We are at Design Appeal stage on a core and shell office project - we have been asked to recalculate ASHRAE 62 compliance based on a theoretical office floor layout incorporating meeting rooms, corridors, lunchrooms etc

We are demonstrating ASHRAE 62 compliance via the VRP Compliance Calculator in Appendix 1 of the LEED Online Form .

We have used Table IEQp1-A1: Mechanical Ventilation – Multiple Zone for each of the AHU.

Each floor is served by two VAV AHUs with VAV boxes supplying air to the space. Return air is via a plenum.
Each space is listed as a separate zone and occupancy category. The default occupancy density has been selected for each zone. The zone areas, air distribution effectiveness, supply air volume and Ds value were filled in accordingly for each zone entered.

Below is the result calculated out for one of the AHU once the ‘Calculate’ button is pressed:

System Population with Diversity (Ps) - 91
Design System Primary supply airflow (Vpsd) (cfm) - 15,458
Uncorrected Outdoor Air Intake (Vou) (cfm) - 1,230
System Ventilation Efficiency (Ev) - 0.9
Required Outdoor Intake Flow (Vot) (cfm) - 1,366
Project Design Outdoor Airflow (cfm) - 1,589 (Input value)

As you can see the design outdoor airflow is higher than the required outdoor intake flow...Howver, once the ‘Calculate’ button is clicked for Table IEQp1-A4 Mechanical Ventilation AHU Summary – VRP Compliance Calculator, it displays shows the ‘Compliance with IEQ Prerequisite 1’ as ‘Y’.

However, the Summary – IEQ Prerequisite 1: Minimum Indoor Air Quality Performance Compliance Documented in the main form still shows as ‘N’.

Also, when the form is reopened again the next time, each AHU table has a red note at the bottom that says ‘Would need over 100% OA Intake’. This note would disappear after the ‘Calculate’ button is clicked.

Even though the calculator indicates that each AHU meets the minimum outdoor air requirement we are concerned that if we submit the credit with the form indicating a "N" and red error note there is a risk that the assessors will deny the credit again.

Are we missing something?? Has anyone experienced a similar error with the Appendix A calculator and form??

Thanks in advance