Under 13-64-150 of the Chicago Code:
All approved smoke detectors installed in buildings hereafter erected shall be permanently wired to the electrical service of each dwelling unit in accordance with the provisions of Chapters 14-8, 14-16 through 14-36 and 14-44 through 14-72* of the municipal code of Chicago.
However, Title 14 of the municipal code has been repealed. So, let's look to another source. Under 425 ILCS 60/3:
(f) In the case of any dwelling unit that is newly constructed, reconstructed, or substantially remodelled after December 31, 1987, the requirements of this Section shall apply beginning on the first day of occupancy of the dwelling unit after such construction, reconstruction or substantial remodelling. The smoke detectors required in such dwelling unit shall be permanently wired into the structure's AC power line, and if more than one detector is required to be installed within the dwelling unit, the detectors shall be wired so that the actuation of one detector will actuate all the detectors in the dwelling unit.
In the case of any dwelling unit that is newly constructed, reconstructed, or substantially remodeled on or after January 1, 2011, smoke detectors permanently wired into the structure's AC power line must also maintain an alternative back-up power source, which may be either a battery or batteries or an emergency generator.
There are also several other sections of the municipal code that seem relevant to your analysis. The first is Section 5-12-070, the Landlord's responsibility to maintain. Under that section, the landlord shall maintain the premises in compliance with all applicable provisions of the municipal code and shall promptly make any and all repairs necessary to fulfill this obligation.
You may be wondering, what does that have to do with smoke alarms? Well, under 5-12-110 of the Municipal code, we see that the failure to provide smoke detectors, sprinkler systems, standpipe systems, fire alarm systems, automatic fire detectors or fire extinguishers where required by the municipal code, shall be considered a breach of the landlord's duty to maintain. Presumably, providing smoke alarms in a fashion inconsistent with the municipal code would be the same as not providing them. This will entitle the tenant to the remedies provided under federal law, as well as those set forth in the municipal code. For example, once the landlord is notified, he is obligated to repair. If he does not, the tenant may terminate.
But what does this mean in terms of liability? If there is a fire, and someone gets hurt, and you knew about but failed to remedy the code violation, are you a monster? Possibly. Will you face criminal or civil liability? I honestly don't know. So I will give you the most unfulfilling answer that one could ever hope to receive on an internet forum: you should probably speak to a lawyer.
Love Fraternal,
Nico