Frost and water damage in buildings
Lesson from Losses 1/2012. Water can be both a blessing and a curse. We are completely dependent upon it, whether for drinking, cooking, cleaning, production purposes in business, or quite simply the operation of buildings. Losing access to water can create great challenges for both businesses and private individuals. Cleaning up water damage can take time, and in the worst cases can involve mould, fungus, rot, and vermin in structures as a result of water damage if clean-up is not carried out quickly enough, or in the right way.
Water expands as it freezes, so it can burst water -pipes and couplings and contribute to breaking weak joints. Damage often appears only when there is a thaw, and water leaks out. Cold surfaces and the degree of frost can mean that leaking water spreads out and re-freezes to become a layer of ice inside the building. Frost problems in Norway can mean that water damage is commonplace. Likewise, poor heating of property and poor insulation of water pipes caused an abnormal amount of frost damage in 2010.
Surprise, surprise: it’s cold in the north
The extremely cold winter and pre-Christmas period in 2010 multiplied the amount of water damage and frost-related damage payments. Over the course of 2010, preliminary statistics from Finansnæringens Fellesorganisation (Finance Norway, FNO) showed that there was at least five times more frost damage than in the previous year in the commercial and industrial market alone.
The causes are complex and difficult to summarise from the statistics. Almost a third of all water damage reported in January 2010 alone was frost-related. For all types of building, damage payments by Norwegian insurance companies are expected to exceed NOK 1,000 million in 2010 in comparison to NOK 150 million the previous year.
It is of course valid to ask whether there should be any surprise about frost-related water damage in Norway. There should not be. Certainly, there have been milder winters in recent decades, but seen over time it should be expected that piping systems would be designed to meet the coldest winter conditions.
Many still expect that installations inside and outside their buildings be in good condition because there has not been water damage so far. But when it is severely cold over a long period, perhaps in combination with black frost (hard frost with little or no snow cover), even piping that has previously been in good condition can break.
The south and western parts of Norway have experienced this, and the 2010 winter was especially cold with a high wind chill factor to increase the effect. Buildings that had not been frost damaged in living memory – which of course in historic terms is not a very long time – were suddenly affected by frost. Sprinkler systems were especially badly affected, as were water pipes laid in outside walls of older buildings combined with insufficient insulation.
Northern Norway was affected by severe black frost both in 2009 and 2010, and, in some spots, the ground frost did not disappear before the ground began to freeze again in the autumn of 2010.
Frost is a problem in Scandinavia
So what is the fundamental cause of this great increase in frost damage? When tenants move out of premises, close businesses for the Christmas holidays, or while they are being renovated, it can be desirable to save electricity costs by lowering the temperature in the premises to ’maintenance levels’. Also, in recent years, winter fuel costs have been high, so that there has been a tendency to set lower temperatures as a savings measure.
However, when the temperature is significantly lower than usual, there is a risk that the interior temperature will fall below zero and that the water pipes will freeze. Cold causes severe stress in the structures of buildings and installations. Water pipes built into outside walls that normally remain frost-free are then in danger of freezing when outdoor temperatures drop to 20-30 degrees below zero over longer periods.
This is a typical cause of damage in holiday homes or in houses when people go away on holiday. In many cases, the water is cut off, but lines are not drained down so there is still water in the pipes, or stopcocks are not completely closed. Pipes that run near windows are leaky, or other cold bridges in the building are also exposed to frost in such cold periods.
In years that are very cold early in the winter, usually before the snow forms an insulating layer, frost will penetrate more deeply into the ground than in a ’normal’ year. Outside pipes that burst in winter are generally buried water pipes that are not well enough insulated against ground frost.
What should be done to prevent frost damage?
The first thing is to trace piping both inside and outside the building. Where pipes and fittings are laid, there can be cold bridges that expose them to unexpectedly low temperatures, even if outside pipe runs are well enough proofed against ground frost. The fact that water pipes freeze because of low inside temperature is the simplest problem to do something about.
Building owners must consciously maintain internal temperatures at a high enough level to prevent fittings freezing. In normal cold spells – i.e., without extreme locations or strong winds in addition – it is reckoned that about 70 W/m2 of floor area is needed to keep the temperature above freezing.
In addition, doors leading to spaces with water systems should be kept open so that air can circulate. This applies equally to both shorter and longer periods of inactivity in the building. An example could be closure over the Christmas holiday of a business when the outdoor temperature is lower than expected.
Modern SD equipment can monitor temperature, and control and issue an alarm if low temperatures are detected. Correspondingly, sprinkler installations should be connected to the alarm control centre so that burst pipe warnings are on the same level as release of the installation. In older wooden buildings, it may be that pipes are buried in outside walls, and there can be cracks, leaks, and structures that form cold bridges enough for water pipes to freeze.
It cannot be assumed that frost damage is prevented during installation of pipes in piping systems, but, with the right installation, water from burst pipes is led to a drain, so that water damage to the building is avoided.
If there is a burst in a pipe and water pours out, a leakage warning that either detects water flow or dampness on the floor can be an alternative for restricting water damage. Pipes and fittings exposed to frost can be protected with trace heat and lagging. Frost in the ground can mean breaks in buried pipes, but burying insulating matting over them can prevent this.
Relatively simple measures can quickly prevent long, troublesome, and expensive interruptions or shutdowns resulting from water damage.
Anders Rørvik Ellingbø