Why Are Frequency and Severity Rates Calculated in Millions per Hour? Plus, Help Needed with Safety Factor Formula

Understanding Frequency and Severity Rates

If anyone knows why frequency and severity rates are only calculated in millions per hour, and not in billions or other units, please share your insights.

Seeking Formula for Calculating the Safety Factor

If anyone knows the formula for calculating the Safety Factor, please share it with me. I am facing a lot of problems due to this. I have a general idea about the Safety Factor, such as the SF of Hoist and Lift is 12, for Running Rigger and Slings is 8, and for other purposes is 6. However, the formula for calculating the Safety Factor is still unknown to me.

Incidence rates should use as the denominator the average number of people exposed to risk (i.e., those persons covered by the injury statistics). Wherever possible, the number of hours worked by them, the number of hours paid for, or failing that, the number of days worked by them should also be used as a second denominator to calculate frequency rates for non-fatal injuries. For convenience, incidence and non-fatal frequency rates can be expressed per thousand persons and per million hours worked or paid for. I don't have any idea why they calculated in MILLIONS instead of billions, etc. Hope our seniors will give a solution.

Question #2 Clarification

Question #2 was not clear to me. If it's possible, can you provide some examples? However, just go to the link provided, and hopefully, you will find a solution. Factor of safety - Wikipedia, the free encyclopedia

Regards,