After some quick research, I find the regs are unclear and ambiguous about the most common types of fuel and stove alternatives in use. They specifically allow "jellied petroleum" which seems to mean "Sterno" fuel, which is actually a jellied alcohol. Does anyone have a stove that burns "jellied petroleum?"
Some alcohol stoves have simmer features which can extinguish the flames if fully closed, there's your "valve" but the regs say nothing about a valve.
"Pressurized liquid" fuel is allowed, although flare ups are a common issue - much more dangerous than spilling an ounce of alcohol. Technically, an alcohol stove is a pressurized liquid stove, it just operates at a very low pressure differential, but it's the same physics - the liquid fuel vaporizes and the resulting gaseous mixture burns through port holes driven by a pressure difference (higher pressure within the stove than externally). The liquid alcohol does not actually burn. I'd hate to argue this to a jury, but it illustrates how the regs are unclear.
No mention of Esbit fuel tabs, which does not flare, spark, spill, or spread.
The NFS needs to get up to speed with the latest products out there, apply some common sense (the most difficult part) and be more specific. I would expect different answers from whoever you happen to get on the phone on any given day.
And one last rant: Regulations should be based on risk backed up by science. They should clearly prohibit or allow certain fuels (e.g. wood), or stove types (e.g. BBQ grills), or some combination, and/or include general prescriptive requirements (e.g. no sparks, spills, combustible fuel with 3ft radius etc etc). This is way too much effort for understaffed and underfunded bureaucrats to fix. Play it safe, there's too much at stake.