Why Don't Fire Hydrants Freeze and Explode?

TL;DR

Fire hydrants in colder climates are designed differently to prevent water from freezing and bursting the pipes, using either wet barrel or dry barrel hydrants.

Transcript

[♪ INTRO] If you live somewhere that gets below freezing in the winter, you’ve probably heard stories of water pipes bursting during cold weather. It happened to my house one time. But you almost never hear about the same thing happening to fire hydrants. Well, that is because we use different types of hydrants in different places, depending on how... Read More

Key Insights

• ❤️‍🔥 Fire hydrants are categorized as wet barrel or dry barrel, depending on the climate they are used in.
• 😒 Wet barrel fire hydrants have water constantly flowing up into the barrel, while dry barrel hydrants are normally empty when not in use.
• 🥶 Dry barrel hydrants are used in colder climates to prevent freezing and bursting of the water inside.
• 🥶 Pipes burst in the winter due to expanding ice exerting pressure on the pipes, and wet barrel hydrants would experience the same issue if used in colder regions.
• 💦 Dry barrel hydrants have the advantage of keeping the water underground in water mains, preventing freezing.
• 😒 Dry barrel hydrants can be harder to repair and are prone to clogging as people sometimes use them as trash cans.
• 🫥 In some countries like the U.K., dry barrel hydrants are entirely underground with only marker or metal plates visible.

Questions & Answers

Q: What is the difference between wet barrel and dry barrel fire hydrants?

Wet barrel fire hydrants have water constantly flowing up into the hydrant when not in use and are used in mild climates. Dry barrel hydrants, on the other hand, are empty when not in use, with water staying underground in water mains.

Q: Why would wet barrel hydrants burst in colder winters?

Wet barrel hydrants would burst in colder winters because freezing temperatures outside the barrel would cause the water inside to freeze. The expanding ice would exert pressure on the hydrant, potentially causing it to crack or explode.

Q: How do dry barrel hydrants prevent freezing and bursting?

Dry barrel hydrants prevent freezing and bursting by keeping water underground in water mains, below the frost line where temperatures don't drop below freezing. When needed, firefighters can release water into the hydrant, and it is drained after use to prevent freezing.

Q: Why aren't dry barrel hydrants used everywhere?

Dry barrel hydrants have a couple of downsides, such as being harder to repair since part of the valve is buried underground. Additionally, they can be subject to clogging as people sometimes use them as trash cans in cities.

Summary & Key Takeaways

• Wet barrel fire hydrants are used in mild climates and have water flowing all the way up into the hydrant. When needed, firefighters turn a valve for the water to rush out. However, these would freeze in colder winters.

• Dry barrel hydrants, on the other hand, are normally empty when not in use, with water staying underground in water mains. Firefighters turn a valve to release water into the hydrant when needed, preventing freezing and bursting.

• Dry barrel hydrants have downsides, including being harder to repair since part of the valve is underground and the potential for clogging due to things being shoved inside.