Class 1 Div 1 and Div 2 Product Design Criteria sources?

[mnucci]

Can anyone recommend a source for Class 1 Division 1 and Division 2 product design guidelines?

I understand the classification definitions but I am looking for a source for design specifications, electrical/mechanical/physical, for compliance with these environments. (A website, manual, consulting firm, etc.)

Any help would be appreciated. Thanks