NFPA Journal - Fall 2022 - 52

In Compliance The Experts
SELECTIONS FROM RECENT
BLOGS ON CODES AND
STANDARDS BY NFPA STAFF
NFPA engineer Brian O'Connor on water mist
systems, which use very small water droplets to
extinguish or control fires:
Water mist systems have been used for specific
applications (such as maritime) for a long time, but
use began to accelerate in the mid-1990s with the
phase out of halon, especially in spaces where water
is limited. There is a long list of applications where
water mist systems have been listed for use, and a
few different ways to apply these systems in a building
or facility. The applications of water mist system
and clean agent systems are similar because they
share several commonalities.
Occupancy protection systems: A water mist system
utilizing automatic water mist nozzles installed
throughout a building or a portion of a building and
intended to control, suppress, or extinguish a fire.
Jonathan Hart, technical lead, Fire Protection
Engineering, on NFPA 25, Standard for the Inspection,
Testing, and Maintenance of Water-Based
Fire Protection Systems, and what it says about
impairment procedures for sprinkler systems that
are out of order:
The standard provides the criteria for the routine
activities that must be conducted to ensure that water-based
fire protection
systems can be relied
upon in the event
of a fire. But what
about when a system
needs to be shut off for
repair or maintenance?
What about when a
water main is broken, a
frozen pipe has burst,
a fire pump has failed,
or another major
issue has been found
during inspection or
testing? At that point,
the building contains a
compromised sprinkler
system and is no
longer protected at the
level that is expected
while the system is in
service. In NFPA 25,
the term for a system
that is out of order is
impairment, regardless
of whether or not it
was planned.
Local application: This configuration is used to
protect a specific hazard or object. An example may
be the protection of a piece of equipment in a large
compartment. The system would be designed to
discharge water mist directly onto the object.
Total compartment application: This type of
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versions of
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and many
more by
NFPA staff
at nfpa.org/
blogs
system provides protection to all fire hazards and
all areas in a compartment. The open nozzles are
positioned in a grid so that water mist discharges approximately
uniformly throughout the entire volume.
Zoned application: This type of system is configured
to discharge mist from portions of a larger
system as required to control fire in a specific part of
a compartment. It would be installed in circumstances
where the water demand for a total compartment
system is beyond the available water supply. Zoning
the water mist piping network, however, requires the
installation of a detection system that can accurately
find the location of a fire.
52 | NFPA JOURNAL * FALL 2022
Impairments need to be addressed and resolved
as quickly as possible in order to provide the expected
level of protection for life and property. If the
impairment is prolonged, additional measures need
to be taken in consideration of life and property
protection.
Chapter 15 is dedicated to addressing the requirements
that include the measures to be taken to
ensure that increased risks are minimized and that
the duration of the impairment is limited. A key provision
here is that the property owner or designated
representative must assign an impairment coordinator
to comply with the requirements of the chapter.
The impairment coordinator should have a detailed
plan ahead of time for how they will handle both
preplanned and emergency impairments and meet
the requirements. Any preplanned impairments need
to be authorized by this individual prior to removing
the system from service.
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NFPA Journal - Fall 2022

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