LED is very solid, because they are enclosure and do not have fragile filaments. In addition, in comparison, the service life of incandescent bulbs is only 3,000 hours, while LED can provide more than 50,000 hours of reliable light and the maintenance period also extends from three months to once a year. According to the US National Institute for Occupational Safety and Health (National Institute for Occupational Safety and Health, referred NIOSH) studies, it have shown that the probability of the accident occurrence during the bulb or lighting maintenance during maintenance is up to 53%. Thus, LED possess longer life and safety package (no glass shell) feature, reducing the chance of worker exposure in danger.