In museum security, the triple pattern of risk (theft from the outside, theft from the inside, and vandalism) covers all high-risk periods and places. The choice of the means of detection depends on the nature of the exhibit, the architecture, the artwork environment, and changes in presentation. In fire detection, instead of choosing one type of detector, the largest possible number of kinds of detectors with a wide range of functions should be considered, based on the particular grounds and risks. In determining security requirements, the first step is site and operation analysis, which involves studying the goals to be attained and then finding the resources to achieve them. Intervention diagrams should be constructed according to the possible risks, including the means for various interventions which determine how much intervention time is required. The use of guards as intervenors is most effective when surveillance areas are manageable and equipment is issued to permit the constant reception of information from guards. Guards should collect security data by geographic sector and transmit it to the other central zone stations for correlation and then to the central supervision station, which is charged with filing the data and providing backup security when needed. Following each security incident, the security director must analyze evidence from the event and make any revisions required for improving security. Security personnel must be trained in the proper use of security equipment, and security drills by day and night should be periodically conducted. For a large museum, a long-range security plan must be developed, since it is not financially possible to secure the entire museum adequately at the outset. The system planned should be adaptable to every new need.