Nat gas pressure drop vs. pipe length

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It's bad there is no regulator. It means your gas pressure will vary widely depending on usage. It also means every bit of gas equipment will be running less efficiently than it might. It also means the gas is distributed at low pressure so there is less available than there would be if it were distributed at high pressure. You also have to take into account your neighbours gas using activities.
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It's bad there is no regulator. It means your gas pressure will vary widely depending on usage. It also means every bit of gas equipment will be running less efficiently than it might. It also means the gas is distributed at low pressure so there is less available than there would be if it were distributed at high pressure. You also have to take into account your neighbours gas using activities. ====================================================== Good points, makes sense. Now I wonder why a place like NYC don't have'em!! And yeah, our gas pressure is low, like 5-7" water, or thereabouts. You could pop the cap off a 2" pipe, and stop the gas EASILY with the palm of your hand.
--
EA




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On 1/10/2013 2:45 AM, Existential Angst wrote:

Because thats how original gas systems were designed. If you need more capacity they install a bigger line.

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I suspect your gas lines are OLD, from the gas light/town gas era. Illuminating gas was made from coal and the line pressure came from the gas storage tank tops that floated on water in the tank walls. All the NG installations around here have regulators either incorporated with the gas meters or immediately before them, the disc- shaped housings are always visible on the outsides of the buildings. So all high-pressure distribution lines around here. There were no gas fields around NYC, it was all illuminating gas at one time. One reason our local gas rates have tripled in the last few years is that the east AND west coasts are sucking all of our NG away with new pipelines. And domestic inside lines are always low pressure, like 10" of water, regardless of regulation. One way to tell if you had illuminating gas is that immediately where the line entered the house, there was a tee with a capped 1' nipple hanging down for a tar trap. Have taken these off in older houses while renovating and found a whole lot of black goo, so were needed. My home town converted from town gas to natural gas in the '30s when they ran the first pipelines from OK to Chicago, my dad remembered having to redrill burners and pilot lights. Still had the gas storage tank next to the packing plant until I was in high school.
Stan
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Stanley Schaefer wrote:

Now those gas storage tanks are next to all Taco Bells! ;-)
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wrote:

It will depend whereabouts on the gas grid you are. Outside my house there happens to be a twelve inch gas main. But most people will only have a two inch or so pipe nearby. And the size of your pool heater depends on the size of the pool, the local climate and how well insulated it is shitfor brains
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On 1/9/2013 11:56 AM, snipped-for-privacy@optonline.net wrote:

here and they have a low pressure distribution system. Guess what do if you want to add more devices? They dig up the existing line and run a larger one.
And even in the case of high pressure distribution systems the regulator and meter are often not large enough to accommodate doubling the gas consumption for say your example. You just simply can't hook into the gas line and hope for the best. There are well known methods and procedures to accommodate additional devices.
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You're right. If this project is getting permits and inspections as it should, then all that would be checked out. The fact that it hasn't tells us something. My initial response was not made thinking in the sense that in a power outage every gas appliance is going to be running at the same time. But you're right that you'd want to run a gas furnace and the generator at the same time. The existing service can very likely run either of those at a time, but the 15KW generator itself at full output could be equal to the full load of the furnace and all the other gas appliances together. It's like adding say a whole house on-demand water heater.
But I think if EA wants to do this right, there are a LOT of even bigger issues than the gas service sizing. He's not only asking about gas pipe sizing, but in another thread also asking about sizing and backflow pressure for a long run of exhaust hose that he's going to hook on to this generator. A generator that has been apparently designed to run on tri-fuel, using a Honda gasoline engines. I'll bet we'd agree that this generator is almost certainly sold as a portable, for use outdoors. I'll bet it has no rating for ever being installed indoors, which given the need for exhaust hose, appears to be the intention. If it was rated for indoor installation, I think he wouldn't be here asking about exhaust pipe sizing, backflow pressures, etc., because that would be spec'd along with how to install it. I'll bet the manual for it clearly says it's for outdoor use only.
So, I bet it's illegal as all hell to install it inside in NYC period, because it almost certainly isn't rated for such use. And even if it is legal, I would expect NYC would have some pretty tough code reqts on such an install, like possibly fireproofing of the area it's in, venting, exhaust piping rating, maybe sprinkler systems, etc. It's bad enough if this is a single family. If it's a NYC townhome or similar there are even more serious implications.
As I said before, if it were me, I'd have gone with a tri-fuel PORTABLE that is 5KW or so, together with a panel lockout kit and inlet. Much lighter weight than a 15KW elephant and plenty enough to run a furnace, a few fridges, freezers, lights, sump pump, etc. Just bring it out when you need it. You can hook it up when needed to a gas quick connect like you;d use for an outdoor nat gas grill. At 5KW, it would also not have the ridiculous gas reqt of the 15KW beast, so you could more likely be able to run it off the existing gas supply.
The other alternative, if you want a permanent install, is to get one rated for such installation. If it has to go indoors, I don't know which ones are rated for that. The nat gas, whole house ones that I've seen from Generac for example, that are market for typical homes, costing $3000 or so, are for OUTSIDE installation only and they make that explicitly clear. I'm sure there are ones rated for indoor, but I'll bet they are in a whole different price range.
It sounds to me like a whole lot of things should have been investigated upfront, before buying the genset.
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wrote:

15 KW is absurdly oversize for a single-family dwelling, except perhaps for northern Alaska, unless the OP plans on serving his entire neighborhood. In that case, he should be worrying about the size of the conductors he will be running across lawns and streets.
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"hr(bob) snipped-for-privacy@att.net" wrote:

62.5 A is absurdly oversize? Not if you have electric heat, or need air conditioning for a whole house in the south. Ny neighbors have an 18 KW propane generator, but they are too cheap to have the tank filled.
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wrote:

The location in the discussion thread is NYC. If he has electric heat there, which I don't believe is the case since he has nat gas, then electric heat is a problem of it's own that needs fixing. Who in their right mind would size an emergency generator to run electric heat for a house?
AC could be an issue, but it's not as vital in most cases as heat is. And instead of spending buckoo bucks on a big honking genset, it might be better to buy a window AC for $100 for an emergency, no? I would think most people can get by with a lot less during an extended outage, instead of trying to power life as usual.
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" snipped-for-privacy@optonline.net" wrote:

house was built. Hell, I lived in one house that was built before water, gas, sewer or electric was availible. It still had four chimneys for coal stoves, and was built prior to 1868.
A well insulated, farily airtight house is better served by electric heat than gas, unless you feed outside air to the furnace.

How about people who are ill? I knew people up north with cancer who need the house to be kept at 60 degrees all of the time.
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wrote:

WTF? Where do you live? Nat gas has been a far better deal than electric heat for most of the USA that requires heating for decades. Unless by electric you really mean a heat pump. Even with older furnaces that were not fed outside air. Right now nat gas is a great deal. Here in NJ, I don't know of a single person that uses electric heat. Gas or oil are 99% of the market. Electric is not even close in cost, nor has it ever been. Electric heat is generally used as supplementary heat for a heat pump system or where very little heat is needed. Certainly not NYC. It could also make sense in some pathological case, where say electric rates are exceptionally low, nat gas or propane are high.

Now I'm suspecting a troll. What person that is ill needs the house at 60F all the time? Assuming it's winter and you live up north, you can keep it at any temp you could normally achieve with a 5KW generator and a furnace that runs on gas or oil. If it's summer and you need 60F, well something is very wrong.
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" snipped-for-privacy@optonline.net" wrote:

house was built. Hell, I lived in one house that was built before water, gas, sewer or electric was availible. It still had four chimneys for coal stoves, and was built prior to 1868.

I live in FLorida right now. There is no natural gas service around here. Just lots of Propane companies.

I have a heat pump. It hasn't been used in years. Instead, i use electric heat for a couple rooms. It cost me about 1/3 2hat it cost to heat the entire house with the heat pump.

those old furnaces depended on air leaks to replace what went up the flue.

There is a huge world outside of New Jersy.

The propane dealers refuse to use a condom, or lubricant.

It was an old Army vet who died of cancer. He was one of the first soliders to report to Ft Rucker, as well as the first group of MPs stationed there. He was a gentleman even though he was , with a sharp mind.Any more stupid questions?
That was SW Ohio, where 90+ days in the summer were the norm.

Not me, not now. I would sit in my briefs and sweat in a 64 degree room when a VA doctor screwed up my medication, and had me on a low sodium diet. It damn near killed me.
I've lived in places where it was over 100, and others that were well below 40 below.
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wrote:

The OP is in NYC. And just because YOU don't have nat gas in YOUR area of FL, doesn't mean it does not exist. I know it's available in many areas of FL. I've been there and used ranges for example.

Thanks for the non-response. Anyone can heat a room or two with electric cheaper than a whole house. But we were talking about electric heat versus gas heat for a whole house, were we not? This is alt.home.repair, isn't it? Not alt.room.repair?

Who the hell cares. Around here they are typically located in the basement. Those gas furnaces were still far cheaper to operate than using electricity for heat. What, is everyone stupid that lives in NY? In ME? OH? IL? PA? About 95% of the heat in those places is nat gas, propane or oil. Very, very little is electric heat. Some small percentage is heat pump/gerothermal. And today when one of those old gas furnaces goes out, you see anyone replacing it with electric heat? They almost always replace it with another gas or oil unit.

Yes and almost all of it is *not* using electric heat. Geez, even in FL they use heat pumps.

Yes, what the hell does that have to do with anything? Because some vet died of cancer sitting in a house that's 60F means what? That's typical? normal?

Sure and he had to have the house at 60F on those days. Yeah, I believe that. And in planning for a generator you have to factor that in. That someday, somtime, you might get cancer. Not just any cancer, but the special kind where you have to have it 60F all the time, even when it's 90F outside

And we should care about that because?
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" snipped-for-privacy@optonline.net" wrote:

No, idiot. I am on news:rec.crafts.metalworking.
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The location in the discussion thread is NYC. If he has electric heat there, which I don't believe is the case since he has nat gas, then electric heat is a problem of it's own that needs fixing. Who in their right mind would size an emergency generator to run electric heat for a house?
AC could be an issue, but it's not as vital in most cases as heat is. And instead of spending buckoo bucks on a big honking genset, it might be better to buy a window AC for $100 for an emergency, no? I would think most people can get by with a lot less during an extended outage, instead of trying to power life as usual. ================================================ Don't forget, this is a LARGE house, with a fair-sized shop, with bigger-than-avg equipment.
In another post, I did address the "life-as-usual" issue, and have made reference numerous times to the "gamble" of choosing a wattage for a generator. I freely admit to being really spooked by Sandy, and proly over-bought as a result, but it may pay off in the next power event, ESP. shop-wise. As I pointed out, shop-wise, I will be shedding loads like crazy, depending on what I'm running, even with 15 kW..
Also, ito of gas draw, I did some inneresting experiments that I'll post on separately. But here, just note that just because the motor is 22 hp, 15 kW, dudn't mean it's ALWAYS sucking up 22 hp worth of gas -- it will RARELY do that. Just like a 300 hp car is using only 15 hp cruising at 60 mph on level highway -- the SAME hp, btw, that a 100 hp car is using, on the same highway. The demand for the full 300 hp is very rare.... unless you are a drug dealer....
At lower power demands, or idle, it will indeed be using more no-load gas consumption than a smaller genset, but proly not a biggie, and certainly not a gas service issue.
Bottom line is, you pay one way or the other.
Another way to have gone was to have STAGED generators -- bitty ones for light stuff, with bigger ones coming on for heavier stuff. I was even considering a smaller dedicated generator just for the cycling air compressor, as that gives the system a bit of a shock. We'll see how stable this genset is with cycling loads like that.
As far as operating it inside, portability and all that, it IS portable, now that it's on a dolly..... And I'm keeping it inside for now mostly for experiments and the monthly 10 min run -- I can easily move it outside for protracted runs. This unit is not much heavier than, say, the 8,750 W Black Max at Sam's club. Plus, I will be monitoring CO closely, to assess the practical viability and safety of running it inside. More on that in another post, really some inneresting stuff. But moving it, running it outside is no big deal.
Bottom line, 15 kW isn't as much as you think -- see my other post on this. And it's all a gamble, anyway. Just too much crazy weather going on around here, too much nail-biting. So ahm broke now, and may never even use this thing, but at least my nails will grow back.
--
EA





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wrote:

Bump =================================================== Amazing if this thing actually works. I basically understand the net result: the gen rotational speed must be kept absolutely in sync, but wow, how this is actually accomplished is beyond me.
But, I guess it's also done "on the Grid", right? When you sell power back to the utility, your power can't be out of phase with utility power, or you'd have a dead short. Solar stuff, which uses a solid state inverter, proly does this relatively automatically. AND, various substations in the grid have to be in sync.... but they don't use inverters, afaik
BeatsTF out of me.... a good Q for a sep. thread.
--
EA





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On Thu, 10 Jan 2013 13:36:54 -0500, "Michael A. Terrell"

Excellent point indeed.
Gunner
The methodology of the left has always been:
1. Lie 2. Repeat the lie as many times as possible 3. Have as many people repeat the lie as often as possible 4. Eventually, the uninformed believe the lie 5. The lie will then be made into some form oflaw 6. Then everyone must conform to the lie
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wrote:

Heh, and in fact, I'll be throwing my asshole neighbor a line.... LOL

Or, if you have a matchine shop.... :) You know what they say, calc your load, and then double it. And factor in that proly it's not a good idea to run a genset at max capacity, that the mfr is stretching things a bit to begin with, etc etc.
It's funny how all this works: On the one hand, I could get by with 3,000 W -- not running le shop, of course. Then, the mind plays with itself, and you wind up considering 30,000 W.... So I compromised w/ 15 kW...... :) :)
Also, innerestingly, the capacity is also dependent on how long the outtage will last. If it's only a day or so, 2-3 kW would be fine. If power is out 2-3 wks, and the laundry is piling up or you been sweating buckets at 100 F for a week, the extra capacity can really help. Oh, and the shop.... :)
Actually, for a week-long outtage, I would actually have to SHED load between the house and the shop. Even in the house istself, you proly wouldn't want to run a dryer and 5-ton CAC at the same time. That's over half capacity of 15kW right there. Factor in all the other stuff, and there's actually not tremendous leeway.
15 kW is, like, ONE 20 hp machine -- theoretically. You proly couldn't even START one 20 hp motor with a 15 kW genset, but you get the idea. Factor in compressors, etc, and actually 15 kW is perty perty tight. Sheeit, 1 kW is consumed by lighting alone!!
But, with proper load-shedding, in a prolonged outtage, I'll be able to at least half-function, as opposed to being utterly paralyzed. Combine all this with the notion that you may NEVER use the goddamm genset, and you can go out of your g-d mind.... LOL
What does Vic Smith say?? Just move to a hotel?? Really, I toyed with that strat, as well. LOL Proly you could get some reimbursement from the utility, no??
--
EA

>
> Excellent point indeed.
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