Ill. Admin. Code tit. 32, § 315.TABLE E – Measurement Apertures for Classification

Spectral Region (μm)	Duration (s)	Aperture Diameter (mm)
0.180 to 0.302	10^-9 to 0.25	1.0
	0.25 to 3 x 10⁴	3.5
0.302 to 2.8	10^-9 to 3 x 10⁴	50.0
2.8 to 10²	10^-9 to 0.3	1.0
	0.3 to 10	1.5 t^3/8
	10 to 3 x 10⁴	3.5
10² to 10³	10^-9 to 3 x 10⁴	11.0

NOTES:	1.	These apertures are used for the measurement of optical power or energy for purposes of laser classification

	2.	When the laser output is intended to be viewed with optics (excluding ordinary eyeglasses) or the laser safety officer determines that there is reasonable probability of accidental viewing with optics, a 50 mm aperture is used if the following conditions are met.

	A)	Viewing with optics presents a more severe hazard than unaided viewing.

	B)	The viewing time is sufficient to constitute a hazard.

	3.	Under normal conditions these exposure durations would not be used for classification (see ANSI Z136.1 (Table 9)).

	4.	For purposes of this Section 315.Table E, the following abbreviations or symbols are used:
	μm	=	micrometers
	s	=	seconds
	mm	=	millimeters
	t^s	=	time in seconds