NFPA Journal - Winter 2021 - 59

In Compliance
These changes often raise questions
as to the extent a sprinkler
system must be brought up to date
with the latest standard, whether the
system needs to be recalculated, and
how extensive testing of the modified
system must be. Fortunately, the
2019 edition of NFPA 13, Standard for
the Installation of Sprinkler Systems,
included a new chapter that compiled
the requirements for these instances,
information that carries over to the
recently issued 2022 edition.
For the purpose of this discussion,
we will focus on situations where the
use or occupancy classification of the
space remains the same-in cases
where that changes, a more complex
analysis is likely required to determine
the impact of changes to design densities,
areas of operation, and several
other possible changes. In those
instances, NFPA 25, Standard for the
Inspection, Testing, and Maintenance
of Water-Based Fire Protection
Systems, places responsibility on the
owner for ensuring an evaluation is
conducted. Many of those evaluations
go beyond the reconfiguration of
office space, where the space protected
is likely to remain a light-hazard
occupancy.
When a building undergoes a renovation
or remodeling, the removal
or addition of walls, partitions, and
ceilings can negatively impact the
effectiveness of the originally designed
sprinkler system. In these instances,
numerous sprinklers must often be
relocated or added in order to appropriately
protect the reconfigured
space. This does not necessarily mean
that the entire system must be reevaluated
to ensure complete compliance
with the latest edition of the standards.
In fact, portions of the existing
system that are not subject to the
modifications can be considered previously
approved under the retroactivity
clause of NFPA 13 and do not need to
be evaluated. Whenever additions or
modifications are made to an existing
system, enough of that system must
be indicated on the plans to make
all conditions clear for the authority
having jurisdiction (AHJ) to evaluate.
NFPA 13 requires calculations be
provided to verify that the system
design flow rate will be achieved
where hydraulically calculated
systems are modified. This does
not necessarily require a full set of
hydraulic calculations, particularly if
the modifications are made in a part
of the system that is not the hydraulically
most demanding. In this case,
the modified portion of the system
can be hydraulically calculated back
to the branch line or riser to the
point where original calculations
are used to show that the design
flow rate can be met. It should be
confirmed with the AHJ to determine
that they will accept this for these
instances.
Newly installed sprinkler systems
must be hydrostatically tested to
check for leaks at a pressure of at
least 200 psi (14 bar) for a period of
at least two hours. When existing
systems are modified such that the
work affects fewer than 20 sprinklers,
the system only requires testing at
the system working pressure. Where
the modification affects more than
20 sprinklers, that portion of the
system must be isolated and tested
at 200 psi (14 bar) for two hours. If
the new work cannot be isolated, the
testing can be done at system working
pressure even if the modifications
involved more than 20 sprinklers.
In general, existing portions of the
system do not need to be subjected to
a new hydrostatic test.
The provisions for existing sprinkler
system modifications in NFPA 13
are intended to ensure that a modified
space has adequate coverage,
that the system demand can still be
met, and that the workmanship of the
modification has been completed well
enough. This is meant to strike an
appropriate balance between ensuring
that the changes are not simply
ignored, and calling for everything to
be brought up to the requirements of
the latest edition of the standard.
Jonathan Hart is technical lead, Fire Protection
Engineering, 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 70 + 70E
Electrical Safety
Emergency disconnects
for one- and two-family
dwellings in the 2020 NEC
By Dean Austin
E
mergency disconnects
for one- and two-family
dwellings may be old hat
to some, but to others
they might be brand new.
Similarly, while the 2020 National
Electrical Code®
(NEC) isn't exactly new
to the world, it may seem new to jurisdictions
that are just adopting it or that
are considering doing so. As of August,
only 13 states had adopted the 2020
NEC, meaning the vast majority of the
country is unable to benefit from the
code's important new requirements.
One of those new requirements is
a section on emergency disconnects,
contained in Article 230 of the 2020
NEC. Section 230.85, " Emergency
Disconnects, " is intended to help first
responders and utility workers mitigate
electrical hazards safely when
the need arises in one- and two-family
dwellings during a fire event.
Standard operating procedures usually
call for first responders to perform a
360-degree evaluation of the structure
and then conduct a hazard risk
assessment before entering-the risk
assessment determines the course
of action to be taken. Under normal
circumstances, the power to a dwelling
can be disconnected simply by turning
off the main service disconnect in
the electrical panel, which may be in a
basement or behind a door. This is not
a big deal-unless the power needs to
be disconnected when a dwelling is full
of smoke and flames.
When the main service disconnect
is unreachable, removing power to a
dwelling now may require removal
of meters or fuses under load. This
increases the likelihood of an electrical
hazard, which is why first responders
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NFPA Journal - Winter 2021

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