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Appendix 8: Emergency Egress
To meet NFPA 130 evacuation criteria, all passengers (i.e. station occupant load) on the station
platform must clear the platform in four minutes and reach a point of safety in six minutes (note
that the six-minute period includes the time to clear the platform). The station occupant load
consists of the entraining load (i.e. all passengers entering the station to board a train) and the
train load (i.e. passengers already on a train) during the peak period.
The entraining load and the train load per platform are the sums of the entraining loads or train
loads per track. A surge factor is applied to the entraining and the train loads in both directions,
and a factor of two is applied to the peak direction to account for one missed headway, per
NFPA 130 requirements. Thus, the station occupant load for Naylor Road Station in 2012 is:
• 2012 AM Peak Station Occupant Load = [2 * surge * (NB entraining load + NB train load] +
[surge * (SB entraining load + SB train load)]
= [2 * 1.3 * (59 + 238)] + [1.3 * (9 + 37)] = 831
• 2012 PM Peak Station Occupant Load = [2 * surge * (SB entraining load + SB train load)] +
[surge * (NB entraining load + NB train load)]
= [2 * 1.3 * (12 + 434)] + [1.3 * (1 + 50)] = 1,225
Note: Naylor Road Station entraining and train loads for 2012 and 2040 are calculated in Tables A-18,
A-20, A-22, and A-24. Values in this example are rounded.
In the high level planning analysis used for this study, passengers disperse according to the
available capacity of the exit points. One escalator is assumed out of service, and the remaining
escalator is assumed to be stopped and usable as a stairway.
Time to Clear Platform
The vertical circulation facilities (e.g. stopped escalator and emergency stairways, not elevator)
may be a limiting factor in how quickly a station platform is cleared. Calculating the exiting
capacity for Naylor Road Station is relatively simplified because passengers would exit via one
of two possible choices, and both lead to the same mezzanine:
1. West stairway and escalator (assumed stopped, but usable as stairway)
2. East stairway (escalator assumed to be completely out of service)
For Naylor Road Station, the west stairway and escalator account for 64 percent of the egress
capacity and station occupant load, while the east stairway accounts for the remaining 36
percent. Using this method, along with calculating passenger walk times, it would take
approximately 3.6 minutes to clear the platform in the morning peak and 5.2 minutes to clear the
platform in the afternoon peak in year 2012. Passengers would clear the platform more slowly in
the afternoon peak period because of the higher station occupant load compared to the morning
peak.
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