You will need pipe types defined, some fitting families loaded, and something to which they will all connect. Equipment is the source of the system, and the pipe and fittings connect everything. It seems pretty simple, but there are several things to consider when setting up the components of a pipe system.
Pipe types allow you to assign materials, connection types, identity data, and the fittings that will be used to connect it all together (see Figure 9.18). Material, Connection Type, and Class are all set up in the Type Settings dialog box. These should all reflect real-world values and the company standards and specifications. Even if you are not using Revit to size or lay out pipe automatically, not setting up the appropriate pipe types can cause headaches down the road.
Pipe types should not be left at Standard and PVC. That hardly covers the necessary piping that a building requires and, more importantly, the plumbing and mechanical engineering will be fighting over what fittings should be standard and what materials should be used. Mechanical piping and plumbing piping should have their own pipe types. Even if exactly the same materials and fittings are being used, there may be changes later, and splitting out pipe types late in a project will undoubtedly eat up a lot of time. This is one area of Revit MEP that enables you to have as many types as you want, so take advantage of it.
Pipe sizes and materials are set up in the Mechanical Settings dialog box (see Figure 9.19), and similar to pipe types, should be separated for plumbing and mechanical piping. In many instances, you would probably be fine using the same material and sizes, but when differentiating them is as simple as selecting the Add Material icon and selecting a source from which to
copy, there is no reason not to create as many sizes and materials as needed. All of these settings should also be determined by using the company standards and specifications. It may seem tedious to set up, but if the inside diameter of a 6″hot water pipe is not true, and you are using a
lot of it, your pipe volume calculations can be skewed.
Used In Size Lists vs. Used In Sizing
In the Mechanical Settings dialog box, Used In Size Lists means that the drop-down list for available sizes will contain this size pipe; this drop-down list can be easily accessed while routing or modifying pipe in the Generate Layout tool. Think of the Used In Sizing option as granting Revit permission
to use a particular pipe size. If neither is selected, the size will not be available to the user.
Fittings should be set up after sizes and materials for a couple of reasons. First, the connection type needs to match. A solvent-welded PVC fitting and a flanged steel fitting are vastly
different. Second, the fittings need to be defined at all the available sizes for that type of pipe; if it goes down to 3/8″or up to 36″, the fitting needs to accommodate. Fittings are going to be very
specific to the type of system, which is another reason to separate pipe types for plumbing and mechanical uses.
Hydronic systems have value even if the equipment is not piped together. Terminal box reheat coils are a good example, because details generally cover their final connections. By simply adding all the terminal boxes to a hydronic supply and hydronic return system, you will be
able to see the total flows for the entire model. You can use this flow summation to ensure that systems are adding up to what you expect and to compare flows between systems.