Evaluation of Intrusion Sensors and Video Assessment in Areas of Restricted Passage [open pdf - 6MB]
"This report discusses an evaluation of intrusion sensors and video assessment in areas of restricted passage. The discussion focuses on applications of sensors and video assessment in suspended ceilings and air ducts. It also includes current and proposed requirements for intrusion detection and assessment. Detection and nuisance alarm characteristics of selected sensors as well as assessment capabilities of low-cost board cameras were included in the evaluation."
Center for Civil Force Protection: http://www.nlectc.org/ccfp