The UL (FRSI) study on PPA (2016)suggest back flow through inlet will always occur. It's noted that continuous monitoring of inlet is important to determine whether back flow is increasing or decreasing to determine adequate exhaust. In all the studies the cone of air completely covers inlet. UL does not mention anywhere any benefits of having cone of air 6" lower for the inlet (video 2013). I'm having difficulty finding research to indicate that cone of air 6" lower is a better option, please advise. Thanks
Would it be possible to use a large heat-resistant fan for negative pressure ventilation near the seat of the fire? I would think that in cases where that would be practical, it would be safer than positive pressure, without the risk of pushing the fire to places where it otherwise wouldn't go.
@@ffjsb How about a fan which is placed below a window, aimed upward to reduce the air pressure right outside the window, along with a sprinkler bar placed above the window so that the expanding steam would divert the fire gases away from the wall or eaves above?
@@ffjsb The purpose of the fan would be to reduce the air pressure immediately outside the window, thus in turn increasing the fraction of fire gases that would go out the window instead of going elsewhere into the structure. In the absence of a spray bar, I would expect this to reduce the spread of fire and smoke inside the structure, but having all of the hot flammable gases mixing with air outside the building could endanger exposures or upper parts of the structure. The purpose of the spray bar would be to guard against such damage. As I see it, both positive pressure ventilation in the unburned area and negative pressure ventilation outside the burning area would both have similar objectives and effects, but in some cases safely using negative pressure immediately outside the fire area may require less reconnaissance and preparation. If one uses positive pressure ventilation when there is an unburned area between the fire and an exterior vent, the positive pressure ventilation might push the fire into that unburned area. If one can see that flames are coming outside a window, that would be a pretty good indication that drawing flames out the window won't propel the fire into an unburned area.
Chief, thanks for the video. I've never been a big fan of pp attack just because there are too many unknowns. The layout of the house, although somewhat predictable, can never be 100% known. You can never be certain where all the fire is and if you make a mistake the results can be catastrophic. Also as soon as you open the door you will grow the fire and elevate the heat and that's before you throw a fan. With all do respect, it's just to risky. Why not make the conditions more attainable by making a quick exterior knock down, controlling the flow path, then putting the fire out. Use ppv in a much more known atmosphere, after you've made some progress. Just food for thought. I would hate seeing someone get burned because they made the wrong call at the wrong time, because that would be easy to do with pp attack due to all the variables. All the best!
Such an incredible video with relatively few views. It's a shame. This is really important, educational stuff.
The UL (FRSI) study on PPA (2016)suggest back flow through inlet will always occur. It's noted that continuous monitoring of inlet is important to determine whether back flow is increasing or decreasing to determine adequate exhaust. In all the studies the cone of air completely covers inlet. UL does not mention anywhere any benefits of having cone of air 6" lower for the inlet (video 2013). I'm having difficulty finding research to indicate that cone of air 6" lower is a better option, please advise. Thanks
I am indian 🇮🇳 Proud of Fire fighter
Very well done. Lt. Rick K. Jr. MFD
great video Chief
greetings from NEW TAIPEI CITY FIRE DEPARTMENT!
!
Would it be possible to use a large heat-resistant fan for negative pressure ventilation near the seat of the fire? I would think that in cases where that would be practical, it would be safer than positive pressure, without the risk of pushing the fire to places where it otherwise wouldn't go.
Heat resistant... not going to happen...
@@ffjsb How about a fan which is placed below a window, aimed upward to reduce the air pressure right outside the window, along with a sprinkler bar placed above the window so that the expanding steam would divert the fire gases away from the wall or eaves above?
@@ffjsb The purpose of the fan would be to reduce the air pressure immediately outside the window, thus in turn increasing the fraction of fire gases that would go out the window instead of going elsewhere into the structure. In the absence of a spray bar, I would expect this to reduce the spread of fire and smoke inside the structure, but having all of the hot flammable gases mixing with air outside the building could endanger exposures or upper parts of the structure. The purpose of the spray bar would be to guard against such damage.
As I see it, both positive pressure ventilation in the unburned area and negative pressure ventilation outside the burning area would both have similar objectives and effects, but in some cases safely using negative pressure immediately outside the fire area may require less reconnaissance and preparation. If one uses positive pressure ventilation when there is an unburned area between the fire and an exterior vent, the positive pressure ventilation might push the fire into that unburned area. If one can see that flames are coming outside a window, that would be a pretty good indication that drawing flames out the window won't propel the fire into an unburned area.
I just had a class on Tactical Ventilation. I want to experience field training to put it into practice
Where can I go.
Great video.
Chief, thanks for the video. I've never been a big fan of pp attack just because there are too many unknowns. The layout of the house, although somewhat predictable, can never be 100% known. You can never be certain where all the fire is and if you make a mistake the results can be catastrophic. Also as soon as you open the door you will grow the fire and elevate the heat and that's before you throw a fan. With all do respect, it's just to risky. Why not make the conditions more attainable by making a quick exterior knock down, controlling the flow path, then putting the fire out. Use ppv in a much more known atmosphere, after you've made some progress. Just food for thought. I would hate seeing someone get burned because they made the wrong call at the wrong time, because that would be easy to do with pp attack due to all the variables. All the best!
hard from the yard first (cool) then go in with PPV
and know your wind conditions if a large window fails, that fan is not going to save you.(with large wind conditions go with the wind)
Excellent