The following text refers to IEC 61228 ed 2.0 "Fluorescent ultraviolet lamps used for tanning - Measurement and specification method.". One should ensure that this version is current at the time of reading and verify whether or not national deviations exist.
This international standard describes the method of measuring, evaluating and marking the characteristics of fluorescent ultraviolet lamps used in tanning appliances.
The spectral irradiance produced by the lamp shall be measured using a suitable spectroradiometer over the range 250-400nm in steps of 1nm with a bandwidth no greater than 2.5nm.The distance between the detector and lamp axis should not be less than 10cm.
The measured spectra irradiance values at 25cm should be weighted against the Erythemal and NMSC action spectra, the effective irradiance should be evaluated over the following ranges:-
Erythemal irradiance, 250≤ λ≤ 400nm
NMSC irradiance 250≤ λ≤ 320nm
NMSC irradiance 320< λ≤ 400nm
Correction factors may be applied to account for lamps having an optimum UV irradiance at an ambient temperature other than 25°C and for lamps measured at a distance other than 25cm.
Based on these results, the lamp marking should be based on the following:-
Wattage- reflector type- UV code
Codes for the reflector type are:-
O Non-reflector Lamp
B Broad reflector angle α>230°
N Narrow reflector angle α<200°
R Regular reflector angle 200°≤α≤230°
The UV code is presented in the form X/Y where
X is the erythemal irradiance in mW.m-2 rounded to the nearest integer
Y is the ratio of the NMSC irradiance ≤320nm to that >320nm, rounded to the first decimal place.
In the attached spreadsheet, the UV code will be calculated given spectral irradiance data, lamp power and reflector type inputs.