Here are two pages that explain so much about New York City building. One page outlines the Department of Buildings Codes and the other explains the steps to file for a work permit.
These two links are possibly the most important links on the whole NYC web site if you are a green contractor in New York because you need to know the code and bureaucracy better than anyone in order to argue your point for green building techniques that may be regarded as strange by the plan examiner or building inspector.