Miss. Code Ann. § 45-11-107

Unless otherwise provided, Sections 45-11-101 through 45-11-111 shall apply to new or remodeled buildings, installations, equipment or conditions; however, Sections 45-11-101 through 45-11-111 shall also apply to existing buildings, installations, equipment, conditions and occupancies where safety to life requires compliance with Sections 45-11-101 through 45-11-111 , as determined by the state fire marshal.