I'm not sure about the seller being liable to inform you, it may be that they didn't know either, the HOA isn't responsible for informing you of anything, but you should have gotten an inspection that included verifying that everything was up to code before you purchased the condo. Of course most inspectors also have contracts that say they're not liable for anything they don't find. However, if the fire codes have changed since the property was built, was there a grandfather clause built into it to ensure that older properties didn't get stuck with it, or is there an avenue to bring the property up to code?