Making NPCs immune to fire?

I’m trying to make a script that involves invincible flaming zombies, but after a few seconds they always die, even though I’ve added a hook to disable them taking damage at all.
I’m assuming this is because they’re coded to be killed X seconds after being ignited, or something. Anyone know what’s going on, and how I could fix this?

Thanks a billion!

Edit: Don’t need this anymore, lock/delete whatever.

Surround the Entity:Kill() in your ignite script with

[lua]if ( !Entity:IsNPC() ) then
// do kill
end[/lua]

The ignite script is just ent:Fire(“ignite”, “”, 0) and it’s only run on a zombie, so I’m not sure if that would help at all.
Apparently they die because the animation sequence is set to kill them after a certain amount of time, so I don’t think I can modify that with Lua.

I ended up making something other than flaming zombies though, so I don’t need this anymore. Thanks anyway though.