Bomb Power Indicator

Bomb Power Indicator, also known by the acronym BPI, was an instrument built to detect nuclear explosions and measure the peak overpressure of their blast waves.

[2] Once readings had been combined with information provided by the Ground Zero Indicators it would be possible to estimate the size of the nuclear explosion in megatons.

The dial was wall mounted and measured readings from 0.1 to 5 pounds per square inch peak overpressure.

Outside of operations the BPI pipe was protected by a screw on cap and there was a drain valve at the base of the instrument to remove any excess rainwater.

If the BPI registered a reading of 0.3 or higher the operator would wait ten seconds before pressing the reset button and making a report to the group control.