No, light fixtures in aircraft maintenance hangars do not inherently need to be explosion-proof. The requirement for explosion-proof fixtures depends on the specific hazardous materials or processes taking place within the hangar, and the proximity of the light fixtures to those hazards.In general, explosion-proof fixtures are necessary in areas where there is a potential for the presence of flammable gases or vapors, such as fuel storage areas or paint booths. However, if the light fixtures are located at a sufficient height above the floor and away from any potential sources of ignition, explosion-proof fixtures may not be necessary.For a hangar with a ceiling height of 90', the distance between the light fixtures and the floor is likely to be sufficient to mitigate any potential explosion hazard. However, it is important to consult with local building codes and applicable safety standards to determine the specific requirements for your particular hangar. Flag for review