Description
Historically within the NFPA 130 community there have been changes surrounding the requirements for various types of stations: open, enclosed, aboveground, and underground. As the implementation of Platform Screen Doors gains more traction, the corresponding configuration of at- or above-grade stations with PSDs is one that does not nicely fit into any of the above categories; it consists of an above ground platform with its edges bounded by PSDs with a canopy roof above. The space above the PSDs may or may not connect to the canopy above either with glazing or louver bands. If the connection is glazed, is it reasonable to consider the station as enclosed? Maybe from a smoke control point of view, but should all the NFPA 130 “enclosed station” criteria be applied considering those are intended for higher risk below ground stations?
A.3.3.57.2 Open Station. This term is intended to apply to public circulation areas and to refer to configurations in which dispersion to the atmosphere is without ducting, without accumulation in occupied areas, and without impacting tenability in egress routes serving the area of fire origin (1).
What if the space between the canopy and PSDs is a louver band? Is that louver band considered ‘ducting’ – albeit very short? Or is it an opening – albeit restricted? How much smoke is required for it to be considered ‘accumulation’? Lastly, if the space between the canopy and PSDs remains open, one could reasonably assume it should be considered an open station. Extensive CFD analyses have been conducted, and the results are surprising. This paper aims to discuss the challenges being faced by this particular configuration, which was initially thought to be not much different than an open-air station; however, the analyses have revealed quite the opposite.
