BLD20130313 Anthony's Beach Cafe FP for Dumbwaiter Installation .htm
From: John J. Westfall
Sent: Friday, January 10, 2014 1:44 PM
To: Bjorback, Leif
Cc: 'steve@anthonys.com'; Kevin Zweber
Subject: BLD20130313 Anthony's Beach Cafe FP for Dumbwaiter Installation
Discussion and resolution regarding the requirements for fire protection in the dumbwaiter shaft.
The 2013 edition of NFPA 13 HBK is used for evaluation.
The restaurant is existing and Anthony’s Beach Café shares tenancy with Anthony’s Restaurant and Port
of Edmonds Operations offices. Proposed is a freight lift one story tall used for moving supplies to
second floor and rubbish to first, thereby dedicating the original elevator to passenger only. The shaft is
one hour rated and the constructed lift assembly provides 90 minute FR providing opening protective
when constructed to detail. The lift will not operate with upper or lower doors open, completing shaft
enclosure during transport. The lift is noncombustible and hoistway is limited combustible. A pit at
bottom of shaft has been constructed to accept the lift.
The dumbwaiter is electrically-controlled by a motor affixed to the top of the lift. The lift control panel is
nd
attached to the 2 floor on a shaft wall outside the hoist way in the kitchen area. There is approx. ¾”
gap at the front of the opening when the assembly is opened for loading, allowing debris to drop into
pit. Installation of a sprinkler at the top of shaft mandates that electrical circuits be shut when sprinkler
is activated. A heat detector also at the top of shaft providing electrical shunt will be required. Shunt
action may be controlled by an open head and butterfly valve controlling that head and electric supply
to motor. Pit sprinklers are often provided in hydraulic lift (not electric) installations, where combustible
fluids could spill NFPA 13 8.15.5.2.
NFPA 13 provides room for omission of sprinklers in elevator shafts. The additional cost of special
installations and the benefit “must be weighed against the small number of fires in elevator shafts”
NFPA 13 8.15.5 HBK commentary. Consideration is made due to the possibility of fire growth and spread
inside to outside of the shaft. The building around shaft is fully protected with sprinklers. A fire escaping
shaft will be held in check by sprinklers. The dumbwaiter cannot be used for personnel or fire
responders, so due consideration for rescue or fire operations is null. The dumbwaiter shaft is a rated
enclosure with the hazards of electric motor problems, or potential ignition of ordinary combustible pit
debris. In this case, a sprinkler at the top of the shaft only leads to additional systems required to assure
the protection water will not apply to electric motor parts. A fire inside the “covered” lift or in the pit
underneath is not readily extinguished prior to burning through the shaft enclosure. In my estimation, a
lone heat detector tied to the monitored building fire alarm system and installed at the top of the
elevator shaft will suffice as early warning for fire responders to provide immediate notification of fire
condition. Responders will then keep fire spread in check.
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John J. Westfall
Fire Marshal
Fire Prevention Services
425-771-0213 Desk
425-775-7721 Fax
425-231-3644 Mobile
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