|
Burst
water
pipes
are
caused
by
the
expansion
of
freezing
ice
against
the
wall
of
the
pipe,
right?
Wrong.
In a
remarkable
series
of
laboratory
and
field
experiments,
researchers
at
the
University
of
Illinois
have
demonstrated
that
the
actual
cause
of
damage
to
freezing
water
pipes
isn't
the
force
of
expanding
ice
on
the
pipe,
but
rather
an
extreme
rise
in
water
pressure
downstream
from
the
blockage.
According
to
the
study,
the
water
pressure
can
rise
in
these
situations
from
about
40
pounds
psi
(per
square
inch)
to
more
than
4,000
pounds
psi.
A
typical
scenario
might
go
like
this:
A
stretch
of
copper
pipe
is
exposed
to
unusually
cold
temperatures,
and
ice
begins
to
form
on
the
pipe's
inside
walls.
Since
water
volume
expands
by
about
eight
percent
as
it
turns
to
ice,
the
ice
formation
eventually
can
completely
block
the
water
flow.
Water
upstream
from
the
blockage
is
able
to
flow
back
to
its
source,
such
as
the
street
connection.
But
the
water
downstream
is
trapped
because
the
faucets
are
closed.
As
the
ice
continues
to
form
and
expand,
pressures
downstream
from
the
blockage
skyrocket.
Because
this
entire
section
of
pipe
experiences
the
same
elevated
pressure,
the
failure
can
occur
at
any
point,
even
within
the
heated
space
of
the
building.
Now
that
researchers
better
understand
the
problem,
they
have
devised
a
simple
effective
solution:
a
modified
faucet
washer
that
enables
the
faucet
to
leak
a
little
under
high
pressure.
This
inexpensive
device
could
eliminate
much
of
the
$400
million
per
year
of
insurance
claims
now
paid
to
homeowners
for
freeze-related
plumbing
damages.
Source:
Ned
Nisson,
Popular
Science
Magazine,
February
1997
How
can
I
prevent
frozen
pipes?
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