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Elevators and Fire

ELEVATOR FIRE SAFETY
by William A. Webb, P.E.

INTRODUCTION

The information advertising this Symposium
aptly stated that, *...there have been a number of
issues related to elevators and fire which have
caused controversy and confusion." This is
evidenced by the complicated approaches some
authorities and designers have developed to meet
the seemingly simple provision to allow automatic
sprinkler protection in elevator hoistways, machine
rooms or machinery spaces. That provision is in
Rule 102.2 which states in part, "A means shall be
provided to automatically disconnect the main line
power supply to the affected elevator prior to the
application of water.”

Another issue which has focused attention on
the continual controversy of using elevators for
egress in fire emergencies, is the need to provide
egress during a fire for the mobility impaired.
Codes have begun to allow such use of elevators
even though the means to properly protect
elevators during a fire emergency has not been
resolved according to some authorities.

In this paper, I shall touch on three of the four
topics of the Symposium. The three topics which I
shall discuss are:

(1) Emergency operation of elevators during a
fire.

(2) Sprinklers in elevator hoistways and
machine rooms.

(3) Handicapped use of elevators

EMERGENCY OPERATION OF
ELEVATORS DURING A FIRE

Most building codes require Phase I elevator
recall to be initiated by smoke detectors in elevator
lobbies and machine rooms. Some also require
smoke detectors in hoistways. A notable exception
to the smoke detector requirement is the New
York City Building Code which allows automatic
sprinkler waterflow to initiate automatic elevator

sprinkler systems. As a matter of fact, the 1978
edition of A17.1 allowed elevator lobby smoke
detectors to be omitted in buildings completely
protected by automatic sprinklers. To satisfy the
New York City Building Code requirements, the
sprinkler waterflow must perform all of the
functions which smoke detectors would otherwise
perform.

Advantages

‘There are advantages to such an arrangement.
Among them is a reduced likelihood of premature
recall. Such premature recall could be caused by
unwanted alarms from smoke detectors. Another
way to describe this situation is that it is more
likely that recall will occur only during a fire.
Smoke detectors, being sensitive devices, can
respond to conditions which they interpret as a fire
but which are not threatening to the building or to
the elevators. Even with cross-zoning or alarm
verification features, the likelihood of premature
recall by smoke detectors is greater than for recall
by sprinkle waterflow specifically because smoke
detectors are intended to respond more quickly
than automatic sprinklers. Because the purpose of
this paper concerns elevators, I refer the interested
reader to the literature for the characteristics of
smoke detectors.

Another advantage of using sprinkler
waterflow in lieu of smoke detectors, at least in the
elevator lobby for automatic elevator recall, is
lower cost.

Disadvantages

Among the disadvantages are that although it
is more likely that the elevator will be recalled only
when there is a fire, it is also more likely that it
will be recalled without any immediate threat to
the elevator. Typically, any automatic sprinkler
waterflow on a floor served by the elevator causes
the elevator to be recalled, unless the elevator is in
a separate fire zone. Consequently, sprinklers


Elevators and Fire

respects, this is an advantage because it would take
the elevator out of occupant service sooner than
with smoke detectors in the elevator lobby, thereby
assuring that occupants will use the intended exits
rather than the elevator. It also makes it more
likely that the elevators will be available for the
fire department when they arrive.

Another disadvantage is that the time to
initiate elevator recall for a fire near the elevator
shaft will likely be greater if recall is initiated by
automatic sprinkler protection rather than if by
elevator lobby smoke detectors. I do not consider
this to be a major disadvantage because although
the sprinklers may take longer to initiate elevator
recall, they should begin controlling the fire once
they operate. It is also likely that the difference in
response time in so far as the threat to the
elevators is not significant.

The response time of the automatic sprinkler
system could be reduced by using quick response
automatic sprinklers. As I mentioned for the
smoke detectors, the difference in response time
would I expect not be significant in so far as the
threat to the elevators is concerned.

Alternate Floor Recall

Many codes now require alternate floor recall
if a fire signal is initiated from the base recall
floor. This generally applies whether or not the
building is protected by automatic sprinklers. I
suggest that such an arrangement is not always
necessary. If automatic elevator recall is initiated
by elevator lobby smoke detectors on a base floor
with a typical office building ceiling height of 10 or
12 feet and the elevator lobby is relatively narrow,
alternate floor recall would be prudent. My
rationale is that it is likely that if the elevator
lobby smoke detector is responding to a fire on the
base floor, persons in the elevator will have
difficulty escaping from the elevator through the
elevator lobby. On the other hand, if the elevator
lobby ceiling height is great, say 20 feet or more, if
the elevator lobby is furnished with hard surfaces
and if it is a large space, it is likely that occupants
of the recalled elevator will be able to escape
without significant danger. I believe this approach
could be used whether or not the building is
protected by automatic sprinklers. One could also
apply the same logic if recall were initiated by
sprinkler waterflow. I recognize, however, that it is
difficult to codify this judgement process.

An advantage of alternate floor recall is that
the elevator shaft doors will remain closed on the
initiating floor, thereby helping to prevent the
smoke from entering the elevator shaft and
possibly contaminating remote floors. A

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57

at great distance away from the ground floor,
perhaps high up in the building. This could cause
anxiety. The elevator and building emergency
communication system should be used to inform
occupants that the elevator is responding as
intended.

SPRINKLER IN ELEVATOR
HOISTWAYS AND MACHINE ROOM

Hoistway Sprinklers

Although some codes require automatic
sprinkler protection in hoistways in order to permit
the building to be considered fully sprinklered, the
logic of such protection is, in my opinion, suspect.
I will recognize that there have been some
instances of fires in elevator cars, that have
occurred because fire from the floor penetrated
into the shaft or were from the fire in the car,
often deliberately set. In each case, automatic
sprinkler protection in the hoistway would have
little effect. In other former cases which occurred,
the building was not protected by automatic
sprinklers. When such protection is provided, it is
unlikely that a fire will penetrate into the shaft. In
the case where fires have occurred in the car, the
fire must reach substantial proportions before it
can operate sprinklers in the hoistway. In my
opinion, it is not very likely that the hoistway
sprinklers would be effective to any substantial
degree in reducing the size of the fire in the
elevator car. Conversely, the elevator shaft
construction and the elevator shaft doors and the
automatic sprinkler protection on the floors should
prevent fire spread from the elevator car from
entering the floors.

Machine Room Sprinklers

The concern expressed for automatic sprinklers
in elevator machine rooms, which apparently has
been substantiated by actual experience, is that
water discharge could affect elevator controls.
Another concern is that water discharge could
affect the elevator brakes. For these reasons, the
elevator code requires power to be disconnected
form the elevators before the water is applied.
While this is simple to state, it is not so simple to
accomplish. A reasonable solution is that
described in interpretation ANSI/ASME A17.1
Inquiry 86-56 which requires heat detectors at each
sprinkler in the elevator machine room. The heat
detectors are to have a lower temperature rating
that the sprinklers. Operation of the heat

detectors cuts the power which should occur before

antamatic cnrinkier aneratinn Smoke. detectors in


58

the machine room cause elevator recall. One
needs to place sufficient smoke detectors in the
elevator machine room to see that the smoke
detectors respond before the heat detectors.

Another solution, which is more complicated
in may opinion and therefore less reliable, is to use
preaction automatic sprinklers with a time delay.
Smoke detectors would recall the elevators and
start a timer. The timer would be set so as to
allow sufficient time for the elevators to be
recalled. Heat detectors would rejease the
preaction valve to admit water to the sprinklers
only after the preset time.

A still more complicated solution is to use a
double-interlocked combination dry-pipe preaction
system. With this arrangement, both the heat
detector and the sprinkler must operate by
discharging air from the sprinkler system, before
water would be discharged. The smoke detector
would cause the elevator recall; the heat detector
would actuate the preaction valve. The actuation
of the dry-pipe valve would interrupt the power
supply to the elevators. Further safety intended to
see that the cars have been "homed" before power
was interrupted would be to interlock the elevator
doors on the home floor to be sure they are open
before the power is interrupted. This arrangement
introduces a further complication and therefore a
greater likelihood of failure.

HANDICAPPED USE OF ELEVATORS
DURING FIRE EMERGENCIES

As I mentioned in the introduction, the model
building codes already have or are considering
proposals to allow the use of elevators on Phase II
firefighter service for evacuating the mobility
impaired in a fire emergency. This is in spite of
strongly held industry opinions that "Presently,
Elevators Are Not Safe In Fire Emergencies." This
is the title of a paper presented by E. H. Sumka of
Westinghouse Elevator Company and published in
ASHRAE Transactions 1987. G. T. Tamura and J.
H. Klote of the National Research Council of
Canada and the National Institute for Standards
and Technology, respectively, have tested means to
provide smoke control for elevators. The system
includes pressurization of the elevator shaft and
elevator lobbies. In a paper entitled “An Overview
of Smoke Control Technology" published by NIST
September, 1987, Klote states, “Before elevator
smoke control can become a reality, the
information developed about elevator smoke
control by the NBS [NIST]/NRCC joint project

Elevators and Fire

needs to be put in a form readily usable to our
design engineers." To date, this has not been done.
For this reason and because guidelines for
emergency evacuation procedures for the mobility
impaired need to be developed, I believe elevator
use should be restricted to buildings protected by
automatic sprinklers and for those buildings having
areas of refuge at the elevators to restrict smoke
spread through the elevator shaft. Their use
should further restricted to evacuating the fire
floor. This is because it is possible that smoke will
infiltrate into the elevator shaft, because vestibule
doors might not close properly. This has occurred
and was reported at the First Interstate Bank fire
in Los Angeles. Although the likelihood of such
smoke infiltration, even with doors propped open
is low in a sprinklered building, the risk of
exposing persons to smoke in the elevator shaft is
probably unwarranted. Occupants are likely to be
safer in an area of refuge where they can wait for
emergency assistance from firefighters.

SUMMARY

This paper is intended to achieve simple,
reasonable and adequate solutions to achieving
Proper response of elevators during fire
emergencies. My intention was to describe an
engineering approach and the basis for applying
engineering judgement to those solutions.

William A. Webb, P.E. Senior Vice President of
Rolf Jensen & Associates, Inc. and serves as a
Technical Officer for the firm. He is experienced
in fire protection systems design, and building
code consulting and negotiation. He has a B.S.
degree in Fire Protection and Safety Engineering
from Illinois Institute of Technology and has
done graduate work in business, law, computer
programming, statistics, and business
administration. He is a member of the Society of
Fire Protection Engineers, the National Society of
Professional Engineers, and the American Society
of Heating, Refrigeration and Air Conditioning
Engineers. Mr Webb is Vice Chairman of
ASHRAE'’s technical committee on Fire and
Smoke Control and Chairman of the Guideline
Project Committee for Commissioning Smoke
Management Systems. As a member of NFPA,
he also serves on several of their standards
writing committees.