Combustable Gas Detector

Originally Posted By: James D Mosier
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Hello all,


I just recieved several tools meters and started fooling around and need some guidance.

Using a UEI CD-100 combustable gas detector at my parents house I found several gas leaks, mostly at valves. Dad got some soapy water and started checking. About 1/2 of the leaks I found are not bubbling, one took several minutes to show up in the soap, and several were more than happy to bubble away. The house has probably been this way for several years, one leak is on a 40 yr old pilot light valve that hasn't been touched for at least 10yrs.

The ones that aren't bubbling just barely sped up the tic, the others sped it up more but not like when I checked an unfired stove burner (my version of a big leak).

My mother in law also has one union that shows very slightly with the meter, this is about 6 months after the gas company checked everything out as ok.

Just how sensitive are these meters?
Is any/every increase in tick rate unacceptable? I triple (min) checked all the minor leaks, leaving the room for fresh air to recalibrate each time.

Thanks for any comments.


--
Jim Mosier

Originally Posted By: mboyett
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Mike Boyett


Capital City Inspections


Austin, Tx


www.capcityinspections.com

Originally Posted By: dedwards
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I’ve never understood why plumbers, electricians, HVAC guys complain when we send them business via discovered discrepancies. I went through Plumbing and HVAC schools and never once did I ever hear to expect small leaks or that small leaks were okay. How small of leak is acceptable is a good question. KInd of like “How small is a miracle?” What may be considered small by one person may not be considered small by the homeowner or even another technician. I write them up anyway and let the other parties fight it out.


Originally Posted By: wdecker
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I usually respond if I get a doubling or rate. I calibrate the meter to about a tick every second or so (outside air). If the this speeds up, I write it up AND notify the seller (safety).


Has a guy, the other day. Seller was also the builder, he was a drywall contractor and 'built' this house himself in 1989. Seller was present during some parts of the inspection. He had tremendous 'pride of authorship' and was REAL sore when I started finding all these 'picky flaws' in his baby.

Found a gas union to the water heater that much more than tripled the tick rate. Could smell gas. Notified him, he said,' Well, we haven't blown up yet. You are too picky. Have you every actually worked construction?'.

Well, I told him. And in front of witnesses as well.

Another gas point on this inspection. His exterior utility gas meter was tilted, side to side, about 30 dgrees. Wrote it up top have it checked by the gas company. Comments?


--
Will Decker
Decker Home Services
Skokie, IL 60076
wjd@DeckerHomeServices.com

Originally Posted By: lewens
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I also have a Tif and got into an arguement with the plumber who came to install my new water heater. It was leaking so I told him and he said I was being too picky. He came back a realized he forgot to dope the joint that was leaking. End of problem and a quick “sorry about that, it shouldn’t have happened”.



Just my usual 12.5 cents


From The Great White North Eh?
NACHI-CAN
www.aciss-brant.com
www.certifiedadulttrainingservices.com/

Originally Posted By: bkelly2
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Gentlemen I am reading this thread with great interest. I have a little experience leak testing things. Using many methods. The thing is everthing leaks, the question then becomes what is an acceptable leak. So far I can not find that information. I am sure when someone finds the leak rate information you will be able to calibrate your instruments to achieve the desired results. So far this is as close as I got.


http://www.amgas.com/ldrefpage.htm


Originally Posted By: rhinck
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I have found that this leakage thing is somewhat subjective. If you call the slightest acceleration in ticking the plumber that gets hired to fix it will not be able to detect it with soapy water. He will more than likely not have an instrument to check it himself and now you have a pissing match going on. I don’t know the answer, but I am very careful to make sure that the leak detector accelerates substantially before I report it.


Here is another thing to think about. If you report a leak you had better leave a note for the homeowner letting him know- just trying to keep everybody out of court.


Rick


Originally Posted By: ekartal
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You will find that many seasoned inspectors will not use this tool unless they smell gas first. It can open a can of worms. If you find one leak better make sure there isn’t a single other. icon_wink.gif


Erol Kartal
ProInspect


Originally Posted By: Brian Kelly
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That is one reason I do not carry any “specialized” tools.


Originally Posted By: tallen
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ekartal wrote:
You will find that many seasoned inspectors will not use this tool unless they smell gas first. It can open a can of worms. If you find one leak better make sure there isn't a single other. ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

Erol Kartal
ProInspect



I keep mine in the truck and I try to only use it when there is nobody looking. ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)


--
I have put the past behind me,
where , however, it now sits, making rude remarks.

www.whiteglovehomeinspections.net

30 Oct 2003-- 29 Nov2005

Originally Posted By: dvalley
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When I started performing inspections three years back, I asked this same question on this board. I received no firm answer.


So, with experience, I can tell you that I've had the same situations with Plumbers stating that the gas leaks (that I have called out) are minor and do not need attention. Hmmmmmmm
I've heard this same statement too many times, so I decided to not utilize my TIFF until I actually smell a strong odor of gas. I can then locate the source with my TIFF.

My advice...Start your calibration outside in fresh air and get a slow continuous tick. Then approach the area in question and any serious leak will give you the audible SIREN. You found the leak.


--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."

Originally Posted By: ekartal
This post was automatically imported from our archived forum.



tallen wrote:
ekartal wrote:
You will find that many seasoned inspectors will not use this tool unless they smell gas first. It can open a can of worms. If you find one leak better make sure there isn't a single other. ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

Erol Kartal
ProInspect



I keep mine in the truck and I try to only use it when there is nobody looking. ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)


Sometimes the temptation is too strong I agree. It's human nature to want to say "hey, look what I found". ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

Erol Kartal


Originally Posted By: phinsperger
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The amount of leakage by itself is only useful from a fuel cost view point. To view it from a safety aspect one has to calculate what the concentration in the air is, or likely to be when at maximum. To do this you can use a meter that display the concentration but again that is only while you are there and have just opened the door to the furnace area.


Lets say you go the extra mile and do a blower door depressurization test to find out how much air infiltration there is in the house with all doors and windows closed. You calculate the concentration to be less than the LEL (4%). So good the home is not going to blow up but what respiration or other problems are there even before the LEL is reached?

So there would seem to be little value in detecting leaks except that if you asked; just about every client would say they would want to know.

I would not want any leaks in my house. Would you? ![aiwebs_002.gif](upload://mGwppwEnrWqEGXBYiZkao7V64mT.gif)


--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
Place your Award Nominations
here !

Originally Posted By: mboyett
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Paul, I agree. Several times in the last couple of months I’ve detected fairly small leaks (and even a couple of big ones) and had told myself I would not be an alarmist the next time I ran across a small leak. Well, there it was, tick/tick/tick…and I just couldn’t help myself. I called it out on the report as a small detectable gas leak that should be further inspected and repaired by a qualified plumber or HVAC tech. I know that I would want to know if it were my house. Again, I’m not bound to the minimum standards and simply feel that I’m exceeding them in this case.



Mike Boyett


Capital City Inspections


Austin, Tx


www.capcityinspections.com

Originally Posted By: dandersen
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I can not justify leak testing every house I inspect.


The smell they put in the gas "stinks" a lot before you actually get to a dangerous level. The equipment you are using is too sensitive to be calling out every tick increase. It is good equipment to sniff out general utility areas(to speed up the inspection process), but to check every fitting?

Natural gas is lighter than air and dissipates quickly. LP on the other hand, will concentrate in low areas till it gets built up to a sufficient capacity to flash.

I only take out specialized test equipment when I have probable cause that there is a problem. In this case, smell the rotten egg.

If I can't get enough of a leak to make a soap bubble, I can't justify the $75 to get a plumber out there. These testers are so sensitive they will pick up the neighbors dog if it farts!

I would recommend that you create a leak (one that only slightly bubbles soap). Detect it with soap and test it with your meter. You may find that there is no tick, rather a scream when you have a real leak. Report accordingly.


Originally Posted By: bkelly2
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Mike read the post above about leak rates. 1x10-3 is considered bubble tight. The meter you are using is about 2 magnitudes more sensitive or in the 1x10-5 range. If you are intent on using your instrument to leak test you might want to follow Mr. Andersens advice and self calibrate your tool. Now if I was tempted to leak test gas lines(I’m not) I would use snoop (joy soap and water). As that would be sufficient.


As for exceeding the standards, sometimes that is not cost effective or efficient. One quick example is threaded pipe for gas lines, don't you think if you exceeded the standard and had an all welded line it would leak less?

Just my thoughts


Originally Posted By: Gary Reecher
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This is from a booklet from Honeywell Corp. a manufacturer of gas valves titled "


THE TRUTH ABOUT GAS LEAKAGE COMPLAINTS


AND GAS VALVES" form number 70-2320


RESPONDING TO GAS LEAKAGE
COMPLAINTS
To respond effectively to gas leakage complaints,
service technicians need to take a two-step approach
before identifying the gas valve as the problem:
First, they must identify the presence of gas by
using a reliable gas detector. And second, they must
verify that the flow of gas coming from the valve is
unacceptable by using a reliable flow meter.
If gas is present in low concentrations as the
result of furnace design and the trace leakage
phenomenon, replacing a gas valve will not solve the
problem. They must educate the appliance owner
about the source of the gas odor and assure them that
it is both safe and normal for that appliance.


Some electronic sniffers are extremely sensitive. Depending upon the pipe dope used they will pick up any solvents in the compound.

If a governing authority ( gas company, municipal inspector) deems it a leak then throw out what Honeywell has written about the ANSI Standard on trace leakage the component will be changed.


--
Gary Reecher, CM
HVAC Service Technician

MechAcc's Carbon Monoxide Site Links

Originally Posted By: wdecker
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Hey;


My gas meter detects it (clearly, not just a little) and I take a wiff (right near the pipe joint) and I smell gas, I am calling it and informing the seller and 'Recommend that you contact the gas company, immediately, for further evaluation'.

I have done this 8 times. Once, I got yelled at by the seller because the gas guy said it was OK. Twice I got yelled at by the seller, but the gas company was called, eventually and fixed it (tightened union). Never got an apology on either of those. Once, I notified seller and he said 'I built this house with my own hands 18 years ago and there is nothing wrong with it!' He had secured the black pipe gas lines with white teflon tape (not allowed and against code, out here). Buyer (my client) backed out of the sale. Four times, seller called gas company and they came during the inspection and verified that there was, indeed, a leak and I got thank you letters from the sellers and looked real good to my client.

Doing just fine.


--
Will Decker
Decker Home Services
Skokie, IL 60076
wjd@DeckerHomeServices.com

Originally Posted By: Caoimh?n P. Connell
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Hi Gents ?


Here is a take from a different perspective.

First of all, heavier than air gases and lighter than air gases will behave exactly the same, they will both perfectly mix in a room and their concentrations will be exactly the same regardless of their intrinsic molecular mix. Heavier than air gases will not settle ? nor will lighter than air gases raise and accumulate in the rafters. Even if you were to carefully fill a balloon with a gas whose molecular weight was say... 30 g/mole and then carefully fill the bottom of the balloon with a another, heavier gas whose molecular weight was, say, 45 g/mole, in very short time, the two gases would perfectly mix and the concentration of the mix would be identical at every point in the balloon. This is true for sealed systems such as bolloons and will occur even quicker in rooms where there are air currents, convection gradients, etc. For all practical purposes, the settling stuff is just myth ? (Having said that it can occur under very special industrial circumstances but not in any housing situations that you will encounter - or if it has occured - RUN!)

Next ? There are two primary types of CGA on the market ? Pellistor and flame ionization detectors. Neither is capable of identifying a gas and, remarkably, neither is capable of actually telling you what the LEL of gas present is, or how close one really is to an explosion. For the moment, I?ll focus on the pellistor type, since they are the most common. Furthermore, unless one has an oxygen meter, one cannot make ANY statement as to the LEL, or how close one is to the LEL.

The meters I have seen used by home inspectors are "go- no go" meters. They are of little value, under most circumstances, in my opinion, since there is no quantification whatever. They may be of limited use for inspectors whose noses are no longer working, since the mercaptans and thiols are detectable at very low concentrations.

Now, most gases have an LEL of between about 1.5% and 15%. The beauty of a CGA is that the heat of combustion for all gases is more or less same regardless of the specific LEL, and therefore, oxidizing the gas on a pellistor will produce about the same amount of heat and, therefore, when applied to a Wheatstone bridge, will result in the same loss of conductance ? giving a reasonably reliable indication of how close one MIGHT be to the LEL.

However, if one measures even 4% LEL, that would be a HUGE problem in an house since at even 4% LEL, that means there is approximately 880 parts per million in the atmosphere. At this concentration, the odour of thiols and mercaptans (the stinky stuff added to fuel gases) would be very powerful indeed.

Next, as mentioned above, the heat of combust is more or less the same? not really, but close enough for explosion work, where we usually build in HUGE margins of error. The relative response of propane to a CGA calibrated on methane is only about half ? that means that it takes twice the concentration to get the same reading ? thus 4% LEL with a methane calibrated GCA means 8% LEL propane! (Typically, I evacuate at 10% LEL).

The issue becomes more complicated in the case of measuring the LEL in closed quarters or confined spaces or at altitude (I sometimes perform work in homes and workplaces at 13,000 feet). Even at sea-level, a reading of say, 4% LEL propane could indicate either 880 ppm or it could indicate that one has so much propane that the concentration is now above the UPPER explosion limit, UEL, and the propane has displaced the oxygen (which in the case of propane begins at about 10%). So, 4% LEL without the benefit of an O2 meter, is a useless number, and warrants caution ? which is why a CGA should never be used in the absence of an O2 meter, since the reading of the GCA is incumbent on two things 1) concentration of the combustible gas, and 2) concentration of O2.

Finally, the toxicity of most fuel gases are relatively low ? for example, contrary to common belief, methane is an odorless, harmless gas. One could breath an atmosphere of 80% methane and 20% oxygen without any harmful effects (provided there was a little CO2 thrown in to ensure proper blood acid balance). Similarly, one could breath in thousands of ppm of propane without ill effects. But why would you do it, eh?
So, from an industrial hygiene perspective, little machines that go ?click, click, click? are of little use, and warrant less consideration unless you have bothered to correlate the frequency of the clicks to a concentrations of a known gas, at a known altitude, at a known relative response.

But then, I go in to buildings with explosive atmospheres all the time, so how smart could I be, eh?

Cheers,
Caoimh?n P. Connell
Forensic Industrial Hygienist
www.forensic-applications.com

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG



Originally Posted By: bkelly2
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Will it sounds like you have perfected your inspection technique and have an acceptable track record, well done. And I do not think teflon tape is ever allowed on natural gas piping anywhere, good call.