Frequency of exceedance any peak exceeding is . Its complement, is the probability of exceedance, the probability that has been exceeded at least once by time . This probability can be useful to estimate whether an extreme event will occur during a specified time period, such as the lifespan of a structure or the duration of an operation. If is small, for example for the frequency of a rare event occurring in a short time period, then Under this assumption, the frequency of exceedance is equal to the probability of exceedance per unit time, , and the probability of exceedance can be computed
Control of Vibration at Work Regulations 2005 is the maximum amount that an employee can be exposed to in a day. The values are measured using a formula which works out the average (A) exposure over an 8-hour day. The values are therefore written as A(8). The rate of vibration of a tool or piece of machinery is then measured in metres (m) per second (s) and written as m/s². In order to help employers calculate the exposure levels using the formula, the Health and Safety executive created an exposure calculator. Regulation 5 requires any employer who exposes employees to risk from vibration to make a 'suitable