As the explosive yield increases, the corresponding pulse duration also increases. For a specified overpressure or dynamic pressure level, the longer the pulse duration the greater the damage. For a fixed scaled distance, (distance/yield)1/3, the overpressure or dynamic pressure is essentially independent of yield. Because of the effect of pulse duration, however, the damage level remains dependent on yield and will increase as yield increases. Structures/components which are classified as "Q" type are more sensitive to this effect than are "P" type structures/components. For each structure/component, two pulse duration factors (with values ranging from 0 to 10) are assigned, corresponding to moderate and severe damage. For "P" type structures/components the pulse duration factors are on the order of 2.5 while for "Q" type structures/components the factors are on the order of 8. Each structure component is also assigned levels of overpressure (Pm and Ps), or dynamic pressure (Qm and Qs), corresponding to moderate and severe damage, along with a fixed reference yield.
The actual yield used in an individual test case is an input variable, and will generally differ from the fixed reference yield. The pulse duration factor, the yield, and the reference yield determine the R-factor which connects the moderate and severe damages with this difference in yield.