For apartment buildings, window guards can protect little ones from dangerous and deadly falls. It's also the law.
Under New York City's Local Law 57 of 2011, apartments whose tenants include young children are required to install window guards. Thus, if you live in a building that has three or more apartments, and a child aged 10 years or younger lives with you, window guards are mandatory--even on the first floor. The landlord is required to install them.
However, if you don’t have a child under 10 and you still want window guards, you may request them and the landlord must install them. Interestingly enough, the only households exempted from this requirement are single-family homes (No explanation is offered by the New York City Housing Preservation and Development website for this exemption).
What Does This Mean for Co-ops and Condos?
The regulation further explains what is required of residents in co-op and condominium buildings. If you own or live in a co-op and you need or want window guards, the management--that would be the co-op corporation and the managing agent--must install and maintain them, just like in a rental building.
In a condominium, you—the owner—are responsible for installation and maintenance. However, hallways that have windows--like in rental buildings and co-ops--are the responsibility of the condo association and their managing agent. That’s the official line, anyway.