5 Super Cool Facts About Manhole Covers

Frp manhole rings

Manhole covers probably aren’t something that most people think about on a regular basis, but they’re incredibly important for a properly-functioning infrastructure and we depend on them more than you realize! Here are just a few interesting facts about these covers:

  • Composite manhole covers can last up to 30 years — sometimes even longer! Cast iron systems were once pretty common but these days it’s well-known that cast iron covers require a lot of maintenance. Because of this, they’re also pretty expensive.
  • Weight is something that really factors into picking out the right cover in order to accommodate highway safety weight limits. The typical iron cast manhole cover weighs anywhere between 100 and 200 lbs., whereas a composite cover can be 63-85% lighter.
  • Manhole cover theft, believe it or not, is a real thing and it can cost municipalities a lot of money. Composite covers are preferred over cast iron covers when considering the possibility of theft because they don’t have any scrap value. In other words, stealing a manhole cover is useless because the materials can’t be used for anything else.
  • There are things called “manhole events,” which is the official-sounding way of talking about an accident that is related to a manhole. These incidents can be very small — perhaps just some smoke being released when something short-circuits — but they can also refer to dangerous and deadly explosions. Lower-quality materials in manholes increase the risk of manhole events.
  • Heavy duty manhole covers are especially important during the summer to reduce the risk of manhole events. These incidents are most likely to occur during the summertime because heavy air conditioning units put out extra electricity, and this electricity runs though the manhole systems.

Manhole covers might just seem like pieces of metal and concrete to the unknowing eye, but they’re actually pretty cool when you take a moment to learn about them!

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