The fire department of Hays, KS rushed to a hotel in June to find that it was not only facing a damaging fire, but also a flow of water that threat- ened to collapse the
building. The cause of that threat – a
malfunctioning sprinkler system.
the problem, and those are difficult – or even impossible – to detect on your own.
To maintain your sprinkler system’s efficacy, the
NFPA – whose standards are often adapted into laws –
requires inspections of the internal piping every five
years. In temporarily shutting down the system, this
inspection checks the piping for obstructions.
However, this standard may not adequately
address the threat of corrosion, which works quickly
and undermines the safety of fire sprinkler systems.
Finding the Causes of Corrosion
Because so many fire sprinkler systems are composed of metal pipes, water and compressed air,
corrosion is always a risk and can begin quickly.
“Corrosion processes can happen almost instantaneously – within seconds of flooding the pipe,” says
Dr. Jeff Pfaendtner, Principal Engineer at Veracis
Engineering in Minneapolis. Corrosion can damage
internal piping quickly if conditions are not right.
Pfaendtner notes, “People might think that water
is just water, regardless of the source. But it’s not.”
Even water treated by municipalities can be suspect
and cause corrosion simply because of the way it may
“To treat water and make it taste better, municipalities may bubble oxygen through the water to settle out
iron. But you may end up with an excess of dissolved
oxygen in the water,” says Pfaendtner. In wet-pipe
systems, the dissolved oxygen often causes some of the
more insidious problems because it goes unnoticed.
And oxygen should not be overlooked in sprinkler
pipes. Corrosion in piping is generally rust accumulation from the presence of three simple substances:
iron, water and oxygen. The removal of just one of
these three will stop most kinds of corrosion, but
that can be difficult in a sprinkler system where
water and iron are often two of the main materials
inherent in systems. Oxygen also finds its way into
preaction and dry systems because they are designed
to be filled with air.
“If you have a significant amount of oxygen and
water coexisting inside your steel pipes, you can have
corrosion and pitting all the way through the pipe
wall in less than five years,” says Jeff Harrington,
President and CEO at Harrington Group, Inc. in
Duluth, GA. Harrington has even seen cases that have
developed within two to three years of installation.
This means that the code requirement of checking
The fire department could not effectively take on
the fire through conventional methods, but it was
able to evacuate the building safely and eventually
extinguish the fire. However, this took nearly seven
hours, and the hotel sustained considerable damage.
Typically, sprinkler systems are incredibly effective
at reducing the impact of fires. The National Fire
Protection Agency (NFPA) found that 96% of sprinkler systems worked in suppressing fires when they
Sprinkler systems provide an important sense of
security because of the safety they offer to buildings
and their inhabitants.
Yet, as with the inci-
dent in Hays, this is
only possible when the
systems are working
properly. If not, they
can allow and con-
tribute to catastrophic
issues – like in Hays –
can be avoided
through locating and
treating the problem in
the sprinkler system.
But even though you
might inspect your
own sprinkler system
often, some major
problems are just not
visible. Damage from
the inside of the pipes
may be the source of
“If you have
oxygen and water
your steel pipes,
you can have
pitting all the
way through the
pipe wall in less
than five years.”
— Jeff Harrington, President
and CEO, Harrington Group,
Inc., Duluth, GA