formula constants embedded in the UTILITY conversions
of meter readings with IU and Eeff dose rates
1000 IU = 1 Med.
1 IU/min = 1/1000 Med/min (or 0.06 Med/hr, which = 1/16.67 MED/hr)
1 Med/hr = 2.33 UVI and 1 Med/hr = 16.67 IU/min.
Thus the conversion constant for IU/min to UVI is 16.67 / 2.33 = 7.1 UVI. Formulas for other parameters (skin type, tan
level, age, etc are footnoted and available
How to use the meter:
For the casual user seeking about 1000 IU from
face/arms exposure, there is no need to use
the spreadsheet parameters. Simply point the
meter at UV source and divide the reading into
1000 for minutes of exposure. Done. Cautionary
note: if you are white type 2 skin (usually
burns, sometimes tans) start out at 50-75% of
calculated minutes until your tolerance to UVR
increases after about 4 exposures. If you are
higher skin type and/or have a base tan, you
will synthesize less than 1000 IU.
For the user seeking more accurate dose
levels, please use the Utility and determine
appropriate dose level for your particular metrics.
Here is a "by the numbers" procedure:
Set meter reading in parameter 1.
2. Set hypothetical dose to same minutes as
shown in parameter 1 sidebar.
3. Set parameter 2 skin type (note IU decrease
as skin type increases)
4. Set % body (note IU increase as % body exposure
increases above 10%)
5. Set SPF if any (note IU large decrease as
SPF increases above 0)
6. Set % tan (note IU decrease as tan level
7. Set age (note IU decrease above and below
baseline 20yr old)
8. Return to parameter 2 and adjust dose duration
up or down to see approximate IU for exposure
care to keep dose below 1 MED for type 2 with
0% tan. Note that dose duration cannot be set
above 4 MEDs for fully tanned sunburn avoidance
purposes. Also note that after 2 MEDs the amount
of IU will stop increasing as the body is much
less able to synthesize cumulative Vit D3 above
Battery operation voltage is 9V down to 6.5V.
Below 6.5V the LCD numbers will begin to dim,
indicating the need for battery replacement.
Under "typical" service load, the
battery should last about 2 years.