Creating Piping Systems

Piping systems are an essential part of designing piping layouts in Revit MEP 2015. 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 Families Browser 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
• Mechanical piping systems:
  • Hydronic Return
  • Hydronic Supply
• Other (You can't use any calculations for this option, so this option is appropriate only for systems that don't require calculations.)

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 in the Project Browser and selecting Duplicate. When duplicating piping systems, it is important to determine what the system classification should be and to 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. In other words, system classifications have limitations: 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.

Selecting the correct system classification can seem obvious for some system types—for example, chilled water is always going to be hydronic flow and return. However, lesser used systems can be more difficult—for example, medical gases and lab gases could fit into a number of different categories. It's essential to ensure that the system classification selected is then communicated to the entire team and used consistently throughout.

Each piping system can be assigned its own project-wide graphic override from within the system type properties (see Figure 11.2). 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 had not yet been built.

One important drawback is that, because the linetype 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 section “Defining Systems Visibility through Filters.”

Creating Pipe Types

Pipe types are typically set up in your company template. They represent the level of detail that your pipes and pipe fittings should display. There are many approaches to organizing your pipe types; in this section, you will examine the most common ones:

• Exact materials and fittings as they would be installed
• Generalized materials and fittings

The first approach is to think of pipe types 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′ (900 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. The benefit of this approach is a more detailed and accurate model. But the downsides can be overwhelming as well. Many systems could vary in materials and fittings, and the engineers may or may not know the material for the system at the time of modeling. And of course, in some cases, having too many material choices and fittings can overwhelm even the most knowledgeable modelers. This is a significant challenge when a company wants to target a high-detail level of the BIM model, but at the end of the day it would accomplish only what the person behind the computer is capable of. And in this case we are not talking about computer skills but engineering knowledge.

The second approach is to simplify things a bit and create pipe types that would cover more real-world systems under a single pipe type—for example, Gravity and Pressure. The gravity pipe type can be used for systems such as waste, grease waste, storm drain, and overflow leader. Pressure can be used for domestic hot water, domestic cold water, hydronic supply, hydronic return, and glycol. The limitations of this method are less-accurate models and volumes of the individual systems. Perhaps a combination of the two can be considered: generalization could be applied to most systems, except those for which volume calculations or the real size of fittings is of significant importance.

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 creates 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 Pipe Segment. You can find out or change the pipe material under the Pipe Segment selection by right-clicking the pipe type and choosing Type Properties Routing Preferences.

Now that you have created your pipe types, you will want to change some of the parameter options. First, start the Pipe command and click Edit Type from the Properties palette. 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 2014 introduced an improved pipe Type Properties dialog box with access to Routing Preferences settings (see Figure 11.3). 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 11.4). You can also designate different pipe segments at different sizes. For example hydronic piping (whether chilled, condenser, or heating water) may be copper up to about a size of 4″ to 6″ (100 to 150 mm) and be carbon steel pipe above that size. If you are going to designate different pipe segments, you must also make sure you set the fittings accordingly at the same sizes.

Under the Identity Data parameters group in the Type Properties dialog box, 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.

Defining Fitting Angles

From Manage MEP Settings Mechanical Settings (see Figure 11.5), you can allow the user to use any angle, allow an angle increment to be used, or predefine the angles of pipe and duct fittings that Revit can use when you are laying out piping. When you are drawing pipes, Revit still displays all angles in their temporary dimensions, but once you click to finish the pipe, the created elbow is rounded to the closest angle you have allowed from the Angles settings. This can enforce the use of industry-standard angles, thus ensuring the use of cheaper fittings for the project instead of custom angle fittings, which usually come at a premium price.

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 Family Browser and choose 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 download manufacturer-specific fittings.

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 Tee to None, and set 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 to 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 panel. 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 (see Figure 11.6). From here you can also change the Roughness setting and segment description or create a new pipe size.

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 11.6).

Using the Fluids Table

Revit MEP uses 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 11.7).

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 11.8a) and then name your piping system (see Figure 11.8b).

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 pipe route (blue) and branches (green):

1. Network This solution creates a bounding box around the components selected for the piping system and then bases several solutions on a main segment along the centerline of the bounding box with branches coming from the main segment.
2. Perimeter This solution creates a bounding box around the components selected for the system and proposes several potential routing solutions. You can specify the Inset value that determines the offset between the bounding box and the components. Inset is available only when the Perimeter option is selected.
3. Intersections This solution bases the potential routing on a pair of imaginary, perpendicular lines extending from each connector for the components in the system. There are potential junctions in the proposed solutions along the shortest paths, where the lines from the components intersect.
4. Custom This solution becomes available after you begin to modify any of the other solutions.

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 the additional manual layout. You can set the mounting height by clicking the Settings button from the Options Bar and inputting a new offset. Make sure to define the offset for both Main and Branch, as shown in Figure 11.9. When you're working with the autorouting command, several factors can affect the outcome—incorrect configuration of connectors, settings conflicting with the proximity of the equipment, elevation of the main pipe route and the branches, selecting flex duct type to be used, and so forth. For optimal results, have a plan view and a 3D view tiled to provide the most feedback about the final layout.

Manual Pipe Routing

When you are modeling pipes in Revit, develop good habits at configuring all the necessary settings while in the Pipe command. This is especially valid for inexperienced Revit users. Developing good modeling habits will serve you in the long run. Don't rush yourself. Take your time to confirm that all the settings are properly configured before you even draw the pipe. Some of the settings to pay attention to are Diameter and Offset from the Options Bar; System Type from the Properties palette; and Justification, Automatically Connect, Inherit Elevation And Size, Slope Off, Slope Up, Slope Down, Slope Value, and Tag On Placement, all available from the ribbon. You see that there are lots of settings to control, and they will certainly affect the outcome. So take your time to develop good habits when you are just starting with Revit.

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/masteringrevitmep2015.
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/masteringrevitmep2015.
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 11.10). Open the default 3D view {3D}, to review the architectural model.

   

4. Open the North Elevation and, from the Collaborate tab, click Copy/Monitor, pull down and click the Select Link choice, and then move the mouse over any architectural element to select the linked file and enter Copy/Monitor mode.
5. Click the Options button. For Reuse Matching Levels, choose Reuse If Within Offset and click OK. This ensures that your existing levels and floor plans will be reused instead of creating duplicates.
6. While still in the Copy/Monitor tool, select the Copy command to copy Level 1 and Level 2, and then click Finish.
7. Open view 1 – Mech. Download the file WSHP - Horizontal.rfa from www.sybex.com/go/masteringrevitmep2015. Choose Insert Load Family. Select WSHP - Horizontal.rfa from where you saved it and then click Open (see Figure 11.11).

   Note that this is a standard Revit file that is included within the U.S. Imperial Content library, and as long as U.S. Imperial Content has been loaded with Revit, the file can also be found at Insert Load Family Imperial Library Mechanical MEP Air-Side Components Heat Pumps.

   

8. Choose Systems Mechanical Equipment, and start placing the water source heat pumps (type 006) into each room. If needed, you can use the spacebar before placing the equipment to rotate it 90 degrees. After you have placed all the heat pumps into the model, right-click the water source heat pump you first placed and choose All Instances Visible In View. Then, in the Properties palette, change the Offset parameter to 9′-0″ (2,750 mm). This will allow you to set the correct elevation of equipment (see Figure 11.12).

   

9. Your system will require a fan coil unit and a closed-circuit cooling tower. Both families are already loaded into your project. Place them into the appropriate locations, as shown in Figure 11.13.

   

10. Next you need a centrifugal pump. Choose Insert Load Family Imperial Library Mechanical MEP Water-Side Components Pumps. Select Centrifugal Pump - Horizontal.rfa and then click Open. Place the pump where you want it to be located in the mechanical room (see Figure 11.14).

    

11. 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 parameter to 8′-6″ (2,600 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 11.15).

    

12. 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 choose Modify | Mechanical Equipment Piping. In the System Type list box, select Hydronic Return, as shown in Figure 11.16.

    

13. 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 11.17), and select all mechanical equipment that contains Hydronic Return connections. Repeat with Hydronic Supply.

    

14. 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 11.18, and then select the equipment connector you want to connect to an existing pipe (see Figure 11.19).

    

    

15. 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.

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.

The display of both fittings and valves can be challenging as you rotate the elements to represent the actual needed position. In some cases, they may become invisible. For example, when you place a valve in plan view at either coarse or medium detail level, you will see its symbolic representation, but if you go to a section, you won't see the valve at all. However, if you change it to fine detail level, you can see the geometry of the valve. This is because the valve is displayed as a symbol when showing single-line pipes, and with all of its 3D modeled geometry when in double-line pipe views. Currently the symbol can be displayed in only two opposite views (two sections, or floor plan and ceiling—in all other views it will be invisible). This is a known limitation with Revit, and to avoid it you should consider developing a standard for displaying valves and fittings, and at a certain level of detail.

Placing Valves

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 11.20). This behavior works even when you remove the valve: The pipes automatically fill in the gap where the valve used to be.

For some logical family categories, you can set this break into functionality in the Family Editor; choose Create Properties Family Category And Parameters (see Figure 11.21).

Adding Piping Insulation

Certain pipes require insulation. In some cases, this may be accomplished by simply annotating the insulated pipe, but in other cases you may need to model and display the pipe insulation. Pipe insulation in most cases is required when pipes are displayed as double lines. Currently, in order to place pipe insulation in Revit, the pipes need to be laid out already. You can do that by selecting individual pipes or entire runs of pipes and fittings and using the Add Insulation command under Modify | Pipes (see Figure 11.22). Pipe insulation visibility can further be controlled from the Visibility/Graphic Overrides dialog box and Object Styles, like any other Revit category. Once insulation has been added, it cannot be selected straight from the model. Rather, select the duct pieces and then click the Edit Insulation button.

Defining Systems Visibility through Filters

Revit MEP 2015 automatically creates logical piping systems for you when you lay out pipes, even when pipes are not connected to equipment. When drawing pipes, you need to specify the system type they belong to. The system type can define the line weight, linetype, color, and system abbreviation. The system abbreviation can be used to define what system will appear on what sheet via filters. This helps you hide the mechanical pipes in the plumbing views, and vice versa.

Establishing a good naming convention for the filters is important, because that would be the order in which 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. We 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! Notice that the Filter By setting is set to System Abbreviation Equals AV, as shown in Figure 11.23. 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.

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. If the view is controlled by a view template, then you must do this through View View Templates Manage View Templates. 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 settings for the pipe. 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 11.24), and they would still control line patterns, color, and line weights for specific cases. An example of this would be when you are using a 3D view. 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. You could then 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 11.25 and Figure 11.26).

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