I am working on a point involving the coal fire. I am Prof. Emeritus Fire Protection Engineering U of Maryland. I am a safety regulatory specialist with publications on carbon monoxide. My biggest problem with the bulkhead theory is the products of combustion /fire size issue. Everyone , including "fire and ice" focuses on
temperature , which is meaningless. A match and a forest fire have the same
temperature. references to temperature in reference to heating the water in the swimming pool are likewise meaningless.
The key issue is fire size which is measured in
watts. (Or BTU/hr) Titanic's fire is an under ventilated smoldering coal fire in a closed steel compartment That means carbon monoxide as a fraction of combustion products is enormous.
That's whey they tell you a charcoal barbeque indoors can kill you quickly.
Carbon monoxide is an odorless gas that causes thousands of deaths each year in North America. Breathing in carbon monoxide is very dangerous. It is the leading cause of poisoning death in the United States.
I have asked about the trimmers openings at the top of the bunkers and I have some measurements for the doors at the bottom. That is the air supply which determines the burning rate and heat output. in the normal case cold air would enter at the bottom and hot products of combustion vent out the top, unless the fire is of a near trivial size those products of combustion are lethal . If the trimmers openings at the top are closed the combustion gets more complex and the CO can go through the roof.
Yuan and Smith CO and CO2 emissions from spontaneous heating of coal under different ventilation rates
October 2011 International Journal of Coal Geology 88(1):24-30
Now if the fire is small enough and has enough air the CO itself can burn to CO2. Boilers are designed to make that happen Coal bunkers are not.
Coal bunkers are normally designed to feed coal by gravity to the access door so working the coal out did not require entering the bunker However if ther is a substantial concentration of carbon monoxide anyone near the door would be directly affected.
These all argue for a persistent but very small smouldering fire