[pitdicker]

It may be nice to know the safety factors used for structural engineering of homes, offices and other regular buildings in the EU.

The Eurocode defines 3 consequence classes: CC1, CC2 and CC3. CC1 has the lowest consequence and is used for regular homes, light industry and agriculture. The chance of dying as a result of structural failure is low, 0.001. The chance for a CC2 building (apartment buildings, offices, hotels etc.) is defined as moderate with 0.03. And CC3 is for special buildings, such as large stadiums, with a high risk of death on structural failure, 0.3. There are other factors that go in defining a consequence class however, including economic and social concerns.

The consequence class maps to the chance that we find it acceptable for a building to collapse in a given year. Causes can be anything, like extreme weather. For CC1 this is 1 in 100, for CC2 1 in 10.000, for CC3 a chance of 1 in 100.000.

So the chance one or more people die in a stadium during a heavy storm due to structural failure could be 1 in 300.000 in a year if you purely look at the statistics behind the structural safety standard.

The statistics map to simple reference values for the loads of wind, snow, rain, usage etc. and easy safety factors. For example CC2 has a safety factor of 1,5 over all variable loads.

[sd9]

> The chance for a CC2 building (apartment buildings, offices, hotels etc.) is defined as moderate with 0.03

Does this mean 3% or 0.03%?

[pitdicker]

If a CC2 building collapses, the expectation is that in only about 3% of the cases this leads to someone dying. I don't know the complete reasoning, but can imagine some factors of why this number is far below 100%: a building is not always in use, there are often warning signs with time to escape, and collapse can be localized (not the whole building).

[sd9]

Makes sense, so this is confounded by the number of people in the building.

30% for a CC3 seemed high to me initially (hence wondering if 0.3 really meant 0.3%). But since it actually means "in 30% of structural failures in CC3 buildings (e.g. a stadium), at least one person dies", it make much more sense because there are probably lots of people in the stadium.

[Snow_Falls]

I agree, it would likely have extremely diminishing returns in terms of lives saved to have more stringent safety requirements. Needs to be a balance after all.