Is there a Secret Tunnel Under those Manhole Covers

Okay first let me say that this topic may or may not be all that interesting to some, after all who really gives any thought to the manhole cover. But since I work in the construction industry I decided what the heck let’s write about them and share the little information that I know about the topic of manholes.

You must remember that I am not a professional when it comes to this subject, I do work around manholes and have never ventured down inside one, in order to go inside a manhole here where I live you first have to take the confined space course which I have not.

The majority of the information that I have included here was given to me by the different crews that I have worked with over the years and in case you haven’t read any of my topics before I should mention that I am a lane tech.

What does that mean you might be asking yourself, simply put it means that I direct traffic around construction crews and that includes when they are working in a manhole.

Installing A Manhole – The beginning of life in the ground

I was lucky enough to be a part of a big construction project here where I live in Vancouver, BC. This is the building of the Olympic Village that was to house the athletes during the Winter Olympics that were hosted back in the year 2010.


It’s hard to believe when looking at the picture that eventually there will be a round cover on the top of this manhole and you’ll be able to walk right  over it without falling in. I thought it would be a fun idea to show you the beginning of it’s life, there was at least three more pieces added to this one to bring it up to ground level.

So you can see that they are buried deep in the ground and all most people ever see is that lid that sits on the top.

Working Underground – Personally I wouldn’t climb down a manhole

I often work with crews that need to enter a manhole for one reason or another, most of the time they just need to go inside to drag out the cable and then they work on it in their truck. This type of work is called splicing and it only happens if the cable is made of fiber optics.

Before they can actually go in to get the cable many of these have to be pumped out because they do fill up with water over time. This usually takes an hour or better depending on the size of pump they use, rarely do they use more than one pump for the water.

photo (2) - copy

Other than taking the confined space course there is a few other things that need to be done before anyone can climb down into these dark holes. There has to be a guard around the open hole and yes they are usually a square shape, weird I know and I have never seen a round guard. Then one of the crew has to lower what is called a sniffer down into the manhole, this tests the air for any form of poison gases that could cause the person harm when they are down there.

Work Begins Safely – Before the job can start there’s a few things that need to be done

Below are the tools that the crew needs before they can even attempt to go down inside, it’s crucial that their safety comes first. Most of them you wouldn’t commonly use around the house or yard and I have mentioned this before don’t try to go in one alone unless you have the knowledge and experience.

  • First they use a special lifter to help with the removal of the cover which can weigh anywhere’s up to 50 kilograms or 110 lbs. I don’t recommend trying to remove one yourself unless you work in the industry.
  • Next they surround the hole with one of those yellow material guards, this helps to ensure that nobody accidentally falls in the hole and it also works as a deterrent for the general public that maybe walking by.
  • Before they can actually go down into the hole they have to use a gas leak detector also known as a sniffer. This ensures that there is no harmful air that could injure or even kill the person that has to be inside the manhole.
  • The blower system is a must have in Vancouver while anyone is working inside a manhole, if there’s not one on site near the hole then the job will be shut down. It’s main purpose is to supply clean air to the person that’s down under the ground.
  • Lastly they always have a submersible utility pump on hand because nine times out of ten there’s usually water which has to be pumped out first.

manhole cover on road

Placing The Manhole – Who decides where to place them in the ground

I have no idea how they choose where to place these, as far as I know it has something to do with the engineering which is way above my pay grade. What I can tell you is where I’ve noticed that they are the most, below is the most popular places that you can spot a manhole.

  • Roadways whether a busy freeway or a quiet rural country road seems to be the most popular and that’s a good thing for me or else I’d be out of a job.
  • They are often found in the center or along the edge of a sidewalk, I have on more than one occasion been on pedestrian watch while the manhole cover is off, making sure nobody falls in.
  • This is rare although I have seen it a few times, they are placed on people’s front lawns, that seems to me to be a little of a hassle for the home owner.

Informational Video – Great way to learn more about the manhole

I thought it would be fun to see if there was any videos available and to my surprise there was quite a few. I handpicked the one that I thought was the most interesting and my favorite is “How it’s made Manhole Covers “.

Below The Ground – What’s really hiding down under the cover

Manholes are becoming more popular here as the aerial lines that hang on the poles are taken down, eventually everything will be placed under ground. This can be a good thing in the event of high winds, earthquakes, and even with the lightning strikes.

So what type of things are hanging around down there deep in the ground under a metal cover that’s to heavy to lift. Well I’m here to tell you nothing that is really all that exciting, no hidden treasures, no secret tunnels, and no you can’t get to the other side of the world by climbing down the ladder.

Below is what you will find down under the ground by entering into these deep dark holes.

  • Your telephone lines and television lines (also known as cable) usually but not always will share the same manhole.
  • Electrical lines will have their very own and for good reason, just think of the high voltage running through those lines. But occasionally they will share one with the telephone and television lines also know has hydro/tel.
  • Another one that stands alone is the sewer manhole and this just speaks for itself, after all who really wants to enter into that smelly hole.

Unique Covers – Infinite variety of designs for the manhole covers

Very few people think of these as a form of art, in fact people don’t usually pay much attention to the covers that hide the hole at the top of the ground. Did you know that almost every town or city has a different design on the manhole covers that’s unique to them.

Surrey manhole

Wrapping Up – The job is complete and time to replace the cover

The covers are generally made of metal making them really heavy, this is so a normal person just wandering by can’t take the cover off for their own safety. Some cities are starting to use decorative manhole covers (like above) instead of the plain ones, I guess they think the pedestrian that walks over them will like what they see, but seriously even I don’t make it a habit to stop and check out these covers when I’m out walking.

Most people and that’s world-wide never give the manhole cover a second look, they drive over them, walk on top of them and from time to time see workers around them.

Manholes differ in sizes and the majority of them are round, but if they happen to be square they are actually called a vault.

This concludes my topic I really don’t know much more about them except I will add that sometimes, it’s rare but does happen a rat is calling it home. The guys always check for critters or bugs like spiders before venturing down to get their cable and really I want you to know

I wouldn’t go down there!!

vancouver manhole

Fun Trivia Question

How would you answer this question about round covers

Did you know: there was a time that Microsoft used to ask this question on their job interviews, this was their way of seeing how a person would react to a question that had more than one right answer. They received a lot of different answers to the question and now I’d like to see what you think.

Remember there is no wrong answer!

Why do you think manhole covers are round?



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s