Structural engineering is part of the engineering sector that deals with the analysis and design of structures and the way they support, or resist loads placed on them. Structural engineering would be considered a specialist subject within the discipline of civil engineering and can also be studied on its own. A structural engineer would be involved in the initial design of a building and large structures. Structural engineers can also be responsible for designing machinery, medical equipment, bridges, vehicles and any other object where the structural integrity of and item can affect the overall function or safety of it. A structural engineer should ensure that their designs satisfy the design criteria, especially relating to safety; serviceability or performance. Buildings are designed and constructed to resist elements including; substantial loads, changing climate conditions and natural disasters such as earth quakes.