Controls: Isolations are NOT required UNLESS the works will directly impact or have the potential to impact adjacent fire systems, or where large amount of dust is likely in which case 5.1.2 applies. Removal of ceiling tiles (not more than 4 nos.) adjacent to installed fire systems does not generally require isolation; however, extreme care should be taken when working at heights which may knock the sprinkler heads. Fire watch is required only if fire detection systems are to be isolated and work area is being unmanned.