 As such, UVA vs UVB rating on lamps only tells you the relative amount of UV, making a 5% lamp really a lamp whose UV spectrum is 5% UVB and 95% UVA.There are no accepted published numbers for rating the overall power for lamps, except the TE (time exposure), which is almost as useless for making comparisons.The TE isn't generally published, although it is usually available from the lamp manufacturer on request.