Sun Bed Testing / Phototherapy (PUVA) / Dose
It is the ultra violet (UV) emission from sun tanning appliances that produce the sought-after effect of the pigmentation of the skin, yet it is well documented that over-exposure can lead to undesirable short-term as well as serious long-term effects.
It is therefore of vital importance to accurately quantify the level of UV emitted by such a source, thereby ensuring that the user does not exceed exposure, else irreparable damage may occur.
The output of all such systems must be tested in accordance with IEC 60335-2-27 2010 “Safety of household and similar electrical appliances. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation".
The quantifying factor used in such measurements is the erythemal irradiance. This is derived from a measurement of the spectral irradiance emitted from the source at the distance of use (relative to the source), weighted against the CIE erythemal action curve.
This latter is a curve describing the relative efficacy of the UV wavelengths toward skin erythema, the reddening of the skin, showing that UVB light is around 1000 times more harmful than UVA.
As with all accurate UV measurements, this measurement system employs a double-monochromator based system, with cosine response input optic for the measurement of spectral irradiance. The optic may be coupled to the monochromator via fibre bundle for ease of measurement.
It is possible to configure this system, with a few minor additions, to permit the measurement of the transmission of protective eye wear for users of such tanning appliances.