Which class of lasers has the potential to present a fire hazard?

Class 4 lasers are known for having the potential to present a fire hazard due to their high power levels and the ability to produce intense light. These lasers can emit a beam that is capable of igniting combustible materials, especially if focused or directed at flammable substances for an extended period.

The characteristics of Class 4 lasers include output levels greater than 500 milliwatts (mW) and their ability to cause severe burn injuries, as well as damage to materials and other objects they interact with. When considering fire safety, the high energy output combined with the potential for sustaining an ignited beam means there must be strict controls and precautions in place when using Class 4 lasers in any environment.

Other classes, such as Class 1, Class 2, and Class 3b, do not possess the same level of fire hazard potential. Class 1 lasers are considered safe under all conditions of normal use, Class 2 lasers are low-powered and can briefly cause damage under certain circumstances, but not typically sufficient to ignite materials. Class 3b lasers, while they can cause eye damage and skin burns, generally do not have the energy levels required to ignite combustible materials. Therefore, Class 4 lasers stand out as a significant concern in