1. Mastering Autodesk Revit MEP 2016 CHAPTER 9: Creating Logical Systems

2. Managing Systems Why are systems important?
Data in one location (the building model)
Aids in making design decisions more efficiently
Improves file performance
Without user-created systems, all components on the Unassigned system cause Revit to calculate through everything on the system when changes are made
Entering all the information needed to accurately represent the mechanical systems in a building may seem like a daunting task at first, but the benefits of having all the information in one place and directly in front of the user can lead to more accurate designs. Instead of flipping between a building load program and a duct sizing chart and trying to keep track of which terminal box is serving which space, systems can handle all of that for the user.

3. Managing Systems Mechanical Settings
Options for Air Density and Air Viscosity
Fluid temperature, viscosity, and density settings for pipe systems
Duct and Pipe settings affect how automatic routing of systems will behave
Before you jump in and start creating systems, there several things that need to be set up to ensure systems work as they should.
The Mechanical Settings dialog contains some of the most critical settings for using systems in Revit MEP Many of these settings have to do with the graphical representation of mechanical components, but there are a few that affect systems, such as the Calculation method that can be set for duct and pipe pressure drop.

4. Managing Systems System Browser
Interface to view all systems in a project
Customizable display of available columns for data reference
Direct link to model components via right-click context menu
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The System Browser summarizes all the systems currently in the model. You can keep track of all the air and water in the building and see your system totals at a glance. The System Browser in Revit MEP 2016 takes this idea a step further by providing a live link to the components in the system as well as some of their parameters.
Ideally every connection on every piece of equipment would be associated with a system, and the Unassigned system category would be empty. This may not be realistic on a large job or where manufacturer content is being used. You may not model every condensate drain, but if the manufacturer has provided a connection point for it, there will be a listing in the System Browser.

5. Creating Systems Air Systems Parameters Connector Properties
Flow Factor
Percentage of system flow seen by the connector
Loss Coefficient
Available only when Loss Method is set to Coefficient
Used with Flow to determine pressure Drop
Flow Configuration
Calculated – sum of downstream flow
Preset – user-defined value
System – percentage of total system
Flow Direction
In, Out, or Bidirectional flow of air at connection point
System Type
Set when connector is added to family
Fitting – allows for pass-through connection to any system
Global – inherits the characteristics of whatever system connects to it
Duct connectors in Revit MEP allow the user to connect ductwork to a family that may represent an air terminal or some type of mechanical equipment.
It takes a good understanding of the parameters besides height and width (or radius) before setup of complex air systems can occur. There are 14 parameters associated with a duct connection when it is not set to Fitting. Not all of the 14 are active all the time.
When a duct connector is set to Fitting, there are fewer parameters because fittings are made to be used by various systems.

6. Creating Systems Air Systems Parameters Connector Properties Shape
Loss Method
Not Defined – no loss accounted for in calculation
Coefficient – based on value of Loss Coefficient parameter
Specific Loss – known value
Pressure Drop
User input value, can be linked to a family parameter
Flow
User input value, in conjunction with Flow Configuration settings
Shape
Rectangular, Round, or Oval
Height, Width, and Radius can be associated with family parameters
Utility
Indicates that the connector is a point of service
Exports to ADSK for use by Civil 3D
Connector Description
User-assigned name of connector
Duct connector parameters continued

7. Creating Systems Pipe Systems Parameters System Types
Hydronic Supply – supply systems other than domestic water
Hydronic Return – return systems other than domestic water
Sanitary – waste piping systems
Domestic Hot Water – plumbing water piping
Domestic Cold Water – plumbing water piping
Other – useful for any specialty piping
Fire Protection – incoming utility fire protection piping or building sprinkler piping
Fire Protection Wet – piping from riser to sprinkler head
Fire Protection Dry – piping from riser to sprinkler head or standpipe
Fire Protection Pre-Action – deluge system piping
Fire Protection Other – glycol antifreeze or chemical suppression
Mechanical piping benefits greatly from systems in Revit MEP Graphics, annotations, flow, and pressure loss can all be handled with a small amount of setup on the front end. Pipes on different systems will not connect to one another even if they are at the same elevation.
Parameters for pipe connectors are similar to the parameters for duct connectors. They determine the behavior of a system and how components can be connected.

8. Creating Systems Mechanical Air Systems Upstream workflow
Select objects with like connectors and create system from contextual tab on Ribbon
Select equipment for the system
It is important not to “add” the equipment to the system; it must be established as the equipment
Line indicates system connectivity
Creating an air system in your model is a simple process of working your way upstream through the components that will make up the system. The components that define the terminal points are selected, and the available system is created via the Ribbon. Once the system is created, you can select the equipment that feeds the terminal components.
Components with multiple connectors can be part of separate systems. For example, the VAV box is the equipment for the air terminal air system, but it can also be the terminal point for an air system driven by a rooftop unit.

9. Creating Systems Mechanical Pipe Systems
Same workflow as for air systems
Work upstream, select terminal points, establish system, select equipment
Pipe types should be created for specific materials
Pipe systems should be created for design and identification
Allows for easy visibility control through view filters
Different fittings may be required based on the system
This is the same workflow as for air systems.
Creating specific system types is a good way to keep your design organized. Then having material-based pipe or duct makes it easy to create view filters that allow for different display of each system.

10. Creating Systems Systems Display
View filters provide the ability to override the display of specific pipe types
Filter by Type Name
Filter by System Type
View filters can be used to assign a color, line type, and line weight to a particular system. The filter can be applied to several categories, and the filter rule can be set to look for a specific system type.