The history of class 3A – A review Available to Purchase

The laser hazard classification system as we know it today has had few fundamental changes since it was first developed by the Z136 Committee in 1971-72, and published in the first edition of the American National Standard Z136.1 (1973). In this first edition, there were five classes, which were reduced to four general classes in the second edition to become compatible with the new (1976) US Federal Laser Product Performance Standard, 21CFR1040. The concept of Class 3A existed in the first editions of ANSI Z136.1, but initially was not given that label. It existed as a transitional subset of Class 3 with reduced requirements. As laser technology developed, the nomenclature 3A evolved to accommodate a power limit, and irradiance limit and expanded wavelength applicability. Now referred to as Class 3R for reduced requirements, the relative risk from accidental exposure remains very similar for all spectral regions, and exposure durations. In the visible and IR-A spectral regions, a Class 3R laser poses a higher risk for a dilated pupil, for ultraviolet Class 3R has a meaningful risk only for very lengthy exposures, and in the far infrared there is again little risk as well. Accidents are exceedingly small in number (four).