875 West End Avenue is rated a fire proof building. In essence this means that the building is constructed to contain fires within a limited area at the point where a fire occurs. The success of the containment depends to a large degree on the location, nature of the fire and how much time elapses before the fire is brought under control (by the FDNY or others).
However there are ways that this inherent containment capability can be compromised. If improper construction leaves openings in walls or floors smoke and eventually fire can spread horizontally and vertically between apartments. This is why the Coop requires that any work done in an apartment be reviewed, approved and, where appropriate, inspected.
But the primary points of vulnerability are the fire safety doors located at the stairwell entrances (both AB and CG sides) and the fire safety door located between the CD and EFG Hallways on every floor. When closed (and they are designed to be self closing) these doors can prevent the spread of a fire from the floor of origin. Anyone who sees a fire door open should close it and/or report it to the staff immediately.
Thank you for your cooperation in this matter.