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  1. #1
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    Default Water Heater Venting

    Does this venting of a water heater look proper? I called it out because of the evidence of back drafting. The sellers said it was professionally installed 3 years ago. The vent goes up about 3 feet then a 90 out the side wall, no power vent.

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    Default Re: Water Heater Venting

    Yep, stick to your guns.

    See if a real professional will put his words in writing, otherwise, your client deserves better than that, power vent, vent thru the roof, or a direct vent, best of all.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  3. #3
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    Default Re: Water Heater Venting

    There is no draft hood.

    Is that a proper and listed 'flexible single wall or Type B gas vent section?

    That does not look like a proper natural draft Type B gas vent cap, and, for Type B gas vents (natural draft) that needs to extend up past the to of the roof at least 2 feet.

    I am sure that Bob H. will point out other issues ... such as lack of proper support, that caulking looking stuff, the clearance to that combustible foam insulation - things like that.

    I am sure that you got that exposed paper facing on the insulation ...

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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    Default Re: Water Heater Venting

    Lots wrong venting that water heat.

    1: Inadequate draft diverter.
    It is not drafting and likely back drafting.
    The plastic bushings are melting for God sake.

    2: I suspect the vessel is damaged.
    Oxidization / rust on the galvanized steel.
    Place a mirror inside the vent mirror side down for 3 seconds and pull it out.
    If there is vapor on the mirror it is likely a damaged vessel.

    venting.jpg

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    Default Re: Water Heater Venting

    Quote Originally Posted by ROBERT YOUNG View Post
    The plastic bushings are melting for God sake.
    What plastic bushings?

    Jerry Peck
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    Default Re: Water Heater Venting

    Quote Originally Posted by Jerry Peck View Post
    What plastic bushings?
    I might be explaining the component incorrectly, so sorry if I am.

    Two plumbing pipes protrude water heater metal jacket. The hot and cold supply lines.
    There is a bushing that insulates the piping and jacket.
    They are nylon or plastic.
    pipe bushing.JPG

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    Default Re: Water Heater Venting

    Quote Originally Posted by ROBERT YOUNG View Post
    Two plumbing pipes protrude water heater metal jacket. The hot and cold supply lines.
    There is a bushing that insulates the piping and jacket.
    They are nylon or plastic.
    Got it - down below the foam insulation I referred to.

    Those are there by design and are intended to withstand the ambient heat of a properly vented water heater (we have both identified venting issues).

    The improper or lack of, as the case may be, of a draft hood is the cause of that plastic bushing melting (that plastic bushing fills the hole in the top of the water heater, enclosing the foam insulation, and the heat trap nipple goes through it).

    That plastic bushing is designed to be there. That foam insulation is not, it was added.

    Is that a 5" or 6" vent placed on the 3" vent outlet so that it completely covers the draft hood? Whatever that vent is - it is not right. Agreed?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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    Default Re: Water Heater Venting

    You should have looked up the model number before saying for sure that it is wrong. It may be wrong, but some direct vent (non-fan assist) models do look a lot like that. The elbow looks very similar to models I have seen. Below is a photo of one example.

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    Default Re: Water Heater Venting

    Quote Originally Posted by Mark Reinmiller View Post
    ... some direct vent (non-fan assist) models do look a lot like that. The elbow looks very similar to models I have seen. Below is a photo of one example.
    That direct vent elbow is rigid (not saying that a flexible type is not available).

    Direct vent ones, by virtue of being direct vent, are sealed and there is no draft hood - a zoom and close look at the top of the water heater (below the vent) looks like a regular water heater without a draft hood.

    Maybe someone installed a direct vent water heater vent on a natural draft water heater? We've all seen some crazy things done to make an install 'work' (using the definition of 'work' the person making the install is likely using ... Git-R-Done ... yes sir, I done got er done jus' now).

    Jerry Peck
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    Default Re: Water Heater Venting

    Quote Originally Posted by Jerry Peck View Post
    Got it - down below the foam insulation I referred to.

    Those are there by design and are intended to withstand the ambient heat of a properly vented water heater (we have both identified venting issues).

    The improper or lack of, as the case may be, of a draft hood is the cause of that plastic bushing melting (that plastic bushing fills the hole in the top of the water heater, enclosing the foam insulation, and the heat trap nipple goes through it).

    That plastic bushing is designed to be there. That foam insulation is not, it was added.

    Is that a 5" or 6" vent placed on the 3" vent outlet so that it completely covers the draft hood? Whatever that vent is - it is not right. Agreed?
    I concur.

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    Default Re: Water Heater Venting

    Quote Originally Posted by Jerry Peck View Post
    Got it - down below the foam insulation I referred to.
    I would say, "poor place for flammable materials." but the installer overlooked that little safety tid bit.

    Quote Originally Posted by Jerry Peck View Post
    Those are there by design and are intended to withstand the ambient heat of a properly vented water heater (we have both identified venting issues).
    Yes, by design they are intended to stop foam bleed out during the manufacturing stage but I think there is a dual or multi engineered design as well.

    My question is, by observation, the bushing intended resistance to heat is being tested.
    How are the bushings doing so far and how much more testing do they need before their intended design fails? They are obviously failing as we discuss their design.

    As well, and out of curiosity, do they, the nylon pipe bushing, isolate the pipe from stray current ? Does the water heater case require bonding or not?

    Jerry, IMO, that gas-fired water heater is a bomb, a vessel under pressure, and a most dangerous component in a home. The venting is rele-vent, but everything is when it comes to gas-fired water heaters.


    Quote Originally Posted by Jerry Peck View Post
    The improper or lack of, as the case may be, of a draft hood is the cause of that plastic bushing melting (that plastic bushing fills the hole in the top of the water heater, enclosing the foam insulation, and the heat trap nipple goes through it).

    That plastic bushing is designed to be there. That foam insulation is not, it was added.

    Is that a 5" or 6" vent placed on the 3" vent outlet so that it completely covers the draft hood? Whatever that vent is - it is not right. Agreed?
    I concur but think there is more here than meets the eye than just the venting.

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    Default Re: Water Heater Venting

    Jeffery, how old was the gas fired water heater?

    Rusting is a common form of corrosion – an electrochemical process and the disintegration of a material into its constituent atoms.

    Corrosion includes; galvanic, pitting, and crevice corrosion.
    Rust, a red, brown mass on the metal surface.

    Galvanised steel corrosion / oxidisation.
    Unlike or dissimilar to iron oxide's red appearance during corrosion, galvanised steel corrosion is dissimilar by mass as well as other qualities that make galvanised steel corrosion uneque.
    The iron in the steel is oxidised to produce rust, which occupies approximately six times the volume of the original material. Just the present of oxide.

    Why is there corrosion at that area of the galvanised steel vent?
    One hypothesis, moisture and gravity.
    Typically I see this type of corrosion when the vessel is leaking.
    This is likely the beginning stages of vessel corrosion, a pipe to vessel connection failure, or upper pipe failure although that is highly improbable.

    Look closely at the formation of the corrosion. I suspect moisture induced corrosion.
    water heater vent pipe.JPG

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    Default Re: Water Heater Venting

    Quote Originally Posted by ROBERT YOUNG View Post
    I would say, "poor place for flammable materials." but the installer overlooked that little safety tid bit.
    Double wall B vent requires minimum 1" to combustible material.

    Single wall vent requires 6" minimum.

    Direct vent should not be open where a draft hood should be.

    As well, and out of curiosity, do they, the nylon pipe bushing, isolate the pipe from stray current ? Does the water heater case require bonding or not?
    A bonding jumper is needed from the cold water pipe to the hot water pipe to effectively bond the metal piping system around the water heater.

    If the water heater was electrically supplied in any way, then the water heater would be grounded through that supply.

    Jerry, IMO, that gas-fired water heater is a bomb, a vessel under pressure, and a most dangerous component in a home.
    EVERY water heater storage tank - gas, electric, oil, solar, whatever the energy source - is a potential bomb ... which is why all water heater tanks and hot water storage tanks require temperature and pressure relief valves.

    Jerry Peck
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    Default Re: Water Heater Venting

    Quote Originally Posted by Jerry Peck View Post
    Double wall B vent requires minimum 1" to combustible material.

    Single wall vent requires 6" minimum.
    When correctly installed.


    Quote Originally Posted by Jerry Peck View Post
    Direct vent should not be open where a draft hood should be.
    Cha-Ching!
    We covered that on a previous thread.



    Quote Originally Posted by Jerry Peck View Post
    A bonding jumper is needed from the cold water pipe to the hot water pipe to effectively bond the metal piping system around the water heater.

    If the water heater was electrically supplied in any way, then the water heater would be grounded through that supply.
    I concur.



    Quote Originally Posted by Jerry Peck View Post
    EVERY water heater storage tank - gas, electric, oil, solar, whatever the energy source - is a potential bomb ... which is why all water heater tanks and hot water storage tanks require temperature and pressure relief valves.
    Natural gas as compared to the other water heater energy sources requires extra vigilance...

    https://www.coolray.com/help-guides/...ter-explosions
    http://www.wsoctv.com/news/local/nat...-hous/52186475
    http://www.theplumbinginfo.com/water...-lurking-home/

    I am astonished that occupant's are safe when I go into homes sometimes. Natural gas water heaters can be a real issue as you well know.

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    Default Re: Water Heater Venting

    Quote Originally Posted by ROBERT YOUNG View Post
    Huh?

    Natural gas is less likely to cause an explosion due to accumlation around the water heater and its pilot than Propane (LPG) is because natural gas is lighter than air (rises and dissipates out of the area if there is a way out) where Propane is heavier than air and accumulates from the floor up, reaching its LEL around the pilot flame sooner than with natural gas having to fill the room from the ceiling down - of course, though, filling the room from the ceiling down puts more gas into the equation when the explosion does occur.

    Electric, solar, and I guess oil too, does not have that same risk of the fuel itself exploding due to a leak - so install a gas leak detector at the water heater which shuts off the gas supply when there is a gas leak.

    The main explosive risk with water heaters is due to the thermal power stored in the heated water ... the gas leak explosion risk is the same around any and all gas appliances ... except possibly for the fact that a person may detect the gas smell, and then except for the fact that the person may actually realize what they need to do (turn the gas of and get to heck out of there, and if the smell is strong, call 911 so the fire department arrives and brings their blue canaries).

    Jerry Peck
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    Default Re: Water Heater Venting

    Quote Originally Posted by Jerry Peck View Post
    Huh?

    Natural gas is less likely to cause an explosion due to accumlation around the water heater and its pilot than Propane (LPG) is because natural gas is lighter than air (rises and dissipates out of the area if there is a way out) where Propane is heavier than air and accumulates from the floor up, reaching its LEL around the pilot flame sooner than with natural gas having to fill the room from the ceiling down - of course, though, filling the room from the ceiling down puts more gas into the equation when the explosion does occur.

    Electric, solar, and I guess oil too, does not have that same risk of the fuel itself exploding due to a leak - so install a gas leak detector at the water heater which shuts off the gas supply when there is a gas leak.

    The main explosive risk with water heaters is due to the thermal power stored in the heated water ... the gas leak explosion risk is the same around any and all gas appliances ... except possibly for the fact that a person may detect the gas smell, and then except for the fact that the person may actually realize what they need to do (turn the gas of and get to heck out of there, and if the smell is strong, call 911 so the fire department arrives and brings their blue canaries).
    I stand corrected.
    Gas & LP should have been behind the posts intent.
    Your correct, Jerry.

    I was pointing to electricity being a lever for ignition.
    As always, Thanks.

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    Cool Re: Water Heater Venting

    Without the make, model and serial number, we're all grasping for straws here. Guys, you can NOT properly comment on a combustion appliance's suitability without this information and referring to the listed instructions-period.

    The venting presented here is unfamiliar to me as any approved or listed venting system. First of all, ALL listed venting will have an indelible embossment or marking noting the mfr. and a listing mark such as UL. To determine if the venting is appropriate for this appliance much less installed correctly you need that information. As for the corrosion present, ANY corrosion is a visible defect and sign of other occult issues such as venting failure. The plastic bushings described are there to electrically insulate the pipes from the outer casing as well as contain the foam during mfg.. The dielectric nipples take care of the connection to the tank proper. Yes, any melting of these bushings should be considered a significant sign of defect and investigated.

    There are three approved means of sidewall vent termination: 1) a listed power vented unit with approved venting for positive flue gas pressure, 2) a sidewall termination power venter with a vent pressure sensor interlock to the gas control and 3) a listed co-axial (pipe in a pipe) true direct vent . There are NO applications where a CAT I gravity vented appliance can terminate at the sidewall.

    The listed instructions would determine the clearances to combustibles. In this case, you have combustibles at the band joist penetration and the foam insulation on the hot water pipe off the top of the unit. See the melted insulation? Aside from all that, the venting has no lateral support at the offset . I don't see how the pipe joints are mechanically attached. Listed venting often uses a quarter turn or snap lock mechanism whereas unlisted venting typically requires a minimum of 3 equidistantly spaced screws per joint (more for diameters over 6").

    I suspect this is a larger diameter unlisted pipe rigged up over the draft hood and unlisted single walled vent connector in some half-you know what attempt at shielding the vent to hopefully reduce the clearances to combustibles. If so, this is an unapproved method of venting.

    The use of a mirror at a draft hood is useless. You can get a situation with high draft where the room air being entrained so fast up the draft hood that it actually can block the flue gases causing them to back up and spill out the base of the unit. This is know as "the curtain effect" and one of the problems with draft hoods. There is a method of venting where the draft hood is replaced with a bullhead tee and double acting barometric damper set to the proper draft with a spill switch wired to the thermocouple using a TC interrupter( Field Controls TC-1A) but you need to get this approved by your AHJ. Every time I show this to a new code official it blows his mind but he approves it because it is a much safer design than a draft hood. A mirror failing to fog up could give the false impression of proper venting. Only combustion analysis would verify this.

    Yes, you need a bonding jumper across cold to hot. There should not be any difference in safety btw NG vs LP but some jurisdictions do require WHs in a pan where installed in attics with a drain pipe to outdoors. The most dangerous appliance feature in any home is a draft hood on a gas combustion appliance bar none regardless of fuel. The biggest problem with draft hoods is--they work just as designed.

    Keep the fire in the fireplace.

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    Default Re: Water Heater Venting

    Quote Originally Posted by Bob Harper View Post
    Without the make, model and serial number, we're all grasping for straws here. Guys, you can NOT properly comment on a combustion appliance's suitability without this information and referring to the listed instructions-period.
    Bob, thank you for bringing me back to my senses.
    I should have been reminded of what you are saying when John K. mirrored your sentiment, "Without the make, model, and serial number, we're all grasping at straws here."

    Sorry John. I should have heeded your observation and let the thread carry on without posting.

    Quote Originally Posted by Bob Harper View Post
    The venting presented here is unfamiliar to me as any approved or listed venting system. First of all, ALL listed venting will have an indelible embossment or markings noting the mfr. and a listing mark such as UL. To determine if the venting is appropriate for this appliance much less installed correctly you need that information. As for the corrosion present, ANY corrosion is a visible defect and sign of other occult issues such as venting failure. The plastic bushings described are there to electrically insulate the pipes from the outer casing as well as contain the foam during mfg.. The dielectric nipples take care of the connection to the tank proper. Yes, any melting of these bushings should be considered a significant sign of defect and investigated.

    There are three approved means of sidewall vent termination: 1) a listed power vented unit with approved venting for positive flue gas pressure, 2) a sidewall termination power venter with a vent pressure sensor interlock to the gas control and 3) a listed co-axial (pipe in a pipe) true direct vent . There are NO applications where a CAT I gravity vented appliance can terminate at the sidewall.
    I hope you do not mind if I save this section and the rest of your post.
    If so, just say so. No offense will be taken what so ever.

    Quote Originally Posted by Bob Harper View Post
    The listed instructions would determine the clearances to combustibles. In this case, you have combustibles at the band joist penetration and the foam insulation on the hot water pipe off the top of the unit. See the melted insulation? Aside from all that, the venting has no lateral support at the offset . I don't see how the pipe joints are mechanically attached. Listed venting often uses a quarter turn or snap lock mechanism whereas unlisted venting typically requires a minimum of 3 equidistantly spaced screws per joint (more for diameters over 6").

    I suspect this is a larger diameter unlisted pipe rigged up over the draft hood and unlisted single walled vent connector in some half-you know what attempt at shielding the vent to hopefully reduce the clearances to combustibles. If so, this is an unapproved method of venting.The use of a mirror at a draft hood is useless. You can get a situation with high draft where the room air being entrained so fast up the draft hood that it actually can block the flue gases causing them to back up and spill out the base of the unit. This is know as "the curtain effect" and one of the problems with draft hoods. There is a method of venting where the draft hood is replaced with a bullhead tee and double acting barometric damper set to the proper draft with a spill switch wired to the thermocouple using a TC interrupter( Field Controls TC-1A) but you need to get this approved by your AHJ. Every time I show this to a new code official it blows his mind but he approves it because it is a much safer design than a draft hood. A mirror failing to fog up could give the false impression of proper venting. Only combustion analysis would verify this.
    Questions:
    1: Is mirror testing still worth pursuing when visual signs are apparent?
    2: Is there reasonably priced flue gas and particle measurement equipment one could purchase?
    I know Testo have HVAC and Atmospheric measurement equipment. any recommendations would be greatly appreciated. I am willing to spend up to four figures. I use a Bacharach Leakator 10 but that's the supply end.


    Quote Originally Posted by Bob Harper View Post
    Yes, you need a bonding jumper across cold to hot. There should not be any difference in safety btw NG vs LP but some jurisdictions do require WHs in a pan where installed in attics with a drain pipe to outdoors. The most dangerous appliance feature in any home is a draft hood on a gas combustion appliance bar none regardless of fuel. The biggest problem with draft hoods is--they work just as designed.
    You must have worked in testing laboratories. You have a vast breadth and knowledge of heat-related vented and unvented systems.
    It's no wonder your name gets mentioned in threads such as this.
    Thank you for chiming in.

    I use to pay a fair percentage of time to NG, LP fired equipment and labeling. NG / LP fired water heaters started the drive for answers. Life pulled me away from many quests. It's time to make the time again.
    Thanks Bob!
    Best regards.

    Please take no offense when I say, "You the king mate!"

    Last edited by ROBERT YOUNG; 04-30-2016 at 03:00 AM.
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    Cool Re: Water Heater Venting

    Thanks Robert. Yes, I have spent many hours working in the R&D test labs, working on product recalls and yes, I have the cell phone for the UL manager in my phone.

    Think about what the mirror test reveals. You expect to see nothing normally assuming that if there is a backdraft condition, the water vapor will condense on the mirror. First of all, you would have to encircle the draft hood as backdrafting often occurs only at one narrow band of radii around the draft hood. You could be testing at say 9 O'clock and see nothing while it's pouring out at 2 O'clock due to unsealed return ducts or a clothes dryer in the CAZ. That's why the bullhead tee with double acting barometric damper is so much better. It focuses any backdraft into one direction where one spill switch is usually adequate and reasonable protection. Not so with round draft hoods. Also, the mirror test reveals the presence of water vapor. It fails to confirm spillage of CO or CO2. A combustion analyzer is the proper test instrument used not only down the flue but around the draft hood. A CA uses a pumped sample draw so the sensor tip only needs to get close, unlike an ambient sensor such as that Leakator 10, which just senses hydrocarbon LEL. I got my last combustion analyzer from my local HVAC supply house on sale but there are several reputable HVAC supply houses that sell them along with the accessories such as replacement water filters, O2 and CO sensors, printer paper, etc. along with calibration kits.

    You can purchase a particle counter for the price of a used car but understand their limitations. They sense particulates--not gases. Particulate emission is not always immediate or consistent. It also does not discriminate the type of particle-just the size and count. Thus, you can have someone bump into some dust covered object and have pm2.5 to pm 10 (microns) particulates suspended in air for as much as 8 hours. This can pervert your test. You would need to know a protocol for such testing including control of the environment (no one in or out for a period prior to testing), seal the house up so no massive air leaks, shut off the air handler if present, no dryer, kitchen hood or bathroom fart fans in operation and no upper level leaks such as open windows or attic access. Then you can test something for particulate emissions once you've established a baseline, given a time interval such as one hour and re-tested to confirm the level has stabilized. They can be used in spot tests such as verifying filter efficacy.

    When I investigate alleged "soot" cases, I don't use a particulate counter. I take environmental samples and have them analyzed by a secret test lab that is utterly reputable and reliable having never been beaten in court. Whether my PhD states the presence of particulates or not that could be attributable to the suspected appliance is gospel. Just understand what lab testing can and can not indicate. It can determine the morphology of particles and clusters as to their source or rule out certain sources such as through polarized light microscopy or PLM. Further analysis by gas chromatography with mass spectrometry (gc/mass spec.) can determine the actual compound present in the sample, which can lead you to the source. Elemental analysis such as Scanning Electron Microscopy (SEM) or X-Ray Fluoroscopy (XRF) are just that: they determine what elements are present. For instance, the presence of sulphur in a sample is not proof the particulate was generated by and fugitive from a specific gas appliance. It just means there's sulfur in the sample. If you test with a particle counter, what does that tell you? That there's either a little or a lot of "stuff" in the air. It doesn't tell you exactly what "stuff" or where this "stuff" came from or how it escaped does it? Particle counters seem more appropriate for clean room testing and the like such as Protected Environments for susceptible patients.

    As for testing when visual signs are present, this means you're relying on the patient to get sick enough to present signs and symptoms rather than testing for the presence of a problem before the patient gets sick( sorry for the medical analogy but its a hold-over from my paramedic days). I'd rather screen for a hazardous substance or condition routinely EVERY time so not only do I catch ALL the ones misbehaving while I'm there but I protect myself! If you wait to run an EKG only when the patient complains of his heart skipping or racing, you've missed possibly several years where you could have diagnosed and intervened early on when the prognosis is much better. Same for combustion appliances.

    Note that any testing you perform during an inspection is a snapshot in time and should be clearly noted as such. Your disclaimers should strongly explain that you cannot be held responsible for conditions of use once you leave. Your results were based upon the conditions extent at the time of the test: house condition (occupied vs. empty vs. transition), weather, other tests ongoing, work ongoing, etc. or changes to the equipment of structure once you leave.

    Instruments such as a Leakator 10 have their place. This type of instrument is a survey meter used to localize fugitive combustible hydrocarbon gases down to a level of 20ppm for methane. A TIFF 8800a would only be able to read 500ppm methane so know your equipment and its limits. Always test a sniffer at a range top burner or open a Sharpie pen. You're just looking for an increase in the tick rate above ambient. Try this simple test: turn on your sniffer outdoors and allow it to warm up then adjust the tick rate to about one tick per second. Now, walk into the doorway and listen to it howl. Modern buildings are FULL of hydrocarbon fumes we breathe daily then wonder why our buildings make us sick. Now, locate some pink fiberglass insulation and pour a little clean water on it then approach with the sniffer--it will howl much faster than dry areas adjacent to the spill. Much of this insulation uses urea formaldehyde resin to adhere the fibers together and your sniffer registered on the aldehyde. It can also smell paraldehyde and acetaldehyde in flue gases when CO is being produced by incomplete combustion. Those sniffers can give 'false positives' on greasy fingerprints, mill oils on metal products, thread cutting oil, pipe dope, soap bubble test solutions, detergents, etc.

    I wouldn't get too deeply into testing the air in homes--you won't be able to sleep at night knowing all the crap your body has to battle. Seriously. BTW, until I get a lab report to the contrary, all that soil the homeowner calls "soot" I call "black particulate matter" because we truly don't know what it is, much less where it came from. I'm working on a $60K subrogation case involving a pellet stove. It's a question of what BPM is fly ash from the stove vs household dirt from the kids vs. candle soot and apportion how much of each in the rooms sampled so the parties can discuss comparative negligence and negotiate who pays what. Just because the lab test reveals some fly ash that can be attributed to the pellet stove doesn't mean the stove mfr. is at fault. The stove is clean with no signs of fugitive particulate escapement. We think they failed to use the ash vacuum properly and thus their negligence caused the soiling. There's a lot more to it than it seems.
    HTH and thanks for the kind words Robert. ping me anytime.

    Last edited by Bob Harper; 04-30-2016 at 05:44 PM.
    Keep the fire in the fireplace.

  20. #20
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    Default Re: Water Heater Venting

    Quote Originally Posted by Bob Harper View Post
    Thanks Robert. Yes, I have spent many hours working in the R&D test labs, working on product recalls and yes, I have the cell phone for the UL manager in my phone.

    Think about what the mirror test reveals. You expect to see nothing normally assuming that if there is a backdraft condition, the water vapor will condense on the mirror. First of all, you would have to encircle the draft hood as backdrafting often occurs only at one narrow band of radii around the draft hood. You could be testing at say 9 O'clock and see nothing while it's pouring out at 2 O'clock due to unsealed return ducts or a clothes dryer in the CAZ. That's why the bullhead tee with double acting barometric damper is so much better. It focuses any backdraft into one direction where one spill switch is usually adequate and reasonable protection. Not so with round draft hoods. Also, the mirror test reveals the presence of water vapor. It fails to confirm spillage of CO or CO2. A combustion analyzer is the proper test instrument used not only down the flue but around the draft hood. A CA uses a pumped sample draw so the sensor tip only needs to get close, unlike an ambient sensor such as that Leakator 10, which just senses hydrocarbon LEL. I got my last combustion analyzer from my local HVAC supply house on sale but there are several reputable HVAC supply houses that sell them along with the accessories such as replacement water filters, O2 and CO sensors, printer paper, etc. along with calibration kits.
    I concur. Astute observation and understod.
    I typically operate the water heater to induce drafting. I allow the water heater 3 to 5 minutes to perform prior a vapor test. Senseless as you point out if the appliance is idling.
    I remember the colleague that developed this test method decifered it word for word from a National Geographics hyroglifics from Tuts tomb.

    Gees Louise, I hope he doesn't follow this post.

    Quote Originally Posted by Bob Harper View Post
    You can purchase a particle counter for the price of a used car but understand their limitations. They sense particulates--not gases. Particulate emission is not always immediate or consistent. It also does not discriminate the type of particle-just the size and count. Thus, you can have someone bump into some dust covered object and have pm2.5 to pm 10 (microns) particulates suspended in air for as much as 8 hours. This can pervert your test. You would need to know a protocol for such testing including control of the environment (no one in or out for a period prior to testing), seal the house up so no massive air leaks, shut off the air handler if present, no dryer, kitchen hood or bathroom fart fans in operation and no upper level leaks such as open windows or attic access. Then you can test something for particulate emissions once you've established a baseline, given a time interval such as one hour and re-tested to confirm the level has stabilized. They can be used in spot tests such as verifying filter efficacy.
    I used an incorrect term, particle counter. I know they can be very expensive and as you correctly point out, why walk down that road with a business.

    Quote Originally Posted by Bob Harper View Post
    When I investigate alleged "soot" cases, I don't use a particulate counter. I take environmental samples and have them analyzed by a secret test lab that is utterly reputable and reliable having never been beaten in court. Whether my PhD states the presence of particulates or not that could be attributable to the suspected appliance is gospel. Just understand what lab testing can and can not indicate. It can determine the morphology of particles and clusters as to their source or rule out certain sources such as through polarized light microscopy or PLM. Further analysis by gas chromatography with mass spectrometry (gc/mass spec.) can determine the actual compound present in the sample, which can lead you to the source. Elemental analysis such as Scanning Electron Microscopy (SEM) or X-Ray Fluoroscopy (XRF) are just that: they determine what elements are present. For instance, the presence of sulphur in a sample is not proof the particulate was generated by and fugitive from a specific gas appliance. It just means there's sulfur in the sample. If you test with a particle counter, what does that tell you? That there's either a little or a lot of "stuff" in the air. It doesn't tell you exactly what "stuff" or where this "stuff" came from or how it escaped does it? Particle counters seem more appropriate for clean room testing and the like such as Protected Environments for susceptible patients.
    Chemicals in soot analysis. Of course. Best left to the experts.


    Quote Originally Posted by Bob Harper View Post
    As for testing when visual signs are present, this means you're relying on the patient to get sick enough to present signs and symptoms rather than testing for the presence of a problem before the patient gets sick( sorry for the medical analogy but its a hold-over from my paramedic days). I'd rather screen for a hazardous substance or condition routinely EVERY time so not only do I catch ALL the ones misbehaving while I'm there but I protect myself! If you wait to run an EKG only when the patient complains of his heart skipping or racing, you've missed possibly several years where you could have diagnosed and intervened early on when the prognosis is much better. Same for combustion appliances.
    Well yes and no, Bob. Testing when visual signs are present are the observations we perform without equipment. I see your point about equipment and its limitations.

    Quote Originally Posted by Bob Harper View Post
    Note that any testing you perform during an inspection is a snapshot in time and should be clearly noted as such. Your disclaimers should strongly explain that you cannot be held responsible for conditions of use once you leave. Your results were based upon the conditions extent at the time of the test: house condition (occupied vs. empty vs. transition), weather, other tests ongoing, work ongoing, etc. or changes to the equipment of structure once you leave.
    Thanks!!!

    Quote Originally Posted by Bob Harper View Post
    Instruments such as a Leakator 10 have their place. This type of instrument is a survey meter used to localize fugitive combustible hydrocarbon gases down to a level of 20ppm for methane. A TIFF 8800a would only be able to read 500ppm methane so know your equipment and its limits. Always test a sniffer at a range top burner or open a Sharpie pen. You're just looking for an increase in the tick rate above ambient. Try this simple test: turn on your sniffer outdoors and allow it to warm up then adjust the tick rate to about one tick per second. Now, walk into the doorway and listen to it howl. Modern buildings are FULL of hydrocarbon fumes we breathe daily then wonder why our buildings make us sick. Now, locate some pink fiberglass insulation and pour a little clean water on it then approach with the sniffer--it will howl much faster than dry areas adjacent to the spill. Much of this insulation uses urea formaldehyde resin to adhere the fibers together and your sniffer registered on the aldehyde. It can also smell paraldehyde and acetaldehyde in flue gases when CO is being produced by incomplete combustion. Those sniffers can give 'false positives' on greasy fingerprints, mill oils on metal products, thread cutting oil, pipe dope, soap bubble test solutions, detergents, etc.
    I wouldn't get too deeply into testing the air in homes--you won't be able to sleep at night knowing all the crap your body has to battle. Seriously. BTW, until I get a lab report to the contrary, all that soil the homeowner calls "soot" I call "black particulate matter" because we truly don't know what it is, much less where it came from. I'm working on a $60K subrogation case involving a pellet stove. It's a question of what BPM is fly ash from the stove vs household dirt from the kids vs. candle soot and apportion how much of each in the rooms sampled so the parties can discuss comparative negligence and negotiate who pays what. Just because the lab test reveals some fly ash that can be attributed to the pellet stove doesn't mean the stove mfr. is at fault. The stove is clean with no signs of fugitive particulate escapement. We think they failed to use the ash vacuum properly and thus their negligence caused the soiling. There's a lot more to it than it seems.
    HTH and thanks for the kind words Robert. ping me anytime.
    Thank you, Bob.

    I understand equipment limitations and use them strictly to help determine condition hypothesis.
    I am pursuing company growth, the right team and solid information and suspect will not be investing in this type of test equipment. Thanks!

    Yourself, Jerry, and all the other contributors offer so much. Thanks for the "ping me anytime." Much appreciated, truly.

    Robert Young's Montreal Home Inspection Services Inc.
    Call (514) 489-1887 or (514) 441-3732
    Our Motto; Putting information where you need it most, "In your hands.”

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