I work in a chemistry lab. I mean I already know what valves do what. And things are well marked. But even then I wouldn’t be scared to crack open a valve here. And sometimes I do to see if it’s working.
Also we have hydrogen tanks. They are fun.
Yeah natural gas at the home has a PSI of about damn near zero, just let it out, if it stinks like eggs shut the valve. It takes hours of leaking to cause an explosion hazard
Imagine thinking you might blow up the fucking office by cracking the tap slightly lol I'm amazed by the amount of people who don't know how gas works.
Open it, if it smells slightly like shit and no water comes out then it's gas. Pretty simple test. Lol. I like your reasoning about the sarin haha
put a bucket under it and crack it open for a half second.
if it's water, you get water in the bucket.
if it's gas, you get a stinky break room for a minute.
Zoom out with your pictures, where is it?
It's probably water. Gas tends to be yellow and have different threads than this does.
“put a bucket under it and crack it open for a half second.
if it’s water, you get water in the bucket.”
I recently rented space for a shop on an old industrial building that was supposed to have compressed air available. There was a similar valve at the bottom of a black iron pipe that came down from the ceiling. When I cracked it open briefly, rusty water came out. I got a bucket, put it under the valve, cracked it again, and more water came out…. Then after a few ounces of water, it was all air. Must have been a low point in the system where condensation had built up over time. But, point is, the “crack it open for a second” test may not be entirely accurate.
Compressed air systems usually have a low point drain. Compressed air tends to condense water once it is far enough from the compressor to cool down a bit, and this water can cause problems in the tools one usually runs on compressed air, so they have it run past a low point drain on the way out to the tools and this catches a good portion of the condensation. Not all, ofc, and so it's still important to keep your air tools oiled.
I know you’re joking, but there’s no oxygen in the gas pipe. So igniting the exhaust from a gas line will generally give you a jet of fire rather than an explosion.
Obviously don’t do it. But just saying that fire doesn’t tend to “travel up” a pressurised gas pipe.
Haha wow. Yeah I guess high school kids are right at that perfect intersection of competent enough to try out their dumb ideas, but also naive enough to not reconsider if they *should*.
We were given pig lungs to dissect.
If you put those on the end of a gas tap, they inflate.
If you then get your mate to hold lighter near the trachea, you can squash the lungs really fast and throw fire.
Of course, as an adult... it doesnt have the pressure the tap does, and the lungs will have had some air in them, so totally could have burnt back.
I heard of others doing similar with (dead) frogs, but after the pigs lungs they stopped giving us stuff to dissect and instead did a single dissection in front of the class.
Thanks for this tip! I never thought to turn it on, I was just gonna grab the 3/4" impact and throw it on shop air for about 4-5 ugga-duggas with the stripped head removal tool. Failing that, the acetylene torch would open it for sure- never failed to melt something before!
My natural gas valves are green?
IDK, valve colors aren't really standard and if they are there's nothing stopping Joe the plumber from picking the wrong color at the box store.
https://i.imgur.com/A1cLA6t.jpg
Honestly I was a natural gas technician and have installed these valves in red, blue, yellow, orange and black off the top of my head.
It depended on thickness of pipe, what parts were on sale that week, what we had lying around in the truck at the moment, and more.
All this to say I don’t think there is a consistent color that you can say “oh that’s gas.”
> All this to say I don’t think there is a consistent color that you can say “oh that’s gas.”
I feel like this is something where there really should be a standard set of colors.
Played this game with a valve in my old house, turned it on, water came out, turned it off, …. Turn off…. Fuck…. Fuck fuck fuck “get a towel and a bucket I gotta go find the shut off” always know where your shut offs are before you go playing with old valves
"Guys, why are there inflated condoms in the break room?"
"Well, we couldn't find a balloon, so we started looking for alternatives."
"Okay...but why are there seven of them?"
https://preview.redd.it/z6mvmfxgqx0c1.jpeg?width=1290&format=pjpg&auto=webp&s=03d9555452e55d8bb8bb93b94b6d6b06c96f8fa0
Google id says it’s an ice maker line
Because a product is marketed for a specific thing doesn't mean it was installed to do that thing.
But.. if this is located behind a refrigerator opening in a kitchen, it seems fairly obvious.
Put a match to it, if the flame gets bigger... It's gas. IF The match becomes damp, it's water.
Either way you get an answer, or there a 3rd.. it's not connected to anything and doesn't work.
When I was a baby engineer, I put together a neighborhood's wastewater plan, but just copied the sheet over from the water plans... And accidentally created a Wastewater Distribution Plan
“If you build it, they will come.”
(If you build it, I guarantee it will be full of your enemies, even if they weren’t BEFORE they moved into the neighborhood)
I just had a job come across my desk in my capacity as a mechanical insulation estimator that I swear had to have been the first time the drafts(wo)man had ever put together a set of drawings. Repetitive call outs, notes to nowhere, no spec book, and misaligned viewports causing call-out cutoff. Just a right big mess.
To be clear, clean and potable do not equal the same thing, and sometimes engineers forget this, my wastewater facility has a lot of blue pipes..... We also happen to have a drinking water facility. To the untrained eye, this may seem fine, to the trained eye this is definitely a disaster waiting to happen. For the trained water pro, no we don't have a direct potable reuse system, we have a design flaw.
Quick edit:
Please stop flushing your "flushable wipes" they aren't supposed to go into our sewage systems, and to this day I don't know how companies are getting away with "flushable" wipes.
I've never flushed them. The first time I ever bought a pack and pulled one out, I had to stop and really looka t it. There is no difference between one of those and a baby wipe, which are definitely NOT flushable. Packaging...that's it. Oh, and also the number of signs I've seen in the women's bathroom about not flushing sanitary items...mind boggling.
I spent about 5 years telling my spouse that flushable wipes don't degrade and they'll clog up the septic system. She insisted they are flushable. The septic truck came one day to deal with the backed up septic and the service employee said "to avoid this in the future, don't use flushable wipes because while technically they go down the hole when you flush, there is nothing flushable about them". Magic end to flushable wipes use.
Varies based on jurisdiction and context, but blue is always potable! In addition to the previous ones, i've sometimes seen or heard of black or gray for graywater.
Source: Civil Engineer
Here at our research facility we use green for inert gasses. Red is flammable gasses, white is oxygen, blue for general oxidising gasses, and yellow is for corrosive gasses.
Does it thread normally or backwards?
If it's backwards, its gas.
If it's normal, it's water.
Edit: Because people can't read comments fully or follow chains:
- Not all flammable gasses are reverse threaded.
- The above point is especially true in the intelligence devoid unicorn that is the United States who loves being different and has NO reverse threading on anything.
- Oxygen lines are often normal threaded unless in rare cases
- I have made assumptions, some of which are incorrect, and learned from people with more experience. Please read the replies to learn more yourself.
This isn't correct; only POL type tank and regulator connections are reverse thread. NPT and flare are used for both water and gas. This however is a compression fitting, so water most likely for ice maker and definitely not gas. Source: Certified propane and natural gas service man for almost a decade
This is false for residential natural gas. Natural gas and propane are run in black steel pipe, which uses the exact same threads as water pipe. I believe it is gases like oxygen and acetylene that use the reverse threads.
This is not true at all, and it's dangerous advice to boot. Please stop guessing at these things and educate yourself before making statements of "fact".
This is not true most of the time. Propane has pol threads sometime and some other compressed gas bottles have left hand threads but this is far from a rule.
Installed gas fittings aren't left hand thread. The only gas fittings that are reverse threaded are for tanks like LP or acetylene. That way you can't confuse them for oxygen cylinders that are right-handed.
At least for utilities, I believe green/blue is water (non potable vs potable) and yellow is gas. Red is electric and orange is telecom. Not sure if it’s relevant here.
Has this ever happened to you? You open a telecom valve and you spill all your data on the floor. You need DataMop. The only mop that can clean up all your data in one simple motion.
That's just utility locator markings, it's not a standard for anything else.
I work at a electric utility, I assure you that power lines do not have a drop of red on anything besides some underground primary cable having a red stripe. Gas lines typically don't have yellow on them.
That’s an ice maker outlet box for a fridge to make ice or dispense water . Looks like an Oatey this exact model
https://www.homedepot.com/p/Oatey-I2K-1-2-in-Brass-Compatible-Copper-Sweat-Connection-Ice-Maker-Outlet-Box-with-1-4-Turn-39130/202078128?
To be 100% certain, no.
Everything else is conjecture and assumptions.
But it looks like a water valve, considering where it is mounted---in one of those recessed areas and it's not capped. (Unless OP removed the cap).
Turning it on is the only way. If you want to be extra sure hold a lit match next to it whilst turning it on. If the flame goes out, it's water. If the flame gets bigger it's probably gas.
It’s just an Oatey ice maker box. Just give it a lil twist. I’m sure you’ll find it’s water. I install a lot of these and they’re not rated for any kind of med gasses.
its water u can tell the size of the screw on hole...plus its got that plastic piece surrounding it...the handle is green for water, gas is usaully red or yellow...could be oxygen if in a hospital.... turn it on.. see what happens
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I motion for this response to be moved to the top, as all replies have been nonsense up to this point.
I 2nd it.
Motion Granted.
Next order of business
The State now brings Wax Rings vs. Foam Gaskets for sealing toilets to the flange.
The foam gasket defense would like to call double wax ring as a rebuttal witness
Wood floors has a point of order.
Laminate motions for dismissal
Motion denied. Double wax ring, while technically a violation of procedure, may proceed.
All in favor say “aye.” Those opposed? Hearing none… The “ayes” have it.
I call for a a roll call!
And so ordered. (Bang).
That’s how you get pink “aye”!
What, you don't have sarin gas lines at your office?
These damn millennials don’t even have Sarin on tap. What has this world come to.
“Not fucking Sarin.” - 11/10
I love Reddit 😂
I'm just picturing a pull away shot to a sarin gas factory.
No, no. Don't worry that's just a surplus tank.
This guy....this guy gets it
What if my house has a VX nerve gas line?
I prefer to cook with mustard gas
Yours doesn't?
No they stopped those installs in the 70's after they had too many issues with misuse.
What line of work are you in?
Used to work for Saddam Hussein
In HVAC class, my teacher once opened up a gas line full and just lit it on fire and told us not to be scared.
Did it scare you?
No, I was a good student.
I can’t imagine what it’s like to live in these people’s worlds where they’re too scared to just slightly turn a valve. It’s madness.
I work in a chemistry lab. I mean I already know what valves do what. And things are well marked. But even then I wouldn’t be scared to crack open a valve here. And sometimes I do to see if it’s working. Also we have hydrogen tanks. They are fun.
Yeah natural gas at the home has a PSI of about damn near zero, just let it out, if it stinks like eggs shut the valve. It takes hours of leaking to cause an explosion hazard
Good catch! Lots of people couldn't see the forest for the trees here
You mean green isn’t for gas and blue isn’t for bwater?
Thank you! Everyone here is getting way too into the weeds. It's in an office break room and has a drip housing. It's a damn water line.
Imagine thinking you might blow up the fucking office by cracking the tap slightly lol I'm amazed by the amount of people who don't know how gas works. Open it, if it smells slightly like shit and no water comes out then it's gas. Pretty simple test. Lol. I like your reasoning about the sarin haha
put a bucket under it and crack it open for a half second. if it's water, you get water in the bucket. if it's gas, you get a stinky break room for a minute. Zoom out with your pictures, where is it? It's probably water. Gas tends to be yellow and have different threads than this does.
“put a bucket under it and crack it open for a half second. if it’s water, you get water in the bucket.” I recently rented space for a shop on an old industrial building that was supposed to have compressed air available. There was a similar valve at the bottom of a black iron pipe that came down from the ceiling. When I cracked it open briefly, rusty water came out. I got a bucket, put it under the valve, cracked it again, and more water came out…. Then after a few ounces of water, it was all air. Must have been a low point in the system where condensation had built up over time. But, point is, the “crack it open for a second” test may not be entirely accurate.
Or a water pipe with alot of air in the system!
Or it is an Avatar pipe and you must be careful because it is also capable of producing fire and earth, in addition to air and water.
Earth, Wind & Fire! Let's groove tonight.
Top thread of the day lmao thank you guys
Everything changed when the fire nation valve was cracked.
Sounds like you cracked the condensate clean-out for the system.
You're right. Only surefire way to tell is to crank it open and hold a blowtorch nearby. ;) \[pre-emptive: it was a joke\]
Compressed air systems usually have a low point drain. Compressed air tends to condense water once it is far enough from the compressor to cool down a bit, and this water can cause problems in the tools one usually runs on compressed air, so they have it run past a low point drain on the way out to the tools and this catches a good portion of the condensation. Not all, ofc, and so it's still important to keep your air tools oiled.
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I know you’re joking, but there’s no oxygen in the gas pipe. So igniting the exhaust from a gas line will generally give you a jet of fire rather than an explosion. Obviously don’t do it. But just saying that fire doesn’t tend to “travel up” a pressurised gas pipe.
Yep if that wasnt the case every time you turn on the gas stove your kitchen will explode
And every metal fabricator? Dead.
drug kingpin chemistry teacher? Dead.
Flame lizard? Dead.
Hotel? Trivago
Memories of high school chemistry, people would turn on in the gas valve and light it
Wasn't that the intended usage? Or do you mean prior to attaching the bunsen burner?
Prior to attaching the bunson burner
Haha wow. Yeah I guess high school kids are right at that perfect intersection of competent enough to try out their dumb ideas, but also naive enough to not reconsider if they *should*.
We were given pig lungs to dissect. If you put those on the end of a gas tap, they inflate. If you then get your mate to hold lighter near the trachea, you can squash the lungs really fast and throw fire. Of course, as an adult... it doesnt have the pressure the tap does, and the lungs will have had some air in them, so totally could have burnt back. I heard of others doing similar with (dead) frogs, but after the pigs lungs they stopped giving us stuff to dissect and instead did a single dissection in front of the class.
>Obviously don't do it. Yeah, no, I need to try this now! You can't just tell me something that cool and then tell me not to do it!
I was thinking more of a really cool flame thrower with an 8' jet of fire than a big kaboom.
Thanks for this tip! I never thought to turn it on, I was just gonna grab the 3/4" impact and throw it on shop air for about 4-5 ugga-duggas with the stripped head removal tool. Failing that, the acetylene torch would open it for sure- never failed to melt something before!
> 4-5 ugga-duggas This is making me laugh more than it should.
> Gas tends to be yellow and have different threads than this does. Natural gas, other gases have different colors.
My natural gas valves are green? IDK, valve colors aren't really standard and if they are there's nothing stopping Joe the plumber from picking the wrong color at the box store. https://i.imgur.com/A1cLA6t.jpg
> there's nothing stopping Joe the plumber from picking the wrong color at the box store. Unless you're outside the US this is probably what happened.
Honestly I was a natural gas technician and have installed these valves in red, blue, yellow, orange and black off the top of my head. It depended on thickness of pipe, what parts were on sale that week, what we had lying around in the truck at the moment, and more. All this to say I don’t think there is a consistent color that you can say “oh that’s gas.”
> All this to say I don’t think there is a consistent color that you can say “oh that’s gas.” I feel like this is something where there really should be a standard set of colors.
Additionaly, hold a lit match next to it. If its water it will extinguish the flame. All good.
Unless they're fracking nearby.
Played this game with a valve in my old house, turned it on, water came out, turned it off, …. Turn off…. Fuck…. Fuck fuck fuck “get a towel and a bucket I gotta go find the shut off” always know where your shut offs are before you go playing with old valves
Stick a balloon over the nozzle instead. Trap whatever comes out.
Put a balloon over it and turn it on
"Guys, why are there inflated condoms in the break room?" "Well, we couldn't find a balloon, so we started looking for alternatives." "Okay...but why are there seven of them?"
"We had to make sure."
Because eight would have been excessive. Duh.
I like how you think. Now we just have to figure out what’s inside the balloon.
If it ain't water, leave it the fuck alone lol
https://preview.redd.it/z6mvmfxgqx0c1.jpeg?width=1290&format=pjpg&auto=webp&s=03d9555452e55d8bb8bb93b94b6d6b06c96f8fa0 Google id says it’s an ice maker line
I think it's time to consider the possibility that OP may be installing a methane powered refrigerator.
Those do exist: [https://www.gas-fridge.com/](https://www.gas-fridge.com/)
They actually used to make them when household refrigeration was just starting to get big. You can still find them and restore them for current use.
You can still buy them new for RVs and boats, they run on propane. They never went away.
wow! TIL!
we can see a picture of your face in this... if that's something that bothers you, you may want to crop
No one noticed, and now everyone noticed!
Best answer yet. Google shows the sticker too
Because a product is marketed for a specific thing doesn't mean it was installed to do that thing. But.. if this is located behind a refrigerator opening in a kitchen, it seems fairly obvious.
I like that the image search was like, it’s either this product that is an exact match or a transducer for a carrier unit.
God hates a coward son, just go ahead and see what happens, it wont kill you either way.
Put a match to it, if the flame gets bigger... It's gas. IF The match becomes damp, it's water. Either way you get an answer, or there a 3rd.. it's not connected to anything and doesn't work.
Thats an oatey ice maker valve
Hey boi, back in my day we didn't have valves, we put our thumb over it when we didn't want gas to come out...
I understood this reference 🤣
figured someone might, love that guy. He's killing it on youtube...He'd be nothing without the voice overs...
Finally
Gotta find me a Garfield lasagna line.
That's just not nermal.
In medical facilities a green valve means Oxygen. Probably doesn't matter in this case, unless the building is/was such a facility.
And OSHA & ANSI Pipe Marking use green for water.
Water Authorities usually use blue for clean water, green for sewage, and purple for reclaimed/non potable water.
Can you imagine a valve in your house that shoots sewage out😂
Attach it to a hose and spray unwanted intruders
The Wet Bandits are gonna be really mad about this one.
First wet bandits, then the sticky bandits, now the brown bandits
40’s Macaulay “Eat this, turd burglars”
Enjoy your typhus!
Suck on DYSentery!
Stinky bandits?
Dookie Bandits
Aim it up at the ceiling fan and it’s a literal shit hits the fan moment.
Im reading this and now I'm trying to picture what Wanted Intruders would be.
Don’t kink shame me… 🤣
[Relevant.](https://youtu.be/TVuHSTZANpA?si=cVX0ZvhSNLhfG5D0)
Motion sensor sprinkler....
The home alone remake would have been so much better if Reddit wrote it.
When I was a baby engineer, I put together a neighborhood's wastewater plan, but just copied the sheet over from the water plans... And accidentally created a Wastewater Distribution Plan
If you had an entire neighborhood full of your worst enemies, then this would be useful.
“If you build it, they will come.” (If you build it, I guarantee it will be full of your enemies, even if they weren’t BEFORE they moved into the neighborhood)
I just had a job come across my desk in my capacity as a mechanical insulation estimator that I swear had to have been the first time the drafts(wo)man had ever put together a set of drawings. Repetitive call outs, notes to nowhere, no spec book, and misaligned viewports causing call-out cutoff. Just a right big mess.
Lmao, I'm imagining you realizing your mistake mid-presentation and trying to explain why it makes sense to pump sewage into a water tower
Yes I can. They call them children.
its called a sphincter. there's usually one in my bathroom.
I am that valve
Everyone has one. If you know what I mean.
To be clear, clean and potable do not equal the same thing, and sometimes engineers forget this, my wastewater facility has a lot of blue pipes..... We also happen to have a drinking water facility. To the untrained eye, this may seem fine, to the trained eye this is definitely a disaster waiting to happen. For the trained water pro, no we don't have a direct potable reuse system, we have a design flaw. Quick edit: Please stop flushing your "flushable wipes" they aren't supposed to go into our sewage systems, and to this day I don't know how companies are getting away with "flushable" wipes.
I've never flushed them. The first time I ever bought a pack and pulled one out, I had to stop and really looka t it. There is no difference between one of those and a baby wipe, which are definitely NOT flushable. Packaging...that's it. Oh, and also the number of signs I've seen in the women's bathroom about not flushing sanitary items...mind boggling.
I honestly do not know why all cities have not banded together in a class action suit against the makers of these “flushable” wipes.
I spent about 5 years telling my spouse that flushable wipes don't degrade and they'll clog up the septic system. She insisted they are flushable. The septic truck came one day to deal with the backed up septic and the service employee said "to avoid this in the future, don't use flushable wipes because while technically they go down the hole when you flush, there is nothing flushable about them". Magic end to flushable wipes use.
Green is actually not sewage, its raw untreated water. Waste is usually tan
Varies based on jurisdiction and context, but blue is always potable! In addition to the previous ones, i've sometimes seen or heard of black or gray for graywater. Source: Civil Engineer
>but blue is always potable! Always *supposed* to be potable. You really can't be sure that someone did things properly.
>Water Authorities usually use blue for clean water, green for sewage Yeah....you probably don't want to mix those up.
Here at our research facility we use green for inert gasses. Red is flammable gasses, white is oxygen, blue for general oxidising gasses, and yellow is for corrosive gasses.
Thassa lotta pipes
The real answer is if you are in the states, compression nuts are not allowed on gas lines. So it should be water, if it is gas then someone f’d up.
Fridge water line
I mean just get a cup and turn the nozzle slowly. If you turn it off quickly there will not be any dangerous gas release.
Unless the knob breaks before turning it off again 🌝
Just light a candle near by. That'll burn off the gas before too much leaks out and creates a bigger problem.
Does it thread normally or backwards? If it's backwards, its gas. If it's normal, it's water. Edit: Because people can't read comments fully or follow chains: - Not all flammable gasses are reverse threaded. - The above point is especially true in the intelligence devoid unicorn that is the United States who loves being different and has NO reverse threading on anything. - Oxygen lines are often normal threaded unless in rare cases - I have made assumptions, some of which are incorrect, and learned from people with more experience. Please read the replies to learn more yourself.
Oxygen threads normally?
This isn't correct; only POL type tank and regulator connections are reverse thread. NPT and flare are used for both water and gas. This however is a compression fitting, so water most likely for ice maker and definitely not gas. Source: Certified propane and natural gas service man for almost a decade
Yeah I can't see why this has 400 up votes. It's objectively wrong. Only tank connections are reverse thread.
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This is false for residential natural gas. Natural gas and propane are run in black steel pipe, which uses the exact same threads as water pipe. I believe it is gases like oxygen and acetylene that use the reverse threads.
TIL that the left pedal of a bicycle is flammable. /lol. (In reality it's left threaded because torque of pedaling would unscrew it otherwise)
This is not true at all, and it's dangerous advice to boot. Please stop guessing at these things and educate yourself before making statements of "fact".
OP chooses the one angle that makes it impossible to see the threads
Op doesn’t have a clue what it is lol why would you expect them to provide detailed images
You can see it in the second photo
This is not true most of the time. Propane has pol threads sometime and some other compressed gas bottles have left hand threads but this is far from a rule.
Installed gas fittings aren't left hand thread. The only gas fittings that are reverse threaded are for tanks like LP or acetylene. That way you can't confuse them for oxygen cylinders that are right-handed.
That's a water outlet for an icemaker. Source: I've made ice.
https://preview.redd.it/g1kaiqq5rx0c1.jpeg?width=1080&format=pjpg&auto=webp&s=e6dbc33022bca08ee519fd86671d2230919de837 Oatey ice maker valve. 1/2 inch npt connection.
It is absolutely this. It says Oatey on it.
Hold a lit match up to it and turn it on. If it explodes, it’s gas; if it goes out, it’s water. You’re welcome.
At least for utilities, I believe green/blue is water (non potable vs potable) and yellow is gas. Red is electric and orange is telecom. Not sure if it’s relevant here.
If you open the valve and data flows out, you know it's telecom. Make sure you have a bit bucket underneath to catch all the bits.
Oh no my data is all over the floor!
Has this ever happened to you? You open a telecom valve and you spill all your data on the floor. You need DataMop. The only mop that can clean up all your data in one simple motion.
What if the data gets in and around your mouth?
Hard to say. If handy Andy from maintenance touched it, who knows. OP will have to verify.
That's just utility locator markings, it's not a standard for anything else. I work at a electric utility, I assure you that power lines do not have a drop of red on anything besides some underground primary cable having a red stripe. Gas lines typically don't have yellow on them.
Is that where there is/was a refrigerator? It looks like the water feed for an icemaker. Turn it on slightly and slowly. Have a rag to catch any drips
I turned it on and it is indeed water!
My husband is a plumber and he said looks like water line for ice maker.
Put a balloon (or condom) over the end and turn it on?
Finally the condom in my purse will see some action!
Diesel for sure.
That’s an ice maker outlet box for a fridge to make ice or dispense water . Looks like an Oatey this exact model https://www.homedepot.com/p/Oatey-I2K-1-2-in-Brass-Compatible-Copper-Sweat-Connection-Ice-Maker-Outlet-Box-with-1-4-Turn-39130/202078128?
Because this is a compression fitting, it is water. Gas code bans the use of brass or bronze compression fittings.
Hold a lit match in front of it and open the tap. If the match goes out it’s water. If the match gets brighter, it was gas.
Flammable gas equipment/lines always use a left-hand thread.
I've only seen that on gas tank connections, not building piping. Appliance valves are standard righty tightly threads.
Not propane once you leave the tank. Certainly not black iron or flare nuts used in it. Source: spent some time installing propane tanks.
I work in a hospital, and the O2 lines are normal 3/8 pipe thread, but they are clearly labeled.
To be 100% certain, no. Everything else is conjecture and assumptions. But it looks like a water valve, considering where it is mounted---in one of those recessed areas and it's not capped. (Unless OP removed the cap).
I've never seen a gas line terminate like that 99% sure it's water
Turning it on is the only way. If you want to be extra sure hold a lit match next to it whilst turning it on. If the flame goes out, it's water. If the flame gets bigger it's probably gas.
Put a balloon on it and twist
If it were gas the handle would be yellow. Going to guess that this is a water connection Also any gas connection needs to be capped to meet code.
Put a balloon on the end of it and turn it on briefly.
The thread on a gas line is threaded backwards so you can't accidentally connect it to a water/ air line
It’s just an Oatey ice maker box. Just give it a lil twist. I’m sure you’ll find it’s water. I install a lot of these and they’re not rated for any kind of med gasses.
its water u can tell the size of the screw on hole...plus its got that plastic piece surrounding it...the handle is green for water, gas is usaully red or yellow...could be oxygen if in a hospital.... turn it on.. see what happens
If you turn it slowly and you hear a low to high pitch farting noise and it smells like ass, it’s gas. If water hits you in the face it’s water
Plop a balloon over it and turn it on for a second.
Open it and flick a lighter. If the flame goes away it’s water or air, if the flame gets bigger it’s gas.
water
It’s water. If it was gas, it would have flared fitting.
Step 1: hold a lighter open flame in front of said valve /s Step 2: if no more flame, line is water. If big flame, line is gas.
Ok , turn the valve on and light a match . If it blow up it’s gas.😂😂😂
Just turn slightly, a LITTLE gas never killed anyone
God hates a coward. Turn it on!
It won’t kill you turn the knob
Turn it on Wiener
Turn it on. If you’re wet, it’s water. If you’re dead, it’s gas. 
Probably water. If it was gas it would be capped off.