Elevators and Fire

53

SPRINKLERS IN ELEVATOR HOISTWAYS
AND MACHINE ROOMS

by William E. Koffel, P.E.

Are sprinklers necessary in elevator machine
Tooms and elevator hoistways? The answer to that
question is a definite maybe. The issue is a prime
example of how our need to codify fire protection
Tesults in an overly simplistic solution that may not
truly be a solution. The purpose of this paper is to
address the issue from an engineering perspective.

PROBLEM DEFINITION

From a fire protection standpoint, the elevator
machine rooms and elevator hoistways offer the
following risks.

« Accumulation of trash and debris in the
elevator shaft provides an easily ignited fuel
source,

+ Elevator machine rooms are not always used
for the sole purpose of housing elevator
machinery.

+ Operational features of elevator shafts can
facilitate vertical transport of fire and smoke.

+ Elevators are often used to transport
firefighters and the disabled during a fire
emergency.

+ A fire in any room can impact on the means of
egress and structural integrity of the building.

Traditional fire protection solutions involving
automatic sprinklers can result in a potential loss
of control of the elevator. The elevator industry
has indicated that the hazardous effects of water on
brakes, shorting of a safety circuit, motor,
generator or transformer are well know.! The
elevator industry has also indicated that sprinkler
protection is unwarranted since most modern
elevator control systems will not operate in
temperature above 100°F.

The latter argument concerning temperature is
not germane to the issue. In fact, one could argue
that the sensitivity of the equipment to such

temperatures is an argument for utilizing quick
response sprinklers. However, it must also be
noted that the sprinklers are installed to protect
more that just the elevator equipment. Besides,
with an increasing desire to utilize elevators for
egress by the disabled, the elevator industry may
need to provide equipment capable of operating at
higher temperatures.

TRASH AND DEBRIS

NFPA 13, Standard for the Installation of
Sprinkler System?, requires a sprinkler to be
installed at the bottom of an elevator hoistway.
The sprinkler is provided to control a fire within
the shaft involving refuse which has collected at
the bottom of the shaft. However, ASME A17.1
Safety Code for Elevators and Escalators requires
that power be disconnected to the elevator prior to
sprinkler discharge. For a fire at the bottom of the
hoistway, this would most likely result in projected
beam smoke detection and a pre-action sprinkler
system. As an alternative, it would appear as if any
water-sensitive equipment could be shielded from
the water discharge. A flow switch could be
installed on the branch line to activate a form of
recall, possibly to the nearest floor, but not permit
Phase II Operation.

If this problem is a real concern, sprinkler
protection at the bottom of the hoistway should be
provided for all elevator hoistways, regardless of
whether the building is protected with sprinklers.

ELEVATOR HOISTWAYS

In addition to a sprinkler at the bottom of the
shaft, NFPA 13 also requires a sprinkler at the top
of the shaft. The effectiveness of this sprinkler has


54

been questioned based on the height of the shaft
and the obstruction of the sprinkler discharge by
the elevator car. The sprinkler does, however, have
a role in reducing the effect of the accumulation of
heated gases at the top of the shaft. The sprinkler
will activate and provide a cooling effect when
superheated gases accumulate at the top of the
shaft.

This being the case, it would appear as if there
are two potential solutions. First, a pre-action
sprinkler system could be installed such that
elevator recall and power disconnect would occur
prior to sprinkler discharge. The use of an
intermediate temperature sprinkler may be
advisable to insure that the heat detector activates
with sufficient time to recall the elevators. In this
instance, elevators would not necessarily need to
recall to the designated level for Phase I operation.
While this would be desirable for fire service
observation of the elevator car, it is more
important to insure that the people are able to
escape from the car. With respect to the fire
service concerns, it should be noted that Phase II
operation should not be permitted and that the
location of the elevators in high-rise buildings is
usually annunciated. The activation of the heat
detector should also activate the building fire
alarm system so that the occupants of the elevator
car are aware of the fire emergency in the building.

The second alternative would be to provide
emergency venting to prevent the accumulation of
heated gases. While elevator hoistway
pressurization is more desirable for emergency use
and smoke management, if sufficient heat
accumulates at the top of the shaft, the
pressurization is not working and venting becomes
necessary. Therefore, the emergency venting should
be provided even if hoistway pressurization is
provided. If adequate venting can be provided,
sprinkler protection at the top of the shaft would
be of minimal benefit except to suppress an
elevator car fire.

If the concerns relative to fire spread in the
shaft are real concerns, then sprinkler protection
or emergency venting should be provided in all
elevator hoistways.

ELEVATOR MACHINE ROOMS

Sprinkler protection in elevator machine
rooms may be provided to address the following
concerns: structural integrity, fire containment,
maintaining tenable egress facilities and ease of
suppression. It must be recognized that the

Elevators and Fire

installation of automatic sprinklers results in
modifications to many building code requirements
for fire resistance ratings. Therefore, the omission
of sprinklers from a portion of the building may
compromise the overall protection of the building.
With this in mind, it would be reasonable to allow
the omission of sprinklers from rooms used solely
for elevator equipment provided such rooms are
enclosed with construction having a fire resistance
tating, are protected with automatic detection to
initiate the building fire alarm system, are located
no more than 75 feet above the level of the fire
department access, and the room does not open
into an exit stairway.

‘When the above conditions do not apply, a
pre-action sprinkler system, with the permitted
used of intermediate temperature sprinklers,
should be installed. It should be noted that
watertight enclosures of the elevator equipment
could be provided thereby allowing the use of a
wet-pipe sprinkler system. Sprinklers have been
used for many years to protect areas with electrical
equipment and therefore can be used in elevator
machine rooms with the appropriate precautions.
Sprinkler protection in elevator machine rooms
should only be required if sprinkler protection is
provided throughout the building.

OTHER ISSUES

The concerns relative to sprinklers in elevator
hoistways and machine rooms are compounded by
the existing provisions for emergency operation of
elevators. The following recommendations should
be considered.

(1) Traditional Phase I and Phase II emergency
operation should be initiated by activation of the
building fire alarm system by a reliable means.
This will minimize the possibility that building
occupants will become trapped in an elevator or
exposed to the hazards discussed above.

(2) Traditional means to initiate Phase I recall
should not allow Phase II operation. If the
problem involves the elevator machine room or
hoistway, even trained emergency personnel should
not used the elevator. Phase II operation should
only be permitted when elevator lobby detectors
activate if a fire exposure to the call button will
not compromise the reliability of Phase II
operation.

If the above two recommendations are
implemented, the installation of sprinklers in
elevator machine rooms and hoistways will not
pose the same hazard as currently identified by the
elevator industry.



: Elevators and Fire
SUMMARY

The first step in resolving the conflict is to
develop a better definition of the problem. For
example, if fires involving rubbish at the bottom of
the elevator hoistway is a problem which needs to
be addressed, then the problem must resolved in
both buildings with and without sprinkler
protection. If it is not a real problem, why single
out sprinklered buildings as requiring sprinklers at
the bottom of the shaft provided the shaft
enclosure requirements are not modified due to
sprinkler protection in the building?

Likewise, if fire spread via the elevator
hoistway is a problem, Why single out sprinklered
building? Emergency venting has been proposed
as a viable alternative to a sprinklers at the top of
the hoistway.

The protection of elevator machine rooms is a
more complex issue since a fire in such a room
results in a fire risk similar to any room.
Therefore, either protection features to prevent
ignition and contain the fire must be implemented
or sprinkler protection provided.

Once the problem has been qualified, if
sprinkler protection is required or desired as a
solution, proper design will result in safe elevator
operations. In some instances, shielding of
equipment or improved equipment enclosure may
result in an acceptable level of protection without
requiring the additional costs (initial and life-cycle)
associated with pre-action sprinkler systems versus
wet-pipe sprinkler systems.

55
NOTES

Donoghue, Edward. "Elevators & Sprinklers,”
The Building Official and Code Administrator,
November/December, 1989, p. 26.

NFPA 13, Standard for the Installation of
Sprinkler Systems, 1989.

ASME/ANSI A17.1, Safety Code for Elevators
and Escalators, 1987.

William E. Koffel, P.E. is president of Koffel
Associates, Inc., an independent fire protection
engineering firm headquartered in Ellicott City,
Maryland. Active in the code development
process, Mr Koffel is a member of the BOCA Ad
Hoc Committee on Fire Protection Systems, the
BOCA Building Code Changes Committee, the
NFPA Technical Committee on Automatic
Sprinklers and Several NFPA Life Safety Code
subcommittees. Mr Koffel has a B.S. in Fire
Protection Engineering from the University of
Maryland and is a registered Professional
Engineer in several states. He is a member of
ASTM, BOCA, ICBO, NFPA, SBCCI, and
SFPE.