re: Wal Mart Sprinklers

Here's how a sprinkler system in a Walmart works. The entire building is sprinkled, including bathrooms and offices. There are usually 4-6 systems per store, most filled with water with some filled with air in weather exposed areas. When a fire starts in an area, the heat will pop a sprinkler head and start spraying that area only. If the fire is large, it may pop more heads in that area. But it will not spray water in a different area. These systems at Walmart typically have a fire pump installed so you're looking at 150 psi coming out of a 1/2" or 3/4" orifice. That's a lot of water coverage. And a lot of damage.