Recommended Alert Limit
This recommended alert limit is the final version used in the app. Before making a more personalized version of the calculations the approximation from Recommended-Alert-Limit-(old) was used.
The recommended alert limit uses information about the Wet Bulb Globe Temperature and your metabolic rate in order to provide information about your situation -- are you working too hard on a hot day? etc. This is visualized for the user on a scale green/orange/red depending on whether you are working too hard in a hot condition or not. Along with a color code the user is also presented with some coping strategies based on his situation.
This is calculated based on the RAL score which is given by the following equation:
RAL = 59.9 - 14.1 * log10(M)
Here, M is the Metabolic rate. The metabolic rate is calculated based on your activity level and your body surface area (BSA) as shown below:
M = BSA * ISO-level * 50,
where ISO level is a value from 1 to 5 and the BSA can be calculated as:
BSA = height^(0.725) * 0.20247 * weigth^(0.425)
The height is in meters and the weight in kilograms.
The RAL score is used together with the WBGT value in order to determine the color code for the users situation.
If the user weighs 80kg and is 1.8m high and has an activity level of 3 (moderate), his BSA would be calculated as:
BSA = (1.8^(0.725)) * 0.20247 * 80^(0.425)
which would make his metabolic rate: BSA * 3 * 50 = 299
To calculate his RAL score 299 is input in the equation for RAL above like as shown below:
RAL = 59.9 - 14.1 * log10(300) => 59.9 - 14.1 * 2.477 = ~ 25C
25C is then the RAL score.
In order to determine which color group the user is within, assuming that we have the WBGT score for the user at the current time, the following logic is used.
- green zone then when the individual is below 80% of the RAL
- yellow from 80-100
- red from 100 to 120%
- the highest dark red when above 120%
| Value | Result | Comment |
|---|---|---|
| WBGT <= 0.8 * RAL | Green | |
| WBGT > 0.8 * RAL and WBGT <= RAL | Orange | |
| WBGT > RAL and WBGT <= RAL * 1.2 | Red | |
| WBGT > RAL * 1.2 | Dark Red |
This screenshots are added to show the results as proof-of-concept this is not the final solution.
- RecommendedAlertLimit.java https://github.com/frksteenhoff/ClimApp/blob/master/ClimApp/app/src/main/java/com/example/android/climapp/wbgt/RecommendedAlertLimitISO7243.java
- DashboardFragment.java https://github.com/frksteenhoff/ClimApp/blob/master/ClimApp/app/src/main/java/com/example/android/climapp/dashboard/DashboardFragment.java
- RALTest.java (testing) https://github.com/frksteenhoff/ClimApp/blob/master/ClimApp/app/src/test/java/com/example/android/climapp/RALISO7243Test.java
