20psi applied to natural gas system in house. How to verify safe?

infloorradiantheat

We are having a whole house generator installed. The new gas line from the gas meter to the generator was put under 20 psi to pressure check the line. It was connected to the gas meter by a ball valve which was closed for the pressure check. The other end of the line had a gauge to check the pressure. The connection between the gauge and the generator was left open.

When the contractor came to hook up the generator they closed the valve near the gauge before removing the gauge, thus locking 20 psi in the line. They then attached the flexible gas hose to the generator and opened the valve on that side, thus applying 20 psi to the generator. They then went to the other side and opened the ball valve, applying 20 psi to the natural gas system.

The gas meter pressure relief valve went off, releasing the pressure and some gas.

They started the generator, shut it down and left. After they left we detected a natural gas smell near our stove. We called the gas company to check for a leak. When we relayed what happened they shut the gas off, changed out their meter and gas relief valve and red tagged the house. The instructions were to have a certified HVAC tech. check all the lines and certify the appliances were safe.

The HVAC tech asked if gas company specified that the lines should be checked with air. We said we didn't know. They analyzed the situation and formed their plans which seemed good. They shut the gas valves at all the appliances. They then turned the gas back on and used the leak detection spray to check all the joints in the basement.

They then turned the gas back on at the boiler and checked the flames. Thought it looked normal. I think they may have spray checked the gas valve area also but didn't really see this.

They turned the valve back on at the stove and smelled gas so turned it off. I think they spray checked this area also to make sure it wasn't leaking with the valve closed.

They left the gas valve off at the generator to check another day as it was late and none of us knew how to access it.

My question is, can/should the gas valve at the boiler and the generator have the pressure checked at the output with a manometer to make sure they are still functioning correctly? Or is the visual flame check sufficient?

I asked the contractor installing the generator (electrician) and they seemed to think it could only check the pressure on the incoming side but they are an electrical contractor and don't seem to be very familiar with natural gas.

Is there anything else we should do to make sure our natural gas system, both lines and appliances, are safe after being exposed to 20 psi?

ratio

Ummmmmm... With 20 PSIG applied to a ½ PSIG gas valve, it must be replaced. All of 'em.

mattmia2

They should at minimum have been checked with a monometer and combustion analyzer. All the automatic valves and regulators probably should have been replaced, but @Tim McElwain would know the code regarding if it is required or not.

infloorradiantheat

Here is a picture of the boiler and the gas valve. Is there anything else in the boiler that would need replaced other than the gas valve in pic 2.
?

HVACNUT

If existing lines were part of the pressure test, the piping should have been disconnected and capped at the appliance. Whoever did the test is at fault. 

EBEBRATT-Ed

I would make the idiots that applied 20psi to the equipment pay SOMEONE ELSE who is qualified to replace the gas valve(s) on all the equipment that uses gas. And set and adjust all gas pressures and do a combustion test

The problem is the gas valves are not just gas valves they are also pressure regulators and are LIKELY damaged by the high pressure.

Gas equipment has a maximum operating pressure of 1/2 a PSI a far cry from 20 psi.

I would call your local gas/plumbing inspector if you don't get immediate satisfaction.

IMHO the equipment is not safe to run

Read about the disaster in Massachusetts around 2017 when the gas company over pressurized the gas lines

infloorradiantheat

HVACNUT,
The plumber who put in the new gas line put a ball valve between it and the meter. He took the handle off the ball valve so it could not be accidentally opened. The pressure test was only done on this segment (from the gauge near the generator up to the closed ball valve). The Xcel gas guy said that in some locations this was against code and there should have been a cap so things like this didn't happen. The existing lines were not part of the pressure test.

EBEBRATT,
We are trying to hold the line on only qualified certified gas professionals working on the gas line. We do have the boiler working providing heat and hot water as the HVAC contractor sent by the generator installer checked the lines with leak detect spray and visually checked the flame. He thought it was fine to leave on. He left the stove and the generator off. I have been worried that both the boiler regulator and the generator regulator may be damaged which is why I posted the question. I have sent this link to a person at Xcel to help clarify for the generator contractor what should be done.

mattmia2

The issue isn't with the piping. The piping is rated for a couple hundred psig or more. The issue is with the gas controls, those are only rated for somewhere under 1 psig and can be damaged in was that would be difficult or impossible to detect.

Most manufacturer's installation instructions require you remove and cap the pipe from the appliance before testing with more than a few psig. the code requires you to follow the manufacturers' instructions, therefore the code requires you to disconnect and cap the piping if you are testing at 20 psig. It is also usually explicitly written in to most codes.

STEVEusaPA

Are you sure it was 20 psi, and not 20" W.C.? Because that's a big difference. I think (hope) it was the latter. 20" WC=.72 psi
Now about whole house generators in general. This is a huge problem with electricians who want to install generators.
The best way (to me) is to hire a generator company. They will pull a permit, contact the gas company with the proper information, and the gas company will let you know if you have enough pressure, and if you need a different meter/relief valve.
Plus you are going to need a generator company to maintain and fix the generator-mechanical and electrical.
Then the generator company will (should) have a licensed plumber and a licensed electrician do the install under their guidance, and the generator company will commission and check the system.
When you know what your new incoming gas pressure will be, your plumber (better-knowledgable hvac tech) can compare that to the maximum operating pressures of your gas appliances, and can adjust gas pressures, and check combustion.

infloorradiantheat

Thanks Steve,
We are sure it was 20 psi as we monitored the gauge for several days to make sure the line would hold air. When the line was first installed it was set to 16 psi by the plumber. It lost air at the rate of 1 psi per day for 8 days. We repeatedly reported the leak to the generator contractor so they could send someone to fix it. We were repeatedly told that it was just a temperature differential which is why we let it go for 8 days as it warmed us significantly and the pressure did not come back. It was down to 8 psi from 16 psi.

They sent the generator check out person to check for the leak. He upped the pressure to 20 psi so he could spray the line with soap. He said it is normally pressure checked at 20 psi anyways. It immediately fell to 19.5 psi so he said he knew there was a leak somewhere. When he found it in our basement he attempted to tighten the connection. It was still there. He called the office and requested the plumber to come and fix it.

The plumber came out and found some grit in the connection. He cleaned it out remade the connection. It was left to be pressure tested at 20 psi. We monitored it and it did not fall so we had the generator check out guy (same one who found the leak) back out to connect up the generator to test it.

Somehow the generator check out guy removed the gauge and either did not know to take the pressure off the line or forgot to take the pressure off the line.

EBEBRATT-Ed

The problem is as I see it

The new gas line was tied into the existing working gas supply and the new piping was isolated by a ball valve. Then the new piping was put under test at 20psi.

If you go by the "book" the new gas piping should have been tested while it was completely disconnected from the gas supply.

Most locations and inspectors are ok with this just being isolated by a ball valve (you save a union & a nipple) and it has become common practice at least in my location.

But we don't test low pressure gas pipe at 20 psi, 5psi is max here

The mistake was they opened the ball valve and let the 20 psi test pressure go backfeed into the gas supply.

@infloorradiantheat

Just make sure someone that knows what they are doing checks things out

kcopp

Testing the line w/ 20 psi was a mistake. This may have actually caused the leak.

mattmia2

EBEBRATT-Ed said:

The mistake was they opened the ball valve and let the 20 psi test pressure go backfeed into the gas supply.

Well, that is why it is supposed to be disconnected and capped off it is tested at over a certain pressure. Also if the valve itself is the leak it would pressurize the whole system.

infloorradiantheat

The most recent comments got me curious. So I searched on our city code.
"11-9-10. - International Fuel Gas Code Amendments.

(A)Section 303.3 of the International Fuel Gas Code is amended as follows:
303.3 Prohibited locations. Items 3 and 4 are deleted in their entirety.

(B)Section 406.4.1 and 406.4.2 of the International Fuel Gas Code are amended to read as follows:

406.4.1 Test pressure. The minimum test pressure to be used on threaded pipe shall be 20 psi gauge pressure. For welded pipe the minimum test pressure shall be 60 psi gauge pressure.

406.4.2 Test duration. The test duration shall be not less than 10 minutes.

https://library.municode.com/co/westminster/codes/code_of_ordinances?nodeId=CD_ORD_TITXILADEGRPR_CH9BUCO_11-9-10INFUGACOAM

In reading this the correct pressure to test at is 20 psi.

ratio

From a liability standpoint, there's no way at all I'd let a low-pressure gas valve or regulator that's been exposed to 40 times it's max operating pressure stay in service.

Jamie Hall

That code section, i I'm not mistaken, applies to the piping itself. It does not apply to any appliances -- such as gas valves or regulators in this instance -- which may be involved.

I'm with the guys above -- anything along those lines anywhere in the structure which was subjected to that much overpressure simply must be replaced. Not optional.

kcopp

What City is this?

EBEBRATT-Ed

Codes are different everywhere. In MA low pressure is testes at 3psi minimum and 5psi maximum. The reason being a lower pressure test gauge (5psi gauge) will show a leak faster that a 20# test using a 30 # gauge.

High pressure gas is tested at 1 1/2 times the working pressure minimum and maybe higher depending on the length of run with 100psi being the maximum

wesPA

Even if the gas valves are working now, I wouldn't trust them. I have seen several gas valves fail after being exposed to 2-5 PSI from a failed regulator.  The policy where I work is always replacing a gas valve if exposed to over pressure. Especially 20 PSI!

infloorradiantheat

wesPA, when they fail what happens? Do they fail off or let too much gas through?

When the Xcel guy changed out his equipment, no testing, no questions asked I wondered if that wasn't what we should be doing. I have enlisted the HVAC contractor's assistance in evaluating this. We were very impressed with their knowledge base.

pecmsg

infloorradiantheat said:

wesPA, when they fail what happens? Do they fail off or let too much gas through?

When the Xcel guy changed out his equipment, no testing, no questions asked I wondered if that wasn't what we should be doing. I have enlisted the HVAC contractor's assistance in evaluating this. We were very impressed with their knowledge base.

Can't answer because the valves were never rated or tested at that pressure!

Jamie Hall

infloorradiantheat said:

wesPA, when they fail what happens? Do they fail off or let too much gas through?
...e.

As @pecmsg said, completely unpredictable since no one was dumb enough to test them at that kind of overpressure.

That said, there are three possible failure modes that come to mind:

They may fail shut. This is your best option, as that way the appliance in question will simply not work and you will be motivated to fix the problem.

They may fail wide open. This is not a particularly good option. Depending on the appliance, you may notice (such as with a kitchen range) and be able to turn the appliance off before you have a major fire. Or another safety, such as might be a rollout switch on a boiler may shut the system off, if the problem is the regulator rather than the gas valve itself. These may motivate you to fixe the problem. Or they may fail wide open without ignition. This will release gas into the structure, which will than blow up. Depending on where you were when it went boom this also may motivate you to do some repairs, although they will be more extensive.

Or keep in mind that there is a flexible diaphragm in the regulators. This may fail and release gas into the structure/ See the last variant of the option above.

What I'm trying to say is quit playing games. Shut the gas to the house off (have the gas company do that) and replace all the regulators and gas valves and other such things.

infloorradiantheat

Thanks Jamie! After reading your comment this morning I turned off the power to the boiler and shut the gas valve leading into the boiler gas regulator. That means that all the gas appliances in our house now have their valves closed. There is still gas coming in from the meter so in the pipes. The HVAC contractor said they would call me this morning.

pecmsg

There should be a valve at the meter that you will need an adjustable to close. If you cant or dont know how call the gas company.

pecmsg

You didn't stat where this job is located. Might need a gas fitter, HVAC, Plumber or a combination of all but everything connected to the gas line need a through going thru.

You stated earlier the gas was red tagged who removed the tag?

infloorradiantheat

pecmsg,
The generator installer sent an HVAC company the night of the red tag. They turned off the valves at all the appliances, turned the gas back on and then sprayed leak detection fluid on the joints in the basement and the valves. They felt the lines were safe. So first they turned back on the boiler and did a visual inspection of the flame. Felt that was good.

Then turned back on the oven. Smelled gas so turned it back off. The gas was also left off at the new generator.

I put the link in for the city code. We are in Westminster Colorado.
https://library.municode.com/co/westminster/codes/code_of_ordinances?nodeId=CD_ORD_TITXILADEGRPR_CH9BUCO_11-9-10INFUGACOAM

infloorradiantheat

We reached out to Honeywell they advise the gas valve should not be used and replaced. Response below:

-----------------

All of our gas valves are rated for a max of 1/2 psi.

We do not recommend using a gas valve to be used with an inlet pressure higher than 1/2 psi, OR after being subjected to such pressure.

Our recommendation is the valve will need to be replace.

Thank you,

pecmsg

1st I would have hired an independent HVAC contractor that isn't in the generator contractor pockets.
The HVAC tech removed the red tag? Not allowed here only the gas company can do that.

your second post answered the questions.......1/2# max. Have ALL gas controls valve replaced. Combustion analyses on heat and hot water appliances.

EBEBRATT-Ed

What @pecmsg said

infloorradiantheat

We are on track to have the boiler, gas oven and generator gas valves replaced. Thanks for all the help!

infloorradiantheat

Forgot to mention that when the red tag was placed I asked if they had to come back to remove it. They said no, the HVAC contractor could remove it.

Tim McElwain

In order to make sure the gas piping system is not leaking shut off all the pilots, Shut the valves ahead of appliances off. Go to the meter and get the 1/2 foot test dial on the upward swing and mark it allow for 5 minutes. If it does not move the piping systems is tight, Now go and open the shut offs ahead of each appliance and with a soap and water mixture and a brush soap the threads on fitting and see if you get any bubbles which would indicate a leak.

The valve is a redundant valve so all that happens in an over pressure situation the second valve closes and stops all flow of gas so it should be alright.

infloorradiantheat

Thanks Tim! I just went out and took a picture of it. There are no pilot lights and everything is turned off by their individual valves (the ones next to the appliances). I'll check it again later to see if anything moved.

Can you elaborate on this? I'm not sure what valve it is referring to.
"The valve is a redundant valve so all that happens in an over pressure situation the second valve closes and stops all flow of gas so it should be alright. "

pecmsg

infloorradiantheat said:

Thanks Tim! I just went out and took a picture of it. There are no pilot lights and everything is turned off by their individual valves (the ones next to the appliances). I'll check it again later to see if anything moved.

Can you elaborate on this? I'm not sure what valve it is referring to.
"The valve is a redundant valve so all that happens in an over pressure situation the second valve closes and stops all flow of gas so it should be alright. "

Call the gas company back and explain you still think theres an issue.

ChrisJ

infloorradiantheat said:

Thanks Tim! I just went out and took a picture of it. There are no pilot lights and everything is turned off by their individual valves (the ones next to the appliances). I'll check it again later to see if anything moved.

Can you elaborate on this? I'm not sure what valve it is referring to.
"The valve is a redundant valve so all that happens in an over pressure situation the second valve closes and stops all flow of gas so it should be alright. "

He's talking about the gas valves inside the appliances that turn the fuel on and off automatically.

infloorradiantheat

We followed Tim's suggestion and took pictures of the gas meter last night and this morning. There has been no movement so all the lines up to the gas shut off valves at all the appliances are good. Yea!

pecmsg

20PSIG isnt even close to max for black pipe and fittings. Its the regulators and control valves that have to be changed!

infloorradiantheat

Pecmsg,
The generator contractor has agreed to change the boiler gas valve (pictured above), the stove gas valve and the generator gas valve. These are all the appliance gas valves attached to the system. I'm assuming these are combo regular and control valves as someone mentioned above that they are regulators of pressure and flow. I think we will then be good.

We currently have everything shut down and the ball valves closed going into all the appliances. We are hoping to get the boiler gas valve replaced today so we can get some hot water.

Thanks to everyone for helping educate us on what should be done.

pecmsg

Any other gas burning equipment Fireplace, BBQ ?

infloorradiantheat

Good reminder but no fireplace or bbq. New boiler gas valve goes in this afternoon so we will have hot showers tonight!

wesPA

The gas valves could fail in different ways as Jamie mentioned.  I'm glad you are getting them replaced, that is the right thing to do.
This was the one job that came to mind, happened a number of years ago:
A church with 20+ RTU's. One large 2PSI regulator served several units. That regulator failed, and without knowing it, was walking by one of the units on a PM and smelled gas. The unit gas valve was not closing, not a good scenario! A week later we found another valve that wouldn't open. We then found the faulty main regulator,  took a bit to find. When you put your manometer on the line while anything was running, the pressure was great. When nothing was calling for heat, the line pressure would very slowly creep up to 2PSI.  That incident took out a total of 3 valves, and that was with them being exposed to 2 PSI, not 20!