lp gas piping

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  • This topic has 12 replies, 5 voices, and was last updated 22 years ago by hj.
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    • #278064

      We are installing a vented gas fireplace. The gas piping is a combination of black pipe [straight run] and ending with a length of gastite flexible tubing [to get through the floor joists to the appliance. The gas feed is coming up through the floor to the side of the unit. Is it still necessary to install a trap? How would it be configured?

    • #297614

      Why would you need a trap ?

    • #297615

      Hi Gerard, years ago some codes required a “drip leg” and the unknowing called it a “TRAP”

      I recently went to a job where it was a case of monkey see monkey do.

      These immigrants from Russia saw drip legs inside a large building complex and decided it would be a fantastic idea to put these outside
      by the gas fired air conditioning systems.

      I couldn’t help but wondering how these fine upstanding citizens would explain to the victims families why they killed so many people when the gas explosion occurred. AND IT WILL NO DOUBT

      I have seen a check valve on natural gas lines cause the tech SAW IT ON AN OIL line thus he figured all fuel lines require them

      I never ask WHY any more when reading anything posted on this gas site I just read the local news papers waiting for the head lines “Building explodes fire marshals investigation continues.

      A few building have blown up over the last few months in NYC and life’s have been lost (3) less than a week ago But hey it makes for interesting reading.

      Once someone has to ask this kind of question JUST sit back and be thankful they do not live next door to you.

      No matter what advice you give your wrong so just play the wait and see game.

      Gas KILLS so do improper appliance hook ups. So rather then get involved Just sit back and enjoy the questions and answers given.

      Make believe these same question’s are the same type they would ask their doctors.

      “Hey Doc I have this severe pain in my chest and stomach should I just take an aspirin” WAIT and see is the only way to keep out of trouble on gas related topics.

      Have a great week end guy and read the newspapers for the BIG BOOM!!!

      The reason Gerard WE professionals cannot answer this kind of question is.

      1- We do not know the actual BTU input of this appliance

      2- We do n NOT know the heating Value of thier local “gas ” supplier

      3- We do NOT know the actual pipe sizing they are talking about

      4- We do not know the developed lenth of piping and fittings

      5- We do not know what the MEA approval number of the fire place is?

      We have no idea if it has a standing pilot light or electronic ignition

      We have no idea of the “free air” available for proper combustion

      So with all these unknown factors lets just wait and see what happens LISTEN to your local news reports and have fun Gerard and enjoy.

    • #297616

      dont see why you whould need one we dont put traps on flex lines in alabamaltho i have seen flakes build up on copper when iv’e taken them apart and wonder should we put traps on copper.but code wise we dont have to.

    • #297617

      More important than a trap is a shutoff valve. Is this a free-standing or built in fireplace. If it is free standing then the steel pipe should be brought through the floor with a shut-off valve and then a connection to the fireplace. The flextite piping should not be used in this installation. If it is a liner for a built in fireplace, then the flexible pipe should be run to a wall shut off valve within three feet of the fire chamber and then steel pipe run from the shut-off to the burner. From your description, and it could just be because it is incomplete, it appears that you may not be making a safe or legal installation.

    • #297618

      Thank you to all that replied. I was especially excited to read Sylvan reply since from his other posts I knew he would spout generalities that have nothing to do with the question. I think it has been said before lighten up!!

      Let me explain the situation further.
      1. I am not an idiot with a death wish.
      2. I have over 25 years in the construction trades.
      3. I had a heating contractor install LP tank and furnace and pipe for dryer and stove.
      4. I had him leave me a tee to allow for a future fireplace. { no sylvan he was not a master gasfitter, but a licensed plumber}
      5. I ran black pipe then some flexible gastite up through the floor.
      6. The fireplace is a Majestic drv33, installed according to their specifications.

      Under the unit in an accessible via a flip down panel area is a hard piped gas valve, a union and a elbow that leads into the area where the gastite flexible pipe comes up through the floor. My question was can I hook directly into the hard pipe at floor level or do I need to go vertically and then horizontally [with a drip leg] and then back down to the hard piping that runs into the appliance.
      I am simply making a mechanical connection of piping and am inquiring about a situation that I want to be technically correct so that when the inspector comes it will be properly done. I’m not piping a powerplant or anything. Yes I know that gas is dangerous, I read the disclaimer on this bulletin board. But the world is not a quaranteed safe place and you have to take responsibility for your own actions. I am confident in my mechanical abilities, I am aware of safety precautions. I have seen some pretty crappy piping jobs done by “qualified people”. Just remember “the ark was built by amateurs, professionals built the Titanic.”

    • #297619

      M sorry Gerry I am so used to hearing from brain dead folks like “Jack” and his home center mentality that I did over react.

      Ok when you told your LMP your going to install a fire place did you give him/her any idea of the BTU input rating?

      Another thing is HJ is 1 million percent correct with the use of flexible piping as opposed to the black steel going through a floor

      About the manufacturers reccommendations read the fine print where it sayslocal codes will prevail.

      Now as for your 25 years in the construction trades Fantastic as I was a roofer/plumber/welder/shipfitter/stationary engineer/ general contractor and IM STILL learning everyday.

      For your peace of mind in the future you should have a local plumbing code book so you know if the installing plumber is following the LOCAL code in the area.

      I feel HJ is also correct with the location of shut off valve (approved ball type gas valves are GREAT)

      OK Gerry now REMEMBER local codes prevail ok? I am NOT second guessing your LMP or YOUR mechanical abilities

      . “My question was can I hook directly into the hard pipe at floor level or do I need to go vertically and then horizontally [with a drip leg] and then back down to the hard piping that runs into the appliance”

      If your coming up through the floor YOU can place the drip leg ( IF REQUIRED) below the floor in the basement. Picture a “T” the drip leg would be on the “run” of the tee the straight through part not the middle (bull) connection so your drip leg would be normaly the vertical part with a cap on it from the bottom of the run ??? I hope you got what I said

      The purpose of the drip was intended to catch moisture in natural gas as manufactured gas is drier. This drip leg was placed on piping either going vertical OR suppose you had gas lines in the ceiling and you supplying gas to a hot water heater in the basement? The piping drop would require a drip leg as condensation could be supplied to the heater and thus extinguishing the flame and the drip leg would catch this before it could cause problems.

      My original post had to deal with a little bit on knowledge as these “Jack” leg mentalities had installed DRIP LEGS outside of a commercial building not realizing IF there was moisture in the winter these lines could freeze RUPTURE and allow the gas to be brought back into the building via the heating/AC system.

      I personally try to use black steel schedule on all my gas piping and use a left and right nipple and coupling in lieu of a union as JACK (legs) will try to play with them causing a leak.

      After the piping is installed PRIOR to final hook up I strongly suggest you pressure test all piping with “AIR.” Gerry if you have any questions please feel free to send me an E mail and your more then welcome to join my plumbers discussion group.

      We not only have a full fledged chemist on the list (he owns a drain cleaning company) we have engineers and manufacturers.
      Your more then welcome to post Questions and answeres and become an active member. Have a great one

      US GC’s have to stick together LOL

    • #297620

      The great thing about these forums or bulletin boards is that as you sit in your pajamas you can tap into a vast quality of experience and information. The thing that precipitated my post was that I was getting conflicting advice about drip legs. Plus I tend to over analysis things and like to know the reasoning behind things. I was of the opinion that the trap was there to capture moisture not flecks of pipe as one person told me. And if the drip leg is there to catch something, since they have not yet suspended the laws of gravity how would this work if you feed up into an appliance. Since I don’t have access to the national gas pipe code I decided to toss it out in a forum to get other opinions. Sylvan was the first person to address what is the drip leg’s purpose. “The purpose of the drip was intended to catch moisture in natural gas as manufactured gas is drier.” Does this mean that drips are not as necessary in LP systems as they are in natural gas but the code still requires them? As for the admonition that local codes could override national code, I live in a town that is lightly regulated. I feel better knowing that I made sure the piping was correct rather than the cursory inspection that I will get from the town inspector.
      I have a problem with Sylvan’s solution to place the drip leg under the floor because the room is on piers and the floor system [2×12’s] will be insulated and closed in. The drip leg would not be accessible and it would be in a cold space. And here we come back to my original question? Does the gas code require a drip on every appliance reguardless of how it is fed?

      PS. I agree with Sylvan I briefly worked for an Internet site that catered to the do-it yourselfer and you would not believe the questions that we got. Unfortunately due to the fact that the site never made any money and I could not conceive how it ever would have made money, here I am running and hooking up the gas line myself. Anybody want some worthless stock options?

    • #297621

      Your installation instructions and local codes will prevail, but in my area a gas fireplace requires an external shutoff valve within three feet of the fireplace so that the gas supply can be terminated in the event of a failure in the fireplace. In this case, a shutoff in the area beneath the fireplace would not comply with this regulation since that could be where the fire is located. Drip legs were required when gas had a lot of impurities. Some manufacturers still show them, especially with LP gas supplied from overhead since the lp orifices are very small and can plug up easily. A supply from below the floor should not need one since the sedimentation will take place in the pipe under the floor.

    • #297622

      Hey Gerry, I posted your latest inquiry on my plumbers discussion list as I use strictly gas supplied from a utility. These folks are from all over the world and hopefully someone can give us the right answer as to LP and drip legs.

      About local codes prevailing over the national code I have found most code authorities take the more stringent code as the National is the bare minimum (in most cases)

      As a GC I would be honored if you did join the plumbers/drainers/gas fitters/ fire suppression piping contractors list as it would give us both insight on the problems facing both sides of the fence. You can E mail privately and we will send you an invite

      The only reason I went and became my own GC was I could not depend on other trades to show up when scheduled so I actually hired my own licensed master electrician, carpenters, tile men, etc., and the rest is history.

      There is one other local source you could contact in the mean time and that is your gas supplier as they should have an available copy of the National fuel gas code

      Hey HJ one question regarding your statement. If you know that impurties are present like the cutting oils or pieces of threaded pipe are present you said below

      “. A supply from below the floor should not need one since the sedimentation will take place in the pipe under the floor.”

      Ok if the piping is under the floor and it becomes blocked with “sedimentation” how do you clear this non exposed piping when it gets completly blocked?

    • #297623

      Gerry, sorry. I states in gas codes that flexible piping cannot penitrate any walls, partions, or ceiling. If it were to penitrate the walls, floors,etc.. it would need a sleeve to provide protection. I would be of the opinion that you should provide a drip leg and run ridge pipe up through the floor and provide a drip leg for the appliance. Its true not all installers are true professionals but it will not negate the liability of all when it is not installed to the manufacturers installation requirements regardless of the inspectors opinion. And thats all he has is an opinion, as all codes in the US state the inspectors is not liabile for his inspections, just the installer. good luck.

    • #297624

      additionally, a lot of states require you to have a LP fitters lisence or LP contractors lisence to be installing gas for LP appliances.

    • #297625

      I was not referring to materials left by poor mechanics. I was referring to flaking due to corrosion on the interior of the pipe. The sediment in a pipe dropping from the attic would gravitate to the gas valve without a trap leg. In an upfeed system, the sedimentation will tend to stay in the pipe and not be carried to the appliance. I hope the idea of gravity is not too complex for you.

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