Emergency lighting systems are used to help the occupants of the building exit safety in an emergency.It consists of many different types of fixtures, including exit signs, outlet lighting, and counterpanic fixtures.In the United States, emergency lighting requirements are formulated by local building regulations, which are usually based on the standards set by the National Fire Department (NFPA.The NFPA Standard 101 addresses life safety issues including emergency and outlet lighting.According to Section VII of nrfpa 101.9.2.1. emergency lighting must be designed to illuminate the area at least 90 minutes after the main power supply is interrupted.Initial lighting level during this 90-The minute cycle must be at least 10 minutes.8 lux (1 ft-Candles) average.Along the exit route, this lighting grade should be measured on the floor.Emergency lighting must be designed to automatically illuminate the exit route in case of emergency.According to Section 7, nrfpa 101.9.2.2, an emergency is defined to open a fuse on a primary power failure or an electrical panel.It can also be defined as any manual behavior that directly or indirectly affects the normal light level.These emergency lighting systems must run continuously or should be able to run automatically in separate cases without the need for manual reset.All emergency lighting must be on the generator or battery-Supply based on backup.According to NFPA 101 7.9.2.3. any generator used for emergency lighting backup power supply must be operated and maintained in accordance with the NFPA Standard 110.Standard 110 specifies the requirements and testing procedures for generators.In section VII of nrfpa 101.9.2.4, the standard of battery backup.According to this standard, reliable rechargeable batteries can only be used, and any batteries used must comply with the national electrical specifications.Section VII of nrfpa 101.9.3.1 declare that all emergency lighting components must be tested in accordance with one of the three specified methods.The first method is a test that lasts at least 30 seconds and must be done every 30 days.The second method can be used on a battery-powered system and must be performed for at least 90 minutes per year.The third test option allows the system to be tested with a special diagnostic device every 30 Angels.The owner shall keep all test and inspection records for review as required by the local fire chief.Section VII of NFPA 101 provides an overview of exit sign requirements.10.According to this standard, all exit signs must display the word "exit" with at least 6 inch letters.The logo must be continuously illuminated at any time the building is occupied.Lighting for exit signs must be provided at least 5-A bright foot candle that can be provided from an external or internal light source.These signs should be placed in all exit doors and stairwells and should be equipped with arrows if the exit path is not clear.