WHAT IS UV RADIATION?

The abbreviation “UV” stands for ultraviolet radiation. This is often identified as UV light, since “light” generally sounds less dangerous than radiation. Per definition we identify radiation, which is visible for the human eye, as light. So strictly speaking, UV light does not really exist. That is an important fact for the user, as he is not able to see the real danger. The possibly visible light is merely luminescence, which is induced by UV. This luminescence is often much weaker and less dangerous than the inducing UV radiation. Due to this the measurement of ultraviolet radiation is important. Therefore our precise UV radiometers can be used.

SPECTRAL RANGES UV-A, UV-B AND UV-C

The UV radiation is divided in three spectral ranges. UVA covers the spectral range from 315 nm to 400 nm. Internationally, the spectral range of UVA is often 320 - 400 nm. The UVA spectral range is technically often used for the adhesive UV bonding and curing of varnishes. In addition, the luminescence and fluorescence tests are often carried out with UVA (here it is defined by the term black light).

SPECTRAL RANGE SUMMARY

	ILV (CIE S 017/E:2011)
UV-A	315 – 400 nm
UV-B	280 – 315 nm
UV-C	100 – 280 nm

Then, in a short wave range, there is the UVB spectral range. The UVB radiation is richer in energy than the UVA radiation and can lead to dermal damages during longer exposure times. Technically, the UVB radiation is used less often than the UVA or UVC radiation, however it plays an important part in the photo stability, i.e. in the UV aging or weathering, since the natural sunlight contains UVB radiation to a minor degree.

UVC radiation is a radiation between 100 nm and 280 nm. Since the air absorbs UVC radiation below ca. 200 nm, this is often considered as the lower limit wavelength. UVC radiation can efficiently be generated by mercury low pressure lamps. The UV radiation yield is up to ca. 40 %, with an electrical power in the range of several hundred watts. The dominant emission is approx. 254 nm. Important applications are the disinfection of surfaces, as well as food packages and the disinfection of potable water. For the UV polymerization, the Hg medium pressure lamp with an electrical power of between ca. 400 W and 24 kW is widespread. Here, the high power allows for high speeds and process times within split seconds.

The following picture shows the different types of electromagnetic radiation and their properties:

Ultraviolet radiation (UV):
- Subdivided into vacuum UV, far UV, mid UV and near UV
- Wavelength range: 100-400 nm
- Photon energy: 12.4-3.1 eV
- Exemplary receivers: Cs-I, Cs-Te, SiC
Visible radiation (VIS):
- Wavelength range: 380-780 nm
- Photon energy: 3.3-1.6 eV
- Receiver: Multi-Alkali-PMT, Si
Infrared radiation (IR):
- Subdivided into near IR, mid IR and far IR
- Wavelength range: 780 nm - 10^6 nm
- Photon energy: 1.6-0.001 eV
- Receiver: Si, Ge, InGaAs, InAs, PbSnTe, PbSnSe

spectral ranges: UV light IR and their detectors

Normative classification of UV radiation

The classification of ultraviolet (UV) radiation into spectral ranges varies depending on the standard and application. The different spectral ranges of UV radiation and their classification in various standards as well as their specific applications are described in detail below.

The International Organization for Standardization (ISO), the German Institute for Standardization and other organizations, such as the CIE, have defined spectral ranges for the applications. These are not always the same. However, the most common classification is:

The classification of the spectral ranges for UV radiation to IR radiation according to e-ILV of the CIE & standard CIE S 017:2020 ILV:

Name	Spectral range
UV-A	315 nm to 400 nm
UV-B	280 nm to 315 nm
UV-C	200 nm to 280 nm
visible radiation	Lower limit: 360 nm and 400 nm*
	Upper limit: 760 nm and 830 nmd 830 nm
IR-A	780 nm to 1400 nm
IR-B	1400 nm to 3000 nm
IR-C	3000 nm to 1 mm

* There are no precise limits to the spectral range of visible radiation as they depend on the amount of radiation flux reaching the retina and the sensitivity of the observer. The lower limit is generally set between 360 nm and 400 nm and the upper limit between 760 nm and 830 nm.

The e-ILV provides free access to all terms and definitions contained in the international standard CIE S 017:2020 ILV: International Lighting Vocabulary, 2nd edition.

In the past, the following classification of UV radiation was used more frequently, especially in the trilingual area:

The spectral ranges for UV to IR radiation according to DIN 5030-2:1982-09 (current) & DIN 5031-7:1984 (withdrawn)

name	Spectral range
UV-C	100 nm to 280 nm
VUV	100 nm to 200 nm
FUV	200 nm to 280 nm
UV-B	280 nm to 315 nm
UV-A	315 nm to 400 nm
VIS	380 nm to 780 nm
IR-A	780 nm to 1400 nm
IR-B	1400 nm to 3000 nm
IR-C	3000 nm to 1000000 nm
MIR	3000 nm to 50000 nm
FIR	50000 nm to 1 mm

The standards deal with spectral radiation measurement; emitters for spectral radiation measurements and radiation physics in the optical field and lighting technology

The classification of spectral ranges according to ISO 21348:2007

The following table provides a detailed overview of the spectral ranges for UVA, UVB and UVC in nanometers (nm) and takes into account specific fields of application in the aerospace industry. These include the determination of solar radiation in natural and artificial environments during space flights, test methods for electrical cables in aviation, and methods for marking wires and cables using UV lasers. The table is also used for designs in the aerospace industry.

name	Spectral range
Vacuum-UV, VUV	10 nm to 200 nm
Extreme UV, EUV	10 nm to 121 nm
FUV, FAR Ultraviolet	122 nm to 200 nm
Ultraviolet C, UVC	100 nm to 280 nm
Ultraviolet B, UVB	280 nm to 315 nm
Near Ultraviolet , NUV	300 nm to 400 nm
UV-A	315 nm to 400 nm
Visible, VIS	380 nm to 760 nm
Purple	360 nm to 450 nm
Blue	450 nm to 500 nm
Green	500 nm to 570 nm
Yellow	570 nm to 591 nm
Orange	591 nm to 610 nm
Red	610 nm to 760 nm
Infrared, IR	760 nm to 1000000 nm
Near Infrared, IR-A	760 nm to 1400 nm
Middle Infrared, IR-B	1400 nm to 3000 nm
Far Infrared, IR-C	3000 nm to 1000000 nm

Further standards and introductions of the spectral ranges

In some areas of photobiology, the wavelength ranges are subdivided from 200 nm to 290 nm, from 290 nm to 320 nm and from 320 nm to 400 nm. Sometimes these wavelength ranges are (incorrectly) referred to as UV-A, UV-B and UV-C. Ultraviolet radiation with wavelengths of less than 180 nm is referred to as vacuum UV radiation. It should be noted that radiation between 380 nm and 400 nm is referred to as visible radiation, although this wavelength range is by definition also in the UV radiation range.

In standards for protection against solar radiation, for example in sunglasses for general use, the upper limit of UV-A is sometimes assumed to be 380 nm. In standards with protection requirements against radiation from artificial sources, the upper limit of UV-A is usually assumed to be 400 nm, which is consistent with the CIE definition. The upper limit of 400 nm is used by ICNIRP, ACGIH, the World Health Organization and in the Directive of the European Parliament and of the Council on the protection of health and safety from the dangers of artificial optical radiation, among others.

In some applications, the ultraviolet spectrum has also been subdivided into "far ultraviolet", "vacuum ultraviolet" and "near ultraviolet"; however, the boundaries necessarily vary depending on the application (e.g. in meteorology, optical design, photochemistry and thermal physics).

In conclusion, it can be said that the classification of spectral ranges into UV radiation, light and IR radiation is application-related.

The following standards have their own classification of spectral ranges for UV radiation

DIN EN ISO 24444 : 2022-07 Cosmetic products, especially for test methods for sunscreens and the in vivo determination of the sun protection factor

DIN EN ISO 24443 : 2022-08 Cosmetic products, application in the field of test methods for sunscreen products

DIN EN ISO 24442 : 2022-10 Determination of the UVA sun protection factor

DIN EN ISO 18369-1 : 2018-04 Ophthalmic optics - Contact lenses - Part 1: Definitions, classification of contact lens materials and recommendations for the notation of contact lens specifications

DIN EN 16981 : 2021-12 Photocatalysis - Glossary of terms;

DIN EN IEC 62471-7; VDE 0837-471-7:2024-04 Photobiological safety of lamps and lamp systems

ISO 20473:2007-04 Railway applications - Front windows for railway vehicles

DIN EN 16782 : 2016-07 Preservation of cultural heritage - Cleaning of porous inorganic materials - Laser cleaning processes for cultural heritage

DIN EN ISO 4007 : 2020-01 Personal protective equipment - Eye and face protection

DIN EN ISO 29464 : 2020-0 Cleaning of air and other gases

DIN EN ISO 9488 : 2022-12 Solar energy

DIN EN 13758-1 : 2007-03 Textiles - Protective properties against ultraviolet solar radiation - Part 1: Test method for garment textiles

DIN EN ISO 105-A08 : 2003-01 Textiles - Tests for color fastness - Part A08: Vocabulary of colorimetry

DIN EN ISO 14692-1 : 2018-02 Petroleum and natural gas industries - Glass-reinforced plastic (GRP) piping - Part 1: Terms, symbols, applications and materials

DIN EN 1330-1 : 2015-05 Non-destructive testing - Terminology

You can download a list of spectral ranges for the standards above here

Downloads

Radiometric quantities and wavelengths