Going over ASHRAE appendix G i noticed that for buildings where thermal zones have not been defined use the perimeter method, 15ft from perimeter. However i am building a core and shell model where the core/lobby on each floor is defined. it is still recommended to use the perimeter zone method in combination with defining the building core zones
If I were in your shoes.... I would not still use the pertimeter zone
method, unless my core zone had a depth from the perimeter of more than 25
ft.
For your model you need to think about the best way to divide your thermal
zones for your project, if you can support your "method" with sound
judgement & explanation for why your approach was taken or needed, then you
are doing the best that you can as a good simulator.
When it doubt it is always, always best to zone the project the same way the
HVAC designers zoned it. If you'd like more feedback or suggestions feel
free to send your floor plans or eQuest file through and there are many of
us that would be happy to make thermal zoning suggestions for your model.
pkg