Final answer:
To decrease the consequence frequency of a plant from 10⁻² to 10⁻⁶, the difference in exponents (-2 to -6) indicates that 8 Independent Protection Layers (IPLs) are needed.
Step-by-step explanation:
To determine how many independent protection layers (IPLs) are needed to reduce a plant's consequence frequency from 10⁻² to 10⁻⁶, we need to understand the concept of logarithmic dilution - which in this case refers to decreasing the frequency by factors of ten. If one IPL decreases the frequency by one power of ten, we can calculate the number of IPLs required by finding the difference in the exponents of the initial and final frequencies.
Consequence frequency reduction:
Initial frequency: 10⁻²
Final frequency: 10⁻⁶
Exponent difference calculation:
Initial exponent: -2
Final exponent: -6
Difference: 6 - (-2) = 8
Thus, it will require 8 IPLs to reduce the consequence frequency from 10⁻² to 10⁻⁶.