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laureth's avatar

What is this common streetside object? (picture)

Asked by laureth (27174points) July 6th, 2011

I see these all the time along the road. The top is pointed, and it has an open area beneath, on top of a pole. They’re usually green, but I’ve seen other colors, especially black. What are they?



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13 Answers

rebbel's avatar

I think they are sniffer poles.

SpatzieLover's avatar

It’s a vent pipe. But what it is venting, I couldn’t say. In some cases it is gas from garbage (if the area was a landfill. In others, it’d be a sewer vent pipe.

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chyna's avatar

Bird house?

SpatzieLover's avatar

I just looked up where you live. Do you have a lot of septic systems there instead? It appears to have a pagoda vent cap which are usually sold to townships/cities with septic vents.

laureth's avatar

I don’t think we have many septics. That picture was taken only a few blocks from my house, on a corner that’s surrounded by businesses and parking lots. I have city water and sewage at my place.

@rebbel – What are they “sniffing”?

@chyna – No place for a bird to enter. The open area is surrounded by metal mesh.

SpatzieLover's avatar

I feel the sewer will give the clue here that it is either venting the gas or is a water standpipe. If it were me with this question it’s a good one, I’d email the photo to my village manager or the head of the local DPW and ask him/her. You’d probably get an answer in a day or so.

I’d like an update if you get an answer

rebbel's avatar

@laureth From what I think I have read once (here maybe) and after a google I think it is to measure traffic pollution.

Brian1946's avatar

I see a what looks like a manhole cover and a power pole next to it.

There could be a cable/pipe vault underneath that area. Those vaults tend to accumulate gases and have to be vented so that workers can safely enter them to do maintenance and/or modifications.

Therefore, it could a vault gas venting pipe. The structure on top of the pipe might be to monitor, direct the flow of, or neutralize those gases.

WasCy's avatar

Since it’s next to a manhole and at a height that should put it above the snow line (one hopes!) and far enough from the street to avoid damage from snow plows, I’m going to go with a vent pipe. (I’m assuming that the manhole is for an underground utility duct. I see the utility pole nearby with conduit apparently going to ground.)

Edit: I would imagine that if you walk over to the manhole cover you can read what it is. Many manhole covers have their “names” (purpose) forged into the casting.

laureth's avatar

I paid a little more attention to these objects as I drove around this weekend, and noticed that (1) they usually come in pairs, and (2) they don’t always have a pole or manhole cover nearby (these were unique to this photo). Hope this helps, if anyone reads this in the future.

WasCy's avatar

In a long run of underground duct or tunnel (one which people will enter from time to time to perform maintenance or inspection, anyway) there will be vents along the run, too. That’s why when you pass many open manholes on the road, there’s a large-diameter (8 – 12” or so) flexible duct running down the opening: the workers actually pump air into the duct / tunnel with them so that they aren’t overcome by a buildup of CO2 gas (primarily in sewers, where CO2 builds up from the decaying organic matter). If they don’t have a vent farther down the system, then the pumped air will only linger where it is pumped, and then go back out the open manhole. With the vent farther down the line, they can get a flow going “from this open manhole to that vent” and breathe safely along that whole section.

And consider that sewers don’t always follow roads. More often than not in a heavily built up area they’ll follow the low points in the ground as much as possible – and even that isn’t certain, since many times (depending on geography and the layout of the entire system) they’ll run to “a” local low point, and there’ll be a pumping station there to send the flow to a higher point to start a new flow.

Espiritus_Corvus's avatar

Vent pipe. I believe that’s a manhole cover nearby. It’s venting the gases that build up in the sewer to prevent a methane explosion. The conical top is to prevent birds from settling on top and donating guano.

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