Question

Outdoor water pipes have to be drained or insulated in winter in a cold climate. Why?

Short answer

Pipes freeze and burst if water expands as ice, so they must be drained or insulated.

Step-by-step solution

Identify the Problem with Cold Climates

In cold climates, the temperature often drops below freezing point (0°C or 32°F). This is important because water expands when it freezes.

Understand What Happens When Water Freezes

When water inside the pipes freezes, it turns into ice. Ice occupies more volume than liquid water, which can create pressure within the pipes.

Recognize the Consequences of Freezing Water in Pipes

The increased volume of freezing water can cause the pipes to crack or burst due to the increased pressure from ice formation.

Explain the Need for Draining or Insulating Pipes

To prevent the pipes from bursting, they should either be drained to remove the water or insulated to keep the temperature inside above freezing. This ensures that no ice forms inside the pipes.

Key concepts

Cold climates

Cold climates are characterized by temperatures that often drop below the freezing point of water, which is 0°C or 32°F. In such environments, managing water systems becomes crucial due to the risk posed by freezing temperatures. When the air temperature falls, surfaces exposed to the air also cool down, including outdoor pipes.

In regions with cold climates, prolonged periods of low temperatures are common. This means there is a constant risk of water freezing in exterior systems, such as irrigation systems, fountains, and outdoor pipes. Anticipating these conditions, it's essential to take preventive measures to protect these systems from the harsh effects of freezing temperatures.

Water expansion

Water has a unique property: it expands when it freezes. Unlike many substances, water is less dense as a solid (ice) than as a liquid. This is due to the molecular structure of water, which forms a crystalline lattice in ice. As water turns to ice, it occupies more space, increasing by about 9% in volume.

This expansion can be particularly problematic in confined spaces. In pipes, this increased volume can lead to high pressure levels, as there is no room for expansion. This pressure can cause the pipes to stress and, if the pressure is too high, result in cracks or bursts. Understanding this expansion is key to preventing damage in plumbing systems.

Pipe insulation

Pipe insulation is a crucial technique used to prevent the pipes from freezing in cold climates. Insulation works by acting as a barrier to the cold temperatures outside, thereby maintaining the water inside the pipes at a temperature above freezing.

Effective insulation can be achieved by:

• Wrapping pipes in insulating foam
• Using electrical heat tape around pipes for added warmth
• Sealing any cracks or gaps in walls where pipes enter to prevent cold drafts

By employing these methods, the risk of ice forming within the pipes is significantly reduced, thus preventing any damage associated with the expansion of freezing water.

Ice formation

Ice formation occurs when water transitions from a liquid to a solid state due to low temperatures. In plumbing systems, this process can be incredibly damaging because as water freezes into ice inside the pipes, it leads to the significant problem of pipe damage.

The sequence of events is straightforward: water cools to its freezing point, forms ice, then expands and increases pressure on the pipe walls. Without sufficient space or flexibility, rigid pipes can crack under the strain.

To manage ice formation, draining the pipes completely before freezing temperatures hit can eliminate the presence of water that could turn into ice. Alternatively, keeping faucets slightly open allows water to steadily flow, which can prevent ice from forming since moving water is less likely to freeze.