THIS SUDDEN DEEP FREEZE WILL CAUSE PROPERTY DAMAGE FROM NON-WINTERIZED PIPE BURSTS EVEN IN SOUTHERN HOMES
REGIONAL
DIFFERENCES - WHY PIPES BURST IN SOUTHERN CLIMATES
Surprisingly,
ice forming in a pipe does not typically cause a break where the ice blockage
occurs. It’s not the radial expansion
of ice against the wall of the pipe that causes the break. Rather, following a
complete ice blockage in a pipe, continued freezing and expansion inside the
pipe causes water pressure to increase downstream -- between the ice blockage
and a closed faucet at the end. It’s this increase in water pressure that leads
to pipe failure. Usually the pipe bursts where little or no ice has formed.
Upstream from the ice blockage the water can always retreat back towards its
source, so there is no pressure build-up to cause a break. Water has to freeze
for ice blockages to occur. Pipes that are adequately protected along their
entire length by placement within the building’s insulation, insulation on the
pipe itself, or heating, are safe.
Generally,
houses in northern climates are built with the water pipes located on the
inside of the building insulation, which protects the pipes from subfreezing
weather. However, extremely cold weather and holes in the building that allow
a flow of cold air to come into contact with pipes can lead to freezing and
bursting.
Water
pipes in houses in southern climates often are more vulnerable to winter cold
spells. The pipes are more likely to be located in unprotected areas outside of
the building insulation, and homeowners tend to be less aware of freezing
problems, which may occur only once or twice a season.
Pipes
in attics, crawl spaces and outside walls are all vulnerable to freezing,
especially if there are cracks or openings that allow cold, outside air to flow
across the pipes. Research at the University of Illinois has shown that “wind chill,”
the cooling effect of air and wind that causes the human body to lose heat, can
play a major role in accelerating ice blockage, and thus bursting, in water
pipes.
Holes
in an outside wall where television, cable or telephone lines enter can provide
access for cold air to reach pipes. The size of pipes and their composition
(e.g., copper or PVC) have some bearing on how fast ice forms, but they are
relatively minor factors in pipe bursting compared with the absence of heat,
pipe insulation and exposure to a flow of subfreezing air.
When
is it Cold Enough to Freeze?
When
should homeowners be alert to the danger of freezing pipes? That depends, but
in southern states and other areas where freezing weather is the exception
rather than the rule (and where houses often do not provide adequate built-in
protection), the “temperature alert threshold” is 20 degrees F.
This
threshold is based upon research conducted by the Building Research Council at
the University of Illinois. Field tests of residential water systems subjected
to winter temperatures demonstrated that, for un-insulated pipes installed in
an unconditioned attic, the onset of freezing occurred when the outside
temperature fell to 20 degrees F or below.
This
finding was supported by a survey of 71 plumbers practicing in southern
states, in which the consensus was that burst-pipe problems began to appear
when temperatures fell into the teens. However, freezing incidents can occur
when the temperature remains above 20 degrees F. Pipes exposed to cold air
(especially flowing air, as on a windy day) because of cracks in an outside
wall or lack of insulation are vulnerable to freezing at temperatures above the
threshold. However, the 20 degrees F “temperature alert threshold” should
address the majority of potential burst-pipe incidents in southern states.
MITIGATING
THE PROBLEM
Water
freezes when heat in the water is transferred to subfreezing air. The best way
to keep water in pipes from freezing is to slow or stop this transfer of heat.
Ideally,
it is best not to expose water pipes to subfreezing temperatures, by placing
them only in heated spaces and keeping them out of attics, crawl spaces and
vulnerable outside walls. In new construction, proper placement can be designed
into the building.
In
existing houses, a plumber may be able to re route at-risk pipes to protected
areas, although this may not be a practical solution. If the latter is the
case, vulnerable pipes that are accessible should be fitted with insulation
sleeves or wrapping (which slows the heat transfer), the more insulation the
better. It is important not to leave gaps that expose the pipe to cold air.
Hardware stores and home centers carry the necessary materials, usually in foam
rubber or fiberglass sleeves. Better yet, plumbing supply stores and insulation
dealers carry pipe sleeves that feature extra-thick insulation, as much as 1 or
2 inches thick. The added protection is worth the extra cost.
Cracks
and holes in outside walls and foundations near water pipes should be sealed
with caulking to keep cold wind away from the pipes. Kitchen and bathroom
cabinets can keep warm inside air from reaching pipes under sinks and in adjacent
outside walls. It’s a good idea to keep cabinet doors open during cold spells
to let the warm air circulate around the pipes. Electric heating tapes and
cables are available to run along pipes to keep the water from freezing. These
must be used with extreme caution; follow the manufacturer’s instructions
carefully to avoid the risk of fire, and check to make sure the product
conforms to UL 2049. Tapes and cables with a built-in thermostat will turn
heat on when needed. Tapes without a thermostat have to be plugged in each time
heat is needed, and may be forgotten.
LETTING
THE WATER RUN
Letting
a faucet drip during extreme cold weather can prevent a pipe from bursting.
It’s not that a small flow of water prevents freezing; this helps, but water
can freeze even with a slow flow.
Rather,
opening a faucet will provide relief from the excessive pressure that builds
between the faucet and the ice blockage when freezing occurs. If there is no
excessive water pressure, there is no burst pipe, even if the water inside the
pipe freezes.
A
dripping faucet wastes some water, so only pipes vulnerable to freezing (ones
that run through an unheated or unprotected space) should be left with the
water flowing. The drip can be very slight. Even the slowest drip at normal
pressure will provide pressure relief when needed. Where both hot and cold
lines serve a spigot, make sure each one contributes to the drip, since both
are subjected to freezing. If the dripping stops, leave the faucet(s) open,
since a pipe may have frozen and will still need pressure relief.
IF YOU SUSPECT A FROZEN PIPE
If
you open a faucet and no water comes out, don’t take any chances. Call a
plumber. If a water pipe bursts, turn off the water at the main shut-off valve
(usually at the water meter or where the main line enters the house); leave the
faucet(s) open until repairs are completed. Don’t try to thaw a frozen pipe
with an open flame; as this will damage the pipe and may even start a building
fire. You might be able to thaw a pipe with a hand-held hair dryer. Slowly
apply heat, starting close to the faucet end of the pipe, with the faucet open.
Work toward the coldest section. Don’t use electrical appliances while standing
in water; you could get electrocuted.
GOING ON A TRIP
When
away from the house for an extended period during the winter, be careful how
much you lower the heat. A lower temperature may save on the heating bill, but
there could be a disaster if a cold spell strikes and pipes that normally would
be safe, freeze and burst.
A
solution is to drain the water system. This is the best safeguard. With no
water in the pipes, there is no freezing. This remedy should be considered even
when the homeowner is not leaving but is concerned about a serious overnight
freeze.
To
drain the system, shut off the main valve and turn on every water fixture (both
hot and cold lines) until water stops running. It’s not necessary to leave the
fixtures open, since the system is filled mostly with air at that point and not
subject to freezing. When returning to the house, turn on the main valve and
let each fixture run until the pipes are full again.
WATER DAMAGE Claims DUE TO Freeze-Up and Burst Water Pipes
Compliments
of
the “polar vortex”, frigid temperatures in the Northeast and in the
Southern
States have caused many water pipes to freeze and burst. Residential
and commercial properties have
been affected. Pipe freeze-up and
unfreezing damages were particularly severe in southern climates, where
piping
systems lack freeze protection more common in the north. Even in the
Northeast, property owners saw
(and continue to see) significant pipe failures. Most of the pipe
bursts occur inside uninsulated and/or unheated janitor closets,
basements, attics, exterior faucets/piping, and so on. In some cases,
fire sprinkler systems froze,
allowing fire to spread due to the lack of fire protection. Malls,
restaurants and other walk-in retail
establishments suffered business interruption, and some lost power as
well as
other utility services.
Most standard plumbing codes reference guidelines
or standards in recognizing freezing of most buildings. Typically, they are as follows:
“A water, soil, or waste pipe shall not
be installed or permitted outside of a building, or concealed in outside walls
or in any space where they may be subjected to freezing temperature, unless
adequate provision is made to protect them from freezing.”
In your evaluation and investigation of
these types of cases, you should keep in mind the absolute cause of the freeze up
and determine whether or not there are issues concerning coverage, liabilities,
subrogation, and ultimately evaluate the damage to determine extent of damage
and reasonable cost for repair or replacement of these items.
We had
already assignments for a frozen pipe activating a sprinkler system which
flooded the insured’s property. Both MSO and ISO policies contain general mitigation of
damages provisions requiring insureds to take reasonable efforts to prevent
further losses from occurring, such winterize the pipes in the home, maintain
heat, etc.
Ex.:
ISO Form HO 00 06 says:
We do
not insure, however, for loss:
C Caused by:
(1) Freezing of a plumbing, heating, air
conditioning or automatic fire protective sprinkler system or of a household
appliance, or by discharge, leakage or overflow from within the system or
appliance caused by freezing. This exclusion does not apply if you have used
reasonable care to:
(a) Maintain heat in the building; or
(b) Shut off the water supply and drain all
systems and appliances of water.
The insurance industry is presented
with claims that surround freezing of water pipes that ultimately burst and
result in property damage claims. There
are many causes for these claims, some of which involve the following:
1.
Improper
maintenance of heat in a building or chase way (occupied or vacant).
2.
Sudden shutdown
of heating system, combined with improper inspection or maintaining of heat in
a building.
3.
Deterioration or
lack of insulation protecting building and water piping.
4.
Mechanical or
electrical malfunction of a control or product.
5.
Inadequate
servicing and maintaining of piping, whether considered to be part of constant
wet or water flow piping, and/or a dry pipe system, which normally does not
allow constant water pressurization.
As the action or inaction of the
insured is critical in determining whether coverage applies, a thorough
examination of the circumstances of the loss is crucial: these claims are fact-sensitive and we can
assist you in properly developing them.
Burst pipes, flooded basements, devastating
structural damage, damaged floors, ceilings, carpets, wiring, furnishings,
wallboard, and mold are a few obvious results of freeze up and pipe burst damage.
These types of problems can result from
maintenance problems, mechanical failure, installation errors, low temperatures
maintained in buildings, or fuel delivery issues. Be sure to learn more about METROPOLITAN’s
proprietary Fuel Usage Analysis Computer Program. This computer program
compares data we retrieve with energy consumption levels to validate the
results of our investigation.
Why do water
pipes burst in winter?
The pipe bursts always in a longitudinal fashion. The burst always occurs at the weakest
portion of the pipe. Because of its
unique properties, water expands as it freezes into ice by as much as nine
percent (9%) in volume. On the other
hand, a metal pipe shrinks when frozen.
In a pipe, ice forms first on the inside wall of the pipe and grows
radially inward until there is a solid plug of ice blocking the pipe. Until
that situation occurs, the expansion of the freezing water in the pipe merely
pushes water back into the water main. When the plug of ice completely blocks
the pipe, it seals water between the plug and a closed valve. If more ice forms
between the plug and the closed valve, the expanding ice has nowhere to go, and
causes the pipe to burst at its weakest point. Hot water pipes will burst much faster than
the cold water pipes.
Pipe bursting occurs when
(1) Freezing temperatures create ice blockages
in water pipes, then (2) Further ice growth applies dangerously high pressures
to a confined water volume.
Most of the research and claims investigated
by METROPOLITAN uncovers results that examine the effect upon the freezing process
of five variables:
1.
Design
temperature.
2.
Pipe
composition, (copper or PVC).
3.
Insulation
level.
4.
Pipe diameter (
1/2” or 3/4”).
5.
Water source
(cold or hot water tap).
The Freezing events in a water pipe can
be sub-divided into four distinct stages:
1.
Initial cooling
through super cooling.
2.
Dendritic ice
formation.
3.
Annular ice
formation.
4.
Final cooling to
ambient temperature.
Timetables for freezing temperatures
can vary, but the testing performed by the University of Illinois confirms the
following:
When a water pipe is exposed to
subfreezing temperatures, heat is transferred from the water, through the pipe
wall and any insulation layers to the sub-freezing air. The temperature of the water begins to fall in
a steep decline. Remarkably, the water in the pipe does not immediately begin
to freeze when it reaches the phase change temperature of zero degrees Celsius,
but continues to fall and approach the temperature of the surrounding air.
In research tests water pipes placed in an unheated, insulated attic consistently started forming ice when the outdoor temperature dipped below 20 degrees Fahrenheit (20 degrees F). Importantly, the 20 degrees threshold is primarily for homes in the south and other areas where freezing may occur once or twice a winter or cold season.
In research tests water pipes placed in an unheated, insulated attic consistently started forming ice when the outdoor temperature dipped below 20 degrees Fahrenheit (20 degrees F). Importantly, the 20 degrees threshold is primarily for homes in the south and other areas where freezing may occur once or twice a winter or cold season.
This process is known as super cooling. It
is possible for water in a pipe to super cool for a considerable length of time
before any ice forms. The temperature at which ice begins to form is known as
the ice nucleation temperature. The nucleation temperature implies a starting, or
a nucleus,
for ice formation. It is often claimed that, when subjected to identical
conditions, a hot water line will burst before a cold water line. One theory
states that premature bursting is the result of greater dendritic ice formation
in hot water pipes than in cold water pipes.
However, testing of water drawn from both
cold and hot water taps revealed that at the time of bursting, there was no difference
if the water was drawn from a cold water source or a hot water source. Further research and investigation is required,
but it is believed that a tendency for hot water pipes to burst before cold
water pipes might be due to the distribution of entrapped air in residential water
systems because of water heating processes. Clearly, you should be aware that the source
of the freezing temperature could be the overall environment, a broken window,
or uninsulated pipe exposed to the obvious temperatures. What occurs is an ice formation pattern in
which there is the expansion of ice, or the growth of ice, through the pipe. As the pipe continues to freeze, particularly
in a vertical situation, the frontier of the ice/water climbs in the pipe. At the same time annular ice against the pipe
wall grows inward.
The Forensic
Investigation
It is METROPOLITAN’s
experience
that there is no substitute for a thorough and comprehensive inspection of the
structures to determine the number of conditions that caused the loss and
whether the conditions worked independently, concurrently, or in a sequence to
cause the damage. For example, some
common questions include:
·
Was the pipe
frozen and burst due to lack of maintenance, wear and tear or incorrect
installation? E.g., old or corroded pipes, or no proper insulation, etc.
·
Was the
frozen pipe damaged due to negligence? did
the insured turn off the heat in the home or commercial property during cold
weather?
·
Did the
boiler or furnace shutdown and caused the pipe freeze-up? Did the boiler or
furnace had a mechanical breakdown or it was shut down by the insured? METROPOLITAN can reveal the causes of these
failures utilizing mechanical evaluation of the boiler or furnace, perform a
fuel usage analysis and perform an examination of the condition of the equipment
installation. We can also determine the
thermostat setting temperature, or whether the fuel run out, along with the
timing of these events. METROPOLITAN
will obtain a copy of the insured’s utility bill and will audit it for the
purpose of making the above determinations.
Our Energy and Fuel Usage Modeling will determine what really happened and
determine the cause of the pipe burst.
·
Was the pipe broken
due to normal wear and tear?
A comprehensive investigation is crucial to good claims
handling. It
is vitally important to conduct bench testing of boiler controls and a Comprehensive
Freeze Up Loss Investigation for freeze up losses. Courts have ruled against companies that have
skimped on their investigations and rushed coverage decisions in these types of
losses. Our clients require prompt and
thorough claims investigation and fact finding and METROPOLITAN delivers high quality services at a highly
competitive price.
It’s
getting colder and with that cold comes the hassle of frozen / broken pipes, if
you don’t take a few precautions. Here are a few winterizing tips that
just might keep me from having to make a service call to your house.
Hose
Bibs
#1 Disconnect all hoses from your hose
bibs! Most hose bibs installed these days are frost free which shuts the
water off inside the wall away from the outside cold but, if you do not
disconnect the hose the water stays trapped in the spout. When the
water freezes it expands and will damage the hose bib. This problem
is usually discovered in the spring or summer when you turn on the bib for
the first time and find water is coming out of your wall. Doing this will save
you a costly repair.
#2 Hose bib covers. You can get these at any of your local home
improvement stores. They are foam,
dome shaped covers you put over your hose bib. These covers help keep the cold away from
the hose bib. Hose bib covers are more important for non-frost free hose
bibs but it wouldn’t hurt to put them an all of your outdoor faucets. Putting these on will also help to remind you
to disconnect your hoses. These covers
cost about 1-2 dollars and are a wise investment.
Insulate Piping
Many people
often don’t realize the importance of insulating piping until it is
too late and pipes are frozen and broken. All pipes in crawl spaces and any piping that
is exposed on the outside of buildings or above the ground needs to be
insulated. Pipes in garages that are not
heated are also vulnerable to freezing in cold weather and should be insulated.
Pump
Houses
All
exposed piping in pump houses should be insulated. It is also important to have
some heat in your pump house so your piping and pressure tank do not freeze. Your local home improvement store will have
several different options for you to help keep your pump house warm and your
pressure tank and piping from freezing. Items
to look for or ask about are heat wire- this is wrapped around piping and warms
up when plugged in. It keeps your pipes
from freezing. Heat lamps can also be installed near your pressure tank and
piping and will help keep your pressure tank and piping warm to protect from
freezing. Both of these options can be
plugged into a temperature sensing plug that turns on when it gets below
a certain temperature and turns off when it gets above a higher
temperature. These can also be
purchased at your local home improvement store and are another great defense
against broken pipes and expensive repairs.
How
to keep pipes from freezing when temperature is going to drop below 32 degrees:
#1
Trickle water from a sink or two to keep water moving in your plumbing system,
moving water takes longer to freeze than water that is not moving, this will
help keep pipes from freezing.
#2
Open cabinet doors under sinks to allow warm air from the room to get back into
the cabinet where pipes are.
#3 Turn
your heat up a little warmer than normal. Warmer rooms mean warmer walls, and
warmer walls help keep the pipes in those walls from freezing.
#4 Cover
foundation vents around bathrooms, kitchens and laundry rooms that are on
exterior walls to help keep the cold out and away from the piping in these
areas. You can buy pre-formed Styrofoam blocks that fit in standard
foundation vents at your local home improvement store. These covers should be
removed when the risk of freezing is over in order to allow cross
ventilation in crawl space areas.
#5 makes
sure that all piping in attics and crawl spaces are covered with
insulation. A lot of houses have blown in insulation in attics which is fine
but it tends to settle and expose pipes. If you have blown in insulation
inspect insulation to make sure it has not settled and exposed piping. Batt
insulation is a better choice in my opinion.
How
to keep this from happening again:
#1 Make
sure that all piping in attics and crawl spaces are covered with
insulation. We cannot stress this
enough. This is where we saw most of
the burst pipes we investigated. Most
attics have blown in insulation and it settles over time exposing pipes. Exposed pipes freeze and burst.
#2 In
older homes that contain copper or galvanized piping consider replacing with
PEX piping. PEX piping may
freeze but it resists breakage. In the 1000’s of investigations we have
performed, not one break was PEX related. However, I did cut out 100’s of feet
of copper and galvanized pipe and fittings.
Metropolitan Engineering,
Consulting & Forensics (MECF)
Providing Competent, Expert and Objective
Investigative Engineering and Consulting Services
P.O. Box 520
Tenafly, NJ 07670-0520
Tel.: (973) 897-8162
Fax: (973) 810-0440
E-mail: metroforensics@gmail.com
Web pages: https://sites.google.com/site/metropolitanforensics/
https://sites.google.com/site/metropolitanenvironmental/
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