S-factor Lookup Charts
Disclaimer
These documents and program are Copyright (c) 2003 RWDI Anemos Limited. No warranty is given or implied. You are welcome to distribute them freely in their entirety but they are not for resale. The documents, charts and program must be used in conjunction with a current copy of BS6399-2:1997 and values from the Code shall always take precedence. Reasonable care has been taken to ensure that these documents are free of viruses, however you are advised to make your own checks before installation.
Instructions
The following charts are included in this Adobe Acrobat document, which you are welcome to print and distribute but which cannot be altered or cut & pasted from. If you need to get a copy of the free Acrobat Reader, follow this link. When you click on the link the document may open in Acrobat within your browser. To save the file either continue and select save from within Acrobat or right click on the link below and select "Save target as..."
Download: S-factor Lookup Charts (PDF 450KB)
Standard Method
- Sb factor for sites in country and <2km in town
- Sb factor for sites >2km in town
Directional & Hybrid Methods
- Sc factor
- St factor
- Tc factor
- Tt factor
The axes of these plots are logarithmic, in keeping with the intervals in the relevant tables within BS6399-2:1997. The charts therefore allow you to use (strictly correct) logarithmic interpolation within those tables but without the tedious bother of having to perform the conversions and two-way interpolations yourself. Simply look up the effective height on the y-axis (allowing for the displacement height caused by upwind obstructions, where it is permitted by the code), then look across to the appropriate value of distance to sea (or town, as appropriate). The value of the factor can then be read directly from the contours plotted, interpolating visually if necessary.
