Real estate is scarce in Hoboken, N.J., so a few years ago our client decided to double his family's living space by buying the condo next door to his own and connecting the two units. After a lengthy permitting process involving both the condo association and the town, the project finally won approval. A key hurdle was the new 6-foot-wide passageway through the fire wall separating the condos. To maintain the wall's integrity, the local building department required a set of fire-rated doors that would automatically close and completely block off the opening if a fire broke out in either...