Why register? ...To Enhance Your Experience
+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 20 of 30
  1. #1
    Forum Member
    Join Date
    Sep 2011
    Posts
    4

    Default Gas and Electric Fans

    Why are gas fans used for commerical buildings?

    I was on a building fire at a school were there was small kitchen fire. The school filled with smoke and 7 gas fans were placed in service in front of two pairs of double doors. Smoke was clear but now the school was filled with CO2. Now the gas fans were shut off and placed three electric fans to clear the CO out of the building. which did the job.

    I perfer electric fans over gas. To me using gas fans it is double the work since the CO2 would go right into the building. Some have the extended hose for CO2 but some are placed incorrect that the wind tunnel just takes it into the building.

    If using a gas fan use it in a proper way. Gas fans can be use for residential homes in some cases. If use properly then use them otherwise I would stick with electric fans.


  2. #2
    Forum Member Bones42's Avatar
    Join Date
    Mar 2001
    Location
    Pt. Beach, NJ
    Posts
    10,656

    Default

    Compare the CFM for equally sized gas fan vs electric fan.

    It's been a few years since we have, but the gas fan outperformed the electric fan by a significant margin.

    As for the CO theory...if the building was full of smoke...wasn't CO already there? Did you run any actual CO measurements before and after?

    We have done some testing and found the actual amount of increased CO was extremely low.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  3. #3
    Forum Member GTRider245's Avatar
    Join Date
    May 2005
    Location
    Augusta,GA
    Posts
    3,056

    Default

    CO2 and CO are not the same thing. Just so you know.

    We run electric at one department, gas at another. They both have their advantages and disadvantages. All comes down to preference and how you operate.
    Career Firefighter
    Volunteer Captain

    -Professional in Either Role-

    Quote Originally Posted by Rescue101 View Post
    I don't mind fire rolling over my head. I just don't like it rolling UNDER my a**.

  4. #4
    Forum Member
    Join Date
    Nov 2009
    Posts
    3,768

    Default

    lil

    did someone take readings to confirm levels????

    also if ther is a fire already, there are fire gases in the building, and you may add a ppm??

  5. #5
    Forum Member len1582's Avatar
    Join Date
    Feb 2002
    Location
    N.J.
    Posts
    1,392

    Default

    I guess you're referring to exhaust fumes from the fan. In order to minimize them being pushed into the building you need to run the hose from the exhaust outlet away from the fan. It might not eliminate everything completely, but it will help. Along with proper placement.
    Last edited by len1582; 09-30-2011 at 11:33 AM.

  6. #6
    Back In Black ChiefKN's Avatar
    Join Date
    Feb 2003
    Location
    The Nice Part of New Jersey
    Posts
    6,981

    Default

    Quote Originally Posted by len1582 View Post
    I guess you're referring to exhaust fumes from the fan. In order to minimize them being pushed into the building you need to run the hose from the exhaust outlet away from the fan. It might not eliminate everything completely, but it will help. Along with proper placement.
    Yes, those extension tubes that fit on the exhaust are pretty critical.

    With that said, there are some much better electric fans then the old box smoke ejectors of old.
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

    "When tempted to fight fire with fire, remember that the Fire Department usually uses water."

  7. #7
    Forum Member
    Join Date
    Nov 2008
    Location
    Mass
    Posts
    1,037

    Default

    Quote Originally Posted by Bones42 View Post
    Compare the CFM for equally sized gas fan vs electric fan.

    It's been a few years since we have, but the gas fan outperformed the electric fan by a significant margin.

    As for the CO theory...if the building was full of smoke...wasn't CO already there? Did you run any actual CO measurements before and after?

    We have done some testing and found the actual amount of increased CO was extremely low.
    Well said, i would say the same thing. The CFM of most gas fans far outweighs the possible minor CO issue.

    We run SuperVac 16" electric smoke ejectors. We use the P164 which has a claimed 5,200 CFM with the venturi effect as our primary ejector. But we have a pair of Tempest 18" Gas powered fans that push over 15,000 cfm each. A fan that is 2" larger in diamater but is pushing almost THREE times the amount of air is a HUGE improvement. The gas fans are not much larger overall. Only about 3" wider, 5" taller and 8" deeper. And a little less then twice the weight. But no cord to carry, deploy and roll up and no need for generators. And the gas fans have wheels unlike the electric fans. So the additional weight is not really a big deal. And with two people, it's a breeze (excuse the pun).

    At the end of the day, i would take a gas fan for commercial, industrial and residential homes any day of the week over electric. The only place i prefer electric fans is for venting apartments where you can put the ejector up in a window.

  8. #8
    Forum Member FyredUp's Avatar
    Join Date
    Jul 1999
    Location
    Rural Wisconsin, Retired from the burbs of Milwaukee
    Posts
    9,858

    Default

    My career FD uses a roughly 10 foot exhaust extension to keep the engine exhaust out of the air flow of the fan.

    We also carry an electric PPV fan. Yes folks, they make PPV fans with electric motors now. There cfm is less than a gas powered fan of the same size, but far more than the old negative pressure box vent fans.
    Crazy, but that's how it goes
    Millions of people living as foes
    Maybe it's not too late
    To learn how to love, and forget how to hate

  9. #9
    Forum Member
    Join Date
    Feb 2009
    Location
    virginia
    Posts
    537

    Default

    Another thing that needs to be taken into consideration is the size of the exit opening. If the exit is to small not enough air is going to exit the structure. If you have 7 fans blowing into one building and only one single door open you are not going to remove enough air.

  10. #10
    Forum Member
    Join Date
    Sep 2011
    Posts
    4

    Default

    Quote Originally Posted by Bones42 View Post
    Compare the CFM for equally sized gas fan vs electric fan.

    It's been a few years since we have, but the gas fan outperformed the electric fan by a significant margin.

    As for the CO theory...if the building was full of smoke...wasn't CO already there? Did you run any actual CO measurements before and after?

    We have done some testing and found the actual amount of increased CO was extremely low.
    Readings were done cause i did them. The readings i got before the fans was 10 CO2 and when gas fans in service it was on the border of 25 ppm

  11. #11
    Forum Member
    Join Date
    Sep 2011
    Posts
    4

    Default

    Quote Originally Posted by len1582 View Post
    I guess you're referring to exhaust fumes from the fan. In order to minimize them being pushed into the building you need to run the hose from the exhaust outlet away from the fan. It might not eliminate everything completely, but it will help. Along with proper placement.
    To add on to exhaust fumes their was a Tower ladder parked behind the fans that blew the truck exhaust inside.

    Yes there was CO2 inside cause of fire but more was added to it. I see the advantages and disadvantages of both my only point to the whole thing is how it was all setup. More work was done that could of been avoided but then again it wasn't my local so nothing i can do. If you saw what i saw you would laugh to see how all setup I do have picture of it but trying figure out how to upload it.

  12. #12
    Forum Member Bones42's Avatar
    Join Date
    Mar 2001
    Location
    Pt. Beach, NJ
    Posts
    10,656

    Default

    Quote Originally Posted by lilbubs52 View Post
    Readings were done cause i did them. The readings i got before the fans was 10 CO2 and when gas fans in service it was on the border of 25 ppm
    25ppm? OSHA allows 35ppm with 8 hours worth of exposure.

    25? I'm not even considering that worth mentioning.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  13. #13
    Forum Member
    Join Date
    Feb 2009
    Location
    virginia
    Posts
    537

    Default

    I bet running the rigs on the bay floor of the firehouse produces higher than 25 PPM CO.

    Just so you know it is CO not CO2.

  14. #14
    MembersZone Subscriber CKirk922's Avatar
    Join Date
    Apr 2005
    Location
    Watching From The Sideline Now
    Posts
    260

    Default

    Practicality is the name of the game. The gas powered fan is the current best solution to portability.

    The electric fan may indeed be equal in cfms but it requires a greater level of strategic positioning and power infrastructure...

    One guy can drag (or two guys can carry) a gas fan on wheels and position and run it easily.

    It may be akin to dragging an extra hose line trying to drag an electric and heavy power supply cord or lug a generator. Distance may limit the positioning of the fan.

    IF you are using this for post attack/knockdown smoke removal- Perhaps,then an apparatus or generator could be repositioned to make fan placement feasible in most situations.
    Last edited by Fireeaterbob; 10-03-2011 at 08:19 AM. Reason: Sensitivity issues
    A coward stands by and watches wrongs committed without saying a word...Any opinions expressed are purely my own and not necessarily reflective of the views of my former departments

  15. #15
    MembersZone Subscriber CKirk922's Avatar
    Join Date
    Apr 2005
    Location
    Watching From The Sideline Now
    Posts
    260

    Default

    I've seen an item in the last year that might have some promise in the construction/remodel industry; There is a door frame ejection fan (electric) that insulation outfits use to negative pressure a home to check for leaks and overall cfm measurement.

    This item completely seals the door entry while hanging low or high in the pathway. This might be an excellent niche tool for post fire control smoke ejection but it definitly is not a first line tool.
    A coward stands by and watches wrongs committed without saying a word...Any opinions expressed are purely my own and not necessarily reflective of the views of my former departments

  16. #16
    Forum Member GTRider245's Avatar
    Join Date
    May 2005
    Location
    Augusta,GA
    Posts
    3,056

    Default

    Quote Originally Posted by Bones42 View Post
    25ppm? OSHA allows 35ppm with 8 hours worth of exposure.

    25? I'm not even considering that worth mentioning.
    OSHA also says to evacuate a residential dwelling at 10 PPM. This should be the limit for when you stop ventilating, whether it be after a fire or during a leak. Assuming you are ventilating with the sole purpose of CO removal that is.
    Career Firefighter
    Volunteer Captain

    -Professional in Either Role-

    Quote Originally Posted by Rescue101 View Post
    I don't mind fire rolling over my head. I just don't like it rolling UNDER my a**.

  17. #17
    Forum Member
    Join Date
    Nov 2009
    Posts
    3,768

    Default

    Quote Originally Posted by Fireeaterbob View Post
    I've seen an item in the last year that might have some promise in the construction/remodel industry; There is a door frame ejection fan (electric) that insulation outfits use to negative pressure a home to check for leaks and overall cfm measurement.

    This item completely seals the door entry while hanging low or high in the pathway. This might be an excellent niche tool for post fire control smoke ejection but it definitly is not a first line tool.
    Setup has been around for many years for clean agent room testing even back to halon

    They are being seen in residental to calc how much air leakage there is in a building

    They do not push much air

  18. #18
    Forum Member Bones42's Avatar
    Join Date
    Mar 2001
    Location
    Pt. Beach, NJ
    Posts
    10,656

    Default

    Quote Originally Posted by GTRider245 View Post
    OSHA also says to evacuate a residential dwelling at 10 PPM. This should be the limit for when you stop ventilating, whether it be after a fire or during a leak. Assuming you are ventilating with the sole purpose of CO removal that is.
    Min levels of exposure...

    OSHA - 50ppm
    NIOSH - 35ppm
    ACGIH - 25ppm

    Here is the link

    Here is another interesting link...showing what is occurring and recorded at certain levels....notice that lowest level for US CO alarm is at 30ppm...
    http://www.coheadquarters.com/ZerotoMillion1.htm
    Last edited by Bones42; 10-03-2011 at 04:35 PM.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  19. #19
    Forum Member GTRider245's Avatar
    Join Date
    May 2005
    Location
    Augusta,GA
    Posts
    3,056

    Default

    Quote Originally Posted by Bones42 View Post
    Min levels of exposure...

    OSHA - 50ppm
    NIOSH - 35ppm
    ACGIH - 25ppm

    Here is the link

    Here is another interesting link...showing what is occurring and recorded at certain levels....notice that lowest level for US CO alarm is at 30ppm...
    http://www.coheadquarters.com/ZerotoMillion1.htm
    Also notice the "action level" for public safety is 9PPM.
    Career Firefighter
    Volunteer Captain

    -Professional in Either Role-

    Quote Originally Posted by Rescue101 View Post
    I don't mind fire rolling over my head. I just don't like it rolling UNDER my a**.

  20. #20
    Forum Member Miller337's Avatar
    Join Date
    Nov 2010
    Posts
    916

    Default

    Quote Originally Posted by RFD21C View Post
    I bet running the rigs on the bay floor of the firehouse produces higher than 25 PPM CO.

    Just so you know it is CO not CO2.
    Oh yeah, It really peeves off the gas moniter on the SCBA compressor.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. How to handle electric in residential gas leak?
    By LawFires in forum Fireground Tactics
    Replies: 6
    Last Post: 07-07-2006, 07:14 AM
  2. Replies: 22
    Last Post: 09-25-2005, 07:07 AM
  3. Gas Leaks
    By WTFD10 in forum Ohio
    Replies: 2
    Last Post: 07-08-2004, 12:13 PM
  4. World Of Fire Report: 06-28-04
    By PaulBrown in forum World of Fire Daily Report
    Replies: 0
    Last Post: 06-29-2004, 12:32 PM
  5. World Of Fire Report: 11-15-03
    By PaulBrown in forum World of Fire Daily Report
    Replies: 0
    Last Post: 11-16-2003, 06:35 PM

Posting Permissions

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