Buildings in San Francisco, California, that have been in operation for forty (40) years or more must undergo structural and electrical inspections in order to assess their general structural and electrical condition and determine whether they are safe for continued use with the current occupancy. San Francisco Structural Engineering carries out structural, electrical, infrared thermography, parking lot illumination, and guardrail certification examinations and gives property owners the required paperwork for compliance with the 40 year recertification criteria.