The fire base was a USA base defense structure developed midway through the conflict with the GLA, following the emergence of weaknesses in the Patriot Missile System. The Fire Base was armed with a 155mm howitzer that could fire a considerable distance, and up to four infantry could be garrisoned around it.
While the howitzer itself was not powerful enough to sufficiently destroy incoming armoured vehicles by itself, garrisoned infantrymen, usually composed of Missile Defenders - would often be more than able to finish the job. Fire Bases worked best in tandem with Patriot Missile System. If garrisoned by a Pathfinder or Rangers, Fire Bases could provide US bases with the effective anti-infantry defense they were otherwise lacking.
In addition this was the only USA defense that did not require a continuous power supply, however it was still vulnerable to EMP weapons or a Microwave tank.
The most common way to utilize the Fire Base was to build a wall of patriots, a wall of fire Bases behind it with as little as a gap as possible between them, missile defenders in the Fire Bases to add extra anti armor/air to the defense and one pathfinder in each Fire Base to deal with infantry.
The Fire Base also did not cost anything towards power, so Generals could build them en masse without building plants, and they could be built nearby key buildings such as oil rigs in the early game, although they will need to be reinforced with other defenses and units as a match progresses, as either Jarmen Kell or a large amount of units will overwhelm it.
Up close against a squad of tanks a Fire Base was of little use, at least without Missile Defenders. The Fire Base itself was actually surprisingly fragile. Artillery units also had sufficient range to attack a Fire Base with impunity, and without garrisoned soldiers it was vulnerable to attacks from the air. Jarmen Kell's remarkable rifle had a surprising effect on Fire Bases, as he could destroy the Fire Base with two to three shots depending on his rank, This is because the Fire Base has only three operators (gunner, loader, and spotter), once they are killed by Jarmen Kell, the Fire Base becomes nonoperational, Thus, it is destroyed because defensive structures cannot be captured. Some fast moving units like the Combat Cycle could simply avoid the shells, also. Toxin and flame weapons like the Toxin Tractor could also kill the infantry garrisoned within it.
- Zero Hour patch 1.01: fixed a bug which caused infantry to become invisible but still selectable if a garrisoned Firebase was sold
- Zero Hour patch 1.03:
- armour adjusted to be vulnerable to snipers and immune to melee and laser damage
- fixed related unfinished building exploit
- A fire base in real life is larger and consists of an operations center, engineering and medical crews, communications and infantry support, alongside multiple (not just one) artillery pieces.
- Fitting in with the overall laser theme, the Fire Base of Laser General was supposed to get a laser guided attack just like the Missile Defender, dubbed "Laser Guided Howitzer". It was never implemented into the final game, Hovever, In the Zero Hour mod Rise of The Reds, the Laser Guided Howitzer was Reimplemented (with different name)
- If a Fire Base is destroyed, all infantry inside are killed as well, bursting into flames, Because of this, the Fire base is the only United States of America building which does not leave Rangers upon destruction.