What is NFPA 520?
This standard is to provide minimum requirements for the design, operation, and maintenance of developed subterranean spaces for safety to life and property from fire and similar hazards associated with subterranean spaces that are developed for public assembly, business, industrial, or other uses.
Official document scope
What does NFPA 520 address?
Criteria cover design, operation, and maintenance concerns including construction features; means of egress; fire alarm, detection, and suppression systems; emergency preparedness; and fire department provisions. This standard does not cover the following types of subterranean spaces: (1) Tourist caverns (2) Wine storage caverns (3) Gas and oil storage reservoirs (4) Hazardous waste repositories (5) Utility installations such as pump stations (6) Working mines (7) Transportation and pedestrian tunnels (8) Aboveground buildings with belowground stories (9) Cut and cover underground structures specifically addressed in the building code