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  • Gas PPV fans and increased CO

    All, I looked for something in earlier topics and cannot find anything that specifically addresses increased CO when using Gas PPV fans to remove the products of combustion after a fire has been extinguished. Has anyone here done any studies or know where I might be able to find something on this. We were discussing the usage of Gas PPV fans and some believe the slight increase is a reason to not use them. I have used the CO meter in the building and once visible smoke is removed the CO levels will bottom out at about 6-8 PPM . Please do not confuse this question with using PPV for Attack , I am simply talking removal after Food on Stove or minor fires.

    In the end our White hats want to eliminate the usage of these fans for such purposes and if there is a reason to do so I am not against it but think they are going a little overboard. The highest levels we ever had that were steady was about 15 PPM but we believe we may have been actually sucking the Exhaust from an Apparatus parked too close.

  • #2
    Hmmm........

    I'm not aware of any links to any Information on that, But, I'd see what the Fan's Manufacturers say about that..... We have High Output Fans, but almost all are Electric.
    Never use Force! Get a Bigger Hammer.
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    Asst. Chief John R. Woods Sr. 1937 - 2006

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    • #3
      Originally posted by no1special View Post
      All, I looked for something in earlier topics and cannot find anything that specifically addresses increased CO when using Gas PPV fans to remove the products of combustion after a fire has been extinguished. Has anyone here done any studies or know where I might be able to find something on this. We were discussing the usage of Gas PPV fans and some believe the slight increase is a reason to not use them. I have used the CO meter in the building and once visible smoke is removed the CO levels will bottom out at about 6-8 PPM . Please do not confuse this question with using PPV for Attack , I am simply talking removal after Food on Stove or minor fires.

      In the end our White hats want to eliminate the usage of these fans for such purposes and if there is a reason to do so I am not against it but think they are going a little overboard. The highest levels we ever had that were steady was about 15 PPM but we believe we may have been actually sucking the Exhaust from an Apparatus parked too close.


      You might want to do a search on this using the search feature along the dark line above. I really think this has been talked about before...
      Stay Safe and Well Out There....

      Always remembering 9-11-2001 and 343+ Brothers

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      • #4
        Cap, I looked and saw a thread in 2006 and 2008. Most were related to Fire attack .I did not find too much on whether there was any documentation either way. As I said I am not trying to change/not change policy that is up to the white hats but just want to know there reasons for this. Hey if they say NO Gas fans , it is no gas fans just trying to figure if there was actual data or just hearsay. I asked them for there input and was told simply "there have been reports of higher CO levels and we want to reduce possibility of further potential injuries." I am looking for anything and of course the manufacturers will say nothing about it they want to sell there wares.


        I just hate teaching recruits about the piece of equipment which is part of Firefighter 1 curriculum yet following that with "but we can't use it by order of the chief" you always get Why? Just like to be able to answer the questions.

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        • #5
          Set up a fan
          Point at a good size room
          Take co reading in room
          Fire up fan
          Let it run for set period of time
          Take readings at set intervals

          Repeat experiment. 3or4 times
          Document results

          Decidefrom there
          http://www.youtube.com/watch?v=JZdEH...e_gdata_player

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          • #6
            Might take two steps to find that answer - see if you can find out stats on a standard small engine such as would be used for a PPV fan, then check out the CFM stats on such fans.

            Made me curious, so I did the numbers.

            A 190cc engine running at 1000 rpm theoretically generates about 7 CFM of exhaust gas. I have no idea how much of that is CO.

            One manufacturer's gas powered PPV fans range from 10,000 CFM to 27,000 CFM.

            That means that between .02% and .07% of the air issuing from the business end of the fan is exhaust gasses, with a lesser percentage being CO.

            My math/logic may be a little iffy here, so corrections are welcome, but I think that works out to between 200 and 700 PPM. Not necessarily a problem to a FF in a pack, but a problem for the unprotected.

            Your calculations may vary.

            From US DOL:
            EXPOSURE LIMITS

            * OSHA PEL

            The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for carbon monoxide is 50 parts per million (ppm) parts of air (55 milligrams per cubic meter (mg/m(3))) as an 8-hour time-weighted average (TWA) concentration [29 CFR Table Z-1].

            * NIOSH REL

            The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for carbon monoxide of 35 ppm (40 mg/m(3)) as an 8-hour TWA and 200 ppm (229 mg/m(3)) as a ceiling [NIOSH 1992].

            * ACGIH TLV

            The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned carbon monoxide a threshold limit value (TLV) of 25 ppm (29 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 15].
            Opinions my own. Standard disclaimers apply.

            Everyone goes home. Safety begins with you.

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            • #7
              We used an exhaust extension. Go to Tempest website to see one


              Exhaust Extension
              The Tempest exhaust extension is the ideal solution for reducing the amount of exhaust and CO introduced during PPV operations. The hose is 2" x 10' and is made of durable polyethylene that can withstand temperatures from –20°C to +375°C. Two hoses can be combined for up to 20' of extension.

              Comment


              • #8
                The internal combustion of a gasoline fan engine also produces
                CO, and although the levels are much lower than those achieved
                by a fire, the FFTG conducted experiments to analyze CO levels in
                the Chicago high-rise apartment. CO meters were placed in both
                stairwells to monitor the fans’ impact on CO levels.
                The results: Without the fans, CO levels in the public hallway and
                the south stairwell almost always reached or exceeded the 800-ppm
                (0.08 percent) limit of the meters used. In most cases, the fans
                decreased CO levels from IDLH conditions to less than 200 ppm


                Quote taken from here....

                http://positivepressureattack.com/im...Flow1109FR.pdf

                It seems to me that the benefits of a gas powered fan outweigh the risks.
                My wise and profound comments and opinions are mine alone and are in no way associated with any other individual or group.

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                • #9
                  Exhaust extensions knock down the majority of the CO buildup within the structure.

                  My past department used them on all of our gas-fired PPV fans, and we saw very minimal CO levels when compared to fans without the extensions.
                  Train to fight the fires you fight.

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                  • #10
                    The previous post aside, as clearing a highrise stair tower and blowing our food on the stove smoke are generally two very different scenarios, we stopped using our gas blowers for smoke removal as we were getting CO reading above 50 PPM on routine smoke removals (popcorn, trashcans, FOTS). First we tried the exhaust attachments, which did help, but we slowly moved to electric blowers on frontline apparatus. Not a great idea to fill a residential elderly building with CO while exhausting the burned popcorn smell, at least that's when we decided to look for alternatives.

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                    • #11
                      Thanks

                      Well I appreciate all of the responses. I had a conversation last night with a Chief officer and we are going to work together in the next month or so to see what we can find out. We plan to run fans at a shopping center under construction where we have hopefully no previous CO and run the fans for different intervals and come up with some sort of baseline to go off of. I will report back when I get some further answers. We also plan to include adding to the gas PPV fan an additional Electric PPV fan in tandem with it to see if it increases or decreases.

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                      • #12
                        We have an electric 110v ejector fan on each our engines and a giant 220v electric fan on our rescue truck. That sucker can provide enough force to blow a 100 lb person off their feet.
                        ALL without fumes or poisonous gasses being emitted into the scene. They also work well for the rehab area under the awning for cooling FF's down on a hot day.

                        Comment


                        • #13
                          Originally posted by islandfire03 View Post
                          We have an electric 110v ejector fan on each our engines and a giant 220v electric fan on our rescue truck. That sucker can provide enough force to blow a 100 lb person off their feet.
                          ALL without fumes or poisonous gasses being emitted into the scene. They also work well for the rehab area under the awning for cooling FF's down on a hot day.
                          You CARRY that much generator on that Mini me Rescue? Hehe T.C.

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                          • #14
                            As noted above the exhaust extension is a very good tool. We have found that when using gas fans to remove smoke we actually created a new dangerous enviroment with CO. Not sure the numbers however our detector was alarming once all the smoke had been removed. No such issue since the extension was installed

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                            • #15
                              Originally posted by Rescue101 View Post
                              You CARRY that much generator on that Mini me Rescue? Hehe T.C.
                              Bite me !!! :-}
                              15 KW harrison how do you think we power the lobster cookers and the refrigerator.

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