UVC glossary on UVC disinfection & Co.

The glossary below contains approx. 220 terms and abbreviations relating to UVC disinfection and UVC disinfection.

Show all A* B* C* D* E* F* G* H* I* J* K* L* M* N* O* P* Q R* S* T* U* V* W* X* Y Z
  • A

    • absorption

      Intake or retention of elektromagnetic waves via conversion to heat, here: 254 nm wavelength radiation.

    • adenine

      Adenine (C5H5N5) is one of the four organic complementary bases in DNA and RNA. It forms two hydrogene bonds with thymine in the DNA-double helix.

    • aerobic

      Organisms which need oxygen (O2) for their metabolic processes are described as aerobic. Most pathogens responsible for skin diseases and respiratory-tract infections belong to the group of aerobic bacteria. Viewed in chemical terms, an aerobic process is an oxidation.

    • amino acid

      Amino acids are organic compounds which join together in long chains to form proteins, among other things. We distinguish approx. 20 different proteinogenic amino acids and a large number of non-proteinogenic amino acids. Amino acids are essential for metabolism and are thus the basis of life.

    • amorphus

      Amorphous is the term used in physics and chemistry to describe material whose atoms form an irregular shape rather than a long-range ordered structure. An amorphous state is generated via rapid heating or cooling. The opposite of an amorphous structure is a chrystalline structure.

    • anaerobic

      Organisms which do not require any oxygen for their metabolic processes are referred to as anaerobic. Enterobacteria (gut or intestinal bacteria), for example, are facultatively anaerobic.

    • anthrax

      Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

    • antibiotics

      Antibiotics are drugs used to treat bakterial or parasitic infectious diseases. Antibiotics used to treat fungal infections are call antimycotics. Discovered in 1928, the first natural antibiotic was penicillin, a mould. Today, antibiotics are also manufactured synthetically. They work either by inhibiting cell-wall formation, preventing protein produktion, disrupting DNA transmission, or a combination of all three strategies.

    • aspergillus

      Mikroorganisms of the Aspergillus genus belong to the thermotolerant moulds. Known members of this genus are Aspergillus niger (black mould), der Aspergillus amstelodami and Aspergillus fumigatus. These organisms grow best at high temperatures. A number of aspergillus species form methabolic products that are toxic for humans (mycotoxins), and which cause food poisoning. In addition, airborne spores  can trigger allergies and even attack organs. Aspergillus spores are extremely UVC-resistant and very high doses are needed. See also: UVC effect – relationship between dose and effect.

    • atom

      An atom is the smallest chemically indivisible unit, consisting of a nucleus and one or more electrons. Atoms are the building blocks of molecules, e.g. oxygen (O2) or water (H2O). An undisturbed atom is electrically neutral.

  • B

    • B. anthracis

      Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

    • B. cereus

      Bacillus cereus is a spore-forming, Gram-positive, facultatively anaerobic and widespread soil bacterium frequently detected in various foods, including in particular rice, since the spores even survive boiling.

    • bacilli

      (sing. bacillus) Rod-shaped bacteria.

    • bacteria

      Bacteria (sing. bacterium) are single-celled microorganisms classified into aerobic and anaerobic strains. Bacteria are prokaryotes. While most bacteria reproduce through cell division, some form spores.

    • baktericidal

      Killing bacteria or germs.

    • biofilm

      Biofilms consist of a thin slime layer (film), in which microorganisms (e.g. bacteria or algae) are embedded. They form mainly in water systems, either on the surface of the water or on an interface with a solid phase. Inside the biofilms the embedded organisims are active and growing so that new microbes continuously are spread into the water. By this e.g. cooling systems and water reservoirs get steadily contaminated. Furthermore on dying biofilms moulds and yeasts can settle down.

    • biozid

      In general, an agent for controlling pests.

    • borrelia

      Borrelia belong to the spirochete phylum - a group of relatively large Gram-negative bacteria which actively propel themselves forward by rotating around their own axis.

  • C

    • cereas

      Originally a synonym for grain rather than a breakfast convenience food such as muesli or corn flakes, cereal derives from the Latin Cerialia, the Roman festivities honouring the gods of agriculture and growth – particularly the grain goddess Ceres.

    • chromosomes

      Chromosome is the name given to the DNA spirally packaged by proteins in eukaryotic cells. A chromosome must be unwound for the replications and transcription process during the cell-division stage.

    • clostridia

      These are anaerobic, spore-forming, Gram-positive bacteria. Clostridia spores exhibit a very high resistance to thermal disinfecton methods and are able to survive a temperature of 100°C for several hours unharmed. Depending on the various investigation methods used, the LD90 value (UVC254nm) for Clostridia lies between 4.9 ... 23 mJ/cm2.

    • cytoplasma

      The gel-like, liquid, organic basic substance, surrounded by the cell membrane, of which a microorganism consists.

    • cytosine

      Cytosine (C4H5N3O) is one of the four complementary coding nucleobases in DNA. Cytosine forms a base pair via three hydrogen bonds with guanine.

  • D

    • decontamination

      Decontamination describes the reduction of pathogenic microorganisms to a safe level for human use. Technically, this means reduction by a minimum of 1 log step, meaning 90%.

    • dimerisation

      The congregation of two monomers.

    • disinfectant (chem.)

      Disinfectants contain active ingredients which either kill or inhibit the growth of microorganisms. Disinfectants require sufficient application time (>10 sec.) and must be used at sufficiently strong concentrations. Some well-known disinfectants are alcohols (e.g. isopropanol), hydrogen peroxide (H2O2), ozone (O3), and tinctures containing iodine.

    • disinfection

      The term disinfection is not clearly defined in a technical sense. Generally, it means a reduction of pathogenic microorganisms by a minimum of 3 and a maximum of 5 log steps. Hence, the term 'UV disinfection' describes the inactivation of at least 99.9% of a given pathogenic population with the aid of UV technology.

    • DNA

      [Abbr. for desoxyribonucleic acid] - The carrier of genetic information.

    • dorno radiation

      The term Dorno radiation is an alternative but no longer current description for UVB radiation. Carl Dorno was a Prussian scientist deeply involved in researching this biologically active radiation.

    • dose

      The term dose describes the defined amount of radiation energy to which an organism is exposed in a particular time frame. In UV disinfection, the dose is usually given in µW*s/cm² or J/m².

    • double helix

      Helix is a term synonymous with 'coil' or 'spiral'. A double helix is therefore a double spiral.

  • E

    • E. coli

      [Abbr. Escherichia coli] - E. coli is a Gram-negative, rod-shaped, facultatively anaerobic and acid producing bacterium, occurring in the guts of humans and animals. It owes its name to its discoverer, bacteriologist and professor of paediatrics Theodor Escherich.

      E. coli is considered to be an indicator bacterium for faecal contamination. It preferentially colonises raw milk, cheese and raw meat. Exposure to UVC causes lethal damage to E. coli. There is probably no microorganism that has been better documented and investigated.

    • elastomer

      Elastomers are elastically deformable plastics which nevertheless retain a fixed shape. After mechanical deformation, they therefore reassume their original shape.

    • electromagnetic spectrum

      The electromagnetic spectrum is the range of all frequencies of electromagnetic waves.

    • electromagnetic wave

      An electromagnetic wave consists of an electrical and a magnetic field component. Unlike pressure waves, electromagnetic waves do not require a medium for propagation; their propagation speed depends on the medium, with propagation in a vacuum taking place at the speed of light. The best-known electromagnetic waves are probably those described colloquially as 'light'.

    • electron

      An electron is an electrically charged elementary particle. An (e-) electron is negatively charged. A positively charged elementary particle (e+) is called a positron.

    • electrostatics

      Theory of resting charges and their temporally stable electric fields.

    • EMC

      [Abbr. for electromagnetic compatibility] - A test criterion  for electric or electronic devices describing their freedom from interference with their surroundings.

    • emission (phys.)

      The sending out of electromagnetic waves.

    • emitter

      From the Latin emittere 'to send out'. In physics, the source of radiation is defined as an emitter. From the same provenance as the term emission.

    • endotoxins

      Endotoxins are lipopolysaccharides found in the outer membrane of Gram-neagtive bacteria. Released during the decay of microorganisms, they have a toxic effect.

    • enterobacteria

      The term enterobacteria (sci. term Enterobacteriaceae) is understood to mean those bacteria occurring in the guts of animals or humans (Gr. enteron = intestine). Enterobacters belong to the family of facultative anaerobes, meaning that the require no oxygen (O2) for their metabolism. A typical member of this family is E. coli.

    • enterococci

      Enterococci (sing. Enterococcus) are Gram-positive anaerobic bacteria arranged in pairs or short chains. They also belong to the type of microorganisms populating the guts of animals and humans.  Enterococci have an important digestive function and are added to fermentation and ripening processes in food production as well as to probiotic foodstuffs to promote intestinal microflora.

    • EPDM

      [Abbr. for ethylene propylene diene monomer] - EPDM is a synthetic rubber used primarily as a sealant and hose material on account of its good elasticity and high resistance to ozone, acid and alkali

    • epidemic

      A localised, heavily massed occurrence of an infectious disease - see also pandemic.

    • erythema

      Medical term for redness of the skin, or a reddish-coloured dermatitis (inflammation of the skin). 

    • EU Directive 2006-25-EG

      EU health and safety directive for protecting workers from the risks arising from artificial optical radiation. The original text of the directive (PDF 844 kB) can be found here...

    • eucaryotic cells

      Also know as eukaryotes - Cells with a membrane-surrounded nucleus in which the DNA is stored in the form of chromosomes.

    • exotoxins

      Exotoxins are poisonous substances constantly being excreted by bacteria.

    • exposure

      The state of being subject to contact with something. 

    • exposure time

      Here: Length of time for which an organism is exposed to UV radiation.

  • F

    • facultative

      non-obligatory

    • faecal bacteria

      Faecal bacteria (e.g. Escherichia coli) is taken to mean all microorganisms populating the guts of animals or humans, whose presence therefore indicates contamination by either excrement or products of fermentation or decay.

    • FDA

      [Abbr. for Food and Drug Administration] - The FDA is the American federal agency responsible for food monitoring and drug licensing. It is subordinate to the Department of Health and Human Services.

    • FEP

      [Abbr. for fluorinated ethylene propylene (perfluoroethylene propylene copolymer)] – FEP is a hydrophobic fluoroelastomer with a high resistance to heat and chemicals.

    • fluorplastics

      The term fluoroplastics describes polymers manufactured from fluorine (F) and carbon (C). Typical fluoroplastics are FEP and PTFE, which are known under the brand name Teflon. Fluoroplastics have a very high resistance to chemicals and intense UV radiation. They also retain good UVC transparency at thin layer thicknesses.

    • FPM

      [Abbr. for fluoropolymer permeable membrane (fluoropolymer rubber)] - FPM is a fluorinated elastomer with very high ozone-, weather- and UV-resistance.

    • fungicide

      Chemical or biological agent for destroying fungal spores und moulds.

  • G

    • gram-negative bacteria

      Gram-negative bacteria have a thin cell wall with a single-layered murein. They therefore absorb no dye during Gram staining, and appear reddish under the microscope. Gram-negative bacteria are primarily rod bacteria and are endotoxic. Well-known members of this family are Legionella, the pseudomonads, and Borrelia.

    • gram-positive bacteria

      Gram-positive Bakterien färben sich bei der Gramfärbung dunkelblau. Ursache ist eine dicke Zellwand mit mehrschichtigem Murein, welches bis zu 50% der Hüllentrockenmasse ausmachen kann. Grampositive Bakterien kommen hauptsächlich als Kokken vor und sie wirken exotoxisch. Beispiele: Listerien, Clostridien, Streptokokken und Staphylokokken.

    • gram staining

      Developed by the Danish bacteriologist Hans Christian Gram, Gram staining is a method for rendering bacteria more visible under the microscope with the aid of a special dye. Depending on differences in their cell-wall structures, bacteria can basically be divided into two groups: Gram-positive and Gram-negative bacteria.

    • guanine

      Guanine (C5H5N5O) is one of the four coding nucleobases of DNA and RNA. Guanine always base-pairs with the complementary cytosine, forming three hydrogen bonds with the latter.

  • H

    • HACCP

      [Abbr. for hazard analysis and critical control points] - A preventive system intended to ensure food safety from manufacture to the consumer.

    • HDPE

      [Abbr. for high density polyethylene] - This thermoplastic polymer has a high resistance to acids, alkalis and chemicals.

    • hepatitis

      Hepatitis is the medical term for an inflammation of the liver which can be caused both by hepatitis viruses as well as by other pathogens such as bacteria and parasites. Of the classic viral hepatitis types, the Hepatitis B infection is the most common. Transmission, as with the HIV virus, is via the direct exchange of bodily fluids. With direct exposure, the viruses in question have a low-to-medium UVC-resistance.

    • herbicide

      weed killer.

    • herpes simplex

      Caused by the herpes simplex virus, herpes is the most common infectious disease of the skin. Although usually occurring as lip herpes (‘cold sores’), other parts of the skin can also be affected. To date, there are no curative treatments for herpes simplex infections, nor does the organism develop an immunity to the virus. With an average lethal dose (LD90) of 5 mJ/cm2, herpes simplex viruses exhibit a relatively high UVC sensitivity in laboratory trials.

    • hg

      chemical symbol for mercury.

    • HIV

      [Abbr. for human immunodeficiency virus] - Belonging to the family of retroviruses, the HIV virus causes the well-known immunodeficiency disease AIDS. Around 100 to 120 nm in diameter, the virus is surrounded by an envelope. Statistically speaking, around 90% of the infections occur if people get transfused with HIV-positive blood, with transmission via bodily fluids being a possibility. Investigations by Henderson et al. revealed the virus to be extremely resistant to UVC radiation.

    • humanpathogenic

      Med. term meaning “causing disease in humans” - see pathogenic.

    • hyphae

      Hyphae (sing. hypha) are microscopically small, long, very thin, branching fungal filaments which develop in all directions from a mould spore on a breeding ground. Hyphae are involved in both feeding and propagation (see conidiophores). A mass of hyphae is referred to as a mycelium.

  • I

    • IFS

      [Abbr. for International Food Standard] - Defined in 2003 by representatives of the European retail-food industry, the IFS is used to audit and certify systems ensuring food safety, as well as quality and conformity in food production. 

    • inactiviation

      Technically speaking, microorganisms are not actually killed off by the lethal impact of UVC radiation, but are rendered ‘inoperative’ or incapable of dividing. Since viruses are by definition not considered to be living organisms, it follows that they cannot be ‘killed off’.

    • infection

      The term infection describes the process by which pathogens penetrate into the body of an organism and multiply therein. Depending on the transmission route, we distinguish between smear infections, contact infections and droplet infections.

    • infectiousness

      Measure for describing the ability of a pathogen to cause actual infection in a host after transmission occurs.

    • infrared radiation

      [IR radiation for short] - this is the spectral range of 780 nm to 1000 µm, i.e. the wavelength range lying between the spectral range of visible light and the so-called terahertz radiation range. The thermal (‘mid-’) IR radiation range lies between 3 µm and 50 µm.

    • intensity (phys.)

      In physics,‘intensity’ describes energy density with respect to an area, and is given e.g. in µW/cm2. In UV disinfection, this information is essential for calculating the lethal dose.

    • ionising radiation

      Ionising describes the type of radiation capable of permanently removing electrons from atoms or molecules, thereby changing the state of charge of the latter two. Radioactive radiation and X-ray radiation are among the typical representatives of ionising energies. Note: UVC radiation has no ionising power, and hence does not figure among the ionising rays. (See also Technology - generating UV rays).

    • ions

      Ions are generally understood to mean atoms that are electrically charged.

    • IP protection

      [Abbr. for international protection] - Types of protection that are classified according to DIN 40050. The letters IP are followed by two digits, the first indicating the degree of protection afforded against the ingress of solid bodies, and the second describing the degree of protection against the ingress of water.

  • J

    • joule

      [Abbr. J] - International unit of measurement for energy, heat quantity and work. Conversion: 1 J = 1 W*s

  • K

    • kb

      [Abbr. for kilobyte] - In computer science, a unit of information consisting of 8 bits of data.

  • L

    • lactobacilli

      [Also known as lactic-acid bacteria] - Lactobacilli (sing. lactobacillus) are anaerobic, Gram-positive microorganisms found in the gut or mucosa of mammals. They are primarily used in the manufacture of dairy products (cheese, yoghurt, kefir, etc.).

    • ld

      Abbr. of lethal dose (which see).

    • LD90

      The LD value can be specified more precisely via an index number. LD 90 is the dose which eliminates on average 90% of an (e.g.) bacterial population.

    • legionella

      The family of Legionella bacteria (scientific name Legionellaceae) contains more than 48 known species as well as numerous subgroups. They are water-dwelling Gram-negative aerobic bacteria that are potentially pathogenic for humans. Since they require still or recirculated water in the 25-50°C range for optimal growth, they are found primarily in air washers, cooling towers, dead pipes, water tanks and shower heads. Legionella are easily and effectively inactivated at even very low UVC doses.

    • lethal dose

      Lethal dose (LD) is the term referring to the dose of a toxin or radiation which is deadly for an organism.

    • lethality

      Lethality describes the ratio of deaths to survivals after a dose of radiation, infection or illness - in other words, the mortality rate. It is therefore a measurement of hazard or risk.

    • light

      Light is the colloquial name given to that portion of the electromagnetic spectrum lying in the 380-780 nm spectral range. This is the range that is visible to the naked human eye, with the limit values varying depending upon source. Consequently, the unfortunately common designation of ‘UV light’ is a contradiction in terms, and, strictly speaking, inaccurate.

    • living organism

      In biology, life forms capable of metabolic processes, replication and evolutionary development (all three criteria must be fulfilled) are known as living organisms.

    • log

      [Abbr. for logarithm] - Although the term ‘log’ is the usual abbreviation for base-10 logarithms, the mathematically correct term here is lg. We speak here of decadic logarithms.

    • log reduction

      In biology, bacterial reduction is indicated in log stages. A log reduction of X therefore means a reduction by X log stages starting from a given population. For example, the reduction by 1 log stage means a reduction of 90%, since only 10 have survived from the original population of 100 (= 10 x 10).

    • log stage

      see also log reduction - In biology, each log stage describes the reduction of a population by a (further) power of ten: in other words, 1 log stage = 90%, 2 log stages = 99%, 3 log stages = 99.9%, etc.

    • logarithm

      The logarithm is an important mathematical function serving to illustrate significantly increasing series of numbers. The logarithm is the inverse operation of the power function ax = b, i.e. x = logb(a) (that is, logarithm of a to base b). This means that if a = 10x, then x = lg a. 

  • M

    • macromolecules

      Macromolecules are extremely large molecules with a relatively large mass, the properties of which remain unaffected by the removal of individual atoms or groups of atoms. DNA and proteins are typical naturally occurring macromolecules, whilst all polymers are typical synthetic macromolecules.

    • melanin

      Melanin is a pigment responsible in humans for skin colour, among othe things, and which protects the skin against harmful UV radiation.

    • melanoma

      also known as black-mole cancer - A melanoma is a malignant tumour appearing as an asymmetrically growing, discoloured change in the skin. 

    • metabolism

      The term metabolism describes the uptake, transport and chemical transformation of matter in an organism, as well as the discharge of metabolic end products into the environment.

    • micrometre

      also micron - The unit µm. Conversion: 1 µm = 0.001 mm. 

    • microorganism

      also microbe - Microorganisms are organic structures so small that they can generally only be seen with the aid of a microscope. Such structures are usually single-celled, although they are occasionally multi-celled.

    • microwatt

      The unit µW. Conversion: 1 µW = 0.001 mW = 0.000001 W.

    • molecules

      The term molecule describes a particle formed from two or more atoms which is at least temporarily stable. Molecules can be formed from atoms of the same element, e.g. oxygen (O2), ozone (O3) and nitrogen (N2), or from atoms of different elements, e.g. water (H2O).

    • monochromatic

      describes radiation of a precisely defined wavelength, as e.g. emitted by a laser. 

    • monomer

      Monomers are reactive molecules which in terms of a basic unit may congregate into chains or networks.

    • MRSA

      [Abbr. of methicillin-resistant Staphylococcus aureus] In the narrower sense, MRSA is taken to mean Staphylococcus aureus strains which are resistant to all beta lactam antibiotics (e.g.penicillin) available up to the present on the market.

    • multiresistance (med.)

      In medicine, the class of pathogens that are resistant to several classes of antibiotics (or to virostatic agents in the case of viruses) are described as multiresistant.

    • murein

      also peptidoglycan - Murein is a three-dimensional biopolymer with a net-like structure functioning as a supporting skeleton of the cell wall in the case of bacteria. The macromolecule consists of amino acids and sugar molecules.

    • mutation

      We speak of a mutation when the highly stable genetic algorithm of the hereditary material (DNA) of an organism undergoes a relatively permanent, stable change. Unlike with a modification, a mutation is permanently replicated.

    • mycelium

      The term mycelium [plural mycelia] refers to the mass of hyphae that form a mould.

    • mycotoxins

      see Aspergilla.

  • N

    • nanometer

      The unit nm. Conversion: 1 nm = 0.000000001 m or 0.001 µm. By way of comparison, a human hair has a diameter of approx. 100 µm.

    • NBR

      [Abbr. for nitrile butadiene rubber] - NBR is a heat-resistant synthetic rubber. It is particularly resistant to petroleum products such as fuel and lubricating oil, petrol and petroleum.

    • norovirus

      Noroviruses (Norwalk Viruses in full) are non-enveloped viruses with single-stranded RNA. They have an extremely high contagiousness, and infection leads to acute gastoenteritis (gastric flu). Hospitals as well as old-age or nursing homes are particularly vulnerable to repeated epidemic norovirus outbreaks.

    • nosocomial infection

      A nosocomial infection refers to an infection contracted in a hospital or care institution.

  • O

    • obligate

      absolutely indispensable, essential.

    • optical radiation

      The electromagnetic wavelength range between 100 nm and 1 mm is referred to as optical radiation. By definition, this includes ultraviolet radiation (UV), the visible light spectrum (VIS) and infrared radiation (IR).

    • organic compound

      Organic compounds are substances composed primarily of hydrogen (H) and carbon (C). Organic chemistry is concerned with the properties, composition and production of carbon compounds.

    • organism

      An organism is an individual life form - see living organism.

    • oxidation

      Oxidation generally refers to the chemical process in which an element reacts with oxygen or in which electrons are lost. 

    • ozone

      Represented as O3 - Ozone is a gas with strong oxidation properties that is toxic in high concentrations. The molecule consists of three oxygen atoms and is therefore unstable. Ozone arises naturally through the effect of solar radiation on the stratosphere.

  • P

    • pandemic

      A pandemic is an infectious disease of temporarily exceptionally high prevalence occurring across national borders. See also epidemic.

    • parasite

      Parasites are organisms which need substances generated by other organisms - termed ‘hosts’ - for their metabolic function. In acquiring these substances, they damage, or even kill (in the case of parasitoids) the host.

    • pathogen

      Pathogens are microorganisms capable of causing disease or illness in living creatures. Their harmful effects are usually due to toxins which they excrete. The opposite of pathogenicity is apathogenicity. The latter is defined as the inability of a pathogen to cause the disease in a specific host organism. Pathogens affecting only humans are termed human-pathogenic.

    • PE

      [Abbr. for Polyethylene] - Besides polyvinyl chloride, polyethylene is the most widely industrially produced thermoplastic. We distinguish between different PE types according to their density. The UVC resistance of all PE types is generally poor, but may vary depending upon colour. See also: HDPE .

    • peak

      The highest point of a specified value: greatest, maximum. 

    • pesticide

      An agent for controlling pests, usually in the sense of a plant-protection product.

    • PET

      [Abbr. for Polyethylene terephthalate] - PET (or PETE) is a thermoplastic polymer resin with either an amorphous or semi-crystalline structure. The amorphous sort is transparent. PET is UV- resistant only to a limited extent, if at all.

    • PGN

      [Abbr. for peptidoglycan] - see murein.

    • photochemistry

      See photolysis.

    • photolysis

      The decomposition or separation of chemical compounds induced by light.

    • photometer

      See radiometer.

    • photons

      A photon is the smallest unit of excitation of an electromagnetic field. It is also called the quantum of the electromagnetic field. A photon has a rest mass of zero and moves in a vacuum at the speed of light. Photons can interact with particles of matter, and can thus also be absorbed.

    • plafond sanitaire technology

      Bactericidally effective UV-radiation roof in the above-head area.

    • plasma

      Here, non-isothermal plasma - Plasma is a mixture of freely mobile electrons, ions and neutral atoms which are in different states of excitation and strongly interact with one another. Stars are typical high-temperature plasmas. We speak of ‘non-isothermal plasma’ when - as in the case of gas-discharge lamps - only the electrons are in a state of thermodynamic balance.

    • pm

      [Abbr. for picometre] - Conversion: 1 pm = 0.001 nm = 0.000001 µm = 0.000000001 mm, i.e. one billionth of a millimetre.

    • polymer

      Polymers are chemical compounds composed of numerous cross-linked monomers that are repeatedly strung together - hence the name polymer (poly = many). Protein is a natural polymer; plastics are typical synthetic polymers.

    • POM

      [Abbr. for polyoxymethylene] - POM is a high-strength thermoplastic with excellent dimensional stability and very good machinability, which is why it is often used for technical applications. Like almost all plastics, POM is not UVC-stable, and its black surface turns grey and dull when exposed to UVC radiation. At very high UVC outputs, the material tends to become brittle.

    • PP

      [Abbr. for polypropylene] - PP is a thermoplastic with high stability and high chemical resistance. It is tougher and more heat-resistant than PE, but becomes brittle at temperatures below 0° C. PP is non-UVC-stable, and with fairly long exposure to UVC radiation the surface of the material is subject to damage and decomposition.

    • prevention

      The taking of precautionary measures to stop undesirable occurrences. 

    • previtamin D

      Previtamin D3 is a precursor of vitamin D3, which is produced in the skin via photolysis under the influence of heat and wavelengths between 290 and 315 nm (UVB).

    • prokaryotic cells

      also prokaryotes - Cells without a true nucleus: see also eukaryotes.

    • prophylaxis

      Medical term for preventive measures for protecting health.

    • protein

      Proteins or albumins are macromolecules (polymers) consisting of amino acids. They are essential elements for growth, repair, function and structure in all living cells. The UV absorption maximum of proteins is 280 nm.

    • protozoa

      Protozoa (sing. protozoon) are a highly heterogeneous group of single-celled eukaryotic organisms. Among the numerous types of protozoa, approx. 40 humanopathogenic, parasitic species are known which cause malaria and dysentery, among others. Because measuring data on the UVC resistance of these organisms has a very large spread, a general statement on the lethal dose is not possible.

    • PS

      [Here, abbr. for polystyrene] - Polystyrene is a transparent thermoplastic. In foamed form this material is also known by the registered trademark Styrofoam. PS is non-UVC-stable.

    • PTFE

      [Abbr. for polytetrafluoroethylene] - PTFE is a thermoplastic fluoroplastic known primarily by the trade name Teflon of the DuPont company. PTFE has outstanding resistance to UVC rays.

    • PUR

      [Abbr. for polyurethane] - PUR is one of the most versatile plastics. Although mainly used in a foamed form, it is also found as a thermoplastic, elastomer, adhesive, varnish, and in the form of fibres.

    • purine

      Purines are nitrogenous compounds which in addition to the pyrimidines constitute the most important components of nucleic acid. The bases adenine and guanine are derived from purine. Formed by the human body itself, purines are broken down into uric acid.

    • PVC

      [abbr. for polyvinyl chloride] - PVC is an amorphous thermoplastic made soft, elastic and malleable by the addition of softeners and stabilisers. Depending on its composition and the proportion of softeners it contains, it is therefore UVC-resistant only to a limited extent.

    • PVDF

      [abbr. for polyvinylidene fluoride] - PVDF is a flame-retardant crystalline thermoplastic with excellent UV resistance. Like PTFE, it is a good electrical isolator, and it is also highly resistant to acids and alkalis.

    • pyrimidine

      Like purine, pyrimidine forms the base component of the organic bases. The bases cytosine, thymine and uracil are derived from pyrimidine.

  • R

    • radiometer

      A radiometer serves to measure electromagnetic waves. These devices are generally based on photodiodes which convert the incoming radiation into a proportional electrical signal. Lux meters and photometers are typical radiometers.

    • radiometry

      Radiometry is the science of radiation measurement, used in astronomy and physics, among others.

    • recipient

      A person, organism or thing that receives something.

    • reflection (phys.)

      Reflection refers to the (partial) return of electromagnetic waves at an interface. Reflection is the opposite of absorption. Since UVC rays have a different wavelength from light, they also behave differently at interfaces in terms of absorption and reflection. Light-reflecting surfaces are therefore not to be understood as synonymous with UVC-reflecting ones!

    • reoviruses

      Reoviruses (sci. family Reoviridae) are unenveloped viruses with double-stranded RNA. The rotavirus (a diarrhoea pathogen), for example, belongs to this group.

    • replication

      The propagation of genetic information (DNA).

    • resistance (bio.)

      Resistance describes the ability of a microorganism to withstand measures taken to destroy it. The increasing resistance of pathogens to antibiotics is of growing concern in medicine.

    • resonance line

      A resonance line is the measurable signal transmitted by excited atoms when transitioning from their excited state to their original state.

    • rickets

      A childhood bone disease that can usually be traced to a Vitamin D metabolic disorder.

    • RNA

      [Abbr. for ribonucleic acid] - DNA matrix generated by transcription.

  • S

    • sensitivity

      Here: responsiveness or susceptibility to UV radiation.

    • significance

      We speak of a significant difference when we wish to express the probability of error according to scientific or statistical standards. Consequently, a high significance expresses a clear measuring result with a low probability of error.

    • silicon

      Strictly speaking, the material silicon is actually chemically a polyorganosiloxane. ‘Silicons’ describes a group of synthetic polymers which are extremely water-repellent. Silicon sealing rings have a very high temperature resistance but are not very resistant to oils, alkalis, acids or fats.

    • solarisation

      here: Owing to the high energy of the UV radiation as well as the process-related deposit build-up on the inside of the quartz tube, the reaction-chamber material increasingly loses the ability to transmit UV radiation. This effect is called solarisation.

    • spectrophotometer

      A radiometer for determining the permeability of media to various wavelengths of the optical rays spectrum.

    • spores (biol.)

      Protozoa, algae, mosses, some bacteria, and especially (mould-) fungi form spores for asexual reproduction and dispersal. Because they have practically no metabolism, they can live for a very long time, even in especially hostile circumstances. Once they find a favourable environment, they become active again and reproduce.

    • staphylococci

      These are non-motile Gram-positive bacteria from the cocci family arranged in grape-like clusters. Staphylococcus aureus (MRSA) in particular has achieved a dubious notoriety owing to its increasing resistance to antibiotics. Staphylococci have only low UVC resistance. Depending on the study and the staphylococcus species in question, the LD90 values for airborne organisms are in some cases significantly below 1.0 mJ/cm2.

    • streptococci

      Like lactobacilli and enterococci, streptococci (sci. classification streptococcaceae) belong to the family of lactic-acid bacteria populating the intestine. They are Gram-positive, anaerobic but aerotolerant pathogens arranged in chains. These potentially pathogenic bacteria are also used in fermentation processes and in the medical regeneration of intestinal flora. Like staphylococci, they exhibit very little UVC resistance, and with few exceptions (here, Streptococcus faecalis) have an average LD90 value of 3.3 mJ/cm2.

  • T

    • teflon

      Teflon is actually a brand name of the DuPont company referring to the material PTFE, a fluoroplastic.

    • thermoplastic

      also plastomer - The term thermoplastics refers to those plastics capable of being deformed under the influence of temperature.

    • thymine

      also 5-methyluracil - Thymine (C5H6N2O2 ) is one of the four coding nucleobases in DNA. It forms the complementary base to adenine via two hydrogen bonds.

    • torr

      torr unit - A torr is the static pressure generated by a column of mercury 1 mm in height. A torr is not an SI unit of measure. Conversion: 1 torr ≈ 133,322 Pa ≈ 0.001333 bar.

    • toxic

      The effect of a toxin is described as toxic. ‘Toxic’ can also be defined as meaning ‘poisonous’. 

    • toxicity

      The degree to which a toxin is toxic or poisonous. 

    • toxin

      A toxin is a biogenic substance capable of damaging an organism by disrupting its physiological metabolic processes. The scientific discipline investigating toxins is called toxicology. Bacterial toxins are divided into exotoxins and endotoxins.

    • transcription

      Transfer of the genetic code of the DNA to the RNA.

    • transmission

      Transfer of the genetic code of the DNA to the RNA.

    • transmit

      To send or convey from one place to another. 

    • transparancy

      A particular material’s permeability to light does not allow us to draw any conclusions whatsoever as to whether it is UVC-transparent! UVC rays are substantially shorter and richer in energy than the electromagnetic waves that constitute ‘light’. With our spectrophotometer, we offer our customers a free service analysing the transmissibility of supplied fluids.

  • U

    • uracil

      Whereas thymine forms the counterpart to adenine in DNA, uracil (C4H4N2O2) takes the place of thymine in single-stranded RNA.

    • UV radiation

      [Abbr. for ultraviolet radiation] - the wavelength range between approx. 400 and 100 nm is generally termed UV radiation. UV radiation lies between the electromagnetic waves of light and X-radiation. The transitions are fuzzy, and thus not consistent in the literature. Depending on the source, the transition to light is given as 380 nm or 400 nm. For the transition range for X-radiation (100 to 1 nm), either the term soft X radiation or extreme UV radiation (XUV) is used.

    • UV resistance

      Industrial information on the UV resistance of a material usually refers to broad-spectrum UVA and UVB exposure, and hence allows only limited conclusions (if any at all) to be drawn in terms of the UVC resistance of the material.
      We therefore offer our customers a free service testing materials, particularly plastics, as to their UVC resistance or UVC transparence.

    • UVA

      [Abbr. for ultraviolet A spectrum] - Long-wave UV rays in the range of approx. 400 (380) to 315 nm are termed UVA rays. The difficulty of establishing limit values can be seen clearly in the example of black-light-lamp emissions.

    • UVB

      [Abbr. for ultraviolet B spectrum] - Medium-wave UV rays in the wavelength range of 315 to 280 nm are termed UVB rays. In the past, they were also called Dorno radiation after the Prussian naturalist Carl Dorno, who researched UVB radiation in depth and studied the biological processes associated with it.

    • UVC

      [Abbr. for ultraviolet C spectrum] - Short-wave UV rays in the wavelength range of 280 to 100 nm are termed UVC rays. UVC rays are also classified into the sub-ranges "far UV" (280 to 200 nm) and "vacuum UV" (200 to 100 nm).

  • V

    • VA

      [Abbr. for Volt-ampere] - A Volt-Ampere (also volt-amp) is the basic unit of apparent electrical power. The value is derived by multiplying the voltage applied to a device (V) by the value of the current consumed by the device (A). See also Watt.

    • vacuum

      In classical physics, a vacuum is defined as space which contains no matter whatsoever. Electromagnetic waves can propagate unimpeded in a vacuum. 

    • vegetative propagation

      The opposite of generative propagation, vegetative propagation describes asexual reproduction in biology.

    • viruses

      Viruses are particles or information carriers dependent for survival upon the metabolism of a host cell, since they themselves have no cytoplasm and are incapable of metabolism. Viruses are thus de facto not living organisms.

    • VIS

      [Abbr. for visual spectrum] - The visible electromagnetic waves - i.e light in the classic sense of the word - are termed VIS radiation.

    • vitamin D3

      is a secosteroid produced in human skin from 7-dehydrocholesterol through the action of UVB radiation.

    • VUV

      [Abbr. for vacuum UV ] - The very short waves in the UVC range of 200 to 100 nm and under are termed vacuum UV. The name comes from the fact that this radiation only propagates in a vacuum.

  • W

    • watt

      [Symbol W] - International unit of measurement for power. Conversion: 1 W = 1 VA.

    • wavelength (phys.)

      The distance between two neighbouring crests or troughs of an electromagnetic wave is referred to as a wavelength. By contrast, the time gap between two consecutive wave maxima or wave minima is termed the frequency.
      In a vacuum, the following always holds true: frequency * wavelength = speed of light. In other words, the longer the radiation wave, the lower its frequency, and vice-versa.

  • X

    • x-rays

      X-rays is the term used to describe the electromagnetic waves lying between the gamma radiation and UV-radiation ranges. X-rays have a wavelength of < 100 nm up to < 1 pm. The boundary zone between UV radiation and X-radiation (or Roentgen radiation, after the scientist who discovered X-rays) is not clearly defined, which is why we speak of wavelengths below 100 nm either as extreme UV rays or ‘soft’ X-radiation. X-rays belong to the category of ionising rays, and are thus subject to the (German) Radiation Protection Ordinance.

    • xerophilic

      Capable of growing and reproducing in very dry conditions. 

    • XUV

      [Abbr. for extreme UV radiation] - Extreme UV radiation is the name given to the 100 to 1 nm range which - depending on the source - is also described as soft X-rays.

  • absorption

    Intake or retention of elektromagnetic waves via conversion to heat, here: 254 nm wavelength radiation.

  • adenine

    Adenine (C5H5N5) is one of the four organic complementary bases in DNA and RNA. It forms two hydrogene bonds with thymine in the DNA-double helix.

  • aerobic

    Organisms which need oxygen (O2) for their metabolic processes are described as aerobic. Most pathogens responsible for skin diseases and respiratory-tract infections belong to the group of aerobic bacteria. Viewed in chemical terms, an aerobic process is an oxidation.

  • amino acid

    Amino acids are organic compounds which join together in long chains to form proteins, among other things. We distinguish approx. 20 different proteinogenic amino acids and a large number of non-proteinogenic amino acids. Amino acids are essential for metabolism and are thus the basis of life.

  • amorphus

    Amorphous is the term used in physics and chemistry to describe material whose atoms form an irregular shape rather than a long-range ordered structure. An amorphous state is generated via rapid heating or cooling. The opposite of an amorphous structure is a chrystalline structure.

  • anaerobic

    Organisms which do not require any oxygen for their metabolic processes are referred to as anaerobic. Enterobacteria (gut or intestinal bacteria), for example, are facultatively anaerobic.

  • anthrax

    Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

  • antibiotics

    Antibiotics are drugs used to treat bakterial or parasitic infectious diseases. Antibiotics used to treat fungal infections are call antimycotics. Discovered in 1928, the first natural antibiotic was penicillin, a mould. Today, antibiotics are also manufactured synthetically. They work either by inhibiting cell-wall formation, preventing protein produktion, disrupting DNA transmission, or a combination of all three strategies.

  • aspergillus

    Mikroorganisms of the Aspergillus genus belong to the thermotolerant moulds. Known members of this genus are Aspergillus niger (black mould), der Aspergillus amstelodami and Aspergillus fumigatus. These organisms grow best at high temperatures. A number of aspergillus species form methabolic products that are toxic for humans (mycotoxins), and which cause food poisoning. In addition, airborne spores  can trigger allergies and even attack organs. Aspergillus spores are extremely UVC-resistant and very high doses are needed. See also: UVC effect – relationship between dose and effect.

  • atom

    An atom is the smallest chemically indivisible unit, consisting of a nucleus and one or more electrons. Atoms are the building blocks of molecules, e.g. oxygen (O2) or water (H2O). An undisturbed atom is electrically neutral.

  • B. anthracis

    Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

  • B. cereus

    Bacillus cereus is a spore-forming, Gram-positive, facultatively anaerobic and widespread soil bacterium frequently detected in various foods, including in particular rice, since the spores even survive boiling.

  • bacilli

    (sing. bacillus) Rod-shaped bacteria.

  • bacteria

    Bacteria (sing. bacterium) are single-celled microorganisms classified into aerobic and anaerobic strains. Bacteria are prokaryotes. While most bacteria reproduce through cell division, some form spores.

  • baktericidal

    Killing bacteria or germs.

  • biofilm

    Biofilms consist of a thin slime layer (film), in which microorganisms (e.g. bacteria or algae) are embedded. They form mainly in water systems, either on the surface of the water or on an interface with a solid phase. Inside the biofilms the embedded organisims are active and growing so that new microbes continuously are spread into the water. By this e.g. cooling systems and water reservoirs get steadily contaminated. Furthermore on dying biofilms moulds and yeasts can settle down.

  • biozid

    In general, an agent for controlling pests.

  • borrelia

    Borrelia belong to the spirochete phylum - a group of relatively large Gram-negative bacteria which actively propel themselves forward by rotating around their own axis.

  • cereas

    Originally a synonym for grain rather than a breakfast convenience food such as muesli or corn flakes, cereal derives from the Latin Cerialia, the Roman festivities honouring the gods of agriculture and growth – particularly the grain goddess Ceres.

  • chromosomes

    Chromosome is the name given to the DNA spirally packaged by proteins in eukaryotic cells. A chromosome must be unwound for the replications and transcription process during the cell-division stage.

  • clostridia

    These are anaerobic, spore-forming, Gram-positive bacteria. Clostridia spores exhibit a very high resistance to thermal disinfecton methods and are able to survive a temperature of 100°C for several hours unharmed. Depending on the various investigation methods used, the LD90 value (UVC254nm) for Clostridia lies between 4.9 ... 23 mJ/cm2.

  • cytoplasma

    The gel-like, liquid, organic basic substance, surrounded by the cell membrane, of which a microorganism consists.

  • cytosine

    Cytosine (C4H5N3O) is one of the four complementary coding nucleobases in DNA. Cytosine forms a base pair via three hydrogen bonds with guanine.

  • decontamination

    Decontamination describes the reduction of pathogenic microorganisms to a safe level for human use. Technically, this means reduction by a minimum of 1 log step, meaning 90%.

  • dimerisation

    The congregation of two monomers.

  • disinfectant (chem.)

    Disinfectants contain active ingredients which either kill or inhibit the growth of microorganisms. Disinfectants require sufficient application time (>10 sec.) and must be used at sufficiently strong concentrations. Some well-known disinfectants are alcohols (e.g. isopropanol), hydrogen peroxide (H2O2), ozone (O3), and tinctures containing iodine.

  • disinfection

    The term disinfection is not clearly defined in a technical sense. Generally, it means a reduction of pathogenic microorganisms by a minimum of 3 and a maximum of 5 log steps. Hence, the term 'UV disinfection' describes the inactivation of at least 99.9% of a given pathogenic population with the aid of UV technology.

  • DNA

    [Abbr. for desoxyribonucleic acid] - The carrier of genetic information.

  • dorno radiation

    The term Dorno radiation is an alternative but no longer current description for UVB radiation. Carl Dorno was a Prussian scientist deeply involved in researching this biologically active radiation.

  • dose

    The term dose describes the defined amount of radiation energy to which an organism is exposed in a particular time frame. In UV disinfection, the dose is usually given in µW*s/cm² or J/m².

  • double helix

    Helix is a term synonymous with 'coil' or 'spiral'. A double helix is therefore a double spiral.

  • E. coli

    [Abbr. Escherichia coli] - E. coli is a Gram-negative, rod-shaped, facultatively anaerobic and acid producing bacterium, occurring in the guts of humans and animals. It owes its name to its discoverer, bacteriologist and professor of paediatrics Theodor Escherich.

    E. coli is considered to be an indicator bacterium for faecal contamination. It preferentially colonises raw milk, cheese and raw meat. Exposure to UVC causes lethal damage to E. coli. There is probably no microorganism that has been better documented and investigated.

  • elastomer

    Elastomers are elastically deformable plastics which nevertheless retain a fixed shape. After mechanical deformation, they therefore reassume their original shape.

  • electromagnetic spectrum

    The electromagnetic spectrum is the range of all frequencies of electromagnetic waves.

  • electromagnetic wave

    An electromagnetic wave consists of an electrical and a magnetic field component. Unlike pressure waves, electromagnetic waves do not require a medium for propagation; their propagation speed depends on the medium, with propagation in a vacuum taking place at the speed of light. The best-known electromagnetic waves are probably those described colloquially as 'light'.

  • electron

    An electron is an electrically charged elementary particle. An (e-) electron is negatively charged. A positively charged elementary particle (e+) is called a positron.

  • electrostatics

    Theory of resting charges and their temporally stable electric fields.

  • EMC

    [Abbr. for electromagnetic compatibility] - A test criterion  for electric or electronic devices describing their freedom from interference with their surroundings.

  • emission (phys.)

    The sending out of electromagnetic waves.

  • emitter

    From the Latin emittere 'to send out'. In physics, the source of radiation is defined as an emitter. From the same provenance as the term emission.

  • endotoxins

    Endotoxins are lipopolysaccharides found in the outer membrane of Gram-neagtive bacteria. Released during the decay of microorganisms, they have a toxic effect.

  • enterobacteria

    The term enterobacteria (sci. term Enterobacteriaceae) is understood to mean those bacteria occurring in the guts of animals or humans (Gr. enteron = intestine). Enterobacters belong to the family of facultative anaerobes, meaning that the require no oxygen (O2) for their metabolism. A typical member of this family is E. coli.

  • enterococci

    Enterococci (sing. Enterococcus) are Gram-positive anaerobic bacteria arranged in pairs or short chains. They also belong to the type of microorganisms populating the guts of animals and humans.  Enterococci have an important digestive function and are added to fermentation and ripening processes in food production as well as to probiotic foodstuffs to promote intestinal microflora.

  • EPDM

    [Abbr. for ethylene propylene diene monomer] - EPDM is a synthetic rubber used primarily as a sealant and hose material on account of its good elasticity and high resistance to ozone, acid and alkali

  • epidemic

    A localised, heavily massed occurrence of an infectious disease - see also pandemic.

  • erythema

    Medical term for redness of the skin, or a reddish-coloured dermatitis (inflammation of the skin). 

  • EU Directive 2006-25-EG

    EU health and safety directive for protecting workers from the risks arising from artificial optical radiation. The original text of the directive (PDF 844 kB) can be found here...

  • eucaryotic cells

    Also know as eukaryotes - Cells with a membrane-surrounded nucleus in which the DNA is stored in the form of chromosomes.

  • exotoxins

    Exotoxins are poisonous substances constantly being excreted by bacteria.

  • exposure

    The state of being subject to contact with something. 

  • exposure time

    Here: Length of time for which an organism is exposed to UV radiation.

  • facultative

    non-obligatory

  • faecal bacteria

    Faecal bacteria (e.g. Escherichia coli) is taken to mean all microorganisms populating the guts of animals or humans, whose presence therefore indicates contamination by either excrement or products of fermentation or decay.

  • FDA

    [Abbr. for Food and Drug Administration] - The FDA is the American federal agency responsible for food monitoring and drug licensing. It is subordinate to the Department of Health and Human Services.

  • FEP

    [Abbr. for fluorinated ethylene propylene (perfluoroethylene propylene copolymer)] – FEP is a hydrophobic fluoroelastomer with a high resistance to heat and chemicals.

  • fluorplastics

    The term fluoroplastics describes polymers manufactured from fluorine (F) and carbon (C). Typical fluoroplastics are FEP and PTFE, which are known under the brand name Teflon. Fluoroplastics have a very high resistance to chemicals and intense UV radiation. They also retain good UVC transparency at thin layer thicknesses.

  • FPM

    [Abbr. for fluoropolymer permeable membrane (fluoropolymer rubber)] - FPM is a fluorinated elastomer with very high ozone-, weather- and UV-resistance.

  • fungicide

    Chemical or biological agent for destroying fungal spores und moulds.

  • gram-negative bacteria

    Gram-negative bacteria have a thin cell wall with a single-layered murein. They therefore absorb no dye during Gram staining, and appear reddish under the microscope. Gram-negative bacteria are primarily rod bacteria and are endotoxic. Well-known members of this family are Legionella, the pseudomonads, and Borrelia.

  • gram-positive bacteria

    Gram-positive Bakterien färben sich bei der Gramfärbung dunkelblau. Ursache ist eine dicke Zellwand mit mehrschichtigem Murein, welches bis zu 50% der Hüllentrockenmasse ausmachen kann. Grampositive Bakterien kommen hauptsächlich als Kokken vor und sie wirken exotoxisch. Beispiele: Listerien, Clostridien, Streptokokken und Staphylokokken.

  • gram staining

    Developed by the Danish bacteriologist Hans Christian Gram, Gram staining is a method for rendering bacteria more visible under the microscope with the aid of a special dye. Depending on differences in their cell-wall structures, bacteria can basically be divided into two groups: Gram-positive and Gram-negative bacteria.

  • guanine

    Guanine (C5H5N5O) is one of the four coding nucleobases of DNA and RNA. Guanine always base-pairs with the complementary cytosine, forming three hydrogen bonds with the latter.

  • HACCP

    [Abbr. for hazard analysis and critical control points] - A preventive system intended to ensure food safety from manufacture to the consumer.

  • HDPE

    [Abbr. for high density polyethylene] - This thermoplastic polymer has a high resistance to acids, alkalis and chemicals.

  • hepatitis

    Hepatitis is the medical term for an inflammation of the liver which can be caused both by hepatitis viruses as well as by other pathogens such as bacteria and parasites. Of the classic viral hepatitis types, the Hepatitis B infection is the most common. Transmission, as with the HIV virus, is via the direct exchange of bodily fluids. With direct exposure, the viruses in question have a low-to-medium UVC-resistance.

  • herbicide

    weed killer.

  • herpes simplex

    Caused by the herpes simplex virus, herpes is the most common infectious disease of the skin. Although usually occurring as lip herpes (‘cold sores’), other parts of the skin can also be affected. To date, there are no curative treatments for herpes simplex infections, nor does the organism develop an immunity to the virus. With an average lethal dose (LD90) of 5 mJ/cm2, herpes simplex viruses exhibit a relatively high UVC sensitivity in laboratory trials.

  • hg

    chemical symbol for mercury.

  • HIV

    [Abbr. for human immunodeficiency virus] - Belonging to the family of retroviruses, the HIV virus causes the well-known immunodeficiency disease AIDS. Around 100 to 120 nm in diameter, the virus is surrounded by an envelope. Statistically speaking, around 90% of the infections occur if people get transfused with HIV-positive blood, with transmission via bodily fluids being a possibility. Investigations by Henderson et al. revealed the virus to be extremely resistant to UVC radiation.

  • humanpathogenic

    Med. term meaning “causing disease in humans” - see pathogenic.

  • hyphae

    Hyphae (sing. hypha) are microscopically small, long, very thin, branching fungal filaments which develop in all directions from a mould spore on a breeding ground. Hyphae are involved in both feeding and propagation (see conidiophores). A mass of hyphae is referred to as a mycelium.

  • IFS

    [Abbr. for International Food Standard] - Defined in 2003 by representatives of the European retail-food industry, the IFS is used to audit and certify systems ensuring food safety, as well as quality and conformity in food production. 

  • inactiviation

    Technically speaking, microorganisms are not actually killed off by the lethal impact of UVC radiation, but are rendered ‘inoperative’ or incapable of dividing. Since viruses are by definition not considered to be living organisms, it follows that they cannot be ‘killed off’.

  • infection

    The term infection describes the process by which pathogens penetrate into the body of an organism and multiply therein. Depending on the transmission route, we distinguish between smear infections, contact infections and droplet infections.

  • infectiousness

    Measure for describing the ability of a pathogen to cause actual infection in a host after transmission occurs.

  • infrared radiation

    [IR radiation for short] - this is the spectral range of 780 nm to 1000 µm, i.e. the wavelength range lying between the spectral range of visible light and the so-called terahertz radiation range. The thermal (‘mid-’) IR radiation range lies between 3 µm and 50 µm.

  • intensity (phys.)

    In physics,‘intensity’ describes energy density with respect to an area, and is given e.g. in µW/cm2. In UV disinfection, this information is essential for calculating the lethal dose.

  • ionising radiation

    Ionising describes the type of radiation capable of permanently removing electrons from atoms or molecules, thereby changing the state of charge of the latter two. Radioactive radiation and X-ray radiation are among the typical representatives of ionising energies. Note: UVC radiation has no ionising power, and hence does not figure among the ionising rays. (See also Technology - generating UV rays).

  • ions

    Ions are generally understood to mean atoms that are electrically charged.

  • IP protection

    [Abbr. for international protection] - Types of protection that are classified according to DIN 40050. The letters IP are followed by two digits, the first indicating the degree of protection afforded against the ingress of solid bodies, and the second describing the degree of protection against the ingress of water.

  • joule

    [Abbr. J] - International unit of measurement for energy, heat quantity and work. Conversion: 1 J = 1 W*s

  • kb

    [Abbr. for kilobyte] - In computer science, a unit of information consisting of 8 bits of data.

  • lactobacilli

    [Also known as lactic-acid bacteria] - Lactobacilli (sing. lactobacillus) are anaerobic, Gram-positive microorganisms found in the gut or mucosa of mammals. They are primarily used in the manufacture of dairy products (cheese, yoghurt, kefir, etc.).

  • ld

    Abbr. of lethal dose (which see).

  • LD90

    The LD value can be specified more precisely via an index number. LD 90 is the dose which eliminates on average 90% of an (e.g.) bacterial population.

  • legionella

    The family of Legionella bacteria (scientific name Legionellaceae) contains more than 48 known species as well as numerous subgroups. They are water-dwelling Gram-negative aerobic bacteria that are potentially pathogenic for humans. Since they require still or recirculated water in the 25-50°C range for optimal growth, they are found primarily in air washers, cooling towers, dead pipes, water tanks and shower heads. Legionella are easily and effectively inactivated at even very low UVC doses.

  • lethal dose

    Lethal dose (LD) is the term referring to the dose of a toxin or radiation which is deadly for an organism.

  • lethality

    Lethality describes the ratio of deaths to survivals after a dose of radiation, infection or illness - in other words, the mortality rate. It is therefore a measurement of hazard or risk.

  • light

    Light is the colloquial name given to that portion of the electromagnetic spectrum lying in the 380-780 nm spectral range. This is the range that is visible to the naked human eye, with the limit values varying depending upon source. Consequently, the unfortunately common designation of ‘UV light’ is a contradiction in terms, and, strictly speaking, inaccurate.

  • living organism

    In biology, life forms capable of metabolic processes, replication and evolutionary development (all three criteria must be fulfilled) are known as living organisms.

  • log

    [Abbr. for logarithm] - Although the term ‘log’ is the usual abbreviation for base-10 logarithms, the mathematically correct term here is lg. We speak here of decadic logarithms.

  • log reduction

    In biology, bacterial reduction is indicated in log stages. A log reduction of X therefore means a reduction by X log stages starting from a given population. For example, the reduction by 1 log stage means a reduction of 90%, since only 10 have survived from the original population of 100 (= 10 x 10).

  • log stage

    see also log reduction - In biology, each log stage describes the reduction of a population by a (further) power of ten: in other words, 1 log stage = 90%, 2 log stages = 99%, 3 log stages = 99.9%, etc.

  • logarithm

    The logarithm is an important mathematical function serving to illustrate significantly increasing series of numbers. The logarithm is the inverse operation of the power function ax = b, i.e. x = logb(a) (that is, logarithm of a to base b). This means that if a = 10x, then x = lg a. 

  • macromolecules

    Macromolecules are extremely large molecules with a relatively large mass, the properties of which remain unaffected by the removal of individual atoms or groups of atoms. DNA and proteins are typical naturally occurring macromolecules, whilst all polymers are typical synthetic macromolecules.

  • melanin

    Melanin is a pigment responsible in humans for skin colour, among othe things, and which protects the skin against harmful UV radiation.

  • melanoma

    also known as black-mole cancer - A melanoma is a malignant tumour appearing as an asymmetrically growing, discoloured change in the skin. 

  • metabolism

    The term metabolism describes the uptake, transport and chemical transformation of matter in an organism, as well as the discharge of metabolic end products into the environment.

  • micrometre

    also micron - The unit µm. Conversion: 1 µm = 0.001 mm. 

  • microorganism

    also microbe - Microorganisms are organic structures so small that they can generally only be seen with the aid of a microscope. Such structures are usually single-celled, although they are occasionally multi-celled.

  • microwatt

    The unit µW. Conversion: 1 µW = 0.001 mW = 0.000001 W.

  • molecules

    The term molecule describes a particle formed from two or more atoms which is at least temporarily stable. Molecules can be formed from atoms of the same element, e.g. oxygen (O2), ozone (O3) and nitrogen (N2), or from atoms of different elements, e.g. water (H2O).

  • monochromatic

    describes radiation of a precisely defined wavelength, as e.g. emitted by a laser. 

  • monomer

    Monomers are reactive molecules which in terms of a basic unit may congregate into chains or networks.

  • MRSA

    [Abbr. of methicillin-resistant Staphylococcus aureus] In the narrower sense, MRSA is taken to mean Staphylococcus aureus strains which are resistant to all beta lactam antibiotics (e.g.penicillin) available up to the present on the market.

  • multiresistance (med.)

    In medicine, the class of pathogens that are resistant to several classes of antibiotics (or to virostatic agents in the case of viruses) are described as multiresistant.

  • murein

    also peptidoglycan - Murein is a three-dimensional biopolymer with a net-like structure functioning as a supporting skeleton of the cell wall in the case of bacteria. The macromolecule consists of amino acids and sugar molecules.

  • mutation

    We speak of a mutation when the highly stable genetic algorithm of the hereditary material (DNA) of an organism undergoes a relatively permanent, stable change. Unlike with a modification, a mutation is permanently replicated.

  • mycelium

    The term mycelium [plural mycelia] refers to the mass of hyphae that form a mould.

  • mycotoxins

    see Aspergilla.

  • nanometer

    The unit nm. Conversion: 1 nm = 0.000000001 m or 0.001 µm. By way of comparison, a human hair has a diameter of approx. 100 µm.

  • NBR

    [Abbr. for nitrile butadiene rubber] - NBR is a heat-resistant synthetic rubber. It is particularly resistant to petroleum products such as fuel and lubricating oil, petrol and petroleum.

  • norovirus

    Noroviruses (Norwalk Viruses in full) are non-enveloped viruses with single-stranded RNA. They have an extremely high contagiousness, and infection leads to acute gastoenteritis (gastric flu). Hospitals as well as old-age or nursing homes are particularly vulnerable to repeated epidemic norovirus outbreaks.

  • nosocomial infection

    A nosocomial infection refers to an infection contracted in a hospital or care institution.

  • obligate

    absolutely indispensable, essential.

  • optical radiation

    The electromagnetic wavelength range between 100 nm and 1 mm is referred to as optical radiation. By definition, this includes ultraviolet radiation (UV), the visible light spectrum (VIS) and infrared radiation (IR).

  • organic compound

    Organic compounds are substances composed primarily of hydrogen (H) and carbon (C). Organic chemistry is concerned with the properties, composition and production of carbon compounds.

  • organism

    An organism is an individual life form - see living organism.

  • oxidation

    Oxidation generally refers to the chemical process in which an element reacts with oxygen or in which electrons are lost. 

  • ozone

    Represented as O3 - Ozone is a gas with strong oxidation properties that is toxic in high concentrations. The molecule consists of three oxygen atoms and is therefore unstable. Ozone arises naturally through the effect of solar radiation on the stratosphere.

  • pandemic

    A pandemic is an infectious disease of temporarily exceptionally high prevalence occurring across national borders. See also epidemic.

  • parasite

    Parasites are organisms which need substances generated by other organisms - termed ‘hosts’ - for their metabolic function. In acquiring these substances, they damage, or even kill (in the case of parasitoids) the host.

  • pathogen

    Pathogens are microorganisms capable of causing disease or illness in living creatures. Their harmful effects are usually due to toxins which they excrete. The opposite of pathogenicity is apathogenicity. The latter is defined as the inability of a pathogen to cause the disease in a specific host organism. Pathogens affecting only humans are termed human-pathogenic.

  • PE

    [Abbr. for Polyethylene] - Besides polyvinyl chloride, polyethylene is the most widely industrially produced thermoplastic. We distinguish between different PE types according to their density. The UVC resistance of all PE types is generally poor, but may vary depending upon colour. See also: HDPE .

  • peak

    The highest point of a specified value: greatest, maximum. 

  • pesticide

    An agent for controlling pests, usually in the sense of a plant-protection product.

  • PET

    [Abbr. for Polyethylene terephthalate] - PET (or PETE) is a thermoplastic polymer resin with either an amorphous or semi-crystalline structure. The amorphous sort is transparent. PET is UV- resistant only to a limited extent, if at all.

  • PGN

    [Abbr. for peptidoglycan] - see murein.

  • photochemistry

    See photolysis.

  • photolysis

    The decomposition or separation of chemical compounds induced by light.

  • photometer

    See radiometer.

  • photons

    A photon is the smallest unit of excitation of an electromagnetic field. It is also called the quantum of the electromagnetic field. A photon has a rest mass of zero and moves in a vacuum at the speed of light. Photons can interact with particles of matter, and can thus also be absorbed.

  • plafond sanitaire technology

    Bactericidally effective UV-radiation roof in the above-head area.

  • plasma

    Here, non-isothermal plasma - Plasma is a mixture of freely mobile electrons, ions and neutral atoms which are in different states of excitation and strongly interact with one another. Stars are typical high-temperature plasmas. We speak of ‘non-isothermal plasma’ when - as in the case of gas-discharge lamps - only the electrons are in a state of thermodynamic balance.

  • pm

    [Abbr. for picometre] - Conversion: 1 pm = 0.001 nm = 0.000001 µm = 0.000000001 mm, i.e. one billionth of a millimetre.

  • polymer

    Polymers are chemical compounds composed of numerous cross-linked monomers that are repeatedly strung together - hence the name polymer (poly = many). Protein is a natural polymer; plastics are typical synthetic polymers.

  • POM

    [Abbr. for polyoxymethylene] - POM is a high-strength thermoplastic with excellent dimensional stability and very good machinability, which is why it is often used for technical applications. Like almost all plastics, POM is not UVC-stable, and its black surface turns grey and dull when exposed to UVC radiation. At very high UVC outputs, the material tends to become brittle.

  • PP

    [Abbr. for polypropylene] - PP is a thermoplastic with high stability and high chemical resistance. It is tougher and more heat-resistant than PE, but becomes brittle at temperatures below 0° C. PP is non-UVC-stable, and with fairly long exposure to UVC radiation the surface of the material is subject to damage and decomposition.

  • prevention

    The taking of precautionary measures to stop undesirable occurrences. 

  • previtamin D

    Previtamin D3 is a precursor of vitamin D3, which is produced in the skin via photolysis under the influence of heat and wavelengths between 290 and 315 nm (UVB).

  • prokaryotic cells

    also prokaryotes - Cells without a true nucleus: see also eukaryotes.

  • prophylaxis

    Medical term for preventive measures for protecting health.

  • protein

    Proteins or albumins are macromolecules (polymers) consisting of amino acids. They are essential elements for growth, repair, function and structure in all living cells. The UV absorption maximum of proteins is 280 nm.

  • protozoa

    Protozoa (sing. protozoon) are a highly heterogeneous group of single-celled eukaryotic organisms. Among the numerous types of protozoa, approx. 40 humanopathogenic, parasitic species are known which cause malaria and dysentery, among others. Because measuring data on the UVC resistance of these organisms has a very large spread, a general statement on the lethal dose is not possible.

  • PS

    [Here, abbr. for polystyrene] - Polystyrene is a transparent thermoplastic. In foamed form this material is also known by the registered trademark Styrofoam. PS is non-UVC-stable.

  • PTFE

    [Abbr. for polytetrafluoroethylene] - PTFE is a thermoplastic fluoroplastic known primarily by the trade name Teflon of the DuPont company. PTFE has outstanding resistance to UVC rays.

  • PUR

    [Abbr. for polyurethane] - PUR is one of the most versatile plastics. Although mainly used in a foamed form, it is also found as a thermoplastic, elastomer, adhesive, varnish, and in the form of fibres.

  • purine

    Purines are nitrogenous compounds which in addition to the pyrimidines constitute the most important components of nucleic acid. The bases adenine and guanine are derived from purine. Formed by the human body itself, purines are broken down into uric acid.

  • PVC

    [abbr. for polyvinyl chloride] - PVC is an amorphous thermoplastic made soft, elastic and malleable by the addition of softeners and stabilisers. Depending on its composition and the proportion of softeners it contains, it is therefore UVC-resistant only to a limited extent.

  • PVDF

    [abbr. for polyvinylidene fluoride] - PVDF is a flame-retardant crystalline thermoplastic with excellent UV resistance. Like PTFE, it is a good electrical isolator, and it is also highly resistant to acids and alkalis.

  • pyrimidine

    Like purine, pyrimidine forms the base component of the organic bases. The bases cytosine, thymine and uracil are derived from pyrimidine.

  • radiometer

    A radiometer serves to measure electromagnetic waves. These devices are generally based on photodiodes which convert the incoming radiation into a proportional electrical signal. Lux meters and photometers are typical radiometers.

  • radiometry

    Radiometry is the science of radiation measurement, used in astronomy and physics, among others.

  • recipient

    A person, organism or thing that receives something.

  • reflection (phys.)

    Reflection refers to the (partial) return of electromagnetic waves at an interface. Reflection is the opposite of absorption. Since UVC rays have a different wavelength from light, they also behave differently at interfaces in terms of absorption and reflection. Light-reflecting surfaces are therefore not to be understood as synonymous with UVC-reflecting ones!

  • reoviruses

    Reoviruses (sci. family Reoviridae) are unenveloped viruses with double-stranded RNA. The rotavirus (a diarrhoea pathogen), for example, belongs to this group.

  • replication

    The propagation of genetic information (DNA).

  • resistance (bio.)

    Resistance describes the ability of a microorganism to withstand measures taken to destroy it. The increasing resistance of pathogens to antibiotics is of growing concern in medicine.

  • resonance line

    A resonance line is the measurable signal transmitted by excited atoms when transitioning from their excited state to their original state.

  • rickets

    A childhood bone disease that can usually be traced to a Vitamin D metabolic disorder.

  • RNA

    [Abbr. for ribonucleic acid] - DNA matrix generated by transcription.

  • sensitivity

    Here: responsiveness or susceptibility to UV radiation.

  • significance

    We speak of a significant difference when we wish to express the probability of error according to scientific or statistical standards. Consequently, a high significance expresses a clear measuring result with a low probability of error.

  • silicon

    Strictly speaking, the material silicon is actually chemically a polyorganosiloxane. ‘Silicons’ describes a group of synthetic polymers which are extremely water-repellent. Silicon sealing rings have a very high temperature resistance but are not very resistant to oils, alkalis, acids or fats.

  • solarisation

    here: Owing to the high energy of the UV radiation as well as the process-related deposit build-up on the inside of the quartz tube, the reaction-chamber material increasingly loses the ability to transmit UV radiation. This effect is called solarisation.

  • spectrophotometer

    A radiometer for determining the permeability of media to various wavelengths of the optical rays spectrum.

  • spores (biol.)

    Protozoa, algae, mosses, some bacteria, and especially (mould-) fungi form spores for asexual reproduction and dispersal. Because they have practically no metabolism, they can live for a very long time, even in especially hostile circumstances. Once they find a favourable environment, they become active again and reproduce.

  • staphylococci

    These are non-motile Gram-positive bacteria from the cocci family arranged in grape-like clusters. Staphylococcus aureus (MRSA) in particular has achieved a dubious notoriety owing to its increasing resistance to antibiotics. Staphylococci have only low UVC resistance. Depending on the study and the staphylococcus species in question, the LD90 values for airborne organisms are in some cases significantly below 1.0 mJ/cm2.

  • streptococci

    Like lactobacilli and enterococci, streptococci (sci. classification streptococcaceae) belong to the family of lactic-acid bacteria populating the intestine. They are Gram-positive, anaerobic but aerotolerant pathogens arranged in chains. These potentially pathogenic bacteria are also used in fermentation processes and in the medical regeneration of intestinal flora. Like staphylococci, they exhibit very little UVC resistance, and with few exceptions (here, Streptococcus faecalis) have an average LD90 value of 3.3 mJ/cm2.

  • teflon

    Teflon is actually a brand name of the DuPont company referring to the material PTFE, a fluoroplastic.

  • thermoplastic

    also plastomer - The term thermoplastics refers to those plastics capable of being deformed under the influence of temperature.

  • thymine

    also 5-methyluracil - Thymine (C5H6N2O2 ) is one of the four coding nucleobases in DNA. It forms the complementary base to adenine via two hydrogen bonds.

  • torr

    torr unit - A torr is the static pressure generated by a column of mercury 1 mm in height. A torr is not an SI unit of measure. Conversion: 1 torr ≈ 133,322 Pa ≈ 0.001333 bar.

  • toxic

    The effect of a toxin is described as toxic. ‘Toxic’ can also be defined as meaning ‘poisonous’. 

  • toxicity

    The degree to which a toxin is toxic or poisonous. 

  • toxin

    A toxin is a biogenic substance capable of damaging an organism by disrupting its physiological metabolic processes. The scientific discipline investigating toxins is called toxicology. Bacterial toxins are divided into exotoxins and endotoxins.

  • transcription

    Transfer of the genetic code of the DNA to the RNA.

  • transmission

    Transfer of the genetic code of the DNA to the RNA.

  • transmit

    To send or convey from one place to another. 

  • transparancy

    A particular material’s permeability to light does not allow us to draw any conclusions whatsoever as to whether it is UVC-transparent! UVC rays are substantially shorter and richer in energy than the electromagnetic waves that constitute ‘light’. With our spectrophotometer, we offer our customers a free service analysing the transmissibility of supplied fluids.

  • uracil

    Whereas thymine forms the counterpart to adenine in DNA, uracil (C4H4N2O2) takes the place of thymine in single-stranded RNA.

  • UV radiation

    [Abbr. for ultraviolet radiation] - the wavelength range between approx. 400 and 100 nm is generally termed UV radiation. UV radiation lies between the electromagnetic waves of light and X-radiation. The transitions are fuzzy, and thus not consistent in the literature. Depending on the source, the transition to light is given as 380 nm or 400 nm. For the transition range for X-radiation (100 to 1 nm), either the term soft X radiation or extreme UV radiation (XUV) is used.

  • UV resistance

    Industrial information on the UV resistance of a material usually refers to broad-spectrum UVA and UVB exposure, and hence allows only limited conclusions (if any at all) to be drawn in terms of the UVC resistance of the material.
    We therefore offer our customers a free service testing materials, particularly plastics, as to their UVC resistance or UVC transparence.

  • UVA

    [Abbr. for ultraviolet A spectrum] - Long-wave UV rays in the range of approx. 400 (380) to 315 nm are termed UVA rays. The difficulty of establishing limit values can be seen clearly in the example of black-light-lamp emissions.

  • UVB

    [Abbr. for ultraviolet B spectrum] - Medium-wave UV rays in the wavelength range of 315 to 280 nm are termed UVB rays. In the past, they were also called Dorno radiation after the Prussian naturalist Carl Dorno, who researched UVB radiation in depth and studied the biological processes associated with it.

  • UVC

    [Abbr. for ultraviolet C spectrum] - Short-wave UV rays in the wavelength range of 280 to 100 nm are termed UVC rays. UVC rays are also classified into the sub-ranges "far UV" (280 to 200 nm) and "vacuum UV" (200 to 100 nm).

  • VA

    [Abbr. for Volt-ampere] - A Volt-Ampere (also volt-amp) is the basic unit of apparent electrical power. The value is derived by multiplying the voltage applied to a device (V) by the value of the current consumed by the device (A). See also Watt.

  • vacuum

    In classical physics, a vacuum is defined as space which contains no matter whatsoever. Electromagnetic waves can propagate unimpeded in a vacuum. 

  • vegetative propagation

    The opposite of generative propagation, vegetative propagation describes asexual reproduction in biology.

  • viruses

    Viruses are particles or information carriers dependent for survival upon the metabolism of a host cell, since they themselves have no cytoplasm and are incapable of metabolism. Viruses are thus de facto not living organisms.

  • VIS

    [Abbr. for visual spectrum] - The visible electromagnetic waves - i.e light in the classic sense of the word - are termed VIS radiation.

  • vitamin D3

    is a secosteroid produced in human skin from 7-dehydrocholesterol through the action of UVB radiation.

  • VUV

    [Abbr. for vacuum UV ] - The very short waves in the UVC range of 200 to 100 nm and under are termed vacuum UV. The name comes from the fact that this radiation only propagates in a vacuum.

  • watt

    [Symbol W] - International unit of measurement for power. Conversion: 1 W = 1 VA.

  • wavelength (phys.)

    The distance between two neighbouring crests or troughs of an electromagnetic wave is referred to as a wavelength. By contrast, the time gap between two consecutive wave maxima or wave minima is termed the frequency.
    In a vacuum, the following always holds true: frequency * wavelength = speed of light. In other words, the longer the radiation wave, the lower its frequency, and vice-versa.

  • x-rays

    X-rays is the term used to describe the electromagnetic waves lying between the gamma radiation and UV-radiation ranges. X-rays have a wavelength of < 100 nm up to < 1 pm. The boundary zone between UV radiation and X-radiation (or Roentgen radiation, after the scientist who discovered X-rays) is not clearly defined, which is why we speak of wavelengths below 100 nm either as extreme UV rays or ‘soft’ X-radiation. X-rays belong to the category of ionising rays, and are thus subject to the (German) Radiation Protection Ordinance.

  • xerophilic

    Capable of growing and reproducing in very dry conditions. 

  • XUV

    [Abbr. for extreme UV radiation] - Extreme UV radiation is the name given to the 100 to 1 nm range which - depending on the source - is also described as soft X-rays.

Show all

  • absorption

    Intake or retention of elektromagnetic waves via conversion to heat, here: 254 nm wavelength radiation.

  • adenine

    Adenine (C5H5N5) is one of the four organic complementary bases in DNA and RNA. It forms two hydrogene bonds with thymine in the DNA-double helix.

  • aerobic

    Organisms which need oxygen (O2) for their metabolic processes are described as aerobic. Most pathogens responsible for skin diseases and respiratory-tract infections belong to the group of aerobic bacteria. Viewed in chemical terms, an aerobic process is an oxidation.

  • amino acid

    Amino acids are organic compounds which join together in long chains to form proteins, among other things. We distinguish approx. 20 different proteinogenic amino acids and a large number of non-proteinogenic amino acids. Amino acids are essential for metabolism and are thus the basis of life.

  • amorphus

    Amorphous is the term used in physics and chemistry to describe material whose atoms form an irregular shape rather than a long-range ordered structure. An amorphous state is generated via rapid heating or cooling. The opposite of an amorphous structure is a chrystalline structure.

  • anaerobic

    Organisms which do not require any oxygen for their metabolic processes are referred to as anaerobic. Enterobacteria (gut or intestinal bacteria), for example, are facultatively anaerobic.

  • anthrax

    Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

  • antibiotics

    Antibiotics are drugs used to treat bakterial or parasitic infectious diseases. Antibiotics used to treat fungal infections are call antimycotics. Discovered in 1928, the first natural antibiotic was penicillin, a mould. Today, antibiotics are also manufactured synthetically. They work either by inhibiting cell-wall formation, preventing protein produktion, disrupting DNA transmission, or a combination of all three strategies.

  • aspergillus

    Mikroorganisms of the Aspergillus genus belong to the thermotolerant moulds. Known members of this genus are Aspergillus niger (black mould), der Aspergillus amstelodami and Aspergillus fumigatus. These organisms grow best at high temperatures. A number of aspergillus species form methabolic products that are toxic for humans (mycotoxins), and which cause food poisoning. In addition, airborne spores  can trigger allergies and even attack organs. Aspergillus spores are extremely UVC-resistant and very high doses are needed. See also: UVC effect – relationship between dose and effect.

  • atom

    An atom is the smallest chemically indivisible unit, consisting of a nucleus and one or more electrons. Atoms are the building blocks of molecules, e.g. oxygen (O2) or water (H2O). An undisturbed atom is electrically neutral.

  • B. anthracis

    Bacillus anthracis is an obligate aerobic, Gram-positive, spore-forming bacterium known as an anthrax pathogen. The spores of this organism are extremely robust, and the bacterium is extremely important as a potential biological weapon on account of its high lethality.

  • B. cereus

    Bacillus cereus is a spore-forming, Gram-positive, facultatively anaerobic and widespread soil bacterium frequently detected in various foods, including in particular rice, since the spores even survive boiling.

  • bacilli

    (sing. bacillus) Rod-shaped bacteria.

  • bacteria

    Bacteria (sing. bacterium) are single-celled microorganisms classified into aerobic and anaerobic strains. Bacteria are prokaryotes. While most bacteria reproduce through cell division, some form spores.

  • baktericidal

    Killing bacteria or germs.

  • biofilm

    Biofilms consist of a thin slime layer (film), in which microorganisms (e.g. bacteria or algae) are embedded. They form mainly in water systems, either on the surface of the water or on an interface with a solid phase. Inside the biofilms the embedded organisims are active and growing so that new microbes continuously are spread into the water. By this e.g. cooling systems and water reservoirs get steadily contaminated. Furthermore on dying biofilms moulds and yeasts can settle down.

  • biozid

    In general, an agent for controlling pests.

  • borrelia

    Borrelia belong to the spirochete phylum - a group of relatively large Gram-negative bacteria which actively propel themselves forward by rotating around their own axis.

  • cereas

    Originally a synonym for grain rather than a breakfast convenience food such as muesli or corn flakes, cereal derives from the Latin Cerialia, the Roman festivities honouring the gods of agriculture and growth – particularly the grain goddess Ceres.

  • chromosomes

    Chromosome is the name given to the DNA spirally packaged by proteins in eukaryotic cells. A chromosome must be unwound for the replications and transcription process during the cell-division stage.

  • clostridia

    These are anaerobic, spore-forming, Gram-positive bacteria. Clostridia spores exhibit a very high resistance to thermal disinfecton methods and are able to survive a temperature of 100°C for several hours unharmed. Depending on the various investigation methods used, the LD90 value (UVC254nm) for Clostridia lies between 4.9 ... 23 mJ/cm2.

  • cytoplasma

    The gel-like, liquid, organic basic substance, surrounded by the cell membrane, of which a microorganism consists.

  • cytosine

    Cytosine (C4H5N3O) is one of the four complementary coding nucleobases in DNA. Cytosine forms a base pair via three hydrogen bonds with guanine.

  • decontamination

    Decontamination describes the reduction of pathogenic microorganisms to a safe level for human use. Technically, this means reduction by a minimum of 1 log step, meaning 90%.

  • dimerisation

    The congregation of two monomers.

  • disinfectant (chem.)

    Disinfectants contain active ingredients which either kill or inhibit the growth of microorganisms. Disinfectants require sufficient application time (>10 sec.) and must be used at sufficiently strong concentrations. Some well-known disinfectants are alcohols (e.g. isopropanol), hydrogen peroxide (H2O2), ozone (O3), and tinctures containing iodine.

  • disinfection

    The term disinfection is not clearly defined in a technical sense. Generally, it means a reduction of pathogenic microorganisms by a minimum of 3 and a maximum of 5 log steps. Hence, the term 'UV disinfection' describes the inactivation of at least 99.9% of a given pathogenic population with the aid of UV technology.

  • DNA

    [Abbr. for desoxyribonucleic acid] - The carrier of genetic information.

  • dorno radiation

    The term Dorno radiation is an alternative but no longer current description for UVB radiation. Carl Dorno was a Prussian scientist deeply involved in researching this biologically active radiation.

  • dose

    The term dose describes the defined amount of radiation energy to which an organism is exposed in a particular time frame. In UV disinfection, the dose is usually given in µW*s/cm² or J/m².

  • double helix

    Helix is a term synonymous with 'coil' or 'spiral'. A double helix is therefore a double spiral.

  • E. coli

    [Abbr. Escherichia coli] - E. coli is a Gram-negative, rod-shaped, facultatively anaerobic and acid producing bacterium, occurring in the guts of humans and animals. It owes its name to its discoverer, bacteriologist and professor of paediatrics Theodor Escherich.

    E. coli is considered to be an indicator bacterium for faecal contamination. It preferentially colonises raw milk, cheese and raw meat. Exposure to UVC causes lethal damage to E. coli. There is probably no microorganism that has been better documented and investigated.

  • elastomer

    Elastomers are elastically deformable plastics which nevertheless retain a fixed shape. After mechanical deformation, they therefore reassume their original shape.

  • electromagnetic spectrum

    The electromagnetic spectrum is the range of all frequencies of electromagnetic waves.

  • electromagnetic wave

    An electromagnetic wave consists of an electrical and a magnetic field component. Unlike pressure waves, electromagnetic waves do not require a medium for propagation; their propagation speed depends on the medium, with propagation in a vacuum taking place at the speed of light. The best-known electromagnetic waves are probably those described colloquially as 'light'.

  • electron

    An electron is an electrically charged elementary particle. An (e-) electron is negatively charged. A positively charged elementary particle (e+) is called a positron.

  • electrostatics

    Theory of resting charges and their temporally stable electric fields.

  • EMC

    [Abbr. for electromagnetic compatibility] - A test criterion  for electric or electronic devices describing their freedom from interference with their surroundings.

  • emission (phys.)

    The sending out of electromagnetic waves.

  • emitter

    From the Latin emittere 'to send out'. In physics, the source of radiation is defined as an emitter. From the same provenance as the term emission.

  • endotoxins

    Endotoxins are lipopolysaccharides found in the outer membrane of Gram-neagtive bacteria. Released during the decay of microorganisms, they have a toxic effect.

  • enterobacteria

    The term enterobacteria (sci. term Enterobacteriaceae) is understood to mean those bacteria occurring in the guts of animals or humans (Gr. enteron = intestine). Enterobacters belong to the family of facultative anaerobes, meaning that the require no oxygen (O2) for their metabolism. A typical member of this family is E. coli.

  • enterococci

    Enterococci (sing. Enterococcus) are Gram-positive anaerobic bacteria arranged in pairs or short chains. They also belong to the type of microorganisms populating the guts of animals and humans.  Enterococci have an important digestive function and are added to fermentation and ripening processes in food production as well as to probiotic foodstuffs to promote intestinal microflora.

  • EPDM

    [Abbr. for ethylene propylene diene monomer] - EPDM is a synthetic rubber used primarily as a sealant and hose material on account of its good elasticity and high resistance to ozone, acid and alkali

  • epidemic

    A localised, heavily massed occurrence of an infectious disease - see also pandemic.

  • erythema

    Medical term for redness of the skin, or a reddish-coloured dermatitis (inflammation of the skin). 

  • EU Directive 2006-25-EG

    EU health and safety directive for protecting workers from the risks arising from artificial optical radiation. The original text of the directive (PDF 844 kB) can be found here...

  • eucaryotic cells

    Also know as eukaryotes - Cells with a membrane-surrounded nucleus in which the DNA is stored in the form of chromosomes.

  • exotoxins

    Exotoxins are poisonous substances constantly being excreted by bacteria.

  • exposure

    The state of being subject to contact with something. 

  • exposure time

    Here: Length of time for which an organism is exposed to UV radiation.

  • facultative

    non-obligatory

  • faecal bacteria

    Faecal bacteria (e.g. Escherichia coli) is taken to mean all microorganisms populating the guts of animals or humans, whose presence therefore indicates contamination by either excrement or products of fermentation or decay.

  • FDA

    [Abbr. for Food and Drug Administration] - The FDA is the American federal agency responsible for food monitoring and drug licensing. It is subordinate to the Department of Health and Human Services.

  • FEP

    [Abbr. for fluorinated ethylene propylene (perfluoroethylene propylene copolymer)] – FEP is a hydrophobic fluoroelastomer with a high resistance to heat and chemicals.

  • fluorplastics

    The term fluoroplastics describes polymers manufactured from fluorine (F) and carbon (C). Typical fluoroplastics are FEP and PTFE, which are known under the brand name Teflon. Fluoroplastics have a very high resistance to chemicals and intense UV radiation. They also retain good UVC transparency at thin layer thicknesses.

  • FPM

    [Abbr. for fluoropolymer permeable membrane (fluoropolymer rubber)] - FPM is a fluorinated elastomer with very high ozone-, weather- and UV-resistance.

  • fungicide

    Chemical or biological agent for destroying fungal spores und moulds.

  • gram-negative bacteria

    Gram-negative bacteria have a thin cell wall with a single-layered murein. They therefore absorb no dye during Gram staining, and appear reddish under the microscope. Gram-negative bacteria are primarily rod bacteria and are endotoxic. Well-known members of this family are Legionella, the pseudomonads, and Borrelia.

  • gram-positive bacteria

    Gram-positive Bakterien färben sich bei der Gramfärbung dunkelblau. Ursache ist eine dicke Zellwand mit mehrschichtigem Murein, welches bis zu 50% der Hüllentrockenmasse ausmachen kann. Grampositive Bakterien kommen hauptsächlich als Kokken vor und sie wirken exotoxisch. Beispiele: Listerien, Clostridien, Streptokokken und Staphylokokken.

  • gram staining

    Developed by the Danish bacteriologist Hans Christian Gram, Gram staining is a method for rendering bacteria more visible under the microscope with the aid of a special dye. Depending on differences in their cell-wall structures, bacteria can basically be divided into two groups: Gram-positive and Gram-negative bacteria.

  • guanine

    Guanine (C5H5N5O) is one of the four coding nucleobases of DNA and RNA. Guanine always base-pairs with the complementary cytosine, forming three hydrogen bonds with the latter.

  • HACCP

    [Abbr. for hazard analysis and critical control points] - A preventive system intended to ensure food safety from manufacture to the consumer.

  • HDPE

    [Abbr. for high density polyethylene] - This thermoplastic polymer has a high resistance to acids, alkalis and chemicals.

  • hepatitis

    Hepatitis is the medical term for an inflammation of the liver which can be caused both by hepatitis viruses as well as by other pathogens such as bacteria and parasites. Of the classic viral hepatitis types, the Hepatitis B infection is the most common. Transmission, as with the HIV virus, is via the direct exchange of bodily fluids. With direct exposure, the viruses in question have a low-to-medium UVC-resistance.

  • herbicide

    weed killer.

  • herpes simplex

    Caused by the herpes simplex virus, herpes is the most common infectious disease of the skin. Although usually occurring as lip herpes (‘cold sores’), other parts of the skin can also be affected. To date, there are no curative treatments for herpes simplex infections, nor does the organism develop an immunity to the virus. With an average lethal dose (LD90) of 5 mJ/cm2, herpes simplex viruses exhibit a relatively high UVC sensitivity in laboratory trials.

  • hg

    chemical symbol for mercury.

  • HIV

    [Abbr. for human immunodeficiency virus] - Belonging to the family of retroviruses, the HIV virus causes the well-known immunodeficiency disease AIDS. Around 100 to 120 nm in diameter, the virus is surrounded by an envelope. Statistically speaking, around 90% of the infections occur if people get transfused with HIV-positive blood, with transmission via bodily fluids being a possibility. Investigations by Henderson et al. revealed the virus to be extremely resistant to UVC radiation.

  • humanpathogenic

    Med. term meaning “causing disease in humans” - see pathogenic.

  • hyphae

    Hyphae (sing. hypha) are microscopically small, long, very thin, branching fungal filaments which develop in all directions from a mould spore on a breeding ground. Hyphae are involved in both feeding and propagation (see conidiophores). A mass of hyphae is referred to as a mycelium.

  • IFS

    [Abbr. for International Food Standard] - Defined in 2003 by representatives of the European retail-food industry, the IFS is used to audit and certify systems ensuring food safety, as well as quality and conformity in food production. 

  • inactiviation

    Technically speaking, microorganisms are not actually killed off by the lethal impact of UVC radiation, but are rendered ‘inoperative’ or incapable of dividing. Since viruses are by definition not considered to be living organisms, it follows that they cannot be ‘killed off’.

  • infection

    The term infection describes the process by which pathogens penetrate into the body of an organism and multiply therein. Depending on the transmission route, we distinguish between smear infections, contact infections and droplet infections.

  • infectiousness

    Measure for describing the ability of a pathogen to cause actual infection in a host after transmission occurs.

  • infrared radiation

    [IR radiation for short] - this is the spectral range of 780 nm to 1000 µm, i.e. the wavelength range lying between the spectral range of visible light and the so-called terahertz radiation range. The thermal (‘mid-’) IR radiation range lies between 3 µm and 50 µm.

  • intensity (phys.)

    In physics,‘intensity’ describes energy density with respect to an area, and is given e.g. in µW/cm2. In UV disinfection, this information is essential for calculating the lethal dose.

  • ionising radiation

    Ionising describes the type of radiation capable of permanently removing electrons from atoms or molecules, thereby changing the state of charge of the latter two. Radioactive radiation and X-ray radiation are among the typical representatives of ionising energies. Note: UVC radiation has no ionising power, and hence does not figure among the ionising rays. (See also Technology - generating UV rays).

  • ions

    Ions are generally understood to mean atoms that are electrically charged.

  • IP protection

    [Abbr. for international protection] - Types of protection that are classified according to DIN 40050. The letters IP are followed by two digits, the first indicating the degree of protection afforded against the ingress of solid bodies, and the second describing the degree of protection against the ingress of water.

  • joule

    [Abbr. J] - International unit of measurement for energy, heat quantity and work. Conversion: 1 J = 1 W*s

  • kb

    [Abbr. for kilobyte] - In computer science, a unit of information consisting of 8 bits of data.

  • lactobacilli

    [Also known as lactic-acid bacteria] - Lactobacilli (sing. lactobacillus) are anaerobic, Gram-positive microorganisms found in the gut or mucosa of mammals. They are primarily used in the manufacture of dairy products (cheese, yoghurt, kefir, etc.).

  • ld

    Abbr. of lethal dose (which see).

  • LD90

    The LD value can be specified more precisely via an index number. LD 90 is the dose which eliminates on average 90% of an (e.g.) bacterial population.

  • legionella

    The family of Legionella bacteria (scientific name Legionellaceae) contains more than 48 known species as well as numerous subgroups. They are water-dwelling Gram-negative aerobic bacteria that are potentially pathogenic for humans. Since they require still or recirculated water in the 25-50°C range for optimal growth, they are found primarily in air washers, cooling towers, dead pipes, water tanks and shower heads. Legionella are easily and effectively inactivated at even very low UVC doses.

  • lethal dose

    Lethal dose (LD) is the term referring to the dose of a toxin or radiation which is deadly for an organism.

  • lethality

    Lethality describes the ratio of deaths to survivals after a dose of radiation, infection or illness - in other words, the mortality rate. It is therefore a measurement of hazard or risk.

  • light

    Light is the colloquial name given to that portion of the electromagnetic spectrum lying in the 380-780 nm spectral range. This is the range that is visible to the naked human eye, with the limit values varying depending upon source. Consequently, the unfortunately common designation of ‘UV light’ is a contradiction in terms, and, strictly speaking, inaccurate.

  • living organism

    In biology, life forms capable of metabolic processes, replication and evolutionary development (all three criteria must be fulfilled) are known as living organisms.

  • log

    [Abbr. for logarithm] - Although the term ‘log’ is the usual abbreviation for base-10 logarithms, the mathematically correct term here is lg. We speak here of decadic logarithms.

  • log reduction

    In biology, bacterial reduction is indicated in log stages. A log reduction of X therefore means a reduction by X log stages starting from a given population. For example, the reduction by 1 log stage means a reduction of 90%, since only 10 have survived from the original population of 100 (= 10 x 10).

  • log stage

    see also log reduction - In biology, each log stage describes the reduction of a population by a (further) power of ten: in other words, 1 log stage = 90%, 2 log stages = 99%, 3 log stages = 99.9%, etc.

  • logarithm

    The logarithm is an important mathematical function serving to illustrate significantly increasing series of numbers. The logarithm is the inverse operation of the power function ax = b, i.e. x = logb(a) (that is, logarithm of a to base b). This means that if a = 10x, then x = lg a. 

  • macromolecules

    Macromolecules are extremely large molecules with a relatively large mass, the properties of which remain unaffected by the removal of individual atoms or groups of atoms. DNA and proteins are typical naturally occurring macromolecules, whilst all polymers are typical synthetic macromolecules.

  • melanin

    Melanin is a pigment responsible in humans for skin colour, among othe things, and which protects the skin against harmful UV radiation.

  • melanoma

    also known as black-mole cancer - A melanoma is a malignant tumour appearing as an asymmetrically growing, discoloured change in the skin. 

  • metabolism

    The term metabolism describes the uptake, transport and chemical transformation of matter in an organism, as well as the discharge of metabolic end products into the environment.

  • micrometre

    also micron - The unit µm. Conversion: 1 µm = 0.001 mm. 

  • microorganism

    also microbe - Microorganisms are organic structures so small that they can generally only be seen with the aid of a microscope. Such structures are usually single-celled, although they are occasionally multi-celled.

  • microwatt

    The unit µW. Conversion: 1 µW = 0.001 mW = 0.000001 W.

  • molecules

    The term molecule describes a particle formed from two or more atoms which is at least temporarily stable. Molecules can be formed from atoms of the same element, e.g. oxygen (O2), ozone (O3) and nitrogen (N2), or from atoms of different elements, e.g. water (H2O).

  • monochromatic

    describes radiation of a precisely defined wavelength, as e.g. emitted by a laser. 

  • monomer

    Monomers are reactive molecules which in terms of a basic unit may congregate into chains or networks.

  • MRSA

    [Abbr. of methicillin-resistant Staphylococcus aureus] In the narrower sense, MRSA is taken to mean Staphylococcus aureus strains which are resistant to all beta lactam antibiotics (e.g.penicillin) available up to the present on the market.

  • multiresistance (med.)

    In medicine, the class of pathogens that are resistant to several classes of antibiotics (or to virostatic agents in the case of viruses) are described as multiresistant.

  • murein

    also peptidoglycan - Murein is a three-dimensional biopolymer with a net-like structure functioning as a supporting skeleton of the cell wall in the case of bacteria. The macromolecule consists of amino acids and sugar molecules.

  • mutation

    We speak of a mutation when the highly stable genetic algorithm of the hereditary material (DNA) of an organism undergoes a relatively permanent, stable change. Unlike with a modification, a mutation is permanently replicated.

  • mycelium

    The term mycelium [plural mycelia] refers to the mass of hyphae that form a mould.

  • mycotoxins

    see Aspergilla.

  • nanometer

    The unit nm. Conversion: 1 nm = 0.000000001 m or 0.001 µm. By way of comparison, a human hair has a diameter of approx. 100 µm.

  • NBR

    [Abbr. for nitrile butadiene rubber] - NBR is a heat-resistant synthetic rubber. It is particularly resistant to petroleum products such as fuel and lubricating oil, petrol and petroleum.

  • norovirus

    Noroviruses (Norwalk Viruses in full) are non-enveloped viruses with single-stranded RNA. They have an extremely high contagiousness, and infection leads to acute gastoenteritis (gastric flu). Hospitals as well as old-age or nursing homes are particularly vulnerable to repeated epidemic norovirus outbreaks.

  • nosocomial infection

    A nosocomial infection refers to an infection contracted in a hospital or care institution.

  • obligate

    absolutely indispensable, essential.

  • optical radiation

    The electromagnetic wavelength range between 100 nm and 1 mm is referred to as optical radiation. By definition, this includes ultraviolet radiation (UV), the visible light spectrum (VIS) and infrared radiation (IR).

  • organic compound

    Organic compounds are substances composed primarily of hydrogen (H) and carbon (C). Organic chemistry is concerned with the properties, composition and production of carbon compounds.

  • organism

    An organism is an individual life form - see living organism.

  • oxidation

    Oxidation generally refers to the chemical process in which an element reacts with oxygen or in which electrons are lost. 

  • ozone

    Represented as O3 - Ozone is a gas with strong oxidation properties that is toxic in high concentrations. The molecule consists of three oxygen atoms and is therefore unstable. Ozone arises naturally through the effect of solar radiation on the stratosphere.

  • pandemic

    A pandemic is an infectious disease of temporarily exceptionally high prevalence occurring across national borders. See also epidemic.

  • parasite

    Parasites are organisms which need substances generated by other organisms - termed ‘hosts’ - for their metabolic function. In acquiring these substances, they damage, or even kill (in the case of parasitoids) the host.

  • pathogen

    Pathogens are microorganisms capable of causing disease or illness in living creatures. Their harmful effects are usually due to toxins which they excrete. The opposite of pathogenicity is apathogenicity. The latter is defined as the inability of a pathogen to cause the disease in a specific host organism. Pathogens affecting only humans are termed human-pathogenic.

  • PE

    [Abbr. for Polyethylene] - Besides polyvinyl chloride, polyethylene is the most widely industrially produced thermoplastic. We distinguish between different PE types according to their density. The UVC resistance of all PE types is generally poor, but may vary depending upon colour. See also: HDPE .

  • peak

    The highest point of a specified value: greatest, maximum. 

  • pesticide

    An agent for controlling pests, usually in the sense of a plant-protection product.

  • PET

    [Abbr. for Polyethylene terephthalate] - PET (or PETE) is a thermoplastic polymer resin with either an amorphous or semi-crystalline structure. The amorphous sort is transparent. PET is UV- resistant only to a limited extent, if at all.

  • PGN

    [Abbr. for peptidoglycan] - see murein.

  • photochemistry

    See photolysis.

  • photolysis

    The decomposition or separation of chemical compounds induced by light.

  • photometer

    See radiometer.

  • photons

    A photon is the smallest unit of excitation of an electromagnetic field. It is also called the quantum of the electromagnetic field. A photon has a rest mass of zero and moves in a vacuum at the speed of light. Photons can interact with particles of matter, and can thus also be absorbed.

  • plafond sanitaire technology

    Bactericidally effective UV-radiation roof in the above-head area.

  • plasma

    Here, non-isothermal plasma - Plasma is a mixture of freely mobile electrons, ions and neutral atoms which are in different states of excitation and strongly interact with one another. Stars are typical high-temperature plasmas. We speak of ‘non-isothermal plasma’ when - as in the case of gas-discharge lamps - only the electrons are in a state of thermodynamic balance.

  • pm

    [Abbr. for picometre] - Conversion: 1 pm = 0.001 nm = 0.000001 µm = 0.000000001 mm, i.e. one billionth of a millimetre.

  • polymer

    Polymers are chemical compounds composed of numerous cross-linked monomers that are repeatedly strung together - hence the name polymer (poly = many). Protein is a natural polymer; plastics are typical synthetic polymers.

  • POM

    [Abbr. for polyoxymethylene] - POM is a high-strength thermoplastic with excellent dimensional stability and very good machinability, which is why it is often used for technical applications. Like almost all plastics, POM is not UVC-stable, and its black surface turns grey and dull when exposed to UVC radiation. At very high UVC outputs, the material tends to become brittle.

  • PP

    [Abbr. for polypropylene] - PP is a thermoplastic with high stability and high chemical resistance. It is tougher and more heat-resistant than PE, but becomes brittle at temperatures below 0° C. PP is non-UVC-stable, and with fairly long exposure to UVC radiation the surface of the material is subject to damage and decomposition.

  • prevention

    The taking of precautionary measures to stop undesirable occurrences. 

  • previtamin D

    Previtamin D3 is a precursor of vitamin D3, which is produced in the skin via photolysis under the influence of heat and wavelengths between 290 and 315 nm (UVB).

  • prokaryotic cells

    also prokaryotes - Cells without a true nucleus: see also eukaryotes.

  • prophylaxis

    Medical term for preventive measures for protecting health.

  • protein

    Proteins or albumins are macromolecules (polymers) consisting of amino acids. They are essential elements for growth, repair, function and structure in all living cells. The UV absorption maximum of proteins is 280 nm.

  • protozoa

    Protozoa (sing. protozoon) are a highly heterogeneous group of single-celled eukaryotic organisms. Among the numerous types of protozoa, approx. 40 humanopathogenic, parasitic species are known which cause malaria and dysentery, among others. Because measuring data on the UVC resistance of these organisms has a very large spread, a general statement on the lethal dose is not possible.

  • PS

    [Here, abbr. for polystyrene] - Polystyrene is a transparent thermoplastic. In foamed form this material is also known by the registered trademark Styrofoam. PS is non-UVC-stable.

  • PTFE

    [Abbr. for polytetrafluoroethylene] - PTFE is a thermoplastic fluoroplastic known primarily by the trade name Teflon of the DuPont company. PTFE has outstanding resistance to UVC rays.

  • PUR

    [Abbr. for polyurethane] - PUR is one of the most versatile plastics. Although mainly used in a foamed form, it is also found as a thermoplastic, elastomer, adhesive, varnish, and in the form of fibres.

  • purine

    Purines are nitrogenous compounds which in addition to the pyrimidines constitute the most important components of nucleic acid. The bases adenine and guanine are derived from purine. Formed by the human body itself, purines are broken down into uric acid.

  • PVC

    [abbr. for polyvinyl chloride] - PVC is an amorphous thermoplastic made soft, elastic and malleable by the addition of softeners and stabilisers. Depending on its composition and the proportion of softeners it contains, it is therefore UVC-resistant only to a limited extent.

  • PVDF

    [abbr. for polyvinylidene fluoride] - PVDF is a flame-retardant crystalline thermoplastic with excellent UV resistance. Like PTFE, it is a good electrical isolator, and it is also highly resistant to acids and alkalis.

  • pyrimidine

    Like purine, pyrimidine forms the base component of the organic bases. The bases cytosine, thymine and uracil are derived from pyrimidine.

  • radiometer

    A radiometer serves to measure electromagnetic waves. These devices are generally based on photodiodes which convert the incoming radiation into a proportional electrical signal. Lux meters and photometers are typical radiometers.

  • radiometry

    Radiometry is the science of radiation measurement, used in astronomy and physics, among others.

  • recipient

    A person, organism or thing that receives something.

  • reflection (phys.)

    Reflection refers to the (partial) return of electromagnetic waves at an interface. Reflection is the opposite of absorption. Since UVC rays have a different wavelength from light, they also behave differently at interfaces in terms of absorption and reflection. Light-reflecting surfaces are therefore not to be understood as synonymous with UVC-reflecting ones!

  • reoviruses

    Reoviruses (sci. family Reoviridae) are unenveloped viruses with double-stranded RNA. The rotavirus (a diarrhoea pathogen), for example, belongs to this group.

  • replication

    The propagation of genetic information (DNA).

  • resistance (bio.)

    Resistance describes the ability of a microorganism to withstand measures taken to destroy it. The increasing resistance of pathogens to antibiotics is of growing concern in medicine.

  • resonance line

    A resonance line is the measurable signal transmitted by excited atoms when transitioning from their excited state to their original state.

  • rickets

    A childhood bone disease that can usually be traced to a Vitamin D metabolic disorder.

  • RNA

    [Abbr. for ribonucleic acid] - DNA matrix generated by transcription.

  • sensitivity

    Here: responsiveness or susceptibility to UV radiation.

  • significance

    We speak of a significant difference when we wish to express the probability of error according to scientific or statistical standards. Consequently, a high significance expresses a clear measuring result with a low probability of error.

  • silicon

    Strictly speaking, the material silicon is actually chemically a polyorganosiloxane. ‘Silicons’ describes a group of synthetic polymers which are extremely water-repellent. Silicon sealing rings have a very high temperature resistance but are not very resistant to oils, alkalis, acids or fats.

  • solarisation

    here: Owing to the high energy of the UV radiation as well as the process-related deposit build-up on the inside of the quartz tube, the reaction-chamber material increasingly loses the ability to transmit UV radiation. This effect is called solarisation.

  • spectrophotometer

    A radiometer for determining the permeability of media to various wavelengths of the optical rays spectrum.

  • spores (biol.)

    Protozoa, algae, mosses, some bacteria, and especially (mould-) fungi form spores for asexual reproduction and dispersal. Because they have practically no metabolism, they can live for a very long time, even in especially hostile circumstances. Once they find a favourable environment, they become active again and reproduce.

  • staphylococci

    These are non-motile Gram-positive bacteria from the cocci family arranged in grape-like clusters. Staphylococcus aureus (MRSA) in particular has achieved a dubious notoriety owing to its increasing resistance to antibiotics. Staphylococci have only low UVC resistance. Depending on the study and the staphylococcus species in question, the LD90 values for airborne organisms are in some cases significantly below 1.0 mJ/cm2.

  • streptococci

    Like lactobacilli and enterococci, streptococci (sci. classification streptococcaceae) belong to the family of lactic-acid bacteria populating the intestine. They are Gram-positive, anaerobic but aerotolerant pathogens arranged in chains. These potentially pathogenic bacteria are also used in fermentation processes and in the medical regeneration of intestinal flora. Like staphylococci, they exhibit very little UVC resistance, and with few exceptions (here, Streptococcus faecalis) have an average LD90 value of 3.3 mJ/cm2.

  • teflon

    Teflon is actually a brand name of the DuPont company referring to the material PTFE, a fluoroplastic.

  • thermoplastic

    also plastomer - The term thermoplastics refers to those plastics capable of being deformed under the influence of temperature.

  • thymine

    also 5-methyluracil - Thymine (C5H6N2O2 ) is one of the four coding nucleobases in DNA. It forms the complementary base to adenine via two hydrogen bonds.

  • torr

    torr unit - A torr is the static pressure generated by a column of mercury 1 mm in height. A torr is not an SI unit of measure. Conversion: 1 torr ≈ 133,322 Pa ≈ 0.001333 bar.

  • toxic

    The effect of a toxin is described as toxic. ‘Toxic’ can also be defined as meaning ‘poisonous’. 

  • toxicity

    The degree to which a toxin is toxic or poisonous. 

  • toxin

    A toxin is a biogenic substance capable of damaging an organism by disrupting its physiological metabolic processes. The scientific discipline investigating toxins is called toxicology. Bacterial toxins are divided into exotoxins and endotoxins.

  • transcription

    Transfer of the genetic code of the DNA to the RNA.

  • transmission

    Transfer of the genetic code of the DNA to the RNA.

  • transmit

    To send or convey from one place to another. 

  • transparancy

    A particular material’s permeability to light does not allow us to draw any conclusions whatsoever as to whether it is UVC-transparent! UVC rays are substantially shorter and richer in energy than the electromagnetic waves that constitute ‘light’. With our spectrophotometer, we offer our customers a free service analysing the transmissibility of supplied fluids.

  • uracil

    Whereas thymine forms the counterpart to adenine in DNA, uracil (C4H4N2O2) takes the place of thymine in single-stranded RNA.

  • UV radiation

    [Abbr. for ultraviolet radiation] - the wavelength range between approx. 400 and 100 nm is generally termed UV radiation. UV radiation lies between the electromagnetic waves of light and X-radiation. The transitions are fuzzy, and thus not consistent in the literature. Depending on the source, the transition to light is given as 380 nm or 400 nm. For the transition range for X-radiation (100 to 1 nm), either the term soft X radiation or extreme UV radiation (XUV) is used.

  • UV resistance

    Industrial information on the UV resistance of a material usually refers to broad-spectrum UVA and UVB exposure, and hence allows only limited conclusions (if any at all) to be drawn in terms of the UVC resistance of the material.
    We therefore offer our customers a free service testing materials, particularly plastics, as to their UVC resistance or UVC transparence.

  • UVA

    [Abbr. for ultraviolet A spectrum] - Long-wave UV rays in the range of approx. 400 (380) to 315 nm are termed UVA rays. The difficulty of establishing limit values can be seen clearly in the example of black-light-lamp emissions.

  • UVB

    [Abbr. for ultraviolet B spectrum] - Medium-wave UV rays in the wavelength range of 315 to 280 nm are termed UVB rays. In the past, they were also called Dorno radiation after the Prussian naturalist Carl Dorno, who researched UVB radiation in depth and studied the biological processes associated with it.

  • UVC

    [Abbr. for ultraviolet C spectrum] - Short-wave UV rays in the wavelength range of 280 to 100 nm are termed UVC rays. UVC rays are also classified into the sub-ranges "far UV" (280 to 200 nm) and "vacuum UV" (200 to 100 nm).

  • VA

    [Abbr. for Volt-ampere] - A Volt-Ampere (also volt-amp) is the basic unit of apparent electrical power. The value is derived by multiplying the voltage applied to a device (V) by the value of the current consumed by the device (A). See also Watt.

  • vacuum

    In classical physics, a vacuum is defined as space which contains no matter whatsoever. Electromagnetic waves can propagate unimpeded in a vacuum. 

  • vegetative propagation

    The opposite of generative propagation, vegetative propagation describes asexual reproduction in biology.

  • viruses

    Viruses are particles or information carriers dependent for survival upon the metabolism of a host cell, since they themselves have no cytoplasm and are incapable of metabolism. Viruses are thus de facto not living organisms.

  • VIS

    [Abbr. for visual spectrum] - The visible electromagnetic waves - i.e light in the classic sense of the word - are termed VIS radiation.

  • vitamin D3

    is a secosteroid produced in human skin from 7-dehydrocholesterol through the action of UVB radiation.

  • VUV

    [Abbr. for vacuum UV ] - The very short waves in the UVC range of 200 to 100 nm and under are termed vacuum UV. The name comes from the fact that this radiation only propagates in a vacuum.

  • watt

    [Symbol W] - International unit of measurement for power. Conversion: 1 W = 1 VA.

  • wavelength (phys.)

    The distance between two neighbouring crests or troughs of an electromagnetic wave is referred to as a wavelength. By contrast, the time gap between two consecutive wave maxima or wave minima is termed the frequency.
    In a vacuum, the following always holds true: frequency * wavelength = speed of light. In other words, the longer the radiation wave, the lower its frequency, and vice-versa.

  • x-rays

    X-rays is the term used to describe the electromagnetic waves lying between the gamma radiation and UV-radiation ranges. X-rays have a wavelength of < 100 nm up to < 1 pm. The boundary zone between UV radiation and X-radiation (or Roentgen radiation, after the scientist who discovered X-rays) is not clearly defined, which is why we speak of wavelengths below 100 nm either as extreme UV rays or ‘soft’ X-radiation. X-rays belong to the category of ionising rays, and are thus subject to the (German) Radiation Protection Ordinance.

  • xerophilic

    Capable of growing and reproducing in very dry conditions. 

  • XUV

    [Abbr. for extreme UV radiation] - Extreme UV radiation is the name given to the 100 to 1 nm range which - depending on the source - is also described as soft X-rays.

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