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Carla,
This was the subject I was trying to recall while on phone with you today. It's on the "Time to 4 MED" thread in HP section on the other site.
Please see new May Looking Fit pg 64, where you can see spectral plot of typical HP lamp/filter. They say in the piece that although it really takes a long time to reach 4 MED, the beds are often labeled as 12-20 min. As said above, the high UVA low erythemal output will give low numbers on MED/hr meter.
Having said that, 3 seems quite low, so your filters must limit UVB to really small amount. And remember to bump up the reading by 1.34 while we are waiting for FDA to make their mind up on how "big" a MED will be. So the 3 = 4.02, or 60 min Te in theory. But follow bed label Te, not one hour.
If and when a hand-held meter is available that follows what Don is calling "tanning action spectrum", it will be helpful for HP.
Meantime just use a model 5.0 for HP, because it's response curve is fairly close to HP output.
Don for LP, using 240/MED reading correlates well to Te. I wonder if there is a relationship with 5.0 reading to HP label max session time?
Like a really strong one can read 199, and a more typical one say 100. If I pick a numerator of 2000 out of thin air:
2000/199 = 10 min
2000/150 = 13 min
2000/100 = 20 min
2000/80 = 25 min
Would probly only work for a certain percentage UVB system however...
Steve
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