When you are working at a job which requires you to be exposed to high heat, electric sparks or even flames of fire, then you need to have adequate protective clothing over and above your regular work clothes. While AR (arc resistant) overalls are suggested for workplaces where electric sparks can fly, for workplaces with fire hazards, FR clothing is needed. FR stands for flame resistant. For people exposed to both risks, AR clothing is suggested, since it affords protection against flames as well, although the converse is not always true. But if you are in a workplace where you are only exposed to flames, the Fire Resistant Coveralls are the best bet for you.