UVA / UVB infos

Information on UV:

Electromagnetic waves in the wavelength between 1 nm and 380 nm are referred to as ultraviolet radiation. For humans UV radiation is invisible and therefore referring to it as UV light is slightly misleading. Depending on its effects and the wavelengths the UV radiation is split into UVA, UVB and UVC.

UVC radiation is completely filter from natural sunlight in the atmosphere and does not reach us down on earth. This is good, as UVC is dangerous as it harms and destroys cells. UVC must not be contained in the spectrum of a reptile lamp!

For the successful husbandry of reptiles a sufficient amount of UVA (315-380 nm) and UVB (280-315 nm) is important in the spectrum of a lamp. Especially from day-active species which inhabit open landscapes, it is know that they can see UVA radiation. Often they have patterns that reflect only in the UVA part of the spectrum. If this radiation is missing from terrarium lighting animals loose the possibility for important parts of the inner species communication! It can happen that without UVA a male cannot discover when a female is ready for mating. The lack of UVA radiation causes a lot of stress for the animal.

The effects of UVB radiation are a bit more complicated. On one side UVB has dangerous effects for humans and causes sunburn and skin cancer. On the other side most vertebrate animals can form their own vitamin D3 with the help of UVB radiation. Vitamin D3 regulates the calcium metabolism and is important for healthy bones. The lack of vitamin D3 can quickly cause rachitis and other metabolic bone diseases. Vitamin D3 can also be supplemented over the food. However, research with tortoises has shown that vitamin D3 which is synthesized in the body with the help of UV, is producing better results. It also is important to know that vitamin D3 is toxic if overdosed and the correct dosage can be tricky when supplementing over the food. Through providing UVB radiation and allowing the animal to form its own vitamin D3, overdosing is hardly possible.

Please consider that UVB radiation on its own cannot guarantee healthy bones as the supply of calcium has to be ensured. Calcium has to be provided over the food, e.g. with Lucky Reptile Bio Calcium products which can ensure the availability of calcium all the time.

How much UV does my animal need?

Little is known of the correct dosage of UVB radiation inside a terrarium and all there is, is based on a few individual species. However, from humans we know that on a sunny day a few minutes outside will be sufficient to cover our Vitamin D3 needs, and that fully clothed with only hands and face able to absorb UVB!

Practical experience with reptiles indicates that a daily, highly concentrated UVB radiation is not necessary either. In nature animals seek out hideouts during the day to avoid the strongest sun periods. There are also indications that reptiles can register the production of certain preliminary stages of vitamin D3 and selectively expose themselves to UVB.

A must in the terrarium is that animals can get away from the UVB which is easily possible with the Bright Sun as these punctiform lamps only have local UV radiation. There is also research that shows that the body does have regulating mechanisms to prevent overproduction of the toxic vitamin D3. However, the regulation is only functioning properly with a very natural UV spectrum. For converting pre-vitamin into vitamin D3 heat is also necessary. This is a strong point for the Bright Sun as it is supplying the necessary heat radiation unlike tubes or compact fluorescent lamps.

It is also proven that the harmfulness of UVB radiation as well as the effectiveness for vitamin D3 synthesis is limited to certain ranges of the UVB spectrum and certain wavelengths are much more effective than others. The forming of vitamin D3 mainly occurs between 280 and 305 nm. The optimum is at 295 nm where 10 times more pre-vitamin D3 is formed than at 310 nm. Due to the dangerous effects of short wavelengths UVB radiation below 290 nm should be avoided. Natural sunlight does not contain UVB below 290 nm.

The Bright Sun simulates the sun like no other lamp. It has a high light intensity and good heat emissions. In addition there are high UVA contents and UVB radiation in the right part of the spectrum for the vitamin D3 synthesis. We have deliberately limited the UV performance to a lower level as that of natural sunlight as we want to maintain high safety for the animals in a limited environment like a vivarium. This makes the Bright Sun save and efficient for providing your animals with the right UVB and allows its use as all day lamp.

UV claims of other manufacturers and UV measurement devices

A lot of manufacturers are still advertising UV percentage values on their packaging. These offer no practical hint if a lamp is suitable for reptiles as it does not consider the wattage and illuminated area (diffusion of UV light). 10% UVB might sound like a lot but if the lamp only has 20W, the UV output is still lower than with a 100W lamp that only has 3% UVB.

Several manufacturers therefore started to give out performance figures in Microwatt/cm2 (μW/cm2) which consider the illuminated area. However, these values can also be misleading as they are highly dependent on the distance to the lamp and only consider the full UVB spectrum. They can therefore not indicate if the lamp has save UVB radiation for animals and will allow it synthesize its own vitamin D3, as for this only certain wavelengths are important.

The situation is quite similar when using broadband UV measurement devices like the Solarmeter 6.2. These devices show the energy in μW/cm2 of a lamp in full UVB spectrum, respectively from 280 to 315 nm. The result is shown for the complete UVB spectrum and it is not possible to know which wavelengths actually are more or less powerful. It is therefore possible that a lamp emits a high amount of energy but only in a very narrow part of the spectrum. It might also be that the energy is distributed over several wavelengths and the energy for the single wavelengths is quite low and only because everything is combined you get a high reading. A lot of UV lamps show a high output at 313 which is typical for the emissions of mercury. This wavelength is not relevant for the vitamin D3 synthesis but a broadband UV meter will show a high value which can be misleading! It is easily possible that a lamp without any significant radiation in the wavelengths from 290-305 nm shows higher values with a broadband UV meter than a good lamp with even spectrum which is many times more effective and safe for UV provision of your animals.
Comparing different UV lamps only by using a broadband UV meter is not possible unless a reliable spectral analysis is available as well which can indicate in which areas of the spectrum UV is emitted. Of course you will find a spectral analysis on the packaging of all our UV products as we have the right measurement devices to analyse lamps in every part of the UVB spectrum. This allows us to guarantee a certain performance in the area of 290-305 nm which puts you on the safe side that a Bright Sun is suitable for providing your animals with enough and the right UVB to allow it to produce its own vitamin D3.

While broadband UV meters like the Solartech 6.2 cannot be simply used for comparing lamps they are still very well suited to judge the aging of a lamp and indicate when the lamp should be replaced. We recommend replacing the Bright Sun if the UVB output has dropped by more than 50%.

UV Calculator

Mit diesem Programm können Sie berechnen, wie sich die UVB Strahlung abstandsabhängig verändert.
Es werden Empfehlungen zur sinnvollen UV Strahlung gegeben.

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