Blue steel columns - what's up with that?

September 18, 2004 4:42 PM

Occassionally found on the sidewalks of Seattle, and probably other cities, steel blue columns stand about three feet tall, bolted down to the concrete. About seven inches in diameter, they are topped with a cap one foot tall with a door in the side. A padlock keeps the door shut. What are these things?

My Flickr buddy Tonx says, "In NYC there were similar thingamajigs that belonged to the phone company where periodically they would plug a big tank of coolant into it - possibly liquid nitrogen." Any corroboration? What is the phone company doing with the liquid nitrogen?

posted by tomharpel to technology (17 comments total)

Do they have triangles on the top? If so, they are monitoring well covers. The wells are designed to monitor existing and/or potential ground water contamination and are generally required to be installed around gas stations, etc. (at least in the South).
posted by ajr at 5:33 PM on September 18, 2004

I don't believe for a moment it would be for liquid nitrogen.

I toyed with the idea that it might be to (gas) nitrogen-flush the utility lines with, so as to kill off anything that might be trying to live in them, but it wouldn't need to be anything so big at all. And besides, they'd just end up with dead rotting things in the lines instead of living things. Not much advantage there.

The photo shows a fairly industrialized area, so I'd be willing to believe it could contain a gas (air) analyzer, testing for ground soil contanimation. My experience is that those are site-specific (ie. torn-down gas stations), but I suppose in an old industry complex, they might stake 'em out on the street corners.

I note that the cylindrical shape and its diameter correspond to a common enough drilling diameter. So my other guess would be a ground-water contanimation analyzer, placed on the corner because the drilling equipment isn't building-compatible and because the blue stump isn't traffic compatible. They'd have drilled to the water level, inserted a sleeve to keep the hole from collapsing, and built the monitoring equipment to fit inside the sleeve.

...but, then, why does it need to be so tall? If the monitoring equipment fits the sleeve, it could just as easily be below ground level.

Hmmm. Good puzzler, tom!
posted by five fresh fish at 5:56 PM on September 18, 2004

To address the sub-question about the use of liquid nitrogen by the NY phone company, it's used to seal breached conduits and to cool transformer vaults.
posted by hashashin at 6:10 PM on September 18, 2004

It looks like a water sampling station to me too. Not groundwater - it taps right into the nearest water main.
posted by ikkyu2 at 7:10 PM on September 18, 2004

If Bush loses the election, at around 3 am those giant spigots will begin flooding the city with natural gas from the city's gas mains. Come 4 am, marshmallow time!

Or, possibly what others have suggested.
posted by squirrel at 9:31 PM on September 18, 2004

The access panel on the sidewalk near the thing reads "CWM" (i think). Might be a clue. "City Water Main"...?
posted by mantid at 10:13 PM on September 18, 2004

i was honestly at first going to suggest that it's a bollard...but those usually only appear around buildings as security measures or around loading docks to stop trucks from running into buildings.
posted by NGnerd at 10:14 PM on September 18, 2004

Weren't those in Kubrick's 2001? Oh.

Squirrel That was very funny (not sarcastic funny). But what literary/film reference is that?
posted by ParisParamus at 10:20 PM on September 18, 2004

fff, liquid nitrogen isn't completely far-fetched - in NYC the phone company leaves big tanks of liquid nitrogen on some street corners with hoses running into manholes which they use to freeze the high-amp mains when they need to cut out and replace sections that have shorted out without depressurizing the insulating oil.

jwz says they do this in LA too.

But, since this is done at random locations wherever needed, I don't see that the permanent posts would be for this.
posted by nicwolff at 10:35 PM on September 18, 2004

NYC has had one--a very big can of liquid Nitrogen, that is--at the SE corner of 57th and Madison for going on four years now. So it's not just a temporary thing, sometimes.
posted by Asparagirl at 2:29 AM on September 19, 2004

hashwolf's Google Answers link is filled with a bunch of hairyassed guesses that are no better than mine, save the explanation for creating solid-oil plugs whilst working on high-voltage lines.

The LN Asparagirl mentions is in the middle of a very high-density business district that undoubtedly has extremely high electrical requirements; it seems to me quite likely that the LN is there either because they're continually mucking with the lines, or because they need to be able to do repair work pronto, with no waiting around for the LN.

Or maybe the can is empty, and the utility simply forgot to remove it. :-)

The blue posts, OTOH, don't seem to be in a high-density area, don't appear to be LN dewar flasks, and are mounted very permanently.

I'm still holding to the gas/water analysis theory. I don't think they're likely to test water mains, though: that could be done from within a building.
posted by five fresh fish at 9:46 AM on September 19, 2004

All the "monitoring well" plates I've seen here in Seattle have been flush with the pavement, not on poles (but usually at/near gas stations, so maybe this is a different kind of monitoring well). A bollard wouldn't have a hatch in the side. The post doesn't look much like the natural-gas-pipeline-monitoring things I've seen (and those usually have a label on the side telling you who to call if it blows up). Mysterious.

Where is this, tomharpal? It looks like somewhere near SODO? Maybe I'll go take a look.

(Thanks for the link to that entry in jwz' journal, nicwolff --- that was amazing!)
posted by hattifattener at 12:34 PM on September 19, 2004

Ah, it's near the REI store downtown. Hm.
posted by hattifattener at 12:48 PM on September 19, 2004

Ah, it's near the REI store downtown. Hm.

That fenced off empty lot just past the SW corner of Denny and Stewart was once a big gas station. Man, you should have seen the cars lined during the Yom Kippur War oil embargo--they were backed up four or five blocks, all the way to Westlake. If the post around there is related to ground water monitoring, there's why.

It's like the empty lot that was at Broadway and Roy, where Broadway splits--another former gas station/toxic waste site that was an empty lot for decades until someone ponied up the dough for the clean up. Now it's a big old condo with shops on the street level.
posted by y2karl at 1:55 PM on September 19, 2004

sorry that google answers link is a little scattered, fff. I have another reference here in print form, but can't find an equivalent online reference to link to. The print reference is from the "F.Y.I." column in the NY Times, where they quote a Bob Varettoni from NYNEX as saying that the nitrogen gas is compressed and blown into the 3-inch cables running under the streets to keep moisture out of the cables.

But this really doesn't address the main question, which is "what are those blue things?" I can't say for sure, but they do remind me of the drinking water sampling stations here in NY, where the DEP can draw water samples for analysis.
posted by hashashin at 2:10 PM on September 19, 2004

Well I submited a request to SDOT. Hopefully they can let us know though the response form indicated a response may take 10 business days.
posted by Mitheral at 2:02 PM on September 21, 2004

It's a water sampling station. From Seattle DOT:

Thank you for writing the Seattle Department of Transportation. I sent your question to our Street Use Division and they informed me that the structure appears to be a water sampling station. By way of this email, I am forwarding your concerns to the Seattle Public Utility Department, who can confirm this.
posted by Mitheral at 9:38 AM on October 4, 2004