Method Charcoal Calculations. Time Required and Things We Probably Did Wrong.

[faust]

Warning! This thread should not be considered an instruction until all the information provided is proven! ​

Hello, I found an interesting source of information.
This is a semi-scientific research on how long different brands of charcoal burn and how much ash produce. We need the first one.
There were some calculations of amount per square units required before:

Wayback Machine

However, I kept asking myself what is the time required to reach a certain concentration if we have no gas analyzers.
According to provided information, the burn time is different but if we divide maximum and minimum time we will get a value less than 2 and that is not a bad news.
Here is the link: http://www.nakedwhiz.com/burntimetest/lumpcompare.htm

This is a very rough estimation, however, so we can understand what we are doing wrong.

If we burn 5 pounds, we get these results:


Or hours per pound:


Let's return back to first source where we needed to calculate the amount of charcoal needed per square unit.
For example, our tent is 4 cubic meters and it is hermetic (all the surfaces are covered with plastic )
The weight of CO in 1 m3 at 100% concentration is:W g = 28.01/22.47*1000= 1247 g
The weight of a gas, in grams, in 1 m3 at a concentration of c, where c is the concentration as a percentage, is:Wc g = W g * c / 100
The weight of CO in 1 m3 at 1% concentration (10 000 ppm) is:W1 g = (28.01 / 22.47) * 1 / 100= 12.47 g
The weight of CO at 1% concentration in a tent of 4 m3 volume is: W tent= 12.47 g * 4= 49.88 g
The proportion of a CO molecule that is carbon is 43%, so the weight of carbon in a tent containing 1% CO is:W carbon = Wtent* proportion of CO that is carbon= 49.88 g * 0.43= 21.4484 g
Finally, the proportion of carbon in the charcoal briquettes used in this incident, as stated in manufacturer information, is 85%. Therefore, the weight of briquettes needed to produce 1% CO in a 4 m3 tent is:W briquettes = W carbon / proportion of briquette that is carbon= 21.4484 g / 0.85= 25.2334 g
Let's assume all the charcoal on market has these 85%, if you know what is the amount of carbon in your charcoal, you can simply change the number.
Now let's go on to the source I found.
We have a range from 1.3 to 2.14 hours/pound. 1 pound is 0.45359 kg
Let's change hours to minutes. It will be 78 and 128,4 minutes appropriately.
As we stated above, we need 25.2334 g of charcoal
0.45359 kg = 453.59 g
In order to get the time required for 25.2334 g to burn, we have to create a proportion:
25.2334/453.59 = TIME1/78 - first case
25.2334/453.59 = TIME2/128.4 - second case
TIME1 = 25.2334*78/453.59 = 4,339 minutes. - that's for 1.3 hours/pound charcoal
TIME2 = 25.2334*128.4/453.59 = 7,1429 minutes - that's for 2.14 hours/pound charcoal
So if we have 5 pounds of charcoal and a hermetic tent, we may need from ~4 to ~7 minutes to reach concentration of 10,000 ppm
Mathematically, though not practically, but it gives a better understanding

Now the interesting part. Failed suicide attempts.
Most of us do not take into account that the information provided here https://web.archive.org/web/20170810020449/https://d.filebox.moe/gegqcwgg.pdf
covers the case when all the charcoal is burnt. But as we know, charcoal burns good amount of hours.
So what will we get if we use only this information? Let's do one more calculation.
On that website we knew that 629 g is for 100 m3 apartment to reach 10,000 ppm, so if we take 5 pounds of charcoal (2267.96 g) and use in the same apartment, the concentration when all charcoal is burnt should be: CONC = 2267.96*10000/629 = 36,056.6 ppm.
However, this concentration is not reached in an instance. If we take Kingsford, it takes 7.72 hours to burn it.
So if we want to know how long it will take to reach 10,000 ppm, we can calculate again and we will get: 7.72*10,000/36,056.6 = 2.14 hours.
2.14 hours for amount which is almost 4 times higher than shown on first website!
I heard enough stories of failed CO attempts and now we found what may happen if we blindly use information from the net and probably for somebody that was the reason why 30-40 minutes did nothing except for a terrible well-being and CO poisoning.

@GoodPersonEffed Might be interesting for you as well.

If you have any information concerning this or disagree with anything, please, feel free to share!