I don't think "should" counts for much in the real world. When the Transamerica Building in San Francisco had a fire some years ago, it was in an elevator cab. Janitors went to lunch around 9:00 PM, leaving their tote bins in the elevator. More than likely a discarded cigarette did the deed. The elevator shaft exhaust system did not operate automatically. None of the fancy floor above, fire floor, floor above worked automatically. The knob on the door to the fancy manual controls in the first floor lobby still had dust on it. It was not used. There was smoke throughout the building. Any or all of that stuff SHOULD have worked.
"å... ...." <[EMAIL PROTECTED]> wrote: Without testing, one can not reliably say how effective the sprinkler at the top of the elevator shaft would have been. Especially if this car recalled to the bottom of the shaft; sprinkler water would primarily wet the walls if this was a one car shaft. Then there is consideration of shielding that the roof of the elevator car provided. Probably too many variables to say what the advantage or stalemate would have been. Had the car returned to the primary recall floor and opened its doors, this would have provided valuable oxygen that otherwise was more limited had the fire burned in a closed shaft. Then again, a closed shaft would have reduced entrainment, and kept the smoke hotter. Certainly sprinklers in the corridor near the elevator car doors would have helped reduce the HRR in this case, although there is the liability of putting lots of water into an elevator shaft with other cars. The scrubbing benefits from sprinkler water might be measurable on soot and smoke temperature, but virtually ineffective on CO dispersement. You have no support here, for the water curtain strategy. As mentioned by CC, these fires are extremely rare, such that in the case of at least high-rise buildings where: a. elevator shafts should be surrounded by smoke-resistant lobbies, and b. cars should be noncombustible, if a fire does occur, the smoke should not spread in untenable amounts past the elevator lobby, with the result that the remainder of the building stays tenable (at least for the duration of egress) despite one evidently plausible worse case elevator-system fire presented to us. Before deciding to return to a sprinklered elevator shaft, we should weigh in the advise from professional research projects focussed specifically on elevator system fire safety, as this is an active field of investigation at the moment. One fire does not warrant a change in risk categorization for elevator system fires. Lesson learned: remove combustibles from elevator cars, shafts, etc. NOTE: this is not an endorsement of Fire Retardant chemicals (for reasons related to the environmental costs of generating and applying these chemicals) in lieu of removing combustibles. An it is realized some power cables are run inside elevator shafts, and they will remain. New building designs should consider tenable egress from elevator fires (what if someone is moving a couple of sofas in the elevator). One approach is emergency notification and exit placement such that this situation is not repeated [where students (a rather robust occupant) were afraid to use the corridor and exit to a stair (apparently on a floor remote from the fire) because the corridor was too choked with black smoke (a surprising finding to my intuition)] under non-stack, non-wind conditions. Alternatively, a smoke control design could be as simple as constructing a passive elevator lobby with active doors held open by magnetic hold opens. Both the exit and smoke control approaches require sufficient documentation to validate their probability of success in the light of building maturation (i.e.under duress of some component failures) as well as performing simply in the line-of-fire. There are enough details and interrelated disciplines (elevator, mechanical ventilation, electrical backup power supplies, egress, and good old-fashioned sprinkler protection) that making an out-of-hand prescriptive design paradigm from this case might be short sighted, though that should not stop us from suggesting potential strategies for peer review. scot deal excelsior fire engineering _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) [EMAIL PROTECTED] Ed Vining 4819 John Muir Rd Martinez CA 94553 925-228-8792 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
