ASHRAE 62.1-2004 and 2009 IMC

This section describes the table that is printed when the Ventilation Calculation Method field in the Project Info command is set to 2009 International Mechanical Code or ASHRAE 62.1-2004. The calculations in the 2009 International Mechanical Code are the same as the calculations in ASHRAE 62.1-2004.

For complete information about how this calculation works and what these various values mean, refer to ASHRAE 62.1.

Ventilation Schedule

The Ventilation Schedule table lists contains sections for the zones in the project. If the whole building is selected to be printed in the Zone or Room to Print field, then every zone is listed. If specific zones are selected, then only the selected zones are displayed and no sections are displayed.

The labels in italics are the names of the variables used in the ASHRAE 62.1-2004 calculations

Each zone is displayed as a separate section in the table. A header with the name of the zone is displayed at the top of each section. The information about the zone is displayed first in the section. Information about each of the rooms is displayed second in the section.

Load Calculations--Print Load Calculations.Print Ventilation Schedule.2009 IMC

System Primary Airflow Vps: The supply airflow required to condition the zone. This value is the same as the Required Supply CFM column in the Supply Air Requirements table. See the Print Supply Air Requirements section for more information. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Average Outdoor Air Fraction Xs: A calculated value equal to Uncorrected Air Intake divided by System Primary Airflow. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Occupant Diversity D: A diversity factor based upon the number of people in the zone. Equal to the People Diversity value set in the Zone List command divided by the total number of people in the rooms in the zone. Defined in equation 6-7 in ASHRAE 62.1-2004 on page 11.

Uncorrected Air Intake Vou: The sum of the Zone Outdoor Airflow values for all the rooms in the zone. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

System Ventilation Efficiency Ev: The minimum Zone Ventilation Efficiency value used to calculated the ventilation airflow required in the zone. Defined in equation A-3 in ASHRAE 62.1-2004 on page 20.

Outdoor Air Intake Vot: The total ventilation airflow required for the zone. Equal to Uncorrected Air Intake divided by System Ventilation Efficiency. Defined in equation 6-8 in ASHRAE 62.1-2004 on page 11.

Zone Air Distribution Effectiveness Ez: Set using the Ez field in the Zone List command. A value less than 1 will increase the ventilation required in the zone. Defined in table 6-2 in ASHRAE 62.1-2004 on page 15.

Primary Air Fraction to Zone Ep: Set using the Ep field in the Zone List command. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Secondary Air Fraction to Zone Er: Set using the Er field in the Zone List command. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Fraction of Supply Air to Zone from Outside Zone Fa: "Fraction of supply air to the zone from sources outside the zone." Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Fraction of Supply Air to Zone from Fully Mixed Primary Air Fb: "Fraction of supply air to the zone from fully mixed primary air." Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Fraction of Outdoor Air to Zone from Outside Zone Fc: "Fraction of outdoor air to the zone from sources outside the zone." Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Room Information

The Room Information section lists each of the rooms in the zone.

The room with the lowest Zone Ventilation Efficiency is highlighted in bold.

Room: The rooms in the zone.

Room Type: Set using the Room Type field in the Edit Rooms command.

People Outdoor Air, Rate Rp: The ventilation rate for the room based upon the number of people. A value is displayed if one of the values in the Ventilation section of the Edit Rooms or Room Project Schedule command are set to CFM / Person. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

People Outdoor Air, People Pz: The total number of people in the room or zone. This value is rounded based upon the Allow Fractional People checkbox in the Project Info command. Set using the SF / Person or People fields in the People section of the Edit Rooms command or the SF / Person or People fields in the People section of the Room Project Schedule command. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

People Outdoor Air, Total Rp*Pz: The ventilation airflow for the room based upon the number of people. Equal to People Outdoor Air, Rate times People Outdoor Air, People.

Area Outdoor Air, Rate Ra: The ventilation rate for the room based upon the area of the room. A value is displayed if one of the values in the Ventilation section of the Edit Rooms or Room Project Schedule command are set to CFM / SF. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Area Outdoor Air, Area Az: The area of the room. Set based upon the room boundary inserted on the drawing. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Area Outdoor Air, Total Ra*Az: The ventilation airflow for the room based upon the area of the room. Equal to Area Outdoor Air, Rate times Area Outdoor Air, Area.

Breathing Zone Outside Airflow Vbz: The ventilation airflow for the room in the breathing zone based the number of people and area of the room. Equal to People Outdoor Air, Total plus Area Outdoor Air, Total. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Zone Outdoor Airflow Voz: The total ventilation airflow required for the room. Equal to Breathing Zone Outside Airflow divided by Zone Air Distribution Effectiveness.ASHRAE 62.1-2004, page 11, equation 6-2. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Zone Discharge Airflow Vdz: The supply airflow required to condition the room or zone. This value is the same as the Required Supply CFM column in the Supply Air Requirements table. See the Print Supply Air Requirements section for more information. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Discharge Outdoor Air Fraction Zd: The fraction of supply air that is outside air. Equal to Zone Outdoor Airflow divided by Zone Discharge Airflow. Defined in the Definitions section of ASHRAE 62.1-2004 on page 22.

Zone Ventilation Efficiency Evz: "The efficiency with which the system distributes air from the outdoor air intake to the breathing zone in a particular zone." Calculated based upon the other values in the Room Information section. The room with the lowest Zone Ventilation Efficiency is highlighted in bold. Defined in equation A-2-8n ASHRAE 62.1-2004 on page 20.


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