Water, Water, Everywhere, Not a drop of heat......

JUGHNE

Our system has buried steel pipe that is plastic or epoxy coated.
It is completely insulated from being grounded. (in contact with the dirt)
An insulating bushing or die electric union is used to isolate the house piping from the company's UG lines and meter.

He may have been testing the integrity of the insulated system and your "ground" wire would have really thrown him off track.

Jean-David Beyer

How does water leak into a gas line that has gas pressure in it.? In my area, the pipe down the street used to run at 8 psi (supposed to be 15 psi) and reduced to 7 inches at the regulator on the way into the meter. Those pipes were put in in about 1950.
About 10 years ago, those old iron pipes (that were leaking) were replaced by a somewhat larger plastic pipe running at 50 psi. But even at 8 psi, for water to leak into the line, the pipe would have to be under over 18 feet of water if I calculate correctly.

Leonard

Yes 18.46 ft to make 8psi water pressure.

Some pipes might run under rivers and you could easily get that kind of depth.

the_donut

Soil is denser than water. As much as 2.5x denser.

JUGHNE

Someone here can clarify this;
I thought there were some postings where the main in the street ran at less than 1 PSI??

That poster certainly had low pressure delivered to them.
Does that set up happen in older gas systems, as far as anyone knows?

Fred

@JUGHNE , I'm "That Poster" and I can tell you they pumped literally hundreds of gallons of water out of the gas main and our entire neighborhood of about 100 homes was without heat, as a result. You can do all the calculations you want but "seeing is Believing". They told me our pressure (low Pressure) should typically run at about 8 PSI. I have a 2" line into my home, A 350K Boiler, a 125K forced air furnace, a 100K forced air furnace, two commercial ranges, one with two full sized ovens, a 50K gas water heater and a gas dryer. The two forced air furnaces are only used as backup should I have an issue with the boiler but everything else is used fairly regularly and gas supply has never been a problem, nor is it now, since they pumped the main out. I will say we are a block and a half away from the Great Miami River but I don't know if our gas main runs under it or not.
They have been out here since this outage and I see they have marked the streets/sidewalks with all the utilities so I'm guessing they have given this area a priority on relining the gas main. When that is done they told me we would be at medium pressure, between 40 and 50 PSI.
I guess I'd have to ask anyone who questions what I have said in this post: How would you hold pressure, to your calculations if there are enough holes in the pipe that it won't hold pressure? For all I know they may have been pumping 50+ pounds of pressure into that main to deliver 8 PSI. The mains in question date back more than 100 years. Pipes installed in 1950, as @Jean-David Beyer mentions, would be considered new to us.

Leonard

About 45+ years ago when we converted grandpa's garage to nat gas I saw them dig the hole in street to tap onto ~ 12-15 inch diameter gas main. Gas men said pressure in main was ~ 7-12 inches WC. Was near heart of the city, so very old gas main. IIRC ~ 6 ft down.

Was interesting to see them arc weld a pipe stub onto the LIVE gas main. Then stick a drill bit into the stub and drill a hole into the LIVE main, with air powered drill. Then plug pipe with what looked like 4 suction cups on a rod, until they were ready to connect rest of the pipe.

Funny thing was we asked for gas service in winter. Back then gas company didn't want to dig the frozen streets. So they piped our supply from neighbor's building ( 6 inches away) till they could dig the street in spring. Fast forward ~30 years , neighbor's rooming house was leveled and became a parking lot. Then years later the guy we sold our garage to called me a bit angry telling me he uncapped a 4 inch pipe and found unmetered live gas. Seems gas company accused him of tapping in when he called them. I told them the history, gas co never bothered to remove their "temporary" feed, that fixed his problems. 40 year "temporary" feed ....

Solid_Fuel_Man

Arc welding to UG has main..... wow....

JUGHNE

Fred, I know you are the poster for this posting.
So if you have about 8 PSI then my theory is blown apart.

I was referring back to someone who said their main gas supply in the street was in inches/ounces. Just as Leonard had just described for grandpa's garage. With that low pressure it would not take much water pressure to get inside through holes.
The compacted dirt would hold the lower gas pressure inside the pipe at such low pressure IMO.

So then Fred you must have a regulator at your meter?

Fred

@JUGHNE , my apologies. I misunderstood your comment. To answer your question, I do not have a regulator at the meter. The two commercial ranges have regulators on them and I assume the regulators are built into the gas valves for the boiler and the forced air furnaces and water heater as there are no individual regulators on those appliances. I haven't looked inside the gas dryer to see if there is a regulator inside but none on the gas line into it.

ChrisJ

Fred said:

@JUGHNE , my apologies. I misunderstood your comment. To answer your question, I do not have a regulator at the meter. The two commercial ranges have regulators on them and I assume the regulators are built into the gas valves for the boiler and the forced air furnaces and water heater as there are no individual regulators on those appliances. I haven't looked inside the gas dryer to see if there is a regulator inside but none on the gas line into it.

You cannot feed an appliance regulator 8 PSI.
If memory serves, they don't want to see over 10 inches or so.

8 PSI would permanently damage them. 8 PSI is around 225 inches of water.

So either you have a regulator at your meter, or the main in the road is 6-10 inches +-.

@Steamhead Please correct me if I'm mistaken?

Fred

@ChrisJ , I know there is a regulator on the commercial ranges. As I said there isn't one on the boilers/furnaces so my assumption is something in the gas valve regulates the pressure. I for sure do not have a regulator in the house where the meter is located or from the 2" line that comes into the basement over to the gas meter. Everything outside is under ground and I doubt that they would bury a regulator. There is no hand hole or man hole out there. I also own a four unit next door and there is no regulator at that meter either. Again no outside hand hole or man hole. As a matter of fact, several years ago I needed the gas to that building shut off at the street and the gas company could never find the shutoff at the street. It was a couple years later when I happened upon it while repairing a section of public sidewalk.

Leonard

Seems all utilities lose track of where their old valves are. Called water co to turn off my water, they started playing with neighbor's' valve, had to call them over and show them where mine was. I previously measured and wrote it's location by water meter in case of emergency.

Hear typical gas pressures inside buldings (after meter) is ~ 7 inch WC, sometimes 2 psi MAX if need to use existing building piping for a new high draw load (15kw generator = 240k BTU/hr). But then need regs at ALL the appliances to drop pressure to something like 7 inch WC for them to run on.

Heard some meters may have internal reg to bring gas main pressure down to something like 7 inchs. But GUESSING that's only for relatively low pressure mains , GUESSING single digits psi ( maybe 2-10 psi ???)

Saw them weld onto LIVE gas main at our other garage too ~ 1980. The one that water vapor in main froze up our meter. So it was likely low pressure too. Not enough air in the main to bring air/fuel ratio above flammable limits, for a fire INSIDE the main. Also as long as main pressure is low no real worries about pressure blowing out moltant metal during welding. Want experienced welder though.

the_donut

Pressure depends where you are at. I have 1/4 psi. My brother-in-law had 5 psi at meter. We manage a few properties with 5 psi. Just depends on the company and what district of service you are in.

Zman

I was just looking over a local gas utility map. It shows all the distribution lines in town being between 26 and 66 psi.
I guess it is just a newer system.
I suspect that the system that can take in 600 gallons of water has some lower pressure areas which are essentially under water. When the pressure in the system is high, gas leaks out. When it is low the water leaks in.

Mark Eatherton

I believe Boston has 8" WC mains if I'm not mistaken. Can't tell you why I think that tho...

ME

Brewbeer

Boston had one of the largest manufactured gas plants back in the day.

Leonard

I remember dad (99) saying here in Manchester NH (~110,000 people now) the gas company had a large coal gasifier downtown by the railroad tracks ( for coal supply).

When I was a kid I remember seeing their 2 LARGE ~ 5 story riveted steel plate gas tanks supported on sides by I beams with steel wheels to allow for thermal expansion of tank .

Jamie Hall

If those big tanks in Manchester are the ones I remember, @Leonard , they were gasometers -- and the whole top of the tank went up and down on those wheels. Maintained a constant pressure regardless of how full the tank was. Ingenious...

A relative of mine works for a water company, and one of her projects has been to locate, survey, and assess the condition of all the valves on their three main aqueducts. Hadn't been done in 20 years... She's found most of them,,,

Leonard

The tanks were on southern end of Elm st, ~ 1000 ft south of valley st. Tanks are gone now but gas company is still there. I remember seeing them as a kid some 50+ years ago.

gasometers ...... that makes more sense, since it had wheels to allow a lot of vertical motion of tank. Didn't quite seem reasonable tank would expand that much from thermal heating. Plus that would explain why I also remember seeing the tanks way down in the support frame. ( as a kid I just assumed they were removing them)

I couldn't see bottom of the tanks, at that point Elm st is about 3 stories over the land tanks are on, and has a bridge. Tanks were BIG and TALL , they also extended ~ 3 stories over Elm st. So maybe 6 stories high, lot of gas. But Manchester was a large city even then, many large millyard buildings weaving cloth too, but that was in my grandparents time.

Tanks looked similar to this link but were much taller ....... https://en.wikipedia.org/wiki/Gas_holder#/media/File:Cross_Gates_Gasholder.jpg

Nice explanation of how the gasometers work, water seal , variable volume.
https://en.wikipedia.org/wiki/Gas_holder

Leonard

Looking at water lip seal of telescoping gasometer it's easy to see why ~ 7inch WC became the standard pressure for gas. The water U tube mamometer seal was only ~ 2ft high. So 7 inch WC gave a good margin of safty they wouldn't blow water out of the U-tube water seal and vent gas from the gasometer

KC_Jones

My grandfather has shoveled snow off the top of that type of tank in Baltimore. The weight could affect the function of the tank so it had to go.

No railings, no safety harness, just nice slippery metal that was sloped to the edge.

EBEBRATT-Ed

I was told Boston still has wooden gas pipe in some locations. @Solid_Fuel_Man , you can weld a live gas line. I have done it. Just don't use too much heat and burn through it. You need oxygen or air to make an explosion and there is only gas inside the pipe

The gas co use to weld on a valve with a nipple onto the main. The valve had something inside it that would pierce the pipe.

Air-air heat pumps can't cut it where it gets really cold.

Water source heat pumps can do the job if sized correctly and if you can afford the expense of drilling the wells. Big $$$$

Leonard

Sort of remember the last time they did welded a valve on main, might have had a short 3-6 inch pipe to the main to keep valve cool. Guessing it was a ball valve, so they could open it and stick a drill bit thru to cut into main. Afterwards pull bit and close valve,do it quick and not going to spill much gas.

Besides think they had blowers to blow fresh air into the hole to dissipate any spilled gas. ( I use window box fans when I work on car gasoline tank for that)

Gordy

It would be interesting to know on the NG side the numbers nation wide. Of course some regions, or suppliers are better than others at maintaining their infrastructure. We always hear about the oil spills, and oil pipe line breaks. NG usually doesn’t make the news unless it’s a catastrophic explosion.

At least with water it makes its way back to the aquifer eventually. As you said Mark many public works programs involve leak detection, and remote meter reading. I use to get a call every spring the next day when topping off the pool in my area.

the_donut

I used to chat with a ng maintenance workeron a regular basis. He’d get called out at least twice a week for an emergency repair. System was automated and he could tell where it was and what was happening. His responsibility was to get out there, mark it, and set up dig equipment for the team who actually repaired the line. The idea of a 6” or 12” main with semiweekly leaks scared the crap out of me while he was super casual about it. I guess the majority of the lines have an automatic valve that trips after certain conditions. I don’t I could sit there next to a potential explosion and wait for the calvary to arrive.

Jean-David Beyer

"Not enough air in the main to bring air/fuel ratio above flammable limits, for a fire INSIDE the main."

When I was taking college chemistry lab as a freshman, our lab was cursed by the previous class of sophomores. Our lab benches had water, compressed air, natural gas, etc. Well the sophomores hooked a hose from the compressed air line into the natural gas line. They got so much air into the gas line that it was impossible to light a Bunsen burner or keep it lit. We basically could not do our lab assignment.

But somewhere in that natural gas supply line, the mixture must have been ideal to make a real mess.

The Steam Whisperer

The comment about variation in maintenance of the gas infrastructure is so true. I understand we still have wooden gas lines in use in Chicago. We regularly have leaks and when talking to the Water department guys, they have had gas mains rupture when they are working 10 feet from the buried gas lines. IIRC, the gas company is only required to supply about 4.5 Inches pressure, even in areas with new mains. Now the gas company is crying about the hundreds of millions of dollars that are needed to rebuild the system after they ran it into the ground for decades while taking big profits. Guess whose paying for all the deffered maintenance and capital improvements....the customers with all sorts of special charges and increased rates. Its reached the point that our middle winter gas bill for our home is now only 1/2 for the cost of gas, the other half is utility charges and, of course taxes. Gas cost is running about $.30/therm, but overall charges across the year are a bout $1.00 per therm. Despite gas being cheaper now than it has been in 50 years, and electrical costs being very high in Chicago, the old estimates of electric heat being 3 to 4 time more expensive than gas is now down to about 2, which means even cheap, inefficient heat pumps are less costly per btu than gas.

End of Rant.....

Brewbeer

Gas co in my town has a very big line replacement project going on right now. They are replacing lines in a large neighborhood built between 1900 and 1930. Given the age of the homes, this neighborhood was probably originally served with manufactured gas and it is the large diameter, low pressure lines that are being replaced. They are in their second month of this work, and it is affecting dozens of streets.

Fred

They've been upgrading gas lines all over our city too. They tagged the path of our gas lines last summer and never did anything but leave the yellow flags in the tree line in front of everyone's home. That lasted about 4 weeks before we all either took them up so we could cut grass or some neighbors just ran over them with their mowers. They came out and tagged again two weeks ago but still haven't done anything on our street. A couple more weeks and we will take the flags up again. It's crazy! Those little skimpy flags aren't made to last for years.

I have a 2' supply line into my house. I'm sure we will have much discussion when they try to reduce that pipe but I need it for a large boiler, two decent sized forced air furnaces, two large commercial ranges, each with six huge burners and griddles, one with a double oven, a gas dryer and a 50 gallon gas water heater.

EBEBRATT-Ed

@The Steam Whisperer

I was told Boston still has wooden gas piping. Hard to believe in this day and age

The Steam Whisperer

A lot of the lines that are finally getting replaced should have been replaced about 60 years ago. Chicago streets are torn up all over the city, because not only is the gas company running new lines, but the city is also replacing water mains and in various areas, relining sewers (alot of sewer work was done over the past 20 years already, however). The streets around my home have been torn up for nearly two years due to the water main and gas main replacements.

Your concern about the service size is a big problem around here. We have consistantly seen both the Gas Company in Chicago and the two company's that serve the suburbs move meters outside and run grossly undersized piping from the meter into the building. If you complain after they do this, they turn around and say that the piping is after the meter and therefore it is the homeowners responsibility. Standard installation is to install a one inch low pressure line to feed upwards a million btu's of equipment in large homes and 1 1/4 inch low pressure lines to feed 2 to 3 million btus. We also see 3/4 services installed for apartments, which is probably OK for capacity, but I believe is against code. The gas company's ignore requirements for permits and the codes as part of the regular part of business. Federal and local Historic District Preservation requirements are ignored (special permits are required for any alteration of the street face of any building). We have also seen the gas company refuse to install properly sized meters for big homes. Locally single family residential services all have a single flat rate for meter charges and the companies refuse to install the larger meters required for big homes.

Steamhead

The Steam Whisperer said:

............ We have also seen the gas company refuse to install properly sized meters for big homes. Locally single family residential services all have a single flat rate for meter charges and the companies refuse to install the larger meters required for big homes.

That's a disaster and lawsuit waiting to happen.

The Steam Whisperer

Yep, as are a lot of other practices, it seems.

Jamie Hall

And the dodgy work surprises somebody? For a municipally endorsed monopoly? If you're really surprised, I want some of whatever you're smoking...

The Steam Whisperer

Yeah, I understand Illinois is the only state that has never had a utility go bankrupt.....hmmmm.