The value for buildings is low beacuse the loads are pressure vessels use 3.5 to 4.0, automobiles use 3.0, and aircraft and spacecraft use 1.4 to 3.0 depending on the materials.
The value for buildings is low beacuse the loads are well understood and the structures are redundant. Pressure vessels use 3.5 to 4.0, automobiles use 3.0, and aircraft and spacecraft use 1.4 to 3.0 depending on the materials.