Short introduction to the PHS-calculation implemented in Javascript

The calculation is based on the annex E in ISO/FDIS 7933, “Ergonomics of the thermal environment -- Analytical determination and interpretation of heat stress using calculation of the predicted heat strain”. The calculation is implemented in the file PHS.js. The PHS.js calculation is used by a number of web applications which are listed here and described below:

• PHS.html http://www.eat.lth.se/fileadmin/eat/Termisk_miljoe/PHS/PHS.html

• PHS_sa.html http://www.eat.lth.se/fileadmin/eat/Termisk_miljoe/PHS/PHS_sa.html

• PHS_std_example.html http://www.eat.lth.se/fileadmin/eat/Termisk_miljoe/PHS/PHS_std_example.html

PHS.html

The application has tabbed UI. There are tabs to

• enter parameters and to get a summary of the result

• get the result as graphs

• get the result as a table

• get information about the PHS-calculation.

The tab “All” shows at the same time all the tabs but the “About” tab.

To run a PHS simulation, use the tab “Parameters”. At start up the parameters have the default values from annex E in ISO/FDIS 7933. The input fields are used to change the parameters. The values in parenthesis are the limits for the value.

The “Start simulation” button runs a simulation of 480 minutes and the end result and a summary of the result is shown.

In tab “Graph” is the result shown as diagrams and in the tab “Table” as a table.

The tab “About” contains links to information about the implementation of the PHS calculation. (Some of the links point to place holders for future material.)

PHS_sa.html

This is a stand alone version of PHS.html. It can be downloaded and used without access to the server. It does not contain the "About" tab.

PHS_std_example.html

This application can be used as a simple test of the PHS.js java script. The "Examples of working conditions" in the annex F of ISO/FDIS 7933 are used. The user interface is similar to that of PHS.html.

The working condition example is selected by the buttons at the top. A simulation is run by the “Start simulation” buttons. The button “Start simulation using standard” is using the algorithms from the standard. The other button uses an algorithms with small changes.

PHS_explorer.html

This application can be used to study the result of a change in one of the input parameters and keeping the other parameters constant. The user interface is a subset of the user interface to PHS.html.

The pivot point is defined by the input parameters.

A number of simulations is done by clicking one of the “Explorer” buttons.

For each input parameter typically 20 simulations are run. The value used for this parameter is varied in step from the minimum to the maximum value. For the other parameters the pivot point is used.