Which procedure to use depends on the configuration of the ventilation system. The zone air distribution effectiveness is entered in the zone properties.ĪSHRAE Standard 62.1 also defines procedures for calculating the outdoor airflow needed at the system-level intake (Vot) to make sure that the required quantity of outdoor air is delivered to each zone (Voz). In this example, a VAV system supplies cool air to each zone from the ceiling, so the zone air distribution effectiveness is 1.0. The zone outdoor airflow is calculated using the following equation:Į z = zone air distribution effectiveness The zone outdoor airflow accounts for the zone air distribution effectiveness (Ez) found in Table 6-2). The next step is to calculate the zone outdoor airflow (Voz), which is the outdoor airflow rate that must be provided to the ventilation zone by the supply air distribution system. The Standard should be set to ASHRAE 62.1 and 170 and the space type can be chosen from the Type dropdown.įor this example, the required ventilation airflow has been calculated for each zone to be: The ventilation requirements are entered in the Create Building section in the ventilation properties. R a = zone population: the number of people in the ventilation zone during typical usageĪ z = outdoor airflow rate required per person as determined from Table 6-1 P z = outdoor airflow rate required per unit area as determined from Table 6-1 R p = zone floor area: the net occupiable floor area of the ventilation zone sq ft or sq m The breathing zone outdoor airflow (Vbz), is determined using Equation 6-1 from ASHRAE Standard 62.1. We'll also discuss how these calculations are implemented in TRACE 3D Plus.ĪSHRAE Standard 62.1 outlines the following procedure to determine the outdoor airflow required for each ventilation zone.ĭetermine minimum outdoor airflow requirement, Vbz, for each breathing zone(s) To demonstrate this procedure, we'll use an example VAV system with three breathing zones.
THE BREATHING ZONE HOW TO
For instructions on how to import libraries, see Importing and Exporting Libraries to and from a TRACE TRL File. Standard libraries for years 20 are attached to this document. Standard libraries for ASHRAE 62.1 year 2007, 2010, and 2013 come with the program. The "Ventilation Rate Procedure" (Section 6.2) in ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality, prescribes the quantity of outdoor air that must be delivered to each zone, based on the expected use of that zone, and then prescribes how to calculate the outdoor airflow needed at the system-level intake. This requires the removal of an equal quantity of air from the building. Ventilation refers to the introduction of an adequate amount of fresh air to dilute contaminants that are generated inside the building (by people, equipment, processes or furnishings).
THE BREATHING ZONE PLUS
Applying ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality for TRACE 3D Plus