Safety factors for loading

Safety factors are introduced by designing for factored loads.

As described above, the safety factors in BS 5950 are applied to the loads only. Clearly none of the load types referred to above can be quantified with absolute precision although dead loads can be calculated more precisely than imposed loads. They are therefore prescribed a lower safety factor (typically 1.4 compared with 1.6 for imposed loads). Where wind loads are considered, the duration of the maximum load (which is based upon maximum gust speed) is so short that the safety factor may be reduced. These various factors are referred to as safety factors for loading and are detailed in Table 2 of BS 5950.