Pipes and Freezing: Understanding the Science Behind Burst Pipes

Have you ever wondered why some pipes burst when they freeze? It's a fascinating phenomenon that involves the properties of water and its behavior when it transitions from a liquid to a solid state. In this article, we'll explore the science behind this issue and discuss best practices to prevent such incidents in residential settings, particularly in colder climates such as in Canada.

The Science Behind Pipe Bursting during Freezing

Water has a unique property that causes it to expand as it freezes. This expansion is due to the molecular structure of water. In its liquid state, water molecules are relatively loosely packed, and they can move around. However, as water cools and begins to freeze, the molecules slow down and arrange themselves into a more rigid, hexagonal structure (ice). This new arrangement takes up more space, leading to an increase in volume by about 9%. This phenomenon is responsible for the pressure that can lead to pipe bursts.

Practical Examples of Pipe Bursting

Let's look at some practical examples to understand the implications of frozen pipes on plumbing systems. For instance, individuals who own summer cottages in Canada often need to drain pipes to prevent freezing and bursting. The same applies to homeowners in colder climates who shut down their water systems for the winter. Even a small amount of water remaining in a low point in the pipe can freeze and create pressure that may cause the pipe to crack. In more severe cases, as mentioned by a plumber, a small amount of water left in the system can lead to major damages, such as in the example of a cast iron pump cracking.

Temperature and Pressure Factors

The freezing process is exacerbated by factors such as temperature and pressure. Placing water under pressure when it is subjected to cold conditions dramatically increases the risk of pipe failure. This is because the pressure within the pipe builds up as the water freezes. In such cases, the pipe expands due to the freezing of two separate sections, creating an incompressible region in the pipe. This pressure buildup can cause the pipe to split, and when the frozen sections thaw, the result is often water spraying out from the split.

Molecular Cohesion and Temperature Effects

A discussion on the molecular level reveals that the behavior of water molecules also plays a critical role in this process. When water is heated, the molecules gain kinetic energy and move more rapidly. Conversely, as it cools, the molecules slow down and begin to bond more closely together. However, the molecular cohesion in hot water is different compared to cold water. The molecules in hot water are less tightly bound, making them more susceptible to the properties that cause freezing. This is why hot water can freeze more quickly than cold water, leading to a higher risk of pipe bursting.

Preventing Pipe Bursting

To effectively prevent pipe bursting, it's crucial to follow some best practices:

Drain and Insulate: Drain water from pipes and insulate them to prevent water from freezing and expanding. Bleed Off System: Check and bleed off any remaining water from any system that may not have been completely drained. Use Freeze-Proof Pipes: Consider using pipes that are specially designed to withstand freezing conditions. Regular Maintenance: Regularly inspect and maintain your plumbing system to identify and address any potential issues.

By understanding the scientific principles behind pipe bursting and implementing preventative measures, homeowners can protect their property from costly and inconvenient damage.

Conclusion

The next time you encounter a burst pipe during freezing conditions, remember the unique properties of water and the pressure built up when it freezes. Proper maintenance and precautions can significantly reduce the risk of such incidents, ensuring the longevity and reliability of your plumbing system.