If you want the igniter to not care that there are other objects in front use Sphere ignite.
Check frequency: How often the raycast is raycasted (Only if Repeating raycast is checked)
Raycast Radius: Radius of the raycast.
Ignite power multiplier: If an object has Ignite time, how much ignition progress is added with each raycast. Current ignition time += Ignite power multiplier * Time.deltaTime.
Mask: Raycast mask.
Repeating raycast: Start repeating raycast on Start()