FREE TOOL
Scaled distance and vibration estimate
Enter the distance to the point of concern and the largest charge firing in any one delay. The panel gives the scaled distance, an estimated peak particle velocity, and the biggest charge per delay that would meet your limit at that distance.
Calculator
This tool needs JavaScript. Your browser has it switched off, so the result panel will not update.
How it works and what it assumes
Scaled distance is the distance divided by the square root of the charge per delay: R ÷ √W. It is the one number most vibration limits and most site regressions are written against.
The estimate uses PPV = K × (R ÷ √W)^−β, the square-root scaling form used in AS 2187.2 and in the USBM work it draws on. K and β describe your ground and your blasting practice, and only a regression of your own monitored blasts gives real values. The defaults are a generic starting point and the tool says so while they are in use.
The largest charge per delay is the same equation solved backwards for W at your limit and distance. It is a planning figure to check against the monitor, not a permission.
Read the explanation
Scaled distance, the number behind vibration limits
Why distance and charge per delay are combined into one number, where the K and β come from, and why the generic values are not yours.
Read about Scaled distance, the number behind vibration limits
Want this fitted to your site?
The free tool is the lite version. The full version uses your products, your ground and your reporting.