The design process for a new low-voltage system should always begin with the question, “What is my customer trying to accomplish?” Once you answer that question, you can profit by talking to various manufacturers about how and at what cost you can achieve your goals.

Goals
Reducing costs is a major goal. How can the security system contribute to reducing costs for the building owner? And how can you, the electrical contractor, assist in achieving that goal? Reducing the risk of loss through theft is one way. Not only would reducing the amount of theft directly affect a customer’s bottom line, but it could also reduce the cost of insurance premiums. According to the 19th Annual Retail Theft Survey conducted by Jack L. Hayes International, a loss prevention/inventory shrinkage control consulting firm: “Shoplifting and employee theft losses totaled more than $6 billion in just 23 retail companies in 2006. Only 2 percent of those losses resulted in apprehension and recovery.” Security systems are, of course, extremely important life safety assets (e.g., in schools, hospitals and places of public assembly). Reducing costs and improving life safety go hand in hand. Failure to adequately provide for people’s safety can lead to lawsuits and increased insurance costs.

Strategies
Once you decide what you want to accomplish, consult with specialists about your options. You should think about long-term and immediate goals. How serious would the consequences be if an intruder got into your customer’s building? What is the likelihood of anyone trying? If protection is needed, you could install intrusion devices on windows and doors. You could add an access control system with a card reader for the entrance. What would make a big difference in overall effectiveness? What if an intrusion device on a window or a controlled access door being forced open would not only initiate an alarm, but also would call up images from security cameras? Your customer would have a visual record of the intruder, how he or she broke in, how quickly a guard arrived, and what he or she did upon arrival. This is not only valuable for law enforcement, but it would expose the vulnerabilities in the facility so that you can take steps to prevent future problems.

A security camera pointed at an entrance could save lives in an emergency situation; someone could view the doors to ensure there are no obstructions and people are evacuating smoothly.

Implementation
What is the best way to integrate video, access control and intrusion sensing? Setting aside the question of cost, the answer is, without doubt, Internet protocol (IP) technology. Digital information can be manipulated in ways that analog cannot. Undeniably, an analog system can be networked, and it would still be possible to have an event such as a forced window that triggers a camera to view a scene, to store the video in a DVR, to send alerts to security personnel and to call up the view from the camera on the security panel.

But in a typical setup in a large residential apartment building in New York, the surveillance system is much simpler. There are cameras in key places, which the personnel at the concierge desk can monitor all at once, or they can bring up an image from a single camera to fill the screen. Images are stored for several days in the DVR and can be reviewed by camera location and time frame. Typically, it is used for only minor purposes and is more than adequate for the application.

IP to the rescue
An incident that occurred in a large crowded public building illustrates what can be done with an IP system that couldn’t have been done with analog. Guards reported that they found a small child wandering around. The child was not old enough to identify her parents. The security official was able to call up the camera in the lobby location where the child was found. Using the building’s security software, the image was superimposed on a floor plan of the lobby where the child was found. Because this was an image that was stored digitally, it could be associated with other stored images. The computer display screen allows manipulation of these images in any direction by means of a mouse click. It was then possible to connect to a series of images tracing the child’s movements through doors and escalators and finally to the point at which she became separated. A guard went to that location and found the frantic parents. Because of the large number of cameras in the building, it would have been nearly impossible to search the DVRs for the needed information in anything resembling a reasonable time period. But once the images are digital, they can easily be manipulated in ways limited only by the cleverness of the software developers.

Thanks to Steve Sachs of Siemens Industry, John Fenske of Johnson Controls, and Romeo Badiu of the Chelsea Lane for providing information for this article.

BROWN is an electrical engineer, technical writer and editor. For many years, he designed high-power electronics systems for industry, research laboratories and government. Reach him at ebeditor@gmail.com or at www.writingengineer.com, an independent professional writing service.