1. #1
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default Venting - WHERE & WHEN?!

    Placing yourselves between the fire and any vent openings?

    The fire is located on the 'C' side of a single story commercial building (rear) and your approach is from the 'A' side (front door entry). There is a mix of heavy gray and brown smoke coming from the 'A' side, under the roof and out of any existing openings. The smoke issuing at the 'C' side is heavy black. If you decide to make this entry/approach in the first place, under what circumstances (if any) would you cross-ventilate by making openings 'behind' your advance? (ie; venting windows on the 'A' side? adjacent to the point of entry)

    What is likely to happen to an under-ventilated fire when such openings are made?

    Where will the fire most likely head for?

    Under what circumstances should a vent opening be made whilst firefighter's are occupying the building?

    Under what circumstances should a vent opening NOT be made whilst firefighter's are occupying the building?

  2. #2
    MembersZone Subscriber
    Shoreman22's Avatar
    Join Date
    Feb 2005
    Location
    Mantoloking, NJ, USA
    Posts
    117

    Default Venting

    What you've described is close to a textbook scenario for backdraft and/or flashover.

    The safest approach would be to have the OVM (outside vent man) locate some windows to break out on side C just as the crew is entering side A, assuming backdraft or flashover is imminent. The fire is going to follow the path to fresh air. If you vent side A as the crew is gaining entry, the fire is going to come right at them - they'll not likely reach the base of the fire and there's a good chance you're going to lose control of the situation - not to mention losing your crew...

    One of the most difficult aspects of a coordinated attack is timing. The hose company cannot attempt entry unless the vent crew is in place and ready to open up. Open up too early and the hose crew will take a beating from quick fire spread. Open up too late and the hose crew will take an equal beating from heat & steam - not to mention a backdraft or flashover, depending upon conditions. The hose team has to have a good idea of where the fire is and they have to advance quickly once the vent team opens up.

    The only scenario I can think of where you would vent on the same side you're entering - and this is strictly theory as I haven't seen it attempted - is if you have reliable information that there are victims trapped in a certain location in the structure and you want to draw the fire away from them to allow for rescue. Other than that, venting as close to the fire as possible is your best bet.

    In terms of when not to vent, you don't want your search teams opening windows during their search unless it's being coordinated with the hose crew. Premature venting can quickly deteriorate the situation and place interior crews in jeapordy from rapidly spreading fire.

    The hose company depends HEAVILY upon an experienced and competent vent team. Engine and ladder companies should drill on coordinated attacks on a frequent basis.

    Hope this helps.

    Stay safe.
    Last edited by Shoreman22; 06-20-2007 at 07:07 AM.
    Proud member of the IACOJ.

    If at first you don't succeed, then skydiving definitely isn't for you....

    "It seemed like a good idea at the time..."

  3. #3
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,867

    Default

    Quote Originally Posted by Shoreman22 View Post

    The safest approach would be to have the OVM (outside vent man) locate some windows to break out on side C just as the crew is entering side A, assuming backdraft or flashover is imminent. The fire is going to follow the path to fresh air.
    Sorry brother, but I would say this might be one of the worst ways to vent if you believe a backdraft is imminent. Taking windows for horizontal vent will likely cause the backdraft vs. prevent it, if it is in fact imminent. Your descriptions and analysis of Paul's scenario leaves me wondering about how closely related you believe flashover and backdraft are?

    If I thought flashover was imminent due to superheated smoke and rollover occurring in the smoke, I'd agree with the venting of windows, being wary that one story commercial buildings often have drop ceilings that can conceal a lot of fire overhead. Vertical ventilation maybe required to adequately vent this fire.

    Whereas indications of a potential backdraft situation (smoke under pressure from the tiniest openings, no visible fire, blacked windows, smoke being drawn into small openings) would require immediate vertical vent before any other horizontal opening is made.

    I'd say Paul's scenario describes a possible backdraft or at least an oxygen regulated fire where vertical vent would best alleviate the conditions. Horizontal openings will likely allow the fire to grow rapidly given the smoke conditions he put forth. And if this is an oxygen regulated fire, as it finds oxygen it will be drawn to the openings.

  4. #4
    MembersZone Subscriber
    Shoreman22's Avatar
    Join Date
    Feb 2005
    Location
    Mantoloking, NJ, USA
    Posts
    117

    Default

    RFD,

    I understand and agree with your point re: the danger of horizontal v. vertical on initial approach when a backdraft is anticipated. I was looking at it from the perspective of a low manpower situation, which is what we typically face. The reality is that it's going to take too long to get a ladder up to a roof with a saw to get an opening made - not to mention that the fire will likely have vented itself by that time. If my OVM takes the windows just prior to entry of the hose crew (from a safe position, of course), there's always the danger of a backdraft. The difference will be that it will have happened prior to my crew attempting entry. Once they enter, they'll be pushing the fire towards the vented windows as they advance. If the venting is done on the same side as entry, as Paul alluded to, the crew never has a chance.
    Proud member of the IACOJ.

    If at first you don't succeed, then skydiving definitely isn't for you....

    "It seemed like a good idea at the time..."

  5. #5
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    OK both of you offer good feedback and points on the scenario as described - I would suggest the conditions are definitely demonstrating 'under-ventilated' with backdraft potential, although no obvious smoke blackening of windows.

    Here is some more information .... 200' x 50' mostly open-plan floor area with a distinct lack of openings on the exterior 'C' side but plenty on the 'A' side. There is a high ceiling, lightweight roof and a slight wind is blowing from 'C' to 'A' side. There are reports of 1-2 remaining occupants within.

    Purely from a 'tactical venting' point of view ....

    Your entry door is open .... what openings should you/should you not make if either flashover or backdraft is believed imminent? RFDACM02 may well be right to suggest cross-ventilation of any sort is likely to enhance backdraft potential. Under what circumstances (if any) is it correct to cross ventilate if it is believed flashover is imminent, if firefighters are committed to the interior?

    If my OVM takes the windows just prior to entry of the hose crew (from a safe position, of course), there's always the danger of a backdraft. The difference will be that it will have happened prior to my crew attempting entry.
    Backdrafts may not always occur instantly and in some instances may occur several minutes after the vent is made; and may even re-occur as interior conditions 'recycle'.

  6. #6
    Forum Member

    Join Date
    Mar 2007
    Location
    Jacksonville Fl
    Posts
    507

    Default

    ill take a stab.

    Construction type? Building Use? Wood Roof or steel?

    Judging by the info given it sounds like the fire is in the rear of the structure moving toward the A side. I would not make anymore horizontal openings. as the stiff wind will spread this fire VERY VERY quickly across an open space. I would send a crew to the roof to see if vertical vent can be accomplished for life and to make it easier on crews inside. have crews inside given condition reports?

    This fire will escalate very quickly if not compartmentalized. Control your openings and pat attn to wind conditions.

    i would never presonally try to cross ventilate a preflashover condition with crews inside
    Last edited by LeatherHed4Life; 06-20-2007 at 04:03 PM.

  7. #7
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,867

    Lightbulb

    Paul, I would suggest this "scenario" is a little to similar the S.C tragedy, and while I honestly believe we need to learn from this to honor our brothers who've passed, this might be a little early. Too often our tactical discussions get a little heated and I wouldn't want anyone in Charleston to think we're doubting them, questioning them or otherwise Monday Morning Quarterbacking them before the brothers are laid to rest. As has been noted elsewhere the national media outlets have started to use Firehouse.com Forums as a place to get information, I hate to see a CNN run a story why noting that people here question tactics or risk/benefit models.

  8. #8
    Forum Member

    Join Date
    Nov 2005
    Posts
    375

    Default

    I too have mixed feelings about this being that it sounds like the Sofa warehouse and at the same time countless number of other stores in most of our's first due areas. I don't know if I should post or not but I am going to even though it is against my better judgement.

    If it is lightweight steel roof construction you don't want to be on the roof cutting. That type roof isn't designed to hold FF's with saws.

  9. #9
    Forum Member

    Join Date
    Jan 2003
    Location
    Chicago
    Posts
    2,503

    Default

    Quote Originally Posted by PaulGRIMWOOD View Post
    Placing yourselves between the fire and any vent openings?

    The fire is located on the 'C' side of a single story commercial building (rear) and your approach is from the 'A' side (front door entry). There is a mix of heavy gray and brown smoke coming from the 'A' side, under the roof and out of any existing openings. The smoke issuing at the 'C' side is heavy black. If you decide to make this entry/approach in the first place, under what circumstances (if any) would you cross-ventilate by making openings 'behind' your advance? (ie; venting windows on the 'A' side? adjacent to the point of entry)

    What is likely to happen to an under-ventilated fire when such openings are made?

    Where will the fire most likely head for?

    Under what circumstances should a vent opening be made whilst firefighter's are occupying the building?

    Under what circumstances should a vent opening NOT be made whilst firefighter's are occupying the building?
    You guys over there don't have many regular truck companies over there, do you? Opening the roof is the best way to go. Single story, heavy smoke, why mess with anything else? When you say lightweight, what exactly do you mean? Bar truss? Heavy wooden bowstring? Whatever it is, it needs to be opened.
    I am a complacent liability to the fire service

  10. #10
    Forum Member

    Join Date
    Mar 2007
    Location
    Jacksonville Fl
    Posts
    507

    Default

    It sounds like a LODD from the early 90's too. In Va i believe at an Advanced auto parts store, 2 killed. However there was light smoke showing on arrival. Im sure there are a few other LODD's that read the same way. Im dont think the Chief is duplicating the most recent tragedy in our profession on purpose. He does pose good questions, regardless of which scenario it may be loosley based on.

    There was some good discussion a while back on tactical vent between him and some FDNY Brothers, an awesome read if you can find it.

  11. #11
    Forum Member

    Join Date
    Nov 2005
    Posts
    375

    Default

    Leatherhead I think you are talking about the brothers from Chesapeake or the Hampton area.

  12. #12
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    Quote Originally Posted by RFDACM02 View Post
    Paul, I would suggest this "scenario" is a little to similar the S.C tragedy, and while I honestly believe we need to learn from this to honor our brothers who've passed, this might be a little early. Too often our tactical discussions get a little heated and I wouldn't want anyone in Charleston to think we're doubting them, questioning them or otherwise Monday Morning Quarterbacking them before the brothers are laid to rest. As has been noted elsewhere the national media outlets have started to use Firehouse.com Forums as a place to get information, I hate to see a CNN run a story why noting that people here question tactics or risk/benefit models.
    OK my brother RFDACMO2 raises this most relevant point and I thank him for doing so. The tragedy in Charleston has left us all with feelings of overwhelming sadness; possibly frustration in not being able to directly do something positive to help; and I am sure a desire to learn (where needed) from all our brothers experiences to the potential benefit of future firefighters.

    It is far too early to 'quarterback' or even comment at this stage on the sequence of events at that particular fire, simply because we don't genuinely know the SOE as they occurred and also out of respect for the bereavement and losses of our grieving Charleston brothers and sisters. It was never my intention to refer to that particular incident and to be honest, at the time I initiated this particular thread there was little information out there as to the strategy & tactics in question. I was merely intending to discuss venting tactics in general and not anything else such as deployment; firefighting or other aspects of a fire operation such as that which occurred at the sofa warehouse fire.

    I actually become aware of information from the US about eight hours after you guys (due to the time differences US-UK) and this morning (UK) I am reading things that might make this 'scenario' too much like the Sofa Superstore. Therefore I would ask you to 'change direction' in some way in an effort to keep what has so far been a constructive debate. I do this out of respect for those in Charleston who have my deepest respect, sympathy and condolences.

    LeatherHed4Life has pointed out that I have initiated debate before on these forums in relation to tactical venting operations as this is an area that particularly interests me. There have been several excellent exchanges of information involving FDNY brothers and I would place two links as examples -

    http://forums.firehouse.com/showthre...hlight=venting

    http://forums.firehouse.com/showthre...hlight=venting

    If I may I will direct this debate in a different way ....

  13. #13
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    Quote Originally Posted by ChicagoFF View Post
    You guys over there don't have many regular truck companies over there, do you? Opening the roof is the best way to go. Single story, heavy smoke, why mess with anything else? When you say lightweight, what exactly do you mean? Bar truss? Heavy wooden bowstring? Whatever it is, it needs to be opened.
    ChicagoFF and others have all made their point well in recommending vertical ventilation as opposed to horizontal (cross) ventilation in the commercial structure 'scenario'. I was initially looking for the rare occasions when you might consider cross venting windows behind your entry and I suppose an example might be where an exterior wind could be used to tactical advantage, to force combustion products away from you and out of the structure. Of course this would need to be controlled and basic principles of PPV apply in that the exit vent must already exist and be large enough in proportion to the air entry point and the strength of the wind etc. I would rarely use PPV in this way for pre-attack across large open floor space. Don't forget that in almost all situations we have an open entry door behind us which serves as a vent opening, allowing air in to feed the fire.

    I would like to compile a list of 'Golden Rules' in relation to venting actions by firefighters .... these you can either 1. Add to; 2. Discuss; or 3. Challenge.

    • Don't undertake venting actions without a clear objective in mind
    • The objective should be both practically viable and achievable
    • Don't create openings that are behind or to the side of advancing firefighters in situations where air might feed the fire to escalate rapidly
    • Consider that isolating the fire might be more constructive than venting it
    • Always anticipate the effects of wind speed and direction prior to making an opening
    • Ensure adequate water is available to deal with the involved fire load and any potential for uncontrolled spread before creating vent openings
    • Where backdraft conditions are in existence do not cross ventilate an occupied structure


    We can develop this list further as we go ....
    Last edited by PaulGRIMWOOD; 06-21-2007 at 10:16 AM.

  14. #14
    Banned

    Join Date
    Feb 2007
    Location
    In my house
    Posts
    2,332

    Default

    I for one was wondering exactly the same thing. When I saw what happened I wondered if venting the front of the building in such a manner was the right thing to do. And I'm not being critical or Monday morning quarterbacking this situation. I just realize I don't know what the right thing to do was. I wanted to ask the question but was afraid of the usual storm it stirs up.

  15. #15
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    Quote Originally Posted by HotTrotter View Post
    I for one was wondering exactly the same thing. When I saw what happened I wondered if venting the front of the building in such a manner was the right thing to do. And I'm not being critical or Monday morning quarterbacking this situation. I just realize I don't know what the right thing to do was. I wanted to ask the question but was afraid of the usual storm it stirs up.
    I truly respect your desire to have such questions answered but again respectfully request we keep this thread away from the Sofa Superstore incident and more specifically directed to general venting tactics. We are not able to ascertain the objectives in the minds of incident commanders at any particular fire unless they have provided testimony to that end.

  16. #16
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,867

    Default

    Paul, I think you're wise to move this away from the scenario at this point, and correct the discussion can still be productive. It is evident that there may exist a large gap in how we train our personnel and how much experience we have in recognizing rapidly evolving fires or other IDLH events (flashover, backdraft, collapse).

  17. #17
    MembersZone Subscriber
    mcaldwell's Avatar
    Join Date
    Apr 2003
    Location
    Panorama, British Columbia, Canada
    Posts
    3,022

    Default

    Paul et al...

    Let me take this another direction for a moment, and relate it to several buildings I have in my community. We have dealt with this style scenario on the very small scale (i.e. hundreds of square feet), but not in the larger commercial occupancies yet.

    We are a ski town, and built into the side of the mountain. Most of our larger commercial buildings have two levels or more that are partially below grade, and therfeore many have only A side access, as the B-D sides are buried. Each level is usually well separated vertically from the rest of the building, and floors above are not a viable option for venting.

    I have one building that fits your description almost to a tee (50 feet deep, with 150 foot frontage), but there are two additional office floors above the large open commercial space, and only one well protected interior stairwell in the B-C corner (with fire rated doors top and bottom). No sprinklers.

    The large 150 foot frontage is all windows, and the main door is located dead center. It is in-fact a child-care center, but lets leave the kiddies out for simplicity.


    My thoughts on a pre-flashover condition are to vent the A side window(s) on the Leeward corner only, to draw the fire in one direction. The leeward aspect would hopefully prevent a recirculation of smoke towards or back in the entrance, and perhaps encourage some horizontal venting via venturi.

    Our attack would then be made through the main entrance, followed by total ventilation of the A side glass once the intial knockdown has been made.




    This scenario can be repeated in five or six of our major structures.
    Thoughts or comments?
    Never argue with an Idiot. They drag you down to their level, and then beat you with experience!

    IACOJ

  18. #18
    Administrator

    Join Date
    Jun 2006
    Posts
    2,480

    Default

    "I truly respect your desire to have such questions answered but again respectfully request we keep this thread away from the Sofa Superstore incident and more specifically directed to general venting tactics. We are not able to ascertain the objectives in the minds of incident commanders at any particular fire unless they have provided testimony to that end."

    Thank you to those handling this in a constructive and senstive manner.

  19. #19
    MembersZone Subscriber

    Join Date
    Sep 2004
    Location
    Quebec, Canada
    Posts
    127

    Default

    Quote Originally Posted by mcaldwell View Post
    Paul et al...


    My thoughts on a pre-flashover condition are to vent the A side window(s) on the Leeward corner only, to draw the fire in one direction. The leeward aspect would hopefully prevent a recirculation of smoke towards or back in the entrance, and perhaps encourage some horizontal venting via venturi.

    Our attack would then be made through the main entrance, followed by total ventilation of the A side glass once the intial knockdown has been made.




    This scenario can be repeated in five or six of our major structures.
    Thoughts or comments?

    Hi,

    We have the same here only our mountain is a little smaller here in the eastern part

    I agree with your venting tactic and would advise, in doing so, to use a narrow pattern on the nozzle (or solid bore ) to minimise air displacement during initial attack. That would avoid pressure build-up in the room and minimise any chances of having hot gases coming straight at you looking for an exit...

    Regards,

    Sly

  20. #20
    Forum Member

    Join Date
    Mar 2007
    Location
    Jacksonville Fl
    Posts
    507

    Default

    Quote Originally Posted by GFDLT1 View Post
    Leatherhead I think you are talking about the brothers from Chesapeake or the Hampton area.
    It was chesapeake in May of '96

  21. #21
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    Quote Originally Posted by RFDACM02 View Post
    It is evident that there may exist a large gap in how we train our personnel and how much experience we have in recognizing rapidly evolving fires or other IDLH events (flashover, backdraft, collapse).
    I think you have nailed it and I believe this problem is common throughout the fire service. Ensuring an effective transfer of knowledge and procedure from training environments to the fireground has always been an issue. I have seen this arise time and again over many years. This is one reason why I sincerely believe we should have detailed and documented SOPs that are followed at every incident, where any deviation from a tactical view must be subsequently be accountable. I think FDNY are one of the best at this as their procedures are both detailed and effective, based on years of fireground experience. However, there is always room for improvement.

    I think also, that there is a distinct lack of appreciation and understanding of how an enclosed fire is likely to behave under a wide range of conditions amongst many company officers and chiefs.

    =RFDACM02I would say this might be one of the worst ways to vent if you believe a backdraft is imminent. Taking windows for horizontal vent will likely cause the backdraft vs. prevent it, if it is in fact imminent.
    =ChicagoFFOpening the roof is the best way to go. Single story, heavy smoke, why mess with anything else?
    =Shoreman22I was looking at it from the perspective of a low manpower situation, which is what we typically face.
    Venting prior to entry under backdraft conditions is a well known strategy. Vertical vents are made by some and yes, horizontal vents by others. As I say, it is important to read and constantly monitor conditions during any subsequent entry as conditions may quickly deteriorate again.

    =MCaldwellMy thoughts on a pre-flashover condition are to vent the A side window(s) on the Leeward corner only, to draw the fire in one direction. The leeward aspect would hopefully prevent a recirculation of smoke towards or back in the entrance, and perhaps encourage some horizontal venting via venturi.

    Our attack would then be made through the main entrance, followed by total ventilation of the A side glass once the initial knockdown has been made.
    I respect your approach to pre-planning by taking high-risk buildings in your area and considering strategy for fire located in different parts of the structure whilst influenced by exterior wind etc. Creating openings to draw fire away from firefighters advancing inside is a known strategy. In theory your suggestion sounds effective and I feel it works with smaller compartmented buildings. I have never used this strategy in a large open planned areas with heavy fire involvement. My belief is that your openings will serve to feed the fire with air and conditions may still deteriorate rapidly.

    * Don't undertake venting actions without a clear objective in mind
    * The objective should be both practically viable and achievable
    * Don't create openings that are behind or to the side of advancing firefighters in situations where air might feed the fire to escalate rapidly
    * Consider that isolating the fire might be more constructive than venting it
    * Always anticipate the effects of wind speed and direction prior to making an opening
    * Ensure adequate water is available to deal with the involved fire load and any potential for uncontrolled spread before creating vent openings
    * Where backdraft conditions are in existence do not cross ventilate an occupied structure
    Last edited by PaulGRIMWOOD; 06-22-2007 at 03:02 AM.

  22. #22
    makes good girls go bad
    BLSboy's Avatar
    Join Date
    Sep 2001
    Location
    On the beach, Fla/OCNJ
    Posts
    2,859

    Default

    This is something that goes back to Firefighting 101, as far as backdraft vs flashover is concerned.

    Flashover happens when all the material in a compartment reaches its ignition temperature, and all inside the compartment is consumed with fire. Its warning signs are extremely high temperature, not being able to withstand temps unless all the way on the ground, "driven to the floor". It can be prevented by "pencilling" the ceiling with quick bursts of a straight stream, which will cool the high temps, but can disrupt the thermal balance, and lead to steam burns. Also, venting the involved compartment will allow the gases to escape, cooling the area, and allowing the Engine Co. to get closer.

    Backdraft happens when all the oxygen is used up by a fire. The temps remain extremly high in the compartment, but with the exclusion of a single element from the fire tetrahedron (heat, fuel, self sustaining chain reaction, and oxidizer), namely O2, the fire goes out. With the reintroduction of O2 into an area with all the other elements in the fire tetrahedron, a rapid oxidation process happens.....Backdraft. The only real way, that I know of the prevent a Backdraft from kicking off, is vertical ventilation. However, in some buildings, after a sustained period of fire, I am not sure how feasible this would be, such as lightweight buildings, Eg. Type II construction.

    Gentlemen, if there are errors in my analyzing of the situation, please, beat me gently
    Last edited by BLSboy; 06-22-2007 at 03:08 AM. Reason: made it easier to read
    AJ, MICP, FireMedic
    Member, IACOJ.
    FTM-PTB-EGH-DTRT-RFB-KTF
    This message has been made longer, in part from a grant from the You Are a Freaking Moron Foundation.

  23. #23
    makes good girls go bad
    BLSboy's Avatar
    Join Date
    Sep 2001
    Location
    On the beach, Fla/OCNJ
    Posts
    2,859

    Default

    Paul;
    with the type of building you are describing, the IC may rule out vert. venting. Would making out OWN openings on the Charlie side be feasible? This is of course, is if it is feasible that we could make them in the first place.
    For example, a pre-fab structure, corragated metal, with bowstring truss roof with same conditions you describe. Would placing an OVM with a K12 saw in the Charlie side to make his own openings work?

    Just throwing out an idea........
    AJ, MICP, FireMedic
    Member, IACOJ.
    FTM-PTB-EGH-DTRT-RFB-KTF
    This message has been made longer, in part from a grant from the You Are a Freaking Moron Foundation.

  24. #24
    EuroFirefighter.com
    PaulGRIMWOOD's Avatar
    Join Date
    Jul 1999
    Location
    UK
    Posts
    831

    Default

    BLSboy - Yes your text book analysis of Flashover and Backdraft phenomena is exactly that .... 'text book' But in reality there are many more aspects from a practical point of view.
    • Flashover is mainly heat-induced
    • Backdraft is mainly air (oxygen) induced
    • Flashover may also be induced by air being fed into the fire area
    • Pencilling a straight stream is one way (but not the best way) of tackling flashover conditions
    • Effectively pulsing water-fog will not upset the thermal layer
    • In such a large open plan area with even an average fire load, a well involved developing fire is not likely to be controlled by hand-lines alone
    • Backdraft conditions in small compartments or buildings may also be tackled using indirect water-fog from the exterior
    • Any openings on the C side as you discuss might be difficult to create and not offer us too much more in way of a tactical advantage

  25. #25
    Forum Member

    Join Date
    Apr 2006
    Posts
    26

    Exclamation

    If I remember correctly, 20 years ago Chief Vincent Dunn expressed in a lecture he was giving on rollover and flashover, that venting store front windows should be delayed as long as possible, or not attempted during offensive operations. He suggested considering the location of a fire, in relation to the window openings, in a building with a higher ceiling. The fire itself will be present once it grows, along with the heat and gases, at the ceiling level. Opening store front windows, horizontally venting, allows air in below the fire. If you consider the theoretical model of the pot belly stove it's quite apparent what he meant. He summed it up by saying it is a difficult decision for a fire officer to determine when horizontal ventilation would be more of a detriment than a benefit. I took away from the class that there is a point in a fires growth when horizontal venting allows fresh air in to feed the fire, and the horizontal opening that was created cannot effectively release the resulting growth of the fire.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Venting Roofs with Solar Panels
    By malba49 in forum Firefighters Forum
    Replies: 12
    Last Post: 10-18-2009, 02:32 PM
  2. vertical venting...
    By KevinFFVFD in forum Firefighters Forum
    Replies: 8
    Last Post: 05-20-2007, 09:50 AM
  3. Just venting some steam...
    By InAndUp in forum Career/Paid Firefighters Forum
    Replies: 132
    Last Post: 11-09-2002, 06:11 PM
  4. Metal Deck Roof Venting
    By JBCat in forum Firefighters Forum
    Replies: 6
    Last Post: 07-10-2001, 05:34 PM
  5. Venting Gas Friend or Foe
    By BURNSEMS in forum Fireground Tactics
    Replies: 5
    Last Post: 10-04-1999, 01:56 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

Log in

Click here to log in or register