WF_Z.L-DEn~-X~ AND soundly constructed buildings have many virtues, among them the ability to serve their intended purpose, to provide a pleasant and esthetic environment, and to become an essential and beautiful backdrop for human life. Furthermore, buildings must be structurally sound and resist loads, such as their own weight, the weight of occupants and contents, wind, and seismic loads. They must keep out rain and other elements; they must provide a healthy indoor environment with regard to heating and cooling and in terms of indoor air pollutants; and they must maintain their functions over an extended service life.