The Social Network & Community JUST for Firefighters
Inquiry on Fire Loading
Hello all, it's been a while. I sincerely hope that everyone is keeping safe out there on the field and being the best they can be.
I'm taking a course this semester at Seneca called, "Building Construction and Fire Protection" and it seems to have a lot of great information to pick up. One of the texts we are using is:
"Brannigan's Building Construction for the Fire Service"
It is a very good read so far, and if you haven't read it nor have it in your library of resources, I highly recommend it! It's a text chock full of fire science, how it applies to buildings and tactical considerations for the fire service.
Anyway, the post header does say inquiry, so here is the inquiry.
I've been reading up on fire loads (I do believe some people also call this fuel loads) which represents the potential fuel available to a fire. In this particular section of the text, it states that every combustible material has it's own caloric value.
For example, Brannigan's text states: "Wood, paper and similar materials are estimated at 8000 BTU/lb. For plastics and combustible liquids, 16 000 BTU/lb is a common estimate, though the value for some of these fuels is much higher"
I understand it's part of a firefighter's job to estimate the amount of water (given it's a material to safely use water on) to use on a material to extinguish it. My inquiry is, just how much water?
If we say for example, that for every pound of paper on fire, which is 8000BTU/lb, and given that water's latent heat of vaporization is 970.3 BTUs, would that mean that a firefighter could estimate the # of gallons (litres for us Canadians, even though we probably still use the imperial system for such measurements of volume) to use on a fire? Or is it a little more complicated than that. I understand that there are many variables involved in such a circumstance, however, it is something that's been itching at the back of my mind. I apologize in advance if I've made this sound more complicated than it should be.
Thank you all for your time, it is appreciated. I've also attached an image of what the text looks like in case anyone is curious.
Cheers!
-DJ
I'm taking a course this semester at Seneca called, "Building Construction and Fire Protection" and it seems to have a lot of great information to pick up. One of the texts we are using is:
"Brannigan's Building Construction for the Fire Service"
It is a very good read so far, and if you haven't read it nor have it in your library of resources, I highly recommend it! It's a text chock full of fire science, how it applies to buildings and tactical considerations for the fire service.
Anyway, the post header does say inquiry, so here is the inquiry.
I've been reading up on fire loads (I do believe some people also call this fuel loads) which represents the potential fuel available to a fire. In this particular section of the text, it states that every combustible material has it's own caloric value.
For example, Brannigan's text states: "Wood, paper and similar materials are estimated at 8000 BTU/lb. For plastics and combustible liquids, 16 000 BTU/lb is a common estimate, though the value for some of these fuels is much higher"
I understand it's part of a firefighter's job to estimate the amount of water (given it's a material to safely use water on) to use on a material to extinguish it. My inquiry is, just how much water?
If we say for example, that for every pound of paper on fire, which is 8000BTU/lb, and given that water's latent heat of vaporization is 970.3 BTUs, would that mean that a firefighter could estimate the # of gallons (litres for us Canadians, even though we probably still use the imperial system for such measurements of volume) to use on a fire? Or is it a little more complicated than that. I understand that there are many variables involved in such a circumstance, however, it is something that's been itching at the back of my mind. I apologize in advance if I've made this sound more complicated than it should be.
Thank you all for your time, it is appreciated. I've also attached an image of what the text looks like in case anyone is curious.
Cheers!
-DJ
- Attachments:
-
-
0763778028.jpg, 54 KB
-
Replies to This Discussion
-
Permalink Reply by Paul Montpetit on
-
MAYBE IN AN IDEAL WORLD ONE MIGHT BE ABLE TO COMPUTE WATER USAGE.....but...THIS IS NOT AN IDEAL WORLD.....OOPS, SORRY ABOUT THE CAPS.....lol...One would also have to realize that not every gallon used will hit the fire and also that energy transfer is not an exact science as well......that's the problem with some "school" courses....many here graduated for schools of higher learning...some from the school of hard knocks....still comes down to putting the wet stuff on the red stuff.....Paul
-
Permalink Reply by Vic Silverfish on
-
It is interesting to do the math and figure out how much water could theoretically be used to extinguish a fire, but the reality is you will never do this in the field. I think we figured a room and contents could be extinguished with just a few litres of water if you were able to convert 100% of it to steam. Of course, there are a ton of confounding factors that make that impossible, so the old adage of "big fire, big water" will always be the driving force behind deciding how to attack a fire. The take home message that I got from his book (admittedly, I read it a LONG time ago) was that you need to be aware of the potentially different amounts of heat coming from a fire.
Example - take a ton of 2x4s as they come off the back of a truck, bound and held together with metal straps. Light that on fire, if you can. How much heat is coming off of that? Now, take the same 2x4s and build a house frame. Light that on fire. A lot more heat, because the amount of available fuel is a lot higher. You would need more water, and your attack may need to be more defensive.
Another example - whenever an old warehouse or factory burns in NY, the fire is much hotter than you would expect from the years of oil and wax applied to the floors. These add a lot of calories to the fire that you might not expect if it was only wood burning.
© 2024 Created by Firefighter Nation WebChief.
Powered by
