NFPA 520-1999 Standard on Subterranean Spaces.
2-4 Electrical Installations. 2-4.1 All new electrical and data communications cable shall comply with the requirements of NFPA 70, National Electrical Code ® . Exception: Nonmetallic conduit to address environmental conditions within common spaces shall be permitted. 2-4.2 Rooms used to store equipment for standby or emer- gency power generation shall be separated from the remain- der of the subterranean space by walls with at least a 2-hour fire resistance rating. 2-5 Control of Smoke Spread. 2-5.1* The movement of smoke between buildings and between buildings and common spaces shall be minimized in accordance with Section 2-5. 2-5.1.1* Exterior building walls as described in Section 2-2 shall be continuous from exterior wall to exterior wall and from floor to roof, including continuity through all concealed spaces, and shall provide an approved means of control of smoke spread. Where pillars are used, the pillar shall be con- sidered part of the exterior wall. 2-5.1.2 Interior smoke barriers required for specific occupan- cies by NFPA 101, Life Safety Code, shall be provided in accor- dance with NFPA 101. 2-5.2 Doors in exterior building walls as described in Section 2-2 shall be in accordance with NFPA 80, Standard for Fire Doors and Fire Windows, and shall be without undercuts, louvers, or grilles. 2-5.3 Dampers and air-transfer openings penetrating exterior building walls as described in Section 2-2 shall close upon acti- vation by heat detection or fusible link.
3-2.3* The travel distance to a portal, a refuge area, or the entrance to an exit passageway system shall be not more than 2000 ft (610 m). 3-2.4 When the occupant load exceeds 5000, a third exit lead- ing to the exterior of the subterranean space shall be pro- vided. 3-3 Occupant Load Determination. The number of occu- pants for exit width calculations from the common space shall either be based on 150 percent of the highest occupant load of a building or 2000 ft 2 (186 m 2 ) per person net floor area, whichever is greater. 3-4* Egress Capacity. The egress width within the common space shall be based on 0.2 in. (0.5 cm) per person for level travel and 0.3 in. (0.8 cm) per person for travel on stairs, based on the occupant load determined in Section 3-3. Exception:* Where a specific approved life safety evaluation of the space is provided. 3-5 Exit Doors. Any door in a required means of egress within the common space shall be openable from the inside without the use of a key or special knowledge or effort. 3-6 Illumination in Common Spaces. 3-6.1 Means of egress within the common space shall have illumination providing a minimum of 1 footcandle (10 lx) measured at the floor level at each hydrant location. Where the line of sight between hydrants is not possible, additional points of illumination shall be provided.NFPA 520 pdf download.