We have 2-story storage areas which are stored group A plastic material. The ceiling height of each story is 6 m and storage height of each story is 5.5-6 m. Storage type is shelf storage; depth of shelf is 1.50 m and height of shelf is approximately 1m. The type of slab of the second story is grille which has 50% opening. How we can protect our 2 story storage areas? Do we have to use in-rack sprinkler type?