NG Pipeline and Sediment Trap?

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Radiant123

New Member
Oct 4, 2009
8
Portland, Oregon
After pretty exhaustive research on home heating options and hearth options, I finally settled on a Jotul 200 Lillehammer DV which was installed here in November (2009).

The problem that prompts this post is that the installer used some rusty black iron pipe for the stove gasline. About 60 feet of pipeline was run from the gas meter to the stove. Of that 60 feet of pipe, about 26 feet runs in the crawl space under this one level ranch style home with attached single car garage. Of that 26 feet, a 20 foot section of pipe has the most rust on its exterior and is in unacceptable condition to this homeowner. Rust has also quickly developed on the pipe exterior right next to the gas meter (located outside next to an exterior garage wall) because it is exposed to the rain.

I'm told by private sector building inspectors that stainless steel flexpipe is actually the preferred material to use: its said to be easier to install and does not rust. What pipe material is commonly used in installations?

Its also said that a sediment trap should be installed immediately behind the stove and downstream from the shutoff valve, and that without the sediment trap, debris could get into the stove and cause problems. Is this correct and are sediment traps commonly installed?
 
Radiant123 said:
After pretty exhaustive research on home heating options and hearth options, I finally settled on a Jotul 200 Lillehammer DV which was installed here in November (2009).

The problem that prompts this post is that the installer used some rusty black iron pipe for the stove gasline. About 60 feet of pipeline was run from the gas meter to the stove. Of that 60 feet of pipe, about 26 feet runs in the crawl space under this one level ranch style home with attached single car garage. Of that 26 feet, a 20 foot section of pipe has the most rust on its exterior and is in unacceptable condition to this homeowner. Rust has also quickly developed on the pipe exterior right next to the gas meter (located outside next to an exterior garage wall) because it is exposed to the rain.

A wire brush & some Rustoleum will take care of that corrosion near the meter.

I'm told by private sector building inspectors that stainless steel flexpipe is actually the preferred material to use: its said to be easier to install and does not rust. What pipe material is commonly used in installations?

Round these parts, Corrugated Stainless Steel (CSS) can only be run indoors, underground (if sheathed) or under a deck. Black Iron Pipe (BIP) is the preferred & accepted material for exposed areas

Its also said that a sediment trap should be installed immediately behind the stove and downstream from the shutoff valve, and that without the sediment trap, debris could get into the stove and cause problems. Is this correct and are sediment traps commonly installed?

You'll hafta check your local codes. We generally install the sediment trap immediately after the shut off where we tap into the gas main. Some codes require the trap within 5 feet of the appliance.
 
DAKSY pretty much summed it up. In this area though, no one has had problems with CSST being run exposed outside. We now put a sleeve over it to protect it, but in the past it was installed "naked". The only thing the manufacturer requires is that any fittings exposed outside need to have water proof silicone tape put over the brass fittings.

The whole sediment trap things is interesting, I will have to research that in the NFPA 54 book. I don't think we have ever installed one, and not one inspector has ever said anything about it. In fact all the new houses being built typically use iron pipe into the house and a manifold, then branch off and use CSST for all the other runs. If they run the CSST right to the appliance, there are no sediment traps on those either. Some of the houses they run iron pipe from the appliance up to the ceiling (with a trap at the bottom), then CSST from there back to the manifold.
 
Do you guys ground your CSST? I think I read somewhere about being certified to do longer runs... or is that just to assemble the pieces?

Matt
 
EatenByLimestone said:
Do you guys ground your CSST? I think I read somewhere about being certified to do longer runs... or is that just to assemble the pieces?

Matt

As of 1 Jan 09, the National Gas Code says we hafta bond (ground) our CSS.
It has to be wired to a grounding stake, a cold water pipe or
directly to the buss bar in the breaker panel...
The theory is that if your home gets struck by lightning,
there will not be an arc between the CSS & the nearest ground.
It doesn't take very much of an arc to burn a hole thru the CSS
(Don't ask me how I know that! LOL), although it won't create
an explosive condition.
It will cause the gas exiting thru the hole to ignite & could
potentially burn a house down...
 
The funny thing is, the mfg's of the CSST have had literature in their design guides about proper bonding / grounding for years, but no one starting paying attention to it until houses started exploding. I don't think any plumbers actually read this documentation though. I mean seriously... why do plumbers ask me what size line they should run to a fireplace? I tell them the BTU of the fireplaces and they are confused... they want to know what size line it needs. So I just tell them if its under 90ft 1/2" is fine, since apparently they don't know what a sizing chart is.
 
<> So I just tell them if its under 90ft 1/2" is fine, since apparently they don't know what a sizing chart is.<>

90 FEET? We tell them as long as it's under 30 FEET for NG, there shouldn't be a problem,
but that depends on what's up stream in the gas line & the BTU draw.
I've seen 20 feet be too short because it was tapped in after both
the hot water tank & furnace. The on-site estimator never looked
to see what diameter feed was off the meter...
 
I think that would be 90ft total from the meter, if I remember correctly on the size chart, with 1/2" that would give just enough BTU to cover most of the fireplaces we sell. If the line down from where they tap off for the fireplace is undersized I can't help them with that. The "longest run" method is quite simple but I have not done it in so long I can't remember the little details. The only time I ever worry about run length is commercial buildings. Dealing with an issue like that right now. They tapped 6 fireplaces off one 1/2" line with 7" WC in it. Longest run is 60ft I think. Luckily they are only 20k BTU fireplaces or we would have major probs. Hopefully if the regulator is just turned up they will work better. Of course it is all our fault that the idiot plumber sized the gas line wrong, so we have to drive an hour away and figure out how to fix it.
 
1. Do moisture and debris travel thru NG pipelines into gas appliances?

2. Do NG appliances experience failures that would otherwise be prevented by having a sediment trap in the line?

3. Does a "drip leg" refer to the same thing as a "sediment trap"?


Radiant 123
 
Radiant123 said:
1. Do moisture and debris travel thru NG pipelines into gas appliances?

2. Do NG appliances experience failures that would otherwise be prevented by having a sediment trap in the line?

3. Does a "drip leg" refer to the same thing as a "sediment trap"?


Radiant 123

My recollection after reviewing this years ago was that moisture in the NG line is uncommon, and generally is known to the NG supplier. But if present, it can condense into water, which could in theory make it to the appliance being supplied with NG. A drip leg is meant to capture this, but I think it's pretty rare these days for NG to contain moisture.

Though most NG supplies do not have moisture in them, all can have sediment, generally from bits of pipe dope, rust particles, etc. So a sediment trap was traditionally required, ideally right before any appliance. I believe this is in the Codes, but maybe not. I think it's a bad idea to skip the sediment traps, especially before a valved appliance like a furnace or water heater.

So a drip leg and a sediment trap are different things, but in practice are both installed as a single T whose arms are oriented vertically, just before the appliance.

I wouldn't worry about the surface rust on the black pipe. There often is at least some, and sometimes quite a lot. If it bothers you, you could brush it off and paint the pipe with yellow rustoleum or similar, thereby identifying it as a gas line. Any pipe exposed to the elements should be painted as a protection anyway, IMO. In many places, it's required.
 
dave11 said:
Radiant123 said:
1. Do moisture and debris travel thru NG pipelines into gas appliances?

Moisture is in the gas itself. Water vapor is a by-product of the NG (or LP) combustion. That's why the glass on DV units gets fogged up when you light them, & why the "Vent-Free" appliances fog up your windows & cause unfinished wooden doors & windows to swell & stick

2. Do NG appliances experience failures that would otherwise be prevented by having a sediment trap in the line?

Yes. I have seen small pieces of flaky rust make it thru the gas line, thru the pilot tube & all the way to the pilot spud (orifice). It doesn't take a very large piece of "crud" to stop the gas flow to the appliance if it gets that far thru the lines

3. Does a "drip leg" refer to the same thing as a "sediment trap"?

Essentially, yes. They are both there to allow for heavier materials to settle out before they can reach the appliance

Radiant 123
 
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