Results 1 to 31 of 31
  1. #1
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Un-vented gas logs in sealed fireplace.

    I inspected a home today that the chimney has been sealed at the damper and at the cap. Un-vented gas logs are installed and the seller said this was recommended by the local gas log supplier. (don't ask me who that is) I think I remember a thread where it was stated that unvented logs are not listed for installation in a masonry fireplace. Though I would not want un-vented gas logs in my home, I can not come up with a good reason that it should not be done other than possible listing problem. Any help with a valid argument appreciated.

    Similar Threads:
    Member Benefits1
    The beatings will continue until morale has improved. mgt.

  2. #2
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Hi Vern,

    Surely the Manufacturers Installation Instructions as "Required" were with the Gas Appliance.

    These Factory Manufacturers Installation Instructions would state you could Willey Nilley change and or block a fire place and Safely install their Gas Appliance.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  3. #3
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    Hi Vern,

    Surely the Manufacturers Installation Instructions as "Required" were with the Gas Appliance.

    These Factory Manufacturers Installation Instructions would state you could Willey Nilley change and or block a fire place and Safely install their Gas Appliance.
    Billy, my goal is to have an argument that somehow supports the idea that having the unvented gas logs installed in a masonry fireplace is less safe than being installed in a sheet metal box.

    The beatings will continue until morale has improved. mgt.

  4. #4
    Join Date
    Aug 2011
    Location
    Bennett (Denver metro), Colorado
    Posts
    1,394

    Default Re: Un-vented gas logs in sealed fireplace.

    Unvented gas sets and fireplaces are not allowed around here. Past experience has found that the flame will fall out of perfect tune and start throwing CO, etc. Regular tuning and tweaking is required to maintain a perfect flame.

    Personally, I hate a blue flame in a fireplace. They're hard to see at night and invisible in daylight. I like an dirty yellow flame in a gas fireplace simply because you can see them.

    If you choose not to decide, you still have made a choice.

  5. #5
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Vern Heiler View Post
    Billy, my goal is to have an argument that somehow supports the idea that having the unvented gas logs installed in a masonry fireplace is less safe than being installed in a sheet metal box.
    Not Installed per Manufactures Installation Instructions.

    Not tested nor Rated as installed it is a carbon monoxide hazard.

    Heck even if you Stack the Logs differently than Instructions ( Tested ) they can be a Hazard.

    I don't know what kind of argument you need?

    Remove Gas Logs as installed they are a Safety Hazard.

    The Same would be true if "the sheet metal box" was not tested and Approved for the Gas Appliance.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  6. #6
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    Not Installed per Manufactures Installation Instructions.

    Not tested nor Rated as installed it is a carbon monoxide hazard.

    Heck even if you Stack the Logs differently than Instructions ( Tested ) they can be a Hazard.

    I don't know what kind of argument you need?

    Remove Gas Logs as installed they are a Safety Hazard.

    The Same would be true if "the sheet metal box" was not tested and Approved for the Gas Appliance.
    Agree that stacking of the logs can change the flame and be CO2 hazard. It is a little harder to explain that the box it is installed in, even though made of a more durable material with much higher fire resistance, can change anything about the flame or be more unsafe than the "listed" sheet metal. Give me something more than, the mfg. has not tried it in this particular fireplace.

    I guess what I need is a well worded disclaimer stating I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved.

    Last edited by Vern Heiler; 03-24-2015 at 06:40 PM.
    The beatings will continue until morale has improved. mgt.

  7. #7
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Vern Heiler View Post
    Agree that stacking of the logs can change the flame and be CO2 hazard. It is a little harder to explain that the box it is installed in, even though made of a more durable material with much higher fire resistance, can change anything about the flame or be more unsafe than the "listed" sheet metal. Give me something more than, the mfg. has not tried it in this particular fireplace.

    I guess what I need is a well worded disclaimer stating I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved.
    The "listed" sheet metal is of a size and shape to help the Vent less Gas Appliance not emit a dangerous level of gases. The altered masonry fire box ruff surface odd shapes meant for the burning of Solid fuel can and will disrupt the efficient combustion of the vent less gas appliance.

    Remove improperly installed Gas appliance located in the masonry fire box as it is a Safety Hazard.
    *it really is that simple.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  8. #8
    Join Date
    Mar 2012
    Location
    Lansdale, PA
    Posts
    876

    Default Re: Un-vented gas logs in sealed fireplace.

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    http://monessenhearth.com/family/Gas-Log-Sets/Vent-Free/Mojo/

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    http://monessenhearth.com/family/Gas-Log-Sets/Vent-Free/Mojo/

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    http://monessenhearth.com/family/Gas-Log-Sets/Vent-Free/Mojo/

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    http://monessenhearth.com/family/Gas-Log-Sets/Vent-Free/Mojo/


  9. #9
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Mark Reinmiller View Post
    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth
    Thanks Mark.

    The beatings will continue until morale has improved. mgt.

  10. #10
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    [QUOTE=Mark Reinmiller;255820]I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces. [quote]

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth [QUOTE/]

    - - - Updated - - -
    [quote]Yes and please read these http://literature.mhsc.com/monessen/...024_MJ27_4.pdf Before Masonry Fire Places Get the okey Dookey.[quote/]

    - - - Updated - - -

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  11. #11
    Join Date
    Mar 2010
    Location
    Prescott, AZ
    Posts
    91

    Default Re: Un-vented gas logs in sealed fireplace.

    An unvented gas log kit in a masonry fireplace. Dumb and dangerous. Then block the damper closed. Extremely dumb and extremely dangerous. I actually saw that once. I called it out as unsafe. The seller called out our local gas gas company to prove me wrong. They not only red-tagged the fireplace, they shut the gas off and put a lock on the meter valve until the fireplace was removed and the chimney uncapped.

    The only unvented gas appliance I would have in my home is a cooking range. I know some of the 'blue flame' wall heaters are pretty safe. But any 'fireplace' where the flame is not solid blue is giving off a lot of carbon monoxide. If that CO is not going outside.....

    You need a good reason to write this up? Here's what I do. Close all doors and windows, turn on all exhaust fans, light that fireplace, pull out the Monoxor II and take a picture of the CO in front of the fireplace.

    I have not failed. I've just found 10,000 ways that won't work. (Thomas Edison)

  12. #12
    Join Date
    Oct 2012
    Location
    Massacusetts
    Posts
    149

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Randy West View Post
    An unvented gas log kit in a masonry fireplace. Dumb and dangerous. Then block the damper closed. Extremely dumb and extremely dangerous. I actually saw that once. I called it out as unsafe. The seller called out our local gas gas company to prove me wrong. They not only red-tagged the fireplace, they shut the gas off and put a lock on the meter valve until the fireplace was removed and the chimney uncapped.

    The only unvented gas appliance I would have in my home is a cooking range. I know some of the 'blue flame' wall heaters are pretty safe. But any 'fireplace' where the flame is not solid blue is giving off a lot of carbon monoxide. If that CO is not going outside.....

    You need a good reason to write this up? Here's what I do. Close all doors and windows, turn on all exhaust fans, light that fireplace, pull out the Monoxor II and take a picture of the CO in front of the fireplace.

    I do believe Mr. West has a brilliant suggestion. List it as unsafe and recommend having the gas company or local fire department check it - if they don't like it - they will red tag it and shut off the gas (if possible). I recently did this to a class mate of mine who had returned home from India and complained the heating system wasn't heating the house over 40 deg - I knew something was up but she would hear non of it so I suggested she have the local fire department come out and check it -findings : no wall left between fire box and air handling system - I wan't the bad guy - OK her husband is pissed at me (he is from India) and now has to spend $ 15 -20 K on a heating system but they are alive and will stay alive despite the ignorance


  13. #13
    Join Date
    Mar 2007
    Location
    Knoxville, TN
    Posts
    2,445

    Default Re: Un-vented gas logs in sealed fireplace.

    Vern,
    You already have what you need to put in the report.. "I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved."

    No need to cite specifics. Its not a normal installation, so it should be checked out by an "expert" with gas logs. This is where you call out for further evaluation by someone that knows more than you do about gas logs.

    - - - Updated - - -

    Vern,
    You already have what you need to put in the report.. "I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved."

    No need to cite specifics. Its not a normal installation, so it should be checked out by an "expert" with gas logs. This is where you call out for further evaluation by someone that knows more than you do about gas logs.

    - - - Updated - - -

    Vern,
    You already have what you need to put in the report.. "I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved."

    No need to cite specifics. Its not a normal installation, so it should be checked out by an "expert" with gas logs. This is where you call out for further evaluation by someone that knows more than you do about gas logs.


  14. #14
    Join Date
    Feb 2013
    Location
    NY
    Posts
    48

    Default Re: Un-vented gas logs in sealed fireplace.

    [QUOTE=Billy Stephens;255822][QUOTE=Mark Reinmiller;255820]I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces. [quote]

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth [QUOTE/]

    - - - Updated - - -
    Yes and please read these http://literature.mhsc.com/monessen/...024_MJ27_4.pdf Before Masonry Fire Places Get the okey Dookey.[quote/]

    - - - Updated - - -
    Your opinions don't take precedence over a manufactures testing and certification. Now the recommendation of a co detector in close proximity can't be argued with.


  15. #15
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    [QUOTE=Phil brody;255839][QUOTE=Billy Stephens;255822][QUOTE=Mark Reinmiller;255820]I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth

    - - - Updated - - -

    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth [QUOTE/]

    - - - Updated - - -


    Your opinions don't take precedence over a manufactures testing and certification. Now the recommendation of a co detector in close proximity can't be argued with.
    That's the Point The Manufacturer would NEVER approve an altered solid fuel firebox for their products installation.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  16. #16
    Join Date
    Dec 2007
    Location
    Holladay, UT
    Posts
    565

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Mark Reinmiller View Post
    I am not a big fan of unvented gas logs, but I have never heard that they are not permitted in masonry fireplaces. I just thought I would take a look at some instructions. Before I got that far, the first link I clicked on said it was a good choice for masonry fireplaces.

    So don't assume they are not permitted unless you know for sure.

    Mojo Vent Free Gas Log Sets by Monessen Hearth
    I don't quite understand this log set posted. The description says realistic flame picture.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah

  17. #17
    Dennis Webber's Avatar
    Dennis Webber Guest

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Vern Heiler View Post
    I inspected a home today that the chimney has been sealed at the damper and at the cap. Un-vented gas logs are installed and the seller said this was recommended by the local gas log supplier. (don't ask me who that is) I think I remember a thread where it was stated that unvented logs are not listed for installation in a masonry fireplace. Though I would not want un-vented gas logs in my home, I can not come up with a good reason that it should not be done other than possible listing problem. Any help with a valid argument appreciated.
    You hit the nail on the head. They are not listed for installation in a masonry fireplace. (Creates too much CO).

    If you decide to allow it, make certain they install a "permanent", Carbon Monoxide alarm nearby (same room). Personally I would prefer a CO/smoke combo alarm.

    Also, I would NOT allow in a sleeping room (for obvious reasons).


  18. #18
    Join Date
    Mar 2012
    Location
    Lansdale, PA
    Posts
    876

    Default Re: Un-vented gas logs in sealed fireplace.

    I get that people hate these things. I do too. But do we as home inspectors decide to tell a homeowner that their gas log should be removed because we think it is unsafe?

    This assumes that the gas log is approved for that use. What part of the statement below says that this particular gas log cannot be used in a masony fireplace?

    "This appliance is for installation only in a solid-fuel burning masonry orUL127 factory-built fireplace, vent free appliance, or in listed ventlessfirebox enclosure. It has been design certified for these installations."


  19. #19
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Vern Heiler View Post
    I inspected a home today that the chimney has been sealed at the damper and at the cap.
    Quote Originally Posted by Mark Reinmiller View Post
    I get that people hate these things. I do too. But do we as home inspectors decide to tell a homeowner that their gas log should be removed because we think it is unsafe?

    This assumes that the gas log is approved for that use. What part of the statement below says that this particular gas log cannot be used in a masony fireplace?

    "This appliance is for installation only in a solid-fuel burning masonry orUL127 factory-built fireplace, vent free appliance, or in listed ventlessfirebox enclosure. It has been design certified for these installations."
    This Statement does not endorse all masonry fireboxes as useable the Installation Instructions http://literature.mhsc.com/monessen/...024_MJ27_4.pdf has very specific size limits.
    Ever seen the old coal fireplaces that were very small and shallow? Or Estate size fireplaces a small tree would fit in.

    Once you start altering the fire box ( aka damper and cap were sealed) you alter the listing and there is No Certification for the gas appliance.

    No Certification of use means it's no longer safe and there for a Safety Hazard.

    If The Home Owner decides to us the unlisted gas appliance and someone is injured,has long term health issues or dies then as a Home Inspector I wouldn't want to take that call.

    Of course you are free to conduct your business as you see fit.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  20. #20
    Join Date
    Mar 2007
    Location
    Near Philly, Pa.
    Posts
    1,643

    Cool Re: Un-vented gas logs in sealed fireplace.

    Wow! A LOT of mis-information on VF logs here. VF logs were tested and listed for use in an 'approved' masonry fireplace and ONLY those factory built fireplaces that have the optional listing under UL 127 for VF or a listed VF universal box. The mfr. is allowed to specify what constitutes a suitable fireplace as is the AHJ. If the mfr. states the fireplace must comply with NFPA 211, then you'd better perform a level II inspection or you're out on a limb and very, very few Fps can pass that inspection. Note that no one has tested VF fireplaces in a code approved masonry fireplace-it is an assumption by ANSIZ21.11.2b that a fireplace suitable for open hearth woodburning would be ok as a VF, which can be a huge mistake. When you close the damper, you lose the cooling effect of that 400-600CFM of air up the chimney so the surrounding masonry gets very hot. We don't know how hot because it is not a tested, listed fireplace. It is ASSumed to be ok. If you install the logs too far forwards, too much radiant heat can project onto the hearth extension and surrounding combustibles. Note the vastly increased clearance requirements to the mantel--usually min. 14" unless a big, ugly 4" canopy is installed across the opening at the lintel.
    FYI, ANSI allows 200 ppm CO on an AF basis for ventfree.

    Now, I personally do not believe in VF and refuse to install them. I have seen and investigated many cases where there was a problem with emissions (both particulate and gaseous) as well as heat damage. However, you can't call something out based off opinion. Arm yourself with the facts.

    Dale Feb's FIRE course below is the best source of training to learn these concepts in my opinion.

    Keep the fire in the fireplace.

  21. #21
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Bob Harper View Post
    Wow! A LOT of mis-information on VF logs here. VF logs were tested and listed for use in an 'approved' masonry fireplace and ONLY those factory built fireplaces that have the optional listing under UL 127 for VF or a listed VF universal box. The mfr. is allowed to specify what constitutes a suitable fireplace as is the AHJ. If the mfr. states the fireplace must comply with NFPA 211, then you'd better perform a level II inspection or you're out on a limb and very, very few Fps can pass that inspection. Note that no one has tested VF fireplaces in a code approved masonry fireplace-it is an assumption by ANSIZ21.11.2b that a fireplace suitable for open hearth woodburning would be ok as a VF, which can be a huge mistake. When you close the damper, you lose the cooling effect of that 400-600CFM of air up the chimney so the surrounding masonry gets very hot. We don't know how hot because it is not a tested, listed fireplace. It is ASSumed to be ok. If you install the logs too far forwards, too much radiant heat can project onto the hearth extension and surrounding combustibles. Note the vastly increased clearance requirements to the mantel--usually min. 14" unless a big, ugly 4" canopy is installed across the opening at the lintel.
    FYI, ANSI allows 200 ppm CO on an AF basis for ventfree.

    Now, I personally do not believe in VF and refuse to install them. I have seen and investigated many cases where there was a problem with emissions (both particulate and gaseous) as well as heat damage. However, you can't call something out based off opinion. Arm yourself with the facts.

    Dale Feb's FIRE course below is the best source of training to learn these concepts in my opinion.
    Bob,
    In a different life I worked with Engineers of Gas logs at the Manufactures Level and have seen some of the difficulties they encountered to obtain a design specific listing. The slightest nuance in log placement spacing can fail a design.

    High stakes smoke and mirrors.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  22. #22
    Join Date
    Mar 2010
    Location
    Prescott, AZ
    Posts
    91

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Bob Harper View Post
    Wow! A LOT of mis-information on VF logs here. VF logs were tested and listed for use in an 'approved' masonry fireplace and ONLY those factory built fireplaces that have the optional listing under UL 127 for VF or a listed VF universal box. The mfr. is allowed to specify what constitutes a suitable fireplace as is the AHJ. If the mfr. states the fireplace must comply with NFPA 211, then you'd better perform a level II inspection or you're out on a limb and very, very few Fps can pass that inspection. Note that no one has tested VF fireplaces in a code approved masonry fireplace-it is an assumption by ANSIZ21.11.2b that a fireplace suitable for open hearth woodburning would be ok as a VF, which can be a huge mistake. When you close the damper, you lose the cooling effect of that 400-600CFM of air up the chimney so the surrounding masonry gets very hot. We don't know how hot because it is not a tested, listed fireplace. It is ASSumed to be ok. If you install the logs too far forwards, too much radiant heat can project onto the hearth extension and surrounding combustibles. Note the vastly increased clearance requirements to the mantel--usually min. 14" unless a big, ugly 4" canopy is installed across the opening at the lintel.
    FYI, ANSI allows 200 ppm CO on an AF basis for ventfree.

    Now, I personally do not believe in VF and refuse to install them. I have seen and investigated many cases where there was a problem with emissions (both particulate and gaseous) as well as heat damage. However, you can't call something out based off opinion. Arm yourself with the facts.

    Dale Feb's FIRE course below is the best source of training to learn these concepts in my opinion.


    Knowing the ANSI and NFPA numbers is great, but not relevant in most home inspections. Most of the time we cannot see exactly what model a gas log kit is, vented or unvented. An improper gas log kit installed in a masonry or preman fireplace can still cause co in the home, even with the damper clamped fully open. If I see something that I know is wrong I can say it. But I stick with my earlier post- close doors and windows, turn on exhaust fans, check in front of the fireplace with a good co tester. Who cares if there is nothing "wrong" if there is co coming into the home? And no fireplace contractor is going to argue with you when there is a photo in the report of co entering the home. The liability is now on them, so they will make sure it's safe, which is what you want for your client.

    The photo is from today's inspection. This was a vented gas only fireplace. It gave off a 'dusty' odor in addition to the co. The seller stated it started 'smelling' 5 years ago and she had not used it since. I suspect there is an obstruction in the vent pipe, but I don't care what the cause is. It's unsafe and I recommended an appropriate contractor. (I turned off the burner at 37 ppm, the co level was still going up and so was the odor.)

    I inspected a brand new home once with a log kit in a preman woodburner. Got co in the home. Builder said I was nuts, went back out and proved it to him. He had the Superior (I believe) rep come out, and all that was wrong was the logs were not installed/aligned properly, as another poster noted. You would never be able to tell that by looking.

    Here in Northern AZ the gas company will red tag ANY unvented fireplace. They allow it in Phoenix, but not above 2000' elevation.

    And the real test----- What would you tell you Mom or sister if she was buying that house?


    IMG_2938.JPG

    I have not failed. I've just found 10,000 ways that won't work. (Thomas Edison)

  23. #23

    Default Re: Un-vented gas logs in sealed fireplace.

    Lots of good information on this thread.

    Primary point, avoid vent-free appliances where possible. These rules also apply to ranges and stoves.

    but if you do install a vent fee appliance, there are lots of rules:


    1. cannot be installed in bedrooms if over 10,000 btu/hr input Per applicable NFPA (Appendix C), International Building Code (IBC), International Residential
      Code (IRC) (2407.5), and Uniform Mechanical Code (UMC) (701.2) building codes, an unvented
      gas appliance shall not have an input rating of 10,000 Btu/hr in a bedroom nor exceed the minimum
      required volume of 50 ft3 per 1,000 Btu/hr of input rating.



    2. the room of installation cannot be a "confined space". “Confined spaces” are defined as any enclosed space that have 50 ft3 of volume or less for every

      1000 Btu/hr of fuel being consumed utilizing the confined space’s air.
    3. some method (i.e. cracking open a window) providing at least 4 SCFH of fresh outside air for every 1,000 Btu/hr input Note that according to the Canadian Standards Association (CSA), ventilation should be four times greater per 1,000 Btu/hr for unvented appliances than for vented appliances. The reason being that unvented appliances do not draw outside air into the apartment or house whereas, vented appliances create the infiltration of outside air to replace the vented flue gases.

    4. the manufacturer dictates if the appliance can be installed in a masonry housing.
    5. a vent-free appliance cannot be used as a primary heating device!
    6. vent-free appliances sucks out the oxygen and replaces it with CO2 and water vapor. Not good! High relative humidity (over 50%) caused accelerated mold growth and excessive condensation on cold surfaces (i.e. interior surfaces of exterior closet walls & windows) Some people have died from lack of oxygen and high CO2 and not from CO poisoning.
    7. CO monitor in the room recommended.
    8. Low oxygen shutoff of appliance recommended.

    Just list these hazards with your report.

    MAS


  24. #24
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Mark Sokalski View Post
    .

    1. the manufacturer dictates if the appliance can be installed in a masonry housing.
    The Listing determines installation.The Manufacture submits designs and if they want an enhanced Listing to encompass more types of fire boxes requires a design change and additional testing.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  25. #25
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,245

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    The Listing determines installation.The Manufacture submits designs and if they want an enhanced Listing to encompass more types of fire boxes requires a design change and additional testing.
    Yeppers ... read the metal tag chained to the gas log set.

    There are reasons that tag is metal and why it is chained to the gas log set.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  26. #26
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Jerry Peck View Post
    Yeppers ... read the metal tag chained to the gas log set.

    There are reasons that tag is metal and why it is chained to the gas log set.
    The metal listing tag is typically under the log set and decorative lava stone etc. As said; moving the logs can change the burn characteristics of the flame and create CO. So I am sticking with disclaiming unvented logs in masonry fireplaces rather than move any part of the setup.

    The beatings will continue until morale has improved. mgt.

  27. #27
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Vern Heiler View Post
    The metal listing tag is typically under the log set and decorative lava stone etc. As said; moving the logs can change the burn characteristics of the flame and create CO. So I am sticking with disclaiming unvented logs in masonry fireplaces rather than move any part of the setup.
    Disclaimed how? Didn't see em. Ask the Gas Guy. HO says Okey Dokey.

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  28. #28
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    Disclaimed how? Didn't see em. Ask the Gas Guy. HO says Okey Dokey.
    Still working on final boiler plate but; "I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved. Recommend further evaluation by qualified gas log contractor."

    The beatings will continue until morale has improved. mgt.

  29. #29
    Join Date
    Aug 2007
    Location
    Memphis TN.
    Posts
    4,311

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    Disclaimed how? Didn't see em. Ask the Gas Guy. HO says Okey Dokey.
    Quote Originally Posted by Vern Heiler View Post
    Still working on final boiler plate but; "I did not have the installation instructions or Mfg. specs. and don't know if the logs are or are not approved. Recommend further evaluation by qualified gas log contractor."
    So B: Ask the Gas Guy.
    *what if they actually have the Required installation instructions retained with the Gas Appliance?

    It Might have Choked Artie But it ain't gone'a choke Stymie! Our Gang " The Pooch " (1932)
    Billy J. Stephens HI Service Memphis TN.

  30. #30
    Join Date
    Mar 2008
    Location
    Charlotte NC
    Posts
    2,303

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Billy Stephens View Post
    So B: Ask the Gas Guy.
    *what if they actually have the Required installation instructions retained with the Gas Appliance?
    If the installation instructions are laid out at the hearth, there is no question. But I'm not holding my breath for that to happen.

    The beatings will continue until morale has improved. mgt.

  31. #31
    Join Date
    Mar 2012
    Location
    Lansdale, PA
    Posts
    876

    Default Re: Un-vented gas logs in sealed fireplace.

    Quote Originally Posted by Bob Harper View Post
    Wow! A LOT of mis-information on VF logs here. VF logs were tested and listed for use in an 'approved' masonry fireplace and ONLY those factory built fireplaces that have the optional listing under UL 127 for VF or a listed VF universal box. The mfr. is allowed to specify what constitutes a suitable fireplace as is the AHJ. If the mfr. states the fireplace must comply with NFPA 211, then you'd better perform a level II inspection or you're out on a limb and very, very few Fps can pass that inspection. Note that no one has tested VF fireplaces in a code approved masonry fireplace-it is an assumption by ANSIZ21.11.2b that a fireplace suitable for open hearth woodburning would be ok as a VF, which can be a huge mistake. When you close the damper, you lose the cooling effect of that 400-600CFM of air up the chimney so the surrounding masonry gets very hot. We don't know how hot because it is not a tested, listed fireplace. It is ASSumed to be ok. If you install the logs too far forwards, too much radiant heat can project onto the hearth extension and surrounding combustibles. Note the vastly increased clearance requirements to the mantel--usually min. 14" unless a big, ugly 4" canopy is installed across the opening at the lintel.
    FYI, ANSI allows 200 ppm CO on an AF basis for ventfree.

    Now, I personally do not believe in VF and refuse to install them. I have seen and investigated many cases where there was a problem with emissions (both particulate and gaseous) as well as heat damage. However, you can't call something out based off opinion. Arm yourself with the facts.

    Dale Feb's FIRE course below is the best source of training to learn these concepts in my opinion.
    Bob, Thank you! We are all entitled to hate things and not recommend them. I don't think we are entitled to tell people something is unsafe and should be removed if that thing is approved by the manufacturer (unless we clearly state that it is our opinion and not fact).


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •