Flame turrets work based on the building privilege system (firing at those without it). When players are present, and within the 90-degree cone in front of the flame turret, the trap will activate, dispensing a considerable amount of fire in a frontal arc up to roughly a foundation square in front of the trap.
When the turret is not engaged, it will sweep a 90-degree arc, with its flame spout menacingly surveying the area in front of the device. This trap also makes an eerie rattling noise as it pivots.
Despite the amount of fire shot out, it is remarkably hard to drain a flame turret. It simply doesn’t use much fuel.
The only viable way to destroy turrets is to damage them from range or utilize another explosive device. For players placing them, they may also be picked up later.