You are here: Home > Support > Knowledge Base > Correctly Using ASHRAE 62.1 or IMC Ventilation Calculations

Correctly Using ASHRAE 62.1 or IMC Ventilation Calculations

Wednesday, January 29th, 2014

Calculating the ventilation rates in zones using ASHRAE 62.1 or the International Mechanical Code is a two-part process using Design Master HVAC.

1. Set the Calculation Method

First, set which method you are using to calculate the zone ventilation rate with the Project Info command.

Ribbon: DM HVAC->Building Definition-> dm_hvac-project Project Info

Pulldown Menu: DM HVAC->Building Definition->Project Info

Set the Ventilation Calculation Method value:

  • Minimum: No adjustment is made to the ventilation rate in the zones. The ventilation is strictly the sum of the ventilation in the rooms that make up the zone. Select this if you are not using the  International Mechanical Code or ASHRAE 62.1.
  • 2006 International Mechanical Code: The ventilation rate is calculated based upon 2006 International Mechanical Code. This calculation method is a simplified version of what is specified in ASHRAE 62.1.
  • 2009 International Mechanical Code: The ventilation rate is calculated based upon 2009 International Mechanical Code.
  • ASHRAE 62.1-2007: The ventilation rate is calculated based upon ASHRAE 62.1-2004.
  • ASHRAE 62.1-2007: The ventilation rate is calculated based upon ASHRAE 62.1-2004.
  • ASHRAE 62.1-2010: The ventilation rate is calculated based upon ASHRAE 62.1-2004.

The calculation that is performed for the ventilation in a zone is exactly the same in all versions of ASHRAE 62.1 and 2009 IMC. If you are using any of those codes, it does not matter which option you select — they all calculate the same.

2. Set the Ventilation Rates

Second, specify the correct ventilation rates in each room in the project. The default ventilation rates will not be correct.

Use the Room Project Schedule command.

Ribbon: DMH: Customization->Project Customization-> dm_dm-roomP Room Project Schedule

Pulldown Menu: DM HVAC->Building Definition->Rooms->Room Project Schedule

For each room type used in the project, set the correct ventilation rates. These rates will be based upon a table in the code you are using.

A common error is to set the calculation method in the first step without setting the ventilation rates correctly in the second step. A major difference between the various versions of the codes is the ventilation rate for each room type. The calculation performed with the ventilation rates is exactly the same. You must manually update the ventilation rates to the correct values; otherwise, the values that are used in your project will be wrong.

Related Articles

Filter by
Post Page
HVAC Load Calculations Training Recording HVAC Training
Sort by

Ventilation Calculations

Design Master HVAC offers two methods for calculating the ventilation air required in a zone: minimum, and ASHRAE 62.1.

24

Training Recording: Ventilation Calculations

This training video teaches you how to configure ventilation calculations in Design Master HVAC.

24

Ventilation or Psychrometric Airflow Values are 0

If your building load calculations don’t show any outside air, ventilation load, or airflow, you must modify your project information or insert supply diffusers with airflow on your drawing.

24

100% Outside Air or Ventilation in a Zone

If a zone requires 100% outside air, you may need to increase the required supply air for rooms in the zone.

18

No Outside Air in Building Load Calculations

If your building load calculations don’t show any outside air, ventilation load, or airflow, you must modify your project information or insert supply diffusers with airflow on your drawing.

14

Room Loads vs. System Loads

The room load only accounts for air supplied to the room, while the system load accounts for the total load of the air handler, including ventilation and plenum loads.

14

Products

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

Support

Contact Support

Install & Update Instructions

Online Training

Knowledge Base

User Manuals

Tutorials

Release Notes

Downloads

Wish List

Remote Support

Company

About

Customer Stories

Awards

Newsletter

Blog

Pricing

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

Free Trial

Electrical for Revit

Electrical for AutoCAD

HVAC for AutoCAD

Photometrics for AutoCAD

©2001-2019, Design Master Software, Inc