Interesting that the system just spreads a blanket of foam at low level when a fire could start at any height.
In 1993 I was one of the two pilots who took a BA B747-400 down to the new maintenance facility at Cardiff. Everybody there was very proud of the place and we were given a guided tour. We were also shown some pictures of the fire suppression system test during commissioning of the building. This is also a foam system. What was quite amazing was that the hangar in the photograph we were shown had foam that was probably 30' or 40' deep! That would be effective.