A question that comes up from time to time on renovations is why some stairs have smoke hatches at the top and others don’t. Under early versions of the BOCA Basic Building Code, all enclosed vertical shafts extending through more than two stories (except for elevators and dumbwaiter hoistways) were required to be automatically vented to the outer air. Compliance with this requirement required the shafts to be provided with skylights, windows of equivalent area or with other approved automatic means of removing hot air and gases. Operation of these devices were required to be controlled by one of the following:
- Fusible links designed to operate at a fixed temperature of not more than 160° F or
- Electric or pneumatic operation under a rapid rise in temperature or 15-20° F per minute
- By other approved means
In Massachusetts, this applied to all buildings constructed between January 1975 and March 1991 (1st – 4th Editions of 780 CMR). Under the base International Building Code (IBC), this is no longer a requirement; however, in some jurisdictions, like New York City, these skylights / hatches are still required (2014 NYCBC 708.12.1). If you are interested in decommissioning this system in a jurisdiction where it is no longer required, it should be discussed and approved by the local code officials as an existing, previously required fire protection system