NFPA Journal - July/August 2017 - 52

Perspectives
systems that allow the person to call and say, "I'm
here. Come get me." But if the person sees fire or
smells smoke, they can choose to take the elevator
to escape, assuming the elevator is still operating
in normal service. It's not safe. But what's more
unsafe, taking the elevator or waiting for the fire
to get to you?
Is that one of the reasons OEEs are needed?
The main reason OEEs are a good thing in my
opinion is that they provide means for people
who have mobility issues to get out during emergencies. It can be older people or small children,
it can be people in wheelchairs, it can be pregnant women, it can be someone with a bad leg,
or anyone else on higher floors in a high-rise
building. It can drastically reduce the time of
evacuation in very tall buildings if the elevators
are used to evacuate occupants in addition to
the stairs.
For people who don't have mobility issues,
what are the problems that arise from stair
evacuation?
In an office building, for example, you can have a
very large occupant load. You can have 500 people
on a floor. If you evacuate five or six floors, that's
thousands of people getting into the stairs, which
become overcrowded. Firefighters are using the
stairs, too. If you have evacuation elevators, it's
much faster.
What makes OEEs different from regular
elevators?
In general terms, it's the building protection features around the elevators-fire walls, protection
from water, heat, and smoke, pressurizing the
lobbies, pressurizing the stairs, and preventing
any bad things from getting into the elevator
systems. Even if there's a fire in the building, the
OEE system is designed to prevent the fire and
smoke from getting into the elevator lobby or
into the elevator hoistway. The OEEs also can run
on backup power, so if you lose the power to the
building, a very large emergency generator is provided and can operate all the passenger elevators
simultaneously.

nfpa.org/
perspectives
READ the Fire
Protection Research
Foundation's 2013
report on evacuation strategies
and systems in tall
buildings.

How does occupant evacuation operation, or
OEO, work with an OEE system?
OEO is how the elevator system is designed per
the ASME Safety Code for Elevators and Escalators to automatically perform a partial or total
building evacuation without somebody pushing a
button or telling the elevators what to do. That's
the complicated electronic program, or computer

52 | NFPA JOURNAL * J U L Y /A U G U S T 2 0 1 7

system, that tasks the elevators to go to specific
floors automatically. It prioritizes where the elevator goes, and when, based on inputs from the
building fire alarm system specified in NFPA 72.
Three buildings under construction in San Francisco will be the first in the U.S. with complete
ASME-compliant OEO. Based on my understanding, New York City and Seattle are also looking
at this.
What's the history behind OEEs?
While the use of elevators during a fire event
has been discussed in one form or another for
more than 100 years, the concept was revisited
in earnest in 2002 following some of the preliminary work on the World Trade Center study from
FEMA and NIST. After September 11, a number
of task groups formed to talk about how to evacuate tall buildings. At first, the thinking was that
we needed more stairs. The IBC was changed to
require that buildings more than 420 feet tall
have an additional stair beyond what the IBC
would normally mandate. Then came the concept
of the evacuation elevator, which originally was
supposed to be in addition to the extra stairs. The
way the IBC is currently written, OEEs can be
used in lieu of the additional stair so long as the
other stairs provide the egress capacity needed for
the building.
What's your take on that arrangement?
I don't like it, personally. I want the additional
stairs. Stairs are passive systems-there is no
smartness to it, there's nothing that can fail. For
economic reasons, though, it may be tempting for
owners and architects to use the OEE exception in
the IBC code in lieu of an additional stair. Stairs
can take up to 250 square feet of area on each
floor. Multiply that by 100 floors in a high-rise
building, and that's a lot of premium real estate
not utilized as rentable space.
How are OEEs addressed in NFPA codes?
Both NFPA 101 and NFPA 5000 have a section on
OEEs. The codes provide the design and operational criteria. No egress credit is given for the
OEE and there are no requirements to provide
an extra stair if the OEE isn't provided. NFPA
72 Section 21.6 has contained information on
occupant evacuation elevators since the 2010
edition. It's been completely revised since then.
We proposed a whole new section based on many
hours of task group work. If the second draft is
passed in July, it'll be included in the 2019 edition of NFPA 72 subject to the membership vote
next June.

http://www.nfpa.org/perspectives

Table of Contents for the Digital Edition of NFPA Journal - July/August 2017