Zoning, Codes, and Laws for Rentals in Baltimore City

[Nicole B.]

Where can I read about the laws that apply to rentals in Baltimore City (in layman's terms)?  I'm about to purchase my first property and will need to do some renovation prior to renting it.  I'm looking for any information on zoning, building codes, etc.

I've noticed, for example, some multi-family units have stairs attached to top floors.  Is this a fire safety requirement, depending on the number of floors or height of the house?