Dear All,

 
We are currently involved in the LEED Certification of a small airport terminal (15.000 m2 of passenger area). The terminal will be an open space (with small semi-enclosed shops) and does not clearly distinguish circulation and waiting zones.

According to airport owner, foreseen peak occupancy will be 1.200 persons – 12,5 m2/person (workers, passengers, etc.).

For purposes of outdoor air flow rates calculation, a design occupancy of 3.000 persons – 5 m2/person – will be considered (well above owner indications to deal with unexpected occupancy events and heterogeneous distribution of passengers across the terminal).

ASHRAE 62.1 table 6-1 does not include airport terminals in the list of available space types. However, it defines two space types that have similarities with the airport terminals:

  1. Transportation waiting (default occupancy: 1 m2/person)
  2. Mall common areas (default occupancy 2,5 m2/person)

Both space types present occupancy densities much higher than owner expectation and HVAC design assumptions.

We will calculate outdoor airflow rate in the terminal based on:

  1. HVAC design occupancy (5 m2/person, well above owner indications – 12,5 m2);
  2. AHSRAE 62.1-2010 minimum ventilation rates;

The question is: are we complying with the ventilation requirements referred in LEED Pre-Requisite Minimum Indoor Air Quality Performance ?  Or must we use the default occupancy densities of ASHRAE 62-1 ? Please note that these occupancies do not represent owner expectations for the terminal and are clearly oversized for such an open-space building.

Thanks in advance.