As determined by the American National Standards Institute (ANSI), there are standard guidelines established for different classes of high-visibility safety vests that are based on specific garment reflectivity needed by workers in an environment where visibility is important. The guidelines, which are known as ANSI 107-2004, designate safety vests into Classes I, II and III that workers have to wear when performing jobs where traffic may pose risk or safety issues, as noted by the Libra Safety website.
Class I safety vests are designed for workers in low-risk environments, such as in a warehouse or on sidewalks where there is little traffic or traffic that is not moving faster than 25 miles per hour. Class I vests need to have 155 square inches of reflective tape and 217 square inches of a material that has a fluorescent background, as noted by the Safety Gear Online website. These vests can yellow or orange and only cover the torso area.
Class 2 safety vests are for working in an environment where traffic is about 50 miles per hour and workers require higher visibility. Workers using these vest types can include crossing guards or baggage handlers in airports. The ANSI standards for these vests require that they contain at least 775 square inches of background material and 201 inches squared of reflective material.
Workers, who require the highest visibility in a working environment, need to wear Class III safety vests, which consist of at least 1,240 inches squared of fluorescent background material and 310 inches squared of reflective material, as noted by Work Zone Safety.