NFPA Journal - Fall 2023 - 54

Codes + Tech
that an inspector is required to look for
when inspecting fire sprinklers from the
floor level. If the sprinkler is damaged,
leaking, or has fluid missing, the sprinkler
must be replaced. However, when
one or more of the other three conditions
(corrosion, loading, and paint on
the sprinkler) exist, the actions that need
to be taken are not as simple and questions
on specifics are likely to arise. The
changes made to this section in the 2023
edition were intended to provide sufficient
guidance needed to make the right
decision about the need to replace sprinklers
with these conditions or to leave
them in service. One change added the
phrase " detrimental to sprinkler performance "
to painted sprinklers as well.
Legacy antifreeze solutions can
remain in existing systems with
strict limitations.
Since 2012, the fire protection community
has been aware of the dangers
of accelerated fire growth when high
concentrations of propylene glycol
and glycerin antifreeze solutions were
discharged on a fire by a sprinkler
system. Since then, the installation
standards have prohibited using
nonlisted antifreeze solutions in new
systems. Unfortunately, the first listed
antifreeze solution wasn't available
until late 2018.
In the 2023 edition of NFPA 25,
subsection 5.3.4.4.1 was modified to
provide options for existing antifreeze
systems installed prior to 2012. One of
those is to allow low concentrations
of the premixed legacy solutions to
remain in systems. Any system with a
legacy solution above specified limits or
any system that needs to have the antifreeze
replaced must be refilled with a
listed solution.
However, because of the listing
limitations, it's not as simple as replacing
the old with a new listed solution.
The listed solutions have system size
limitations and hydraulic calculation
criteria that must be considered. To
allow the use of new listed solutions, an
exception was included in 5.3.4.4.1 that
allows their use outside of their listing
limitations to refill systems if adequate
freeze protection is provided.
54 | NFPA JOURNAL * FALL 2023
Using nitrogen as a corrosion
inhibitor allows a hydraulic calculation
trade-off for dry and
preaction systems.
The 2022 edition of NFPA 13, Standard
for the Installation of Sprinkler
Systems, introduced a new allowance
for the hydraulic calculations of dry
and certain preaction systems using 98
percent or greater purity of nitrogen
from a listed nitrogen generator for the
air supply. A C value of 120 can be used
instead of the normal C value of 100.
To ensure that the systems using the
increased C factor maintain the proper
nitrogen supply, the 2023 edition of NFPA
25 added new requirements specifying
that any time the nitrogen generator
is repaired or replaced, it must be with
another nitrogen generator capable of
maintaining the design concentrations.
In Chapter 13 there are also new testing
requirements for systems when the C
factor of 120 was used. When a preaction
or dry system uses this C factor, an
adequate nitrogen supply must always be
maintained for the life of the system.
Changes were made that address
conditions requiring an obstruction
investigation.
Chapter 14 in NFPA 25 includes three
separate and distinct sections. Section
+
All parties concerned
need to be familiar
with the updates in the
latest edition of NFPA 25.
The protection of life and
property is at stake.
14.2, Assessment of Internal Condition
of Piping, includes requirements to
be performed on a five-year basis to
determine the internal condition of
all metallic piping systems. Section
14.3, Obstruction Investigation and
Prevention, includes a list of 16 conditions
that trigger an investigation of
the system piping on an as-needed
basis. Unlike the assessment in Section
14.2, there is no set frequency for an
obstruction investigation. Section 14.4,
Ice Obstruction, applies only to pipes
passing through spaces where the
temperature is maintained below 32°F.
There were no changes to sections
14.2 or 14.4 in the 2023 edition of the
standard. However, there were several
changes to Section 14.3 and the list of
16 triggers that initiate an obstruction
investigation. Additionally, the number
and location of the internal examination
points were changed from four to
five, which now includes three branch
line locations.
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NFPA Journal - Fall 2023

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