Why it may not be strictly “risk management,” protecting personnel from the elements is – should be – important to all practitioners.
In the summer
The thermometer may not record a really warm temperature, but the body complains it’s too hot for comfort.
The problem is a combination of temperature and relative humidity.
- What IS “relative humidity?”
Relative humidity, as defined by The Free Dictionary is “The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage.” (See http://www.thefreedictionary.com/relative+humidity .)
The formula for figuring out the heat index is more than a little complicated, but no one has to be a math maven to get the numbers.
The National Weather Service (NWS) has an online function that lets people plug in the important numbers
- Temperature in F or C (but not K)
Relative Humidity in percentage.
at http://www.hpc.ncep.noaa.gov/html/heatindex.shtml
- While the NWS calculator lacks a Kelvin entry option, if you really, really must work with a Kelvin temperature, you can convert K to F or C with the calculator at http://www.allmeasures.com/temperature.html .
If you really MUST know the formula, the NWS has the formula linked from the calculator page; click on “How do we calculate the heat index?”
There even is a heat index chart link – “Heat Index Chart and Explanation” – just below the calculator at … heatindex.shtml.
In the winter
The NWS comes to the rescue once again, this time at http://www.crh.noaa.gov/ddc/?n=windchill.
Links from this URL connect to a Wind Chill Calculator and to both New Wind Chill Chart and Old Wind Chill charts.
Like the heat index calculator, the wind chill calculator requires two inputs:
- Temperature in F or C
Wind speed in mph
(You can convert metrics to miles per hour at Online Conversions at http://www.onlineconversion.com/speed.htm.)
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