NFPA Journal - Spring 2021 - 38

In Compliance
ventilation is required; if it is between
200 feet and 1,000 feet, then natural or
mechanical ventilation is needed; if it is
greater than 1,000 feet, mechanical ventilation is required. NFPA 130 also requires
additional safety features including exit
signage, illumination, properly sized
egress routes, as well as noncombustible
rail ties and walking surfaces.
NFPA 130 acknowledges that passenger vehicles are a large source of fuel for
a fire. The standard addresses this issue
by preventing fire ignition and mitigating fire impact. These approaches
are addressed through electrical safety
measures as well as requiring the interior and exterior surfaces of the vehicles
to go through extensive testing to ensure
high levels of fire safety performance.
While both aboveground and underground passenger rail systems present
unique and challenging scenarios, with
the proper design and installation these
systems can be safe and reliable means
of transportation.
Brian O'Connor is a technical services
engineer at NFPA. NFPA members and AHJs can
use the Technical Questions tab to post queries on
NFPA 13 at nfpa.org/13. To follow the progress
on the upcoming edition of the code, visit nfpa.
org/13next

NFPA 72

Fire alarms, signaling, and
emergency communication

Determining the extent
of fire alarm
acceptance testing
By Jonathan R. Hart
ome of the most common
questions received by
NFPA staff have to do
with additions and modifications to fire protection
systems. In today's world of shell space
buildings, increasing tenant turnover,
and frequent building modifications
both large and small, it's no wonder
that the systems providing fire and life
safety must be constantly evaluated and
tweaked to maintain compliance.

S

NFPA's technical question service
(TQS) recently received a question
about the extent of testing that would
be required when adding three initiating devices to a fire alarm control
unit (FACU). In this case, the FACU
was connected to multiple networked
FACUs.
The correct place to start here is
Chapter 14 of NFPA 72®, National Fire
Alarm and Signaling Code®, which
includes criteria for initial acceptance
testing, routine inspection, testing,
and maintenance, as well as a section
on reacceptance testing for fire alarm
systems. The first and easiest answer
to the question is that the three new
initiating devices need to be functionally tested. This is stated clearly
and concisely in the code, and you'd
be hard pressed to find anyone who
might argue with that.
For a conventional system where no
other changes are made, including to
the site-specific software, that might
be all the testing that's necessary. The
way the question was asked, however,
indicated that this situation involved
an addressable fire alarm system and
therefore required changes be made to
the site-specific software. When this is
the case, NFPA 72 requires more extensive testing. This will first require that
all the functions known to be affected
by the change be fully tested. In this
case, any function activated by the
three new initiating devices must be
tested and could include notification
appliances, elevator recall, pressurization, other relay functions, and
annunciator labelling, to name a few.
In addition to functionally testing the three devices themselves, as
well as all of the associated outputs,
an additional 10 percent of initiating devices, up to a maximum of 50
devices, that are not affected by the
change must also be tested in order
to verify correct operation. This is
because, while modern software-driven
fire alarm systems are easily modified to accept new devices or to change
the address or response of existing
devices, these steps are often handled
by changes to the site-specific software in the fire alarm control unit.

That means that what may seem like
a minor change may have unintended
consequences to inputs or outputs not
meant to be changed.
This is where the question submitted through TQS got interesting. As
mentioned, the three new initiating devices were being added to a
single FACU that was connected to
several other FACUs. The submitter wanted to know if the additional
10 percent of initiating devices (up to
50 total) requiring testing was for the
single FACU or for initiating devices
connected to the networked FACUs.
The impact of this determination was
that where the three initiating devices
were being added was part of a control
unit that had a total of 50 initiating
devices, whereas the total amount of
initiating devices for the networked
system was over 1,000. That meant
the difference between testing an
additional five initiating devices (10
percent of 50) versus an additional 50
initiating devices-a significant difference in time and effort.
To answer this, we needed to know
the functions of the specific system in
more detail than we were provided. If
activation of devices that report to the
FACU in question are limited to that
control unit, then the 10 percent could
be limited to the single control unit.
If the activation of devices that report
to the FACU in question transmit
and cause functions to occur at other
FACUs via network or other communication means, then those would
need to be included as part of the 10
percent, or up to 50 devices.
Whichever situation is appropriate, the 10 percent sample should be
selected randomly and include at least
one device per initiating device circuit
or signaling line circuit (SLC). If all
the devices are installed on one SLC,
multiple devices (a 10 percent sample)
should be tested at different sections
of the circuit. Use of comparison algorithms, or programs that compare two
sets of data to determine the differences between them, can also help
determine where program changes
may have occurred, but are not an
alternative to the testing.

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NFPA Journal - Spring 2021

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