NFPA Journal - May/June 2020 - 56

in a large-scale test to replicate the
perceived real behavior of the system.
Some countries have chosen to include
large-scale testing of façade systems in
their requirements, while others have
opted to use large-scale façade testing
in addition to testing of individual
components.
The effort is commendable, but it
actually raises an important issue:
while these countries are all trying
to mitigate the same hazard, there
are almost as many tests as there are
countries with testing requirements.
The 2014 FPRF report, for example,
mentions no fewer than 15 variations
of these tests from various countries.
In addition, similar protocols have
also been developed by the International Standards Organization. As
with general fire requirements, the
various tests that have been developed
to assess combustible exterior façades
are largely based on local experience
and often replicate a scenario seen
in a catastrophic fire that occurred
in the country. As a result, key differences can exist in the tests, including
heat exposure, testing geometry, and
criteria for passing the test. The same
exterior wall system might get very
different results in different tests, one
deeming it safe and another unsuitable for its intended purpose. Fire,
however, does not recognize geopolitical borders and behaves the same way
everywhere. Yet, worldwide, our testing contains no consistent scientific
basis that could help eliminate these
critical safety differences from country
to country.
Some countries allow the use of
performance-based design, an engineering approach to fire protection
that is based on fire safety goals and
objectives, analyses of fire scenarios,
and the quantitative assessment of
design solutions. This methodology
is an incredible tool that allows fire
protection engineers to solve complex problems like exterior façade
safety-but it requires an expert-level
understanding of the systems being
analyzed. Unfortunately, the lack
of understanding of how different
materials interact within combustible
exterior wall assemblies during fire

makes it difficult for professionals to
become experts on this topic.
As a result, in some countries the
designs related to combustible exterior
wall assemblies apply two assumptions:
that façade components will behave similarly in any scenario, and that there is a
rule allowing for interpolation or extrapolation between tested façade systems.
Research shows that these two assumptions are incorrect. Since a minor change
in the material, geometry, or assembly of
a façade system can drastically impact
its combustibility, it is dangerous to
assume that these variations can be used
interchangeably in building design without further research.

WHERE IS THE DATA?
These are the kinds of problems that
can be traced directly to the absence
of accurate data-without it, we can
understand neither the true scope of
the problem nor the details necessary
to create consistent testing requirements and building regulations. That
void also results in an ongoing struggle to help policy makers understand
the critical link between energy-efficient buildings and fire safety. I once
encountered a politician who said to
me apologetically that until there were
"bodies on the table," exterior façade
safety was simply not an issue that
would receive political attention.
So how do we improve our data
gathering, and how do we leverage it
for maximum effect? The short answer
is that it isn't easy. Even in the US,
where I would argue we have the most
comprehensive fire data collection anywhere in the world, we cannot obtain
the kind of granular data needed to
help us better understand this problem. The fire incident data in the US
is collected through the National Fire
Incident Reporting System (NFIRS).
After a fire incident, NFIRS can be
used to record data about the item
first ignited, the performance of the
automatic sprinkler system, and
other critical pieces of information.
Since NFIRS uses a limited number of
choices within each data element, it
provides minimal information about
complex fire problems such as those
discussed here.

A similar shortage of data exists
internationally. Researchers from different countries have indicated that
incident reports often provide limited
information about the type of façade
system, the components used in the
assembly, and the development of the
fire. Another limitation of international
data is that different metrics are often
recorded by different countries. If
data collection is inconsistent between
nations, it is impossible to compare the
frequency of incidents without a high
level of uncertainty.
At an international conference on
fire safety of façades in Paris last year,
someone asked if we knew whether the
façade systems involved in the fires we
see around the world had fulfilled local
requirements, or if they had passed
locally mandated large-scale testing.
Sadly, the answer to each question was
no. With no consistent way of collecting incident data, it is impossible for us
to quantify how different requirements
around the world impact the level of
risk. With few exceptions, we continue
to validate unknown quantities of different building materials with various
test methods and often install them
with an undertrained workforce bound
by minimal regulations. The progression of these practices is seemingly
bottlenecked by a lack of knowledge
related to fire incident data to validate
or disprove hypotheses.
It is important to recognize that
there is an opportunity to learn from
failures, and even successes, and
develop strategies based on real-world
fire incidents. The education of stakeholders, growth from previous failures,
and quantification of this global issue
demand much more data than are
currently available today. As a champion of building safety, we recognize a
need to address this issue, and we look
forward to discussing it in an array
of upcoming public forums. I have no
doubt that we possess the ability to
devise new ways to collect and share
this information. Until we do, we will
continue to try to solve a set of problems we can barely identify.
BIRGITTE MESSERSCHMIDT is director of
Applied Research at NFPA.

56 | NFPA JOURNAL * M A Y / J U N E 2 0 2 0

Building Facades feature_05.20 FINAL.indd 56

5/4/20 1:36 PM
NFPA Journal - May/June 2020

Table of Contents for the Digital Edition of NFPA Journal - May/June 2020
