Tier Law and Legal Definition
According to 6 CFR 27.105 [Title 6. Homeland Security; Chapter I. Department of Homeland Security, Office of the Secretary; Part 27. Chemical Facility Anti-Terrorism Standards; Subpart A. General] the term tier shall mean “the risk level associated with a covered chemical facility and which is assigned to a facility by the Department. For purposes of this part, there are four risk-based tiers, ranging from highest risk at Tier 1 to lowest risk at Tier 4.”