Diesel or petrol pumps for the water....
The main problem with petrol as a fuel for machinery involved with firefighting is that petrol vapourises at a lower temperature than diesel. This caused the death of the Cockatoo crew in the Dandenongs part of the Ash Wednesday fires of 1983. Their fire truck had a petrol motor and, when they stopped on a fire trail to check on the approach of a fire the motor was turned off. The petrol in the fuel line vapourised and created a gas lock, preventing liquid fuel from reaching the carburettor and getting the vehicle started. Following a recommendation from the subsequent Royal Commission, all CFA vehicles (and their pumps) commissioned since then have had only diesel as fuel. The fact that diesel motors use liquid fuel injected into the combustion chamber (rather than relying on a vapour fuel) helps.

It's gonna get AWFUL hot inside that place if there is a fire. The windows will shatter if they get hot enough or if water hits the hot glass.

It might be fireproof construction, but the interior can burn like Hell in high wind.

I think your man has covered those contingencies with his metal screens fitted over the doors and windows. Of course, he has to be there to fit them but, from the report, I gather he is close to retirement age.

I hope he's planning to evacuate when a fire comes again. I would hate to be inside when the oxygen is sucked out and his "air supply" explodes in the heat.

I may be misinterpreting Rapaire's gist here but the notions that houses have the air sucked out of them and explode need some clear thinking applied.

People's accounts of their houses exploding were carefully investigated after the Ash Wednesday (and subsequent) fires; almost all involved a window (usually a large one) directly exposed to the flame front. Most of a room's contents are flammable and plastics (you'd be surprised how much plastic there is in most houses) vapourise under intense radiation coming through windows. With a superheated vapour/air mix in the room it only takes a small ignition source (often a spark through a ventilator or the glass breaking) and you have sudden conflagration of the mix. It seems like an explosion. It is also the only circumstance where "oxygen is sucked out" of a house that isn't densely surrounded by other built structures (vide Kurt Vonnegut's experiences in Dresden).

Your man's house is relatively isolated and I suspect his bunker with its air tanks is located where it would be relatively cool.

Cheers, Rowan