Terrance brings up an interesting point. Post crash fires are apparently responsible for many fatalities. I suspect that the exact number of fatalities that can be attributed directly to the post crash fire is difficult to determine as a crash survivor may be fatally injured but alive at the time of the fire.  I do not think there is an effective solution for fuel carried in the wings but, armoring fuel carried in the passenger compartment may be desirable.

Race cars achieve fuel safety by limiting the amount of fuel on board, holding the fuel in a foam filled rubberized fuel bladder, placing that bladder within the protective structure of the car and (in the case of formula cars) adding energy absorbing material (aluminum honeycomb) to the nose of the car. Race car fuel vents are typically large diameter as rapid fueling is usually a requirement. The fuel vents feature a Discriminator Valve that will allow air to pass but will close in the presence of fluids. In human physiology this functionality is provided by the anal sphincter.

Implementing effective race car type fuel safety in an airplane is problematic because it would involve one or more of; increased cost, increased weight, reduced range and increased maintenance.  In a IV or ES you would need roughly 22 unique fuel bladders that would require interconnections (fuel and vent) and be removable via access hatches for maintenance. Since wings are sometimes "removed" during accidents, the individual bladders would need to maintain their integrity and the fuel and vent lines would need to seal.  Bladders have been used in aircraft applications. Many spam cans use them and, in one Lancair case, I was involved in the design of a bladder tank that was installed in the back seat of a IV to provide additional fuel for transoceanic flights.

Back in the 1970s and '80s research was conducted to investigate adding aluminum foam to the fuel tanks of airliners. The foam would limit the vaporization rate of the fuel and therefore limit the fire expansion rate.  This research culminated in the radio controlled crash of an airliner in the desert. Unfortunately, because of poor controllability, one of the jet's engines struck the  "wing rippers" installed on the runway  and the hot engine parts defeated the foam suppression. A spectacular fireball ensued. Bummer.

My gut tells me that adding fuel bladders to the wings will have only a limited effect on safety and be prohibitively expensive to install and maintain. The increased opportunity of a fuel leak (and loss) may actually increase the probability of an accident even if decreasing the probability of a post crash fire.

The header tank is another matter altogether. I don't think it is ever a good idea to have large quantities of flammable or hot fluids in the passenger compartment. If you must have fuel in the passenger compartment then armoring against taking a 100LL shower is a good thing.

Regards
Brent Regan