As winter approaches and temperatures continue to drop, water utilities must prepare to deal with the hazards of cold weather like water main breaks and equipment outages. These issues are highly visible and easy to identify, but there is another risk that is often overlooked: ice accumulation inside water tower tanks.
While less common than other risks, ice damage can be extremely costly and could result in a total loss of a tank or entire water tower. During normal operations, water levels inside a water tank fluctuate with supply and demand. When water levels do not fluctuate enough to restrict freezing, ice forms at the top surface of the water. Some issues you might see when a tank freezes include:
- An ice bridge that spans the width of the tank can collapse as it melts and the impact can cause significant damage to a water tower if the water level is decreased
- Heavy ice can pull on mounted equipment inside the tank, damaging gauges and ladders or even creating holes in the tank
- Free-floating pieces of ice can damage coatings as they scrape the inside of the tank’s surface
- If vents are blocked by ice, water leaving the tank can cause a vacuum, which could partially or totally collapse a tank
Prevention Methods
Unfortunately, many operators don’t realize the problem until it’s too late. If you see ice forming on the lakes or ponds in your community, there’s a good chance there is a cap of ice inside your storage tanks. Consider these preventative options to stay ahead of ice formation:
- Reduce the water level before cold weather hits. A lower water level prevents overflow and protects against damage caused by expansion.
- Install a mixing system to keep water circulating and to prevent static conditions. The turnover will also break up any surface ice that has formed.
- Install a tank heating and insulation system to maintain an internal temperature that is above freezing.
- Regularly inspect tanks for possible damage or leaks. Even a small trickle of water can quickly freeze an overflow pipe.
- Utilize deep cycling methods to continually refresh the tank with warmer water from the treatment plant.
- Use pumps that pull water from the bottom of the tank and circulate it to the top. This helps keep warm water in the top of the tank, preventing ice formation.
While you can’t avoid cold weather, industrial tank owners are encouraged to implement a plan to prevent frozen water from affecting your operations.