Emergency preparedness is a very important part of preservation program management. No institution is immune from disaster. The Library of Congress itself suffered the ravages of two major fires in the 19th century. However, the most frequent cause of damage to collections in general is from water, or a combination of fire and water. Historically, water damage results from the failure of aging building elements such as air-conditioning drip pans, drain pipes, built-in joints, and so forth. Other damage and loss have been caused by failure of cooling or humidity control systems, vandalism and theft, and by the presence of the necessary fire suppression systems. In addition, the shut-down of environmental control systems during building maintenance and renovation can result in emergency conditions for collections.