Gas shut off valve

[apostolakisl]

There is a market in CA it is reg you have to have a earth quake gas shut off in some houses. Unfortinally these are all mechnical.

How does that work? Is it automated or is it just a standardized location/type of valve so that authorities can quickly find it and shut it off manually?

Seems like an automated valve for earthquakes would be very tricky. You would need a seismographer of sorts plus the powered valve. Very possible, but likely very expensive!

 

[apostolakisl]

Sorry, don't want to confuse anyone. Didn't mean to imply that NG and CO are the same, chemically or by physiological effect. Just saying that "I" treat them the same as far as an automated response. If it's there, let me know so I can act on it.

Rick

P.S. Maybe I'll automate the pet door.

I didn't really mean to imply that you said anything erroneous, I was just expanding on the subject.

I wonder if your dog would use the door or just hang out sniffing the foul odor?

 

[sda]

You might want to look at what this company has.

http://www.strandearthquake.com/prod_seis_...01_rem_act.html

 

[apostolakisl]

You might want to look at what this company has.

http://www.strandearthquake.com/prod_seis_...01_rem_act.html

Well there you have it. A "seismic" valve. Also can be tripped by any 24 volt source. I guess this is exactly what the guy who started this thread wanted, except that he doesn't necessarily need the "seismic" model. Wonder what it costs.

I was thinking, a way to build a seismic switch is to have a ball bearing that sits in a small gently sloped well made of a conductor. Around the periphery you have a second conductor that is separate from the conductor in the well. Then you have a latching relay that is triggered when the two conductors are connected. During an earth quake, the ball bearing would get knocked around closing the circuit between the two conductors triggering the latching relay which would then close the valve. Of course it would be very important to mount this device level and firmly attached to something that doesn't jiggle except in earth quakes.

 

[Vycor]

Well if the guys gas is gonna leak, its GONNA leak. I see some replies about "well it could cause an explosion" yeahhhhh but in his defense, if the things leaking gas, its already leaking gas into the house, so having a valve ATTEMPT to fix it until he gets there isnt a bad idea. Now of course the valve COULD leak but thats what his sensors for.

Heck even a water valve is a BANDAID and when it closes, its closing for a reason, something has to get fixed.
If his gas sensor goes off and it ATTEMPTS to close the valve, again its a bandaid to prevent more gas from going into the home then it detected.

I like the idea, but like most said, gas has different codes and you'll want to check on it. If you go AGAINST code you may be liable and not only that, your insurance MAY NOT cover any damages in the event of an issue.

But unlike water, where if your water pipe starts leaking and you don't know about it it'll cause a lot of damage, which is what sensors are for to say "hey you, check your basement its leaking" a gas sensor will do the same... only when gas leaks its not necessarily going to start causing damage.

What i think might be an alternative to this, is to have the gas sensor trip a fan relay to EXHAUST any gas in the area it detected it. Gas doesnt do damage right away, its when it builds up enough in an area to become explosive it can level a house (Happened a few towns over from me earlier this year). But if you have something that goes "ohh crap we smell gas" and then it alerts the fire department/you and at the same time starts to VENT that gas, well then at least your giving yourself some added insurance that not only is the fire department on the way, but your also venting that gas out of the house to prevent an explosion

 

[apostolakisl]

Well if the guys gas is gonna leak, its GONNA leak. I see some replies about "well it could cause an explosion" yeahhhhh but in his defense, if the things leaking gas, its already leaking gas into the house, so having a valve ATTEMPT to fix it until he gets there isnt a bad idea. Now of course the valve COULD leak but thats what his sensors for.

Heck even a water valve is a BANDAID and when it closes, its closing for a reason, something has to get fixed.
If his gas sensor goes off and it ATTEMPTS to close the valve, again its a bandaid to prevent more gas from going into the home then it detected.

I like the idea, but like most said, gas has different codes and you'll want to check on it. If you go AGAINST code you may be liable and not only that, your insurance MAY NOT cover any damages in the event of an issue.

But unlike water, where if your water pipe starts leaking and you don't know about it it'll cause a lot of damage, which is what sensors are for to say "hey you, check your basement its leaking" a gas sensor will do the same... only when gas leaks its not necessarily going to start causing damage.

What i think might be an alternative to this, is to have the gas sensor trip a fan relay to EXHAUST any gas in the area it detected it. Gas doesnt do damage right away, its when it builds up enough in an area to become explosive it can level a house (Happened a few towns over from me earlier this year). But if you have something that goes "ohh crap we smell gas" and then it alerts the fire department/you and at the same time starts to VENT that gas, well then at least your giving yourself some added insurance that not only is the fire department on the way, but your also venting that gas out of the house to prevent an explosion

The vent idea sounds like the best from a liability standpoint. It would be hard to be blamed for a gas leak if you never touched any gas lines. If you vent the area and call for help, you are doing way more than 99.9% of the popluation. According to this website http://www.engineeringtoolbox.com/explosiv...mits-d_423.html you need to keep methane (pretty much what NG is made of) to less than 5% to not go boom even with an ignition source.

 

[justinm001]

This would be great though for a NG Grill wouldn't it? The handle on my manual valve broke off and we've just been leaving the line on, which leaks NG to the outside. I can smell the gas sometimes. Has anyone found this type of valve?

 

[drozwood90]

What i think might be an alternative to this, is to have the gas sensor trip a fan relay to EXHAUST any gas in the area it detected it. Gas doesnt do damage right away, its when it builds up enough in an area to become explosive it can level a house (Happened a few towns over from me earlier this year). But if you have something that goes "ohh crap we smell gas" and then it alerts the fire department/you and at the same time starts to VENT that gas, well then at least your giving yourself some added insurance that not only is the fire department on the way, but your also venting that gas out of the house to prevent an explosion

The vent idea sounds like the best from a liability standpoint. It would be hard to be blamed for a gas leak if you never touched any gas lines. If you vent the area and call for help, you are doing way more than 99.9% of the popluation. According to this website http://www.engineeringtoolbox.com/explosiv...mits-d_423.html you need to keep methane (pretty much what NG is made of) to less than 5% to not go boom even with an ignition source.

Sounds like a good idea, but make sure it's a NG rated relay. Or optical...plus the motor is sealed or something. The problem with "NG" explosions isn't that it becomes dangerous...but that when someone throws a switch, or a motor turns on (compressor on a fridge), there is generally a spark. That ignites the NG, but only if there is a proper mixture of NG and air.

Personally, if you add a fan, THAT or the turning ON of THAT could cause the explosion. I think if you wanted to be really safe, use an optical relay to engage a pneumatic valve that opens a window. Even then, I don't think that's totally safe as someone not understanding what's going on, could turn a light on and BAM! Badness...it's just a very dangerous situation. I personally wouldn't want any automation on there, but an alert is good, and a powered lock on the door to let in a trusted neighbor who could open a window and turn the gas off. The e-mail should consist of reminder instructions that a flashlight should be used, and should be turned on BEFORE entering the house. Then no light switches should be used, the heater should be disabled, fridge should be disabled...essentially anything that could cause a spark. Automation should be disabled to ensure no automatic lights go on. Then the neighbor could go turn the gas off and open a few windows.

I dunno, I think just an alert is good. This is too dangerous to try to "automate". Just my $0.02.

--Dan

P.S. As this is so dangerous, please take my post as my opinion and not necessarily "proper" or "informed" advice. I would suggest calling the gas company or some other authority (local "gas" plumbing company, as some areas the gas company's responsibility stops at the meter, then it's up to private companies to deal with everything INSIDE the house) to get their take on it and have THEM advise you properly. Make sure you get someone that understands you have an automated system that can control things, explain the valves you found, and be persistent. Eventually you will get someone that can conceptualize what you are talking about (I'd say 99% won't and just tell you either nothing useful or don't do anything like that). I'd also get a record of them advising you (if you have to pay them for the advice, that's better as you paid to be told by an expert what to do), and make sure they know you are taking a record, as if something happens, then you should be protected. Make your customer aware of this stuff, as they will feel better that you are getting advice from a NG expert to ensure their safety. I'm sure that will go a long way. I know it would with me and it would make me feel better about the "upcharge" that came from needing to bring in an expert (esp. if you can get someone from the NG Authority on the issue...that'll carry more weight then a we can plumb everything guy).

 

[Vycor]

Personally, if you add a fan, THAT or the turning ON of THAT could cause the explosion. I think if you wanted to be really safe, use an optical relay to engage a pneumatic valve that opens a window. Even then, I don't think that's totally safe as someone not understanding what's going on, could turn a light on and BAM! Badness...it's just a very dangerous situation. I personally wouldn't want any automation on there, but an alert is good, and a powered lock on the door to let in a trusted neighbor who could open a window and turn the gas off. The e-mail should consist of reminder instructions that a flashlight should be used, and should be turned on BEFORE entering the house. Then no light switches should be used, the heater should be disabled, fridge should be disabled...essentially anything that could cause a spark. Automation should be disabled to ensure no automatic lights go on. Then the neighbor could go turn the gas off and open a few windows.

Actually it wouldnt cause an explosion. Even if you had a lit cigarette in a room with gas leaking... it won't ignite until it reaches a certain %. Theres still too much oxygen in the room for it to ignite. When it does ignite its been filling for a few hours and then one spark sets it off.

But if the sensor detects the presence of gas it'll be at a low level that you could have an open flame and it still wouldnt do much. It'll start to exhaust the gas before it reaches a dangerous level (which is what the sensor is detecting anyway, its detecting it at a non-dangerous level to prevent it from getting so concentrated it goes boom)

Don't forget a fan isnt gonna set it off... if anything the oil burner pilot light will set it off first (which is usually what happens, it gets to a certain level, BOOM)

 

[drozwood90]

I agree with everything you said...except:
"Don't forget a fan isnt gonna set it off"

It can. You are right, chances are...probability is...

BUT, there's a chance...I guess I just don't like using anything that can support a life/ death scenario, that isn't certified. There's too great a value to risk it IMO.

The OP is free to do as he wishes, I just wanted to get across, talk to an Authority and get it on paper (a report that he paid for would be nice) which goes into detail stating exactly what you said.

Then I'd be 100% with the fan solution. I really do agree with you that chances are, the pilot would "boom" go first, but what if the leak was upstairs? Depending on the home layout, it may never get downstairs in the concentrations you are talking. Then upstairs fills, fridge does it's thing and boom. There's a million scenarios.

Heck, one of these might really be the best solution, as it also vents the "whole" house (as they claim):
http://www.waveventilation.com/jump/technology.cfm
i.e. you probably don't need an HRV / ERV with something like this running. I'm sure not AS efficient as an HRV / ERV, but it has the benefit of venting specifically the basement.

--Dan

 

[apostolakisl]

Methane needs between 5 and 15% concentration to be explosive when mixed with room air according to the website I sited earlier. I don't know how the NG detector works. It would be worth checking into what the gas concentration is that trips the sensor. Let's just say it is detecting at .1% then switching on a fan when the detector trips won't be able to cause an explosion.

Since gas lines are usually located near gas appliances and since it is near and within the appliance where the vast majority of fittings that could leak are located, odds are that should a leak ocurr, that would be the area. And since gas appliances by their very nature are designed to ignite natural gas, the most likely explosive event would be that the appliance itself ignites gas that leaked from a nearby failure. Life isn't perfect, you have to play the odds, and that is where I see the odds looking most dangerous.

 

[lorenkoeman]

I won't comment on the advisability of the plan but the farms that I work with almost all have Maxon valves on their natural gas dryers. Of course theirs are much bigger than what you need, they typically have a 2" line running to a 25 million BTU burner) but it looks like they make some smaller stuff as well.

I am not sure where to buy them, but here is the link to the mfg's website:

https://www.maxoncorp.com/Pages/product-Valves-Shut-Off

 

[Ira]

Doing a periodic exercise of the gas valve to make sure it will close would be a pain if you have anything with a pilot light. Especially if it's a gas hot water heater located in the attic (like mine).

Ira

 

[Vycor]

Maybe the original topic poster can let us know what he has around his gas... im assuming its hooked to an oil burner in which case an exhaust fan going out a window or a hole in the wall will not set it off before the pilot light does... also what kind of gas sensor is he using so we can see what % it trips at... anything below the "trigger" level would be fine to use a fan.

But id like to see a shut off valve also, thats great as well. Heck i'll take a shut off AND an exhaust fan.

He'd need to be able to manually open the valve however so that he can diagnose the system when it goes off.

I doubt that ANYTHING will set it off, oince he gets an alert he'll naturally tell his alarm company (or in todays world, that would be an alarm the alarm company gets right away along with a fire)... sure beats NOT notifying anybody, including the homeowner and then a possible BOOM.

 

[hult]

Ok now that I installed a gas sensor the person wants a gas cut off valve (of course) like the elk water valve I need something 3/4" has anyone used one or know where to get one?

Assuming you mean "natural gas" when you write "gas", thar's one of them in every gas furnace sold. An OEM for general purpose natural gas valves is ASCO. An eBay search on ASCO gas 3/4" yields 17 hits.

The 3/4" valve that I use on my Onan 15KW natural gas generator engine is a SIEBE SNC-1014-31B rated at 12vdc 0.9amp, 0.5 psi gas pressure (much more than needed with home natural gas supply.) They were made for at least a couple of decades but have been obsoleted.

Point is, DC- and AC-operated natural gas valves are ordinary and common.

... Marc