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Fire Dpt. Says Nat. Gas. Engine Generator Not Emergency

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    Fire Dpt. Says Nat. Gas. Engine Generator Not Emergency

    This came out of left field, but I was informed by my GC that they were told by the fire dpt. that a Natural Gas generator is not considered emergency and only a Diesel generator can be considered emergency.

    I've never heard of this anywhere in any local state or national codes. Mass. Bldg. code clearly does not state this.

    Has anyone ever heard of such a thing?

    #2
    The NEC states allows it when approved by the AHJ. I'm not sure what's changed but up until a few years ago we never installed a natural gas emergency generator.

    700.12(B)(3) Dual Supplies. Prime movers shall not be solely de-
    pendent on a public utility gas system for their fuel supply
    or municipal water supply for their cooling systems. Means
    shall be provided for automatically transferring from one
    fuel supply to another where dual fuel supplies are used.
    Exception: Where acceptable to the authority having ju-
    risdiction, the use of other than on-site fuels shall be per-
    mitted where there is a low probability of a simultaneous
    failure of both the off-site fuel delivery system and power
    from the outside electrical utility company.
    Last edited by infinity; 10-10-18, 04:09 PM. Reason: Added Code Section
    Rob

    Moderator

    All responses based on the 2017 NEC unless otherwise noted

    Comment


      #3
      Originally posted by infinity View Post
      The NEC states allows it when approved by the AHJ. I'm not sure what's changed but up until a few years ago we never installed a natural gas emergency generator.

      700.12(B)(3) Dual Supplies. Prime movers shall not be solely de-
      pendent on a public utility gas system for their fuel supply
      or municipal water supply for their cooling systems. Means
      shall be provided for automatically transferring from one
      fuel supply to another where dual fuel supplies are used.
      Exception: Where acceptable to the authority having ju-
      risdiction, the use of other than on-site fuels shall be per-
      mitted where there is a low probability of a simultaneous
      failure of both the off-site fuel delivery system and power
      from the outside electrical utility company.
      For this reason, you will never find a natural gas fired fire pump. There may be a few in the hinterlands (I personally know of one) but you won't find new installs. Like, the last 20 years or so.

      Comment


        #4
        oh boy I'm gonna be bankrupt. I didn't know that

        Comment


          #5
          Natural gas lines, supplied by gas companies, can and usually are, shut off when fire departments request it. My cousin is a fireman who has said many times to me that I should not get a gas or natural gas generator as backup for my property because they are both more flammable than diesel. I am not an6 expert but can only say that when it comes to fire hazards, I listen to my cousin...he is the expert.
          Student of electrical codes. Please Take others advice first.

          Comment


            #6
            On our last project a 720 unit apartment building with some retail we used a NG generator for all life safety. First time in my career that I've ever seen that.
            Rob

            Moderator

            All responses based on the 2017 NEC unless otherwise noted

            Comment


              #7
              We always get it in writing first from the AHJ before we consider natural gas for 700 or 701 gens.

              I recently had it for a NJ gen and had to provide the letter back to the AHJ during construction and saved my butt
              Ron

              Comment


                #8
                We’ve had NG approved as long as they meet the 10 seconds in some areas of WI.

                Comment


                  #9
                  Originally posted by Adamjamma View Post
                  Natural gas lines, supplied by gas companies, can and usually are, shut off when fire departments request it. My cousin is a fireman who has said many times to me that I should not get a gas or natural gas generator as backup for my property because they are both more flammable than diesel. I am not an6 expert but can only say that when it comes to fire hazards, I listen to my cousin...he is the expert.
                  Your cousin is absolutely right. From a flammability risk, diesel is the way to go. The problem for emergency generators is that depending on the load they need to support, you may run into a problem storing enough fuel on site to meet however long it has to run. It may be as little as 24 hours, but in Florida they are requiring nursing homes provide power to run A/C for 96 hours. Most localities won't let you put that much fuel on your property, but natural gas is use it when you need it.

                  Comment


                    #10
                    Some good points above. I agree with flammability, but I'm a fireman, and I'd want natural gas at my house all day long. Depending on your risk assessment, it would depend on fuel reliability in my mind. Earthquakes are possible here, but most extended outages have been blizzard/ice related that I have experienced. Natural gas interruptions have been extremely rare, and our emergency services building has a natural gas fired generator too. The other issue that has come up over time has been generators with large day tanks having stale fuel issues.

                    Comment


                      #11
                      Well, in the areas I have worked at the most, Natural Gas is not an option..not available so only petrol, diesel, and propane as options other than battery banks... thank god...
                      Student of electrical codes. Please Take others advice first.

                      Comment


                        #12
                        Originally posted by Designer69 View Post
                        This came out of left field, but I was informed by my GC that they were told by the fire dpt. that a Natural Gas generator is not considered emergency and only a Diesel generator can be considered emergency.

                        I've never heard of this anywhere in any local state or national codes. Mass. Bldg. code clearly does not state this.

                        Has anyone ever heard of such a thing?
                        The way I read the code cited, Propane could also be used.


                        I know what I don't know, and I know where to go to find it!

                        Comment


                          #13
                          Originally posted by Strathead View Post
                          The way I read the code cited, Propane could also be used.
                          If the property meets the storage limits (if any). Propane is flammable while diesel is combustible, so you are likely to be able to store more diesel than propane.

                          Comment


                            #14
                            Originally posted by Designer69 View Post
                            oh boy I'm gonna be bankrupt. I didn't know that
                            RIP. Hope it all works out.....:

                            But maybe you could see about changing the jets to LPG and adding storage tanks somewhere if the AHJ will agree.


                            Like others said, it’s pretty much always diesel. And you’d need to spec the tank size; specs usually require EC to include a full tank of fuel in the bid.


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                            Comment


                              #15
                              Is an on-site propane tank an option? Talk to the generator manufacturer. You should be able to get a valve that switches to an onsite propane tank in the event of low gas pressure on the NG pipeline. Generator will have a reduced kW rating when on propane.

                              Comment

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