What are these checks for?
To validate the parameters that most constrain a design at concept or remodel stage: accessibility, egress, occupant load, daylight and ventilation, floor area ratio and glazing ratio. They show early whether an idea fits the code.
They don't replace design documents: the architect demonstrates code compliance.
Which codes apply in the US?
The IBC and IRC cover egress, occupant load, light and ventilation; the 2010 ADA Standards cover accessibility; zoning ordinances set FAR, lot coverage and setbacks.
Local amendments often add requirements.
How do egress and occupant load work together?
First work out occupant load from area and use; that number sizes doors, corridors and stairs and decides how many exits are needed. With several exits, no single exit may carry more than half the load.
Accessible ramps complete routes where there are level changes.