There is another discussion in our group and since my Google Foo and Rules Lawyering skill is not very high, I decided to bring this up.
According to swarm traits
A swarm composed of Fine or Diminutive creatures is immune to all weapon damage.
After that it stated that:
A swarm is immune to any spell or effect that targets a specific number of creatures
And main thing about alchemist fire/bomb is that:
A swarm takes half again as much damage (+50%) from spells or effects that affect an area, such as splash weapons and many evocation spells.
From description of splash weapon:
A splash weapon is a ranged weapon that breaks on impact,
means splash weapon is a weapon, not spell or effect. More over is says:
A hit deals direct hit damage to the target, and splash damage to all creatures within 5 feet of the target.
I rule that statement C (defined later than A or B), overrides both statement A and statement B, allowing any splash weapon to be an exception from weapons that can attack swarm and making it deal extra half again as much damage (+50%), despite not being spell or effect (confirmed by statements D and E).
Do you agree on my ruling or you think it should be otherwise around?
If there is some official statement about alchemical fire vs swarm than, could you please link it up. I am already aware about damaging swarms with flaming/cold/electricity weapon and damaging swarms with rays.