Measurement of Non-Laser Optical Radiation Safety at Work

App. 010

General Requirements

The European Directive 2006/25/EC [1] lays down minimum requirements for the protection of the health and safety of workers from the risks related to artificial optical radiation. It is implemented in law by all member states and covers exposure of skin and eyes to ultraviolet, visible and infrared (to 3000nm) radiation, both from coherent (laser) and non-coherent (non-laser) light sources. The exposure limit values in the directive are based on the work of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) [2].

The methodology for determining exposure levels to laser radiation follows the well-established IEC 60825 [3] standard whereas for non-laser radiation the CIE/CEN standards in the form of EN 62471:2008 [4] is applicable.

Hazards relating to skin and the front surface of the eye require the measurement of irradiance whereas hazards to the eye itself require the measurement of radiance. EN 62471:2008 considers the following six hazards with respect to exposure over a period of up to eight hours:

Hazard	Wavelength range	Bioeffect
Hazard	Wavelength range	Eye	Skin
Actinic UV	(200 – 400)nm ^(*)	Cornea – photokeratitis Lens – cataractogenisis Conjunctiva – conjunctivitis	Erythema Elastosis
Near UV	(315 – 400)nm	Lens – cataractogenisis
Blue light	(300 – 700)nm ^(*)	Retina – photoretinitis
Retinal thermal	(380 – 1400)nm^(*)	Retina – retinal burn
IR radiation eye	(780 – 3000)nm	Cornea – cornea burn
Thermal skin	(380 – 3000)nm		Skin burn
^()Action spectra weighting applied*

Photobiological hazards considered in IEC EN 62471 and EU Directive 2006/25/EC

It should be noted that there are some minor differences between EN 62471:2008 and the limits in IEC 62471:2006 [5] with respect to blue light small source and retinal thermal weak stimulus limits that result from revisions in ICNIRP guidelines.

The X1-3 Hazard Optometer facilitates the measurement of all UV and blue light hazards within the scope of EN 62471. The XD-45-HUV hazard detector measures actinic UV and near UV irradiances and the XD-45-HB blue light hazard detector measures blue light weighted radiance within the required fields of view. With the stray light corrected BTS2048-UV spectroradiometer spectral measurements can be performed, see our scientific publication showing such sophisticated measurements using an array spectroradiometer.