Exit lights shall be green LED and have stencil face with green letters. In small renovation projects, red LED may be used to match existing signs. In architecturally-sensitive applications: use edge-lit type such as Lithonia LRP.
Flush mount types are desirable because they are more vandal-proof. Consider vandal-resistant models for dormitory design.
Self-contained exit signs powered by a radioactive source (tritium or similar) and photoluminescent exit signs are not acceptable.