supply (CHWS, HHWS) piping systems, as well as duplicate the hydronic return to make the chilled and hot water return systems (CHWR, HHWR). Next, she right-clicks each and sets the graphic override for each system to match the office standard line weights, line types, and colors.

Now all that remains is to select the Pipe command and, before clicking to start a run, select the newly created system type in the Properties palette and model her pipe. The graphic overrides apply across the whole project, so every view will automatically show the mechanical pipe with the correct graphic settings.

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One important drawback is that, because the line type settings for piping systems are applied in all views, the common dashed-line patterns that are used with single-line pipe display (coarse or medium detail) will also dash the double-line pipe views (fine detail). For this reason, you can apply view filters to override any piping system graphic overrides. View filters are discussed in more detail later in this chapter in the “Defining System Visibilities through Filters” section.

Creating Pipe Types

To understand Revit MEP pipe types, imagine them from the perspective of the installer. The pipe type is related to the material and style of fitting used. For instance, both chilled and hot water mechanical pipes, 3′ (914 mm) in diameter and under, are commonly constructed from copper with soldered or brazed sweat joint fittings. This should be the basis of your pipe type.

To modify and create new pipe types, in the Project Browser choose Families ⇒ Pipes ⇒ Pipe Types and then right-click the Standard type. Select Duplicate. This will create the additional pipe types you will need for your project. Next, right-click the duplicated pipe types and rename them to the pipe types you require. It is preferable to rename them to the pipe material type selected under the Pipe Segment. You can find out or change the pipe material under the Pipe Segment selection by right clicking over the pipe type and going to its Type Properties ⇒ Routing Preferences.

Now that you have your pipe types created, you will want to change some of the parameter options. First, right-click the pipe type you want to edit and select Type Properties. This opens the Pipe Type parameters. With regard to careful space planning, the accurate selection of fittings is the most important and most time-consuming task when setting up your pipe types.

Revit MEP 2013 introduces and improved pipe Type Properties dialog box with Routing Preferences (see Figure 11.2). In the past you could assign only one elbow or tee family per pipe type; now you have the option to set different fittings based on the pipe size you are drawing (see Figure 11.3).

Figure 11.2 Type Properties dialog

Figure 11.3 Routing Preferences dialog

Under the Identity Data parameters group, the following parameters are available: Keynote, Model, Manufacturer, Type Comments, URL, Description, Assembly Description, Assembly Code, Type Mark, and Cost. If you have a certain manufacturer, model, or other special note that you want to denote on the plans, you can use these settings to describe your pipe type further (see Figure 11.2).

Selecting Fittings for Routing Preferences

Before you can adjust the Routing Preferences, you need to create the fittings that will go with your system pipe types. To accomplish this, open the Project Browser and choose Families ⇒ Pipe Fittings. Then select the fittings that will be required for your Pipe Type parameters. You can either load the appropriate family from the Autodesk library or other source or right-click each of the family fittings and duplicate standard generic Elbow, Cross, Coupling, Tee, and Transition fittings. After duplicating or loading each desired fitting, rename them to the associated material of each pipe that you previously duplicated to create your pipe types (see Figure 11.4).

Figure 11.4 Duplicating and renaming fittings to match pipe types

One noteworthy option that is missing from the Fitting parameters is a pipe spud. To date, Autodesk has not included this pipe fitting family with its content. However, several pipe spud families can be downloaded from the Internet. If you would like to use one in your Steel-Welded pipe type, you first have to load the family into your project. Next, duplicate your pipe type and rename it Steel-Welded-Tap. It is critical that you have a separate pipe type because the Preferred Junction Type fitting parameter is set here. Change it to Tap, set the Tee to None, and the Tap parameter to Pipe Spud (the name of the family you have downloaded or created). Now you will be able to easily choose whether to model pipe with tee fittings by selecting the pipe type Steel-Welded, or model with spud-style tap fittings by selecting Steel-Welded-Tap.

Choosing Pipe Materials and Sizes

To access the pipe material settings, choose Systems ⇒ Plumbing & Piping and then select the small arrow in the lower-right corner of the ribbon. This opens the Mechanical Settings dialog box. (Alternatively, choose Manage ⇒ MEP Settings ⇒ Mechanical Settings.) Next, choose Pipe Settings ⇒ Segments And Sizes. If you want to create a new pipe segment, you can duplicate an existing pipe segment and rename it to the new pipe segment required (see Figure 11.5). From here you can also change the Roughness setting and Segment Description or create a new pipe size.

Figure 11.5 Creating new Segments And Sizes

Adjusting the Pipe Sizing Table

If you want to adjust the sizing table, choose Systems ⇒ Plumbing & Piping, and select the small arrow in the lower-right corner of the panel to open the Mechanical Settings dialog box. Next, choose Pipe Settings ⇒ Segments And Sizes. You can duplicate the schedule of pipe and apply the pipe wall thickness as required. You can also select and deselect the piping sizes to match your design standards (see Figure 11.5).

Using the Fluids Table

Revit MEP will use the fluids table when you are sizing your pipes or determining pressure drop. You can add information concerning temperature, viscosity, and density to the fluids table. To do this, choose Systems ⇒ Plumbing & Piping, and select the small arrow in the lower-right corner of the panel to open the Mechanical Settings dialog box. Next, choose Pipe Settings ⇒ Fluids. Then duplicate one of the fluid categories that is close to the one you need, and modify it as required (see Figure 11.6).

Figure 11.6 Fluids table settings

Pipe Routing Options

The size of a mechanical piping model can grow quite large because of the amount of fluids constantly transferred, so it is very important that routing is closely coordinated. Using Revit MEP 2013, you can improve visual coordination with color-coded systems and use interference checking to monitor conflicts with cable trays or sprinkler piping. Two routing options are available when you set out to design your piping model: the autoroute option and the manual routing option. Both are described in this section.

In smaller systems, the autoroute feature may be beneficial. However, in most circumstances, manual routing will be of greater benefit to you. This is because a good design engineer can optimize a system with regard to construction of pipe and coordination with other trades, especially structure.

Automatic Pipe Routing

Ideally, you have everything set up in your pipe types before you begin routing piping. To start automatic pipe routing, first assign your equipment to a piping system. Select two or more pieces of mechanical equipment and, from the Modify | Mechanical Equipment tab, click Create Systems ⇒ Piping (see Figure 11.7a) and then name your piping system (see Figure 11.7b).

Figure 11.7 Create your piping system.

Next, select any piece of equipment assigned to the system and click the Generate Layout button. You have four options for generating the layout: Network, Perimeter, Intersections, and Custom. Each one has several routing solutions from which you can choose, consisting of a main (blue) and branches (green):

The autoroute feature is most useful in small, simple layouts. Usually, the greatest benefit comes from using the autoroute pipe as a starting point and finishing with additional manual layout. You can set the mounting height by clicking the Settings button from the Options tab and inputting a new offset. Make sure to define the offset for both Main and Branch (see Figure 11.8).

Figure 11.8 Autoroute piping layout

Manual Pipe Routing

Manual routing of piping is the next method. When routing, manually start the piping run at the elevation that you know will most likely be out of the way of other disciplines. Use the following steps to set up and place mechanical equipment, create a hydronic supply and return, and manually route pipe to all pieces of equipment:

1. Open the Ch11_Project.rvt file found at www.sybex.com/go/masteringrevitmep2013.

2. One of the best practices is for the architectural model to be linked into the mechanical model. Download the model C11_base.rvt file found at www.sybex.com/go/masteringrevitmep2013.

3. Choose Insert ⇒ Link Revit, select the directory into which you downloaded the Revit base, select Auto - Origin To Origin from the Positioning drop-down, and then select Open. By selecting Origin To Origin, you are assured that the model will be properly located (see Figure 11.9). Open the default 3D view, {3D}, to review the Architectural model.

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Figure 11.9 Linking the Revit model, Auto - Origin To Origin

Importance of Templates

To improve productivity in piping layouts, make sure to create and maintain project templates that contain your company standards. Properly created project templates ensure that everyone in your firm is on the same page when creating mechanical piping systems. For more information on how to create project templates from existing projects, refer to Chapter 2, “Creating an Effective Project Template.”

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4. Open the NORTH Elevation and, from the Collaborate tab, select the Copy/Monitor tool. When prompted, select the link file and then select the linked files for Level 1 and Level 2. Click the Finish button.

5. From the View tab, choose Plan Views ⇒ Floor Plan, and create views for Level 1 and Level 2. Open Level 1.

6. Choose Insert ⇒ Load Family ⇒ Imperial Library ⇒ Mechanical ⇒ MEP ⇒ Air-Side Components ⇒ Heat Pumps. Select WSHP - Horizontal.rfa and then select Open (see Figure 11.10).

Figure 11.10 Water source heat pumps

7. Choose Systems ⇒ Mechanical Equipment, and start placing the water source heat pumps (type 006) into each room. After you have placed all the heat pumps into the model, right-click the water source heat pump you first spotted and choose All Instances ⇒ Visible In View. Then, from the Properties dialog box, select Offset and change the offset to 9′–0′ (2750 mm). This will allow you to set the correct elevation of equipment (see Figure 11.11).

Figure 11.11 Verifying the offset for the correct elevation

8. Your system will require a boiler and a closed-circuit cooling tower. Choose Insert ⇒ Load Family ⇒ Imperial Library ⇒ Mechanical ⇒ MEP ⇒ Water-Side Components ⇒ Boilers. Select Boiler.rfa and then select Open. Repeat the process to load the Cooling Tower - Closed Circuit - Counterflow - 37-211 MBH.rfa file from the Cooling Tower directory located in Water-Side Components. After locating these in the project, place them into the appropriate locations, as shown in Figure 11.12.

Figure 11.12 Placing mechanical equipment

9. Next you will need a centrifugal pump. Choose Insert ⇒ Load Family ⇒ Imperial Library ⇒ Mechanical ⇒ MEP ⇒ Water-Side Components ⇒ Pumps. Select Centrifugal Pump - Horizontal.rfa and then select Open. Place the pump where you want it to be located in the mechanical room (see Figure 11.13).

Figure 11.13 Placing the pump in the mechanical room

10. You are now in a position to start routing piping. Route your mains first so you can make sure that most of the piping will fit before connecting all the branches to the mains. Select the proper piping material before starting your layout. This will help if you need to do a quantity takeoff for budgeting purposes. To route your pipe, choose Systems ⇒ Pipe. Change the offset to 8′–6″ (2600 mm) and pipe size to 2″ (50 mm); also make sure to select the pipe system type and route piping mains in the corridors and into the mechanical room (see Figure 11.14).

Figure 11.14 Routing pipe mains

11. Before you start connecting piping, you will need to make sure that your mechanical equipment is set up for both hydronic supply and return systems. To do this, select one of the pieces of mechanical equipment, and then go to Modify | Mechanical Equipment ⇒ Piping and under System Type select Hydronic Return (see Figure 11.15).

Figure 11.15 Creating mechanical piping systems

12. After you have selected the hydronic return, go to the Edit Piping System tab, select Edit System, and edit the Hydronic Return system name. Then select Add To System (see Figure 11.16), and select all mechanical equipment that contains Hydronic Return connections. Repeat with Hydronic Supply.

Figure 11.16 Adding equipment to systems

13. Cutting sections when routing piping can really improve the coordination success of your Revit model. If you want to automate things a bit, instead of drawing all the pipes yourself you can select any equipment with pipe connectors, select Connect Into from the Modify | Mechanical Equipment tab, shown in Figure 11.17, and then select the equipment connector you want to connect to an existing pipe (see Figure 11.18).

Figure 11.17 Selecting Connect Into

14. Repeat steps 6 through 13 for all your piping systems. Taking a few minutes to review any clashes between the structure, mechanical, and architectural models can really cut down on potential field conflicts. After you have coordinated with other services/structures and verified your layout, the layout will be complete.

Figure 11.18 Using Connect Into

Pipe Fittings

Without fittings, piping would not be worth a whole lot. Fittings help shut off the flow, help regulate temperature, and help save lives. In Revit, most fitting families have the following functions:

Using Pipe Fitting Controls

Understanding pipe fitting controls can really make life easier if you are routing a lot of piping. When you are laying out your piping, turn 90 degrees to create an elbow. If you click the elbow, you will notice a plus (+) sign. If you click that sign, it will change from an elbow to a tee, allowing you to add more piping and continue your pipe routing. If you click the minus (-) sign, it will downgrade the fitting. When you see the symbol on a fitting, it allows you to rotate the fitting, and the symbol allows you to flip the fitting.

Placing Fittings

When you need to add valves to your piping, select the System tab and then select Pipe Accessory. Use the Type Selector to select the type of valve you want to use. Most valves are break into types, so you can place them into a pipe run, and they will break into the piping, maintaining connections at either end (see Figure 11.19).

Figure 11.19 Fitting breaks into a piping system

For most logical family categories, you can set this break into functionality in the Family Editor; choose Create ⇒ Properties ⇒ Family Category And Parameters (see Figure 11.20).

Figure 11.20 Fitting breaks into the definition

Defining Systems Visibility through Filters

Revit MEP 2013 will automatically create the logical piping systems for you when you lay out pipes, even when pipes are not connected to equipment. When drawing pipes you will need to specify what system type it belongs to. The system type will define the line weight, line type, color, and system abbreviation. The system abbreviation can be used to define what system will appear on what sheet via filters. This will help you hide the mechanical pipes in the plumbing views and vice versa.

Establishing a good naming convention for the filters is very important, because that would be the order you see them in your Properties palette when drawing pipes. The default examples of filters and their settings are not going to get you too far with your projects. I recommend that you take your time and come up with a complete list of systems that your company uses and create them as system types and filters in Revit MEP. Organizing all of them in Microsoft Excel can be very beneficial! (See Figure 11.21.) Notice that the Filter By setting is set to System Abbreviation Equals AV. Bear in mind that the parameter System Abbreviation was not available prior to Revit MEP 2012 and the settings would be different for those projects and templates. To create new filters simply click the New button in the lower-left corner.

Figure 11.21 Sample filters and their settings

Once the filters have been created, go into each view where you want the different disciplines to show up and type VG to bring up the Visibility/Graphic Overrides dialog box. Click the Filters tab, and add the newly created filters. Using the Visibility check boxes on the Filters tab, you can define the systems to be visible in that view. In the past filters were used to also define color, line patterns, and in some cases line weights. Since Revit MEP 2012 the recommended place to control those is in the system type. This way, those settings will be global rather than per view. However, the filters would still be managed and would control what system is visible in what view (see Figure 11.22).

Figure 11.22 Adjusting visibility of pipe and duct systems through filters

Now that your plans are coordinated and displaying the way you require, you are well on your way to completing your documentation.

Earlier we said that colors, line types, and line weights should be controlled via the system type. Well, every rule has its exception, and here is a great example for this. When you control the colors and line patterns of your systems in the 3D views, it will color the contour of the pipe, making the pipes hard to see. Instead of going that route, you could override those in the filters with a solid pattern; this way, your 3D views would be a lot easier to view and understand (see Figure 11.23 and Figure 11.24).

Figure 11.23 The same model displayed without filter overrides (on the left) and with overrides (to the right)

Figure 11.24 Applying filter overrides for 3D views

The Bottom Line