In most cases you need to install sprinklers in your cleanroom. There are two exceptions. One, the city your cleanroom is located in may not require sprinklers. Two, if you have a different approved fire suppression system.
Most new cleanrooms used recessed head fire sprinklers. This provides a smooth cleanroom ceiling surface that does not collect dirt and is easy to clean. When there is a fire the sprinklers push the cover out of the way, and the sprinkler head descends into the cleanroom.
Older cleanrooms may have exposed fire sprinkler heads. The disadvantage of this design is the sprinkler head can collect dirt. It is also easily damaged if you are trying to wipe down or mop the cleanroom ceiling.
There are other options to fire sprinklers in cleanrooms. There are foam fire suppression systems and freon based fire suppression systems. They are significantly more expensive to install in your cleanroom and have significant annual testing costs. However, some cleanrooms have chemicals that can be explosive if exposed to water that prevent the use of water fire sprinklers. Other cleanrooms have millions of dollars of equipment and do not want to risk water damage.