mechanical equipment category-air handling unit

8/9/2019 Mechanical Equipment Category-Air Handling Unit

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REVIT CATEGORY‐SPECIFIC GUIDELINES:

MECHANICAL EQUIPMENT CATEGORY – AHU FAMILIES

This

document

includes

Autodesk

specifications

for

the

creation

of

Revit

Air

Handling

Unit

families

within

the

Revit

Mechanical Equipment category. Following the criteria suggested by both this guide and the Revit Model Content

Style Guide will enable manufacturers and other content creators to create Air Handling families that adhere to

Autodesk and Autodesk® Seek standards for Revit Mechanical Equipment families.

While this document contains specific air handling unit family creation guidelines, it is not intended to provide

specifications for every kind of air handling unit. A sample air handling unit family is provided as an example to

convey the standards outlined within this document, but many other air handling unit types may be created using

these resources as a reference.

RMCSG 2.1 — page 1


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AIR HANDLING UNITS Category: Mechanical Equipment

Behavior: Non‐hosted

Family Template(s):

Imperial Templates

• Mechanical Equipment.rft

Metric (generic) Templates

• Metric Mechanical Equipment.rft

NOTE: Do not use the wall or ceiling hosted family templates as they will not work in a MEP file with a linked

architectural model.

NAMING CONVENTIONS

Use the following guidelines when naming a new air handling unit family:

Format:

< Functional

Type>

‐

‐

‐

‐

Note: Refer to the Revit Master Part Type List (included in the download package) for information on approved

Function Types and Subtypes.

Guidelines:

• Create unique names for each air handling unit family.

• Use natural language to name the family.

The family name should describe how the family is identified in the real world (for example, in catalogs or

by manufacturer).

• If possible, do not include the family category in the family name.

•

Use a Descriptor

parameter

to

include

a model

number,

cooling

or

flow

rate,

if

appropriate.

• Capitalize the leading letters in each portion of the family name.

• Keep file names as short as possible.

Family names must display in dialogs and in Type Selector.

• Do not use spaces between words in file names. To separate words within a syntax element (e.g.,

Manufacturer or Descriptor), use the underscore character (_).

• If a type catalog is to be used with a family, name the type catalog (.txt file) with the same name as the

family.



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Examples:

• Air_Handling_Unit– Packaged–Acme_Mechanical–Series_I–(30‐50Ton)

• Air_Handling_Unit–Modular–Acme_Mechanical–Series_3– (750‐1200CFM)



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SUBCATEGORIES

The mechanical equipment family template (mechanical equipment.rft) that is provided with the Revit software

creates

subcategories

that

you

can

use

to

control

the

display

of

air

handling

unit

geometry

(see

Table

1

below).

You may not need to use the default subcategory that is provided by the mechanical equipment family template.

You may also need to add subcategories. Table 2 below contains a list of Autodesk‐approved subcategories that

you can add to mechanical equipment families. If you need to add subcategories that are not listed in Table 2, use

the subcategory naming conventions and approval procedure described in the Revit Model Content Style Guide.

Table 1 ‐ Default subcategories and settings provided by the Mechanical Equipment.rft template:

Category/Subcategory

Line Weight

Line Color Line Pattern Material Projection Cut

Mechanical Equipment

1 ‐

Black Solid Hidden Lines 1 ‐ Black Dash

Table 2 ‐ Create these additional subcategories as needed:

Category/Subcategory

Line Weight

Line Color Line Pattern Material Projection Cut

Air Handling Unit 1 ‐ Black Solid



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CONNECTOR SETTINGS

This section includes the parameters for typical connectors used in Air Handling Units. It is important to verify the

connector

settings

before

testing

the

family.

Typical AHU Connectors

ID Connector Description Discipline Placement Shape / Type

1 Equipment Power Electrical Face Power

2 Chilled Water Connection Inlet Piping Face Round

3 Chilled Water Connection Outlet Piping Face Round

4 Heating Water Connection Inlet Piping Face Round

5 Heating Water Connection Outlet Piping Face Round

6 Supply Air HVAC Face Rectangular

7 Return Air HVAC Face Rectangular

8 Condensate Drain Piping Face Round

HVAC Connector Parameters:

ID 6 7

Flow Direction Out In

System Type Supply Air Return Air

Flow Configuration Calculated Calculated

Flow Actual Supply Airflow Actual Return Airflow

Loss Method

Not

Defined Not

Defined

Pressure Drop N/A N/A

Pipe Connector Parameters:

ID 2 3 4 5 8

Connector

Description

Chilled Water

Connection Inlet

Chilled Water

Connection

Outlet

Heating Water

Connection Inlet

Heating Water

Connection

Outlet

Condensate

Drain

Flow Direction In Out In Out Out

System Type Hydronic Supply Hydronic Return Hydronic Supply Hydronic Return Sanitary

Allow Slope

Adjustments

No No No No Yes

Flow

Configuration

Preset Preset Preset Preset Preset

Flow Family – Actual

Chilled Water

Flow

Family – Actual

Chilled Water

Flow

Family – Actual

Heating Water

Flow

Family – Actual

Heating Water

Flow

Family – Actual

Condensate

Drain Flow



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ID 2 3 4 5 8

Loss Method Not Defined Specific Loss Not Defined Specific Loss Not Defined

Pressure Drop 0 Family – Cooling

Coil Water

Pressure Drop

0 Family – Heating

Coil Water

Pressure Drop

N/A

Radius

Family – Chilled

Water

Connection Inlet

Radius

Family – Chilled

Water

Connection

Outlet Radius

Family – Heating

Water

Connection Inlet

Radius

Family – Heating

Water

Connection

Outlet Radius

Family –

Condensate

Drain

Connection

Radius

Electrical Connector Parameters:

ID 1

Power Factor 1.0

Apparent Load

Family

– Apparent

Load

Voltage Family – Voltage

System Type Power ‐ Balanced

Load Classification HVAC

Power Factor State Lagging

Balanced Load Yes

Number of Poles Family – Number of Poles



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REFERENCE PLANES

Use reference planes in air handling unit families to control dimensioning and snapping. A number of predefined

and named reference planes are provided by the template used when creating an air handling unit family. (See

Table 1 below)

Table 1 ‐ Reference Planes provided by the Mechanical Equipment.rft template:

Name Is Reference (strength) Defines Origin?

Center (Left/Right) Center (Left/Right) (Strong) Yes

Center (Front/Back) Center (Front/Back) (Strong) Yes

‐ Not a Reference Yes

Table 2 ‐ Reference Planes to be added to the Mechanical Equipment family file:

Name Is Reference (strength) Defines Origin?

Rename “‐“ to “Bottom” Bottom Yes

Top Top No

Front Front No

Back Back No

Left Left No

Right Right No

When you need to add reference planes to an air handling unit family:

• Any reference planes that you do not need to dimension or snap to, should be set to an Is Reference value

of Not a Reference.

• Keep reference plane naming consistent with those provided by the template.



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PARAMETER USAGE

A list that contains all Autodesk‐approved parameters, Revit Master Parameter List.xls, is provided in the download

package.

The

Mechanical

Equipment

section

of

this

list

contains

all

of

the

approved

parameters

for

Air

Handling

Unit families. In the following image, a small sample of the shared parameters for Mechanical Equipment is shown.

IMPORTANT: Refer to the Revit Master Parameter List for complete information.

In addition, a master shared parameter .txt file which including standard Autodesk shared parameters is also

included in the download package.

Make sure that any parameters added to an air handling unit family are included in the Revit Master Parameter

List. If new unlisted parameters are needed, use the parameter naming conventions and approval procedure

described in the Revit Model Content Style Guide.

The next sections describe some of the parameters that should be considered, or possibly included when creating

an air handling unit family for distribution.



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DIMENSION PARAMETERS

The main dimension parameters for air handling unit families are:

• Width

•

Supply

Air

Connection

Width

• Supply Air Connection Height

• Return Air Connection Width

• Return Air Connection Height

• Length

• Height

The Height and Width parameters determine the basic dimensions of the air handling unit family. The Supply and

Return Air Connection Width and Height parameters control the dimensions for the air connections and geometry.

When the family is loaded into a project and an air handling unit is created, height, length and width dimensions

will display the Height, Length and Width parameter values.

CSI – OMNICLASS 1.0, MASTERFORMAT 2004, AND UNIFORMAT II PARAMETERS

On Autodesk Seek, air handling unit families can be located by the appropriate CSI Omniclass 1.0, MasterFormat

2004, and UniFormat II codes. When sharing content with Autodesk Seek, indicate the code within the

classification that should be assigned to the content.

Refer to the Revit Model Content Style Guide for information on including CSI Classification Codes with Revit

families.

AUTODESK SEEK‐SPECIFIC SHARED PARAMETERS

In

addition

to

the

system

parameters,

there

are

a

number

of

shared

parameters

that

can

be

added

to

air

handling

unit families. Many of these parameters can be used to filter results when searching for air handling unit families

on Autodesk Seek. It is recommended to add these parameters to manufactured air handling units intended for

distribution on Autodesk Seek.

Refer to the Revit Master Shared Parameter File.txt (included in the download package) for a list of the Autodesk‐

approved shared parameters.

COST PARAMETER

When creating a manufactured air handling unit for distribution on Autodesk Seek, it is recommended to not

specify actual data for the Cost parameter as the value will change with time and/or configuration of the specified

product. (To

locate

the

Cost

parameter,

open

the

Family

Types

dialog

for

the

family,

and

scroll

to

the

Identity

Data

section.)



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TYPES

NAMING CONVENTIONS

All air handling unit families must include one predefined type. Predefined types should be generated for

families that are available in standard sizes. Unless they represent nominal sizes, type names should include

units or capacity and include a unit indicator.

Format:

For manufacturer‐specific air handling unit content:

Use a descriptive, catalog code for the air handling unit name and size:

Ton ‐ BTU ‐ ‐

If the family name includes any specific property, exclude that value from the type name.

Example:

Family: Air_Handling_Unit– Packaged–Acme_Mechanical–Series_I–(30‐50Ton)

Types: 30 Ton – Electric Heat – 208V/60Hz/3Ph

40 Ton – No Heat – 230V/60Hz/3Ph



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AIR HANDLING UNIT REPRESENTATIONS IN STANDARD VIEWS

TYPICAL

ELEVATION

VIEW

View Scale: 1/2 = 1’=0” (Imperial)

1:20 (Metric)

Representation features:

• Minimal detail, optimized for performance

TYPICAL PLAN VIEW ‐ COARSE/MEDIUM DETAIL


1:20 (Metric)


•

Minimal detail,

optimized

for

performance



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TYPICAL PLAN VIEW ‐ FINE DETAIL


1:20 (Metric)


• More detail

• Model Lines representing additional unit features

Origin:

Insertion Point: Left and Back Corner



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PREVIEW VIEW


•

A 3D

view

of

the

air

handling

unit

• Turn off visibility of annotation categories in Visibility/Graphics

• Set the Model Graphics Style to Shading with Edges

• Set Detail Level to “Fine”

• Use a Temporary Hide/Isolate to hide any connection objects

NOTE: See the Revit Model Content Style Guide for Preview view creation guidelines.



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BEST PRACTICES

In addition to the guidelines published in the Revit Model Content Style Guide, use these Mechanical Equipment‐

specific best practices:

TYP E CATALOGS

• Create a type catalog for Mechanical Equipment families that contain more than six types (sizes).

PERFORMANCE

• Do not model hidden faces or internal components.

• Avoid modeling curved surfaces where possible. Only model curved surfaces where essential to depict the

part design.

• Avoid excessive use of voids, formulas, and arrays.

CONNECTORS

• Add a description for each connector. The description should detail the intent of the connector (for

example, Heating Water Supply In, Heating Water Return Out, Chilled Water Supply In, Supply Air, Return

Air, etc).



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TESTING GUIDELINES

Use these Mechanical Equipment‐specific testing guidelines as a supplement to the general testing guidelines in

the

Revit

Model

Content

Style

Guide.

1. Open a test project:

To test an imperial family, use the MEP_AHU_Testing_Template_Imperial project (included in the

download package).

The test project includes pre‐defined systems, rooms, and spaces to test the family’s ability to interface

with each kind of element. Each of the views is set to the corresponding level of detail. The project also

includes Coarse, Fine, and Medium versions of certain views. The views are set this way so you can add an

element to one view, and then open the two other views to inspect the element the different levels of

detail.



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2. Load the air handling unit family in the test project:

If the family uses a type catalog, select and load all the family types to verify that they load correctly. (To

select all types, select the first type, press and hold Shift, and select the last type.)

In a plan view (Level 1 Mech – Coarse):

3. Using the default type (size) that displays in the Type Selector when you start the Mechanical Equipment

command, place an air handling unit into the project.

4. Test each air handling unit instance:

• Check the insertion point of the air handling unit.

• Verify that the air handling unit connector objects function correctly for mechanical, electrical and

piping.

• Draw pipe or duct of appropriate duct/pipe type from each connector.

o Verify appropriate physical connectivity for each pipe/duct.

o Verify that all filters in the testing environment apply to each drawn pipe/duct.

• Create mechanical, piping, and electrical systems and verify the proper function of the unit in each

system.

• Edit element properties and verify that the AHU updates correctly.

5. Repeat Steps 3‐4, placing air handling units of the largest and smallest types in the family into the project

space, and verify that the connections and systems are retained.

6. For all air handling units in the test project:

• Open the Coarse, Fine, and Medium plan views, and verify that each air handling unit plan

representation displays correctly in the different levels of detail.

• Dimension to all expected references and verify correct snapping behavior.



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In the remaining views (elevations, sections, 3D views, preview):

7. Inspect the air handling unit in each view in Coarse, Medium, and Fine detail levels.

8. In 3D View, inspect the air handling unit geometry:

•

Spin the air handling units with the SteeringWheel, and verify that all geometry is constrained as

expected.

Check for unconnected geometry and/or plan representations that may be disconnected from the

geometry.

• Apply the following Model Graphics Style to the view, and verify that any materials applied to the air

handling unit display correctly:

o Hidden Line

o Shading with Edges

o Modify the material parameters, reapply the Hidden Line and Shading with Edges graphics

styles, and verify the change of materials is represented.

9.

In elevation views (North/South/East/West) and in the 3D views, verify that the air handling unit

geometry displays as expected.

10. The Preview view is set to the current view.

In any view:

11. Create a mechanical equipment schedule and verify the air handling unit parameters (including any

shared parameters that were applied) schedule correctly.

12. Select an air handling unit in the test project, and:

• Verify the air handling unit type properties.

• Check all parameter names to ensure they adhere to naming conventions and do not contain errors.

For each mechanical connection:

13. Ensure proper connection of appropriate HVAC components to the AHU.

• Connect supply, return, exhaust and outside air duct to air terminals and VAV boxes.

• Connect hydronic supply and return pipe for the heating and chilled connections to pumps, chillers

and boilers.

o For chilled water and heating water connections, create the logical hydronic system

separately from the test AHU, and then connect the connections with pipe.

o For condensate drain connections, create the logical systems from the test AHU as system

type “Sanitary,” and then connect the connection with pipe.



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• Verify that airflow data updates at the appropriate AHU connector.

The imperial template includes 1 diffuser for a return air system at 500CFM and 2 diffusers for a

supply air system at 500CFM/ea.

• Modify the airflow for at least one component connected to each major duct run.

• Re‐verify the airflow data.

•

Verify that

flow

data

updates

at

the

appropriate

AHU

connector.

• Modify the flow for at least one component connected to each major pipe run.

• Re‐verify the flow data.

14. Ensure proper transfer of electrical data to a circuit and panel.

• Create a power circuit for each electrical connector on the AHU.

• Connect the circuit to an appropriate power panel.

• Verify that the number of poles and apparent load values are properly reflected in the panel circuit

manager.

• Change the AHU properties to an alternate type.

•

Verify that

the

electrical

data

updates

as

expected

in

the

power

panel.

mechanical equipment category-air handling unit

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