Laser Classification

Purchased Lasers

Commercially purchased lasers are classified either by the US Performance Standard (21 CFR 1040) of the Center for Devices and Radiological Health (CDRH) or the International Code (IEC 60825-1). Classification is based on the level of hazard of the laser beam during normal operation and includes factors such as wavelength, power output, accessible emission level, and emission duration. Commercially purchased lasers bear a sticker indicating the laser class. The following classes are defined:

  • Class 1 and 1M

Class 1 laser systems do not emit hazardous radiation under normal operating conditions. The laser is either of low power or the class 1 laser systems incorporates an “embedded” higher-power laser, which can be accessed only if safety interlocks are defeated or bypassed during servicing. In this case, the system temporarily reverts to the original laser classification.

A class 1M laser system has an expanded beam and is only hazardous when viewed through magnifying optics. M stands for magnification.

  • Class 2 and 2M

Class 2 laser systems are limited to the visible portion of the spectrum (400-700 nm) and to an output of 1 mW for continuous wave lasers. The natural aversion reaction to bright visible light (0.25s) is expected to protect the eyes from damage. A class 2M laser has an expanded beam and it can have a higher output. It is potentially hazardous if viewed through magnifying optics.

  • Class 3R (formerly 3a) and 3b

A class 3R laser system is potentially hazardous under some direct and specular (mirror-like) reflection viewing conditions if the eye is relaxed (focused at infinity). The natural aversion reflex is NOT adequate protection but the probability of an injury is small. The output is limited to 5 mW.

A class 3b laser system is more powerful than a 3R and is NOT safe for direct viewing or viewing of specular reflections. The output is limited to 0.5 W for continuous wave lasers.

  • Class 4

A class 4 laser system has an output of more than 0.5 W (continuous wave). It is damaging to the eye and skin from the direct beam and diffuse reflections (scattering), and a potential fire hazard. The beam can also generate airborne contaminants and hazardous plasma radiation.

Self-Assembled and Modified Lasers

Lasers that have been built or modified at the University of Illinois need to be classified and registered with IEMA through DRS. Classification can be done according to ANSI Z136.1 which is very similar to the CDRH and IEC classifications.

The following two tables are taken from ANSI Z136.1 and were compiled to aid in the classification of a laser system. Ask DRS for assistance.

Continuous Wave (CW) Point Source Lasers

Wavelength (nm)

Laser type

Wavelength (nm)

Class 1a (W)

Class 2 (W)

Class 3 b (W)

Class 4 (W)

Ultraviolet
180 to 280

Nd:YAG (Quadrupled)

266

<9.6 x 10-9 for 8 hours

None

>Class 1 but <0.5

>0.5

Argon

275

Ultraviolet
315 to 400

He-Cd

325

<3.2 x 10-6

None

>Class 1 but <0.5

>0.5

Argon

351, 363, 350.7

Krypton

356.4

Visible
400 to 700

He-Cd

441.6 only

<4 x 10-5

> Class 1 but <1 x 10-3

> Class 2 but <0.5

>0.5

Argon (visible)

457

<5 x 10-5

476

<1 x 10-4

488

<2 x 10-4

514

<2.2 x 10-4

Krypton

530

Nd:YAG (doubled)

532

He-Ne

543

400 - 500

<0.4CB x 10-4

Dye

460 - 500

He-Se Dye

550 - 700

<4 x10-4

He-Ne

632

InGaAIP

670

Ti:Sapphire

350 - 500

Krypton

647.1, 676.4

Near Infrared
700 to 1400

GaAlAs

780

<5.6 x 10-4

None

> Class 1 but <0.5

>0.5

GaAlAs

850

<7.7 x 10-4

GaAs

905

<1.0 x 10-3

Nd:YAG

1064

<1.9 x 10-3

He-Ne

1080

<1.9 x 10-3

1152

<2.1 x 10-3

InGaAsP

1310

< 0.03

Nd:YAG

1319

< 0.025

Far Infrared
1400 to 1 mm

InGaAsP

1550

<9.6 x 10-3

Holmium

2100

Erbium

2940

Hydrogen Fluoride

2600 - 3000

He-Ne

3390 only

Carbon Monoxide

5000 - 5500

Carbon Dioxide

1060

Water Vapor

118000

<9.5 x 10-2

Hydrogen Cyanide

337000

a Assumes no mechanical or electrical design incorporated into laser system to prevent exposures from lasting to Tmax = 8 hours (one workday); otherwise the Class 1 AEL could be larger than tabulated.

b The Class 3R AEL is defined as 5 times the Class 1 AEL for invisible lasers and 5 times the Class 2 AEL for visible lasers (wavelength between 400 nm and 700 nm).

AEL: Accessible emission limit.

Single Pulse Point Source Lasers

Wavelength (nm)

Laser type

Wavelength (nm)

Pulse Duration (s)

Class 1 (J)

Class 3b (J)

Class 4 (J)

Ultraviolet 180 to 400

Excimer (ArF)

193

20 x 10-9

<2.4 x 10-5

> Class 1 but <0.125

> 0.125

Excimer (KrF)

248

20 x 10-9

<2.4 x 10-5

Nd:YAG Q-switched (quadrupled)

266

20 x 10-9

<2.4 x 10-5

Excimer (XeCl)

308

20 x 10-9

<5.3 x 10-5

Nitrogen

337

20 x 10-9

<5.3 x 10-5

Excimer (XeF)

351

20 x 10-9

<5.3 x 10-5

Visible     400 to 700

Rhodamine 6G (Dye laser)

450 - 650

1 x 10-6

<7.7 x 10-8

> Class 1 but <0.03

> 0.03

Copper vapor

510, 578

2.5 x 10-9

Nd:YAG (doubled) (Q-switched)

532

20 x 10-9

Ruby (Q-switched)

694.3

20 x 10-9

Ruby (Long pulse)

694.3

1 x 10-3

<3.9 x 10-6

Near Infrared
700 to 1400

Ti:Sapphire

700 - 1000

6 x 10-6

<8.4 x 10-8

Alexandrite

720 - 800

1 x 10-4

<7.6 x 10-7

> Class 1 but <0.033

> 0.033a

Nd:YAG (Q-switched)

1064

20 x 10-9

<7.7 x 10-7

> Class 1 but <0.125

>0.125

Far Infrared 1400 to 1mm

Erbium:Glass

1540

10 x 10-9

<7.9 x 10-3

> Class 1 but <0.125

> 0.125

Co:Mg-Fl

1800 - 2500

80 x 10-6

<7.9 x 10-4

Holmium

2100

250 x 10-6

<7.9 x 10-4

Hydrogen Fluoride

2600 - 3000

0.4 x 10-6

<1.1 x 10-4

Erbium:Glass

2940

250 x 10-6

<5.6 x 10-4

Carbon Dioxide

10,600

100 x 10-9

<7.9 x 10-5

Carbon Dioxide

10,600

1 x 10-3

<7.9 x 10-4

a Class 3b AEL varies from 0.033 J to 0.480 J corresponding to wavelengths that vary between 720 and 800 nm.

References

Code of Federal Regulations Title 21. 21 CFR 1040.10 Laser Products

American National Standard for Safe Use of Lasers. ANSI Z136.1 - 2014, tables C1 and C2

Last Update: 10/14/2016