test

Proposition: Many important things about architecture are in motion. People: this activity generates what is called a circulation system of doors, hallways (corridors), stairs, elevators, and so on. Air: without movement of air, breathing within buildings would become dangerous, instead of healthy. Traditionally, natural ventilation (or leakage) through windows provided fresh air. Increasingly in modern buildings, air is provided mechanically through ducts, and is conditioned as required. Water: provided for drinking, cleaning, and for removal of wastes. So it enters the building through pipes, and leaves the building through a different set of pipes. The two sets of pipes can never come in contact with each other.