The snow load duration factor is 1.15 times the standard 10-year sustained maximum load rating as long as the accumulated time under this load is not more than 2 months. Does this mean that

1. a. the snow load being at the duration factor of 1.15 for 2 months continuously (experimental
case) is at the same level of safety as

b. permanently being at the standard load rating (control case)

when assuming that the experimental case is well under the under standard load rating for the rest of the year, or

2. does the experimental case impart additional risk compared to the control case from the long-term perspective?

Basically, this is asking whether the standard practice allows the control case to use up the safety margin (factor of safety minus one) of the standard load rating only because its short term means that the probability of other loads happening simultaneously will be negligibly small, or whether the safety margin of the standard load still applies on top of the maximum load at full duration allowed by the duration factor.

For example, if the snow season is especially long one year but not especially intense at any given moment, meaning that the roof at any given time is at the forseeable maximum snow load accounted by the duration factor but that it is at that load for a whopping 4 months rather than the expected maximum of 2 months, does that mean the roof will cave in, probably causing the pancake effect to collapse the entire building too?

As for another example under main question, will having the load at any given time within the timeframe moderately exceeding the snow load duration factor, but not having the duration exceed that, make the roof or even building collapse?

Under the hypothetical case that load duration factors in standard practice already use up all of the safety margins for the standard load ratings, this means that exceeding the load duration factor also exceeds the safety margin. Since this exceeds the safety margin, does this mean that exceeding the load duration factor will guarantee a collapse?

In civil engineering in general, does being at the rated limit mean that there is a negligible chance of failure if everything is done perfectly (too small to be measured, such as 1ppb) and does being at the upper limit of the safety margin practically guarantee a failure if everything else is done perfectly (too large to measure a successful case, such as 99.9999999% failure rate)?