Dirt traps, drip legs, on gas lines. Ever find anything in them? Asking for a friend.

Teemok

They seem to be a waste of labor and materials with my climate and gas supplier. Do they catch condensate where you are? Is there stuff in your gas?
They were removed from our code here for a spell a while back. Then.... lawyers annnnd boom they came back. They seem to be a useless vestige of a time when coal was turned into natural gas that came with dust n chunks in it that clogged pilots and valves.

I had an inspector insisted the dirt leg must be upstream of the flex connection. Other inspectors let the ignorant send gas through the barrel of a horizontal T with the branch leg hanging down.

If you had crap in your gas lines from a new install, would it really save equipment better than an inlet screen? Maybe that's the value. Maybe you guys on very old systems get stuff coming through them. For three decades I've check them for fun, hoping a diamond will fall out but nothing, ever.

EdTheHeaterMan

I believe the old timer plumbers in Sea Isle City NJ experienced this crap in the drip leg issue. But that is when the gas mains were low pressure. Read this comment: https://forum.heatinghelp.com/discussion/comment/1730834#Comment_1730834

EBEBRATT-Ed

They were call "drips" back in the day when manufactured gas was used and it was wet. Gas now contains little moisture so they are not needed for that purpose. As a "Dirt leg" they are still important to keep dirt and pipe chips out of valves and regulators.

EdTheHeaterMan

I like 'em to purge the air out of the gas line after a repair or a meter change.

Teemok

"Dirt legs" that I personally (anecdotal) in 30+ years have never found any thing in? I haven't seen one before a regulator but maybe that's a thing.
I would say screens do a good job with pipe chips.
A flare connection or union works as well for purging but hey, sometimes a dirt leg is all we have, some how.
That's two solid votes in favor of the modern existence of "dirt legs".

I think the lawyers conversation went like this:
PG&E, is there any thing in your gas that might in any foreseeable case ever require a dirt leg?
No, it's really very clean.
Can you guaranty it's 100% clean?
Well.....No we can't.
Given this established risk,
DIRT LEGS ARE LAW!

Larry Weingarten

Hi, I've found both dry materials and tar like stuff in drip legs. In my area one out of forty relief valves on water heaters is plugged solid. If a bit of grit got under a gas valve seat, so it couldn't close, and the water heater didn't have a working relief valve, things could get pretty nasty. It's too late great a risk not to do, so I'm a fan of drip legs. 👌
Yours, Larry

SuperTech

EdTheHeaterMan said:

I like 'em to purge the air out of the gas line after a repair or a meter change.

Wouldn't cracking open the union be a lot easier?

SuperTech

One time I found what appeared to be a bunch of cutting oil in the drip leg.

Mad Dog_2

Besides that, it just doesn't look right without a drip leg/dirt pocket.  Also a great place to pop on a manometer for gas pressure testing. I'm putting em in, regardless!   Mad Dog 🐕 

hot_rod

It could have something to do with the gasline piping. All the new development around here have plastic lines in the street and into the homes. So maybe less potential for rust and scale "dirt"

Older steel lines are probably more of a problem.

Bottom line, no harm in having a dirt/ drip legs

Alan (California Radiant) Forbes

To answer your question, no, and I’ve carefully removed the drip leg nipple and turned them over on a clean rag many times as I’m curious. 

Used to be San Francisco required drip legs on any horizontal to vertical changes in direction. Now, that would be very convenient for future piping additions. 

ChrisJ

With gas companies using regulators at their meters now, how could there be anything in the gas? Wouldn't liquid and debris compromise the regulator's operation? And I've been told the regulator at my house has 50 psi on the street side.

That'd be a bad day if that got something stuck in the seat.

Mad Dog_2

For years, inspectors wanted to see a drip leg 🦵 if you jumped under a beam or what have you.  All of a Sudden around 2000 or so, the codes changed and it became a real No No overnight:  "What's this Sweeney?? I don't wanna see these no more!  This is "a future " for the Homeowner or a G.C. to run a line to a BBQ or gas fireplace.  Take it out!!"   Mad Dog 🐕 

ScottSecor

I have seen leftover cutting oil, small metal chips and water/condensate.

I suspect the cutting oil and the metal chips were from the pipe threading.

I suspect the water may have been from some of the "wet" gas lines in some areas near me or perhaps they were from basements that were flooded with five or ten feet of water?

EBEBRATT-Ed

Used to put dirt legs at every drop or at the bottom of every rise. No longer required. Just at most appliances (not required at a gas dryer)

And not allowed outdoors in a freezing environment.

Teemok

I put them in because its the law and I like to pass inspections. Look right? It wouldn't take long for it to look right.
On the theoretical grit in valve point: Is a 90 degree turn in gas flow better protection than a couple screens?
Cutting oil: Ok, I can see how that can happen. Very avoidable but fair point.
A water claim just showed up. Is that a regular thing to find water in them in your area? or a one off "Wet"gas hmm. I've heard the lore but never met a witness to it.
Relatively cheap minimum insurance is what they seem to be. Insurance I've never seen a claim on.
I've always expected to see some oil at some point but never have.
We lost our tails at some point but men's nipples are still around and they don't do much either.

Mad Dog_2

I don't think I like the way this conversation is headed Tee..  ha ha 😂 🤣 😆 😄. Mad Dog 

ratio

I dumped a handful of auger bit sawdust out of one once. I guess the gas was roughed in & then the hole up to the range was drilled.

But my favorite use is to add illegal appliances. A dirt leg, a few flex connectors (I like to reuse the perfectly good old ones that I come across), maybe an adapter or six, and Bob's your Uncle!

hot_rod

Mad Dog_2 said:

I don't think I like the way this conversation is headed Tee..  ha ha 😂 🤣 😆 😄. Mad Dog 

Rogue Teemok

I like cheap insurance?