Facilities are the most consistently underused alliance content in the game: permanent buffs, a predictable capture rule, and — at three of the four levels — no dead troops. Century Games documents the whole system.
Six types, four levels
The published list of Facility types is Defense, Training, Gathering, Tech, Expedition and Production. Facilities come with different levels, and the higher the level, the more powerful their effects after occupation. Pick targets by what your alliance is short of, not by what is closest — a Training Facility is worth far more to an alliance mid-troop-upgrade than a Gathering one.
You cannot attack what you are not next to
The rule that stops most first attempts: you need to first connect Alliance Territory with the Facility on the map. The official answer to "why can't I battle to occupy a Facility" is simply check whether your alliance territory is adjacent to your target. Facility campaigns are therefore territory campaigns first — you expand toward the buff, then fight for it.
Once the countdown ends, the battle begins, and the capture condition is time held: Lv. 1 — 15 minutes, Lv. 2 — 20 minutes, Lv. 3 — 25 minutes, Lv. 4 — 30 minutes. And a clause worth planning around: if a Facility is not occupied within 24 hours, control is given to the alliance that previously occupied it. Stalling a contest until the clock runs out favours the incumbent — useful when you are the incumbent, fatal when you are not.
The first time a Facility is occupied, the occupying alliance obtains rewards.
The casualty rule, and the myth it kills
Century Games: other than the battles at Lv. 4 Facilities, which result in lost troops, battles at Facilities of other levels only result in severely injured troops.
Two things follow. First, Lv. 1–3 Facility fights are close to free practice — severely injured troops are recoverable, so contesting them is the cheapest real PvP experience your alliance can get. Second, Fortress battles are not the only alliance content where troops die. Lv. 4 Facility battles kill too. If your alliance treats a Lv. 4 push like a Lv. 2 push, you will find out the hard way — expand your Infirmary first.
Protection, and what survives a server transfer
After Protection Status activates, the Facility stays protected for 3 days. That is your consolidation window: three days where the buff is yours and nobody can take it, which is exactly when you should be pushing territory toward the next target rather than resting.
Two short official answers that matter to anyone moving servers. Do Facility buffs remain effective after crossing the server? Yes. And can you attack players in the same state but from different alliances after crossing? Yes. So the buffs you hold travel with you, and crossing does not make you safe.
Why this belongs in your Canyon Clash prep
One connection most alliances miss: Facility buffs are on the list of buffs that work inside Canyon Clash, while deployment capacity, marching speed and rally buffs are not. Taking a Facility in the week before a Clash is one of the few things that measurably improves your legion's performance in a battlefield where most of your stat sheet is switched off.
Sources: Facilities — types, hold times, casualty rule · Why can't I battle to occupy a Facility · Facility protection lasts 3 days · Facility buffs after crossing the server · Attacking other alliances after crossing · Facility buffs work in Canyon Clash