Suit of Armor
Jul 1, 2003 12:00 PM
BY TOM PATRICK MCAULIFFE
As CCTV surveillance technology has improved, so have the enclosures that protect the cameras from vandals, criminals and prying eyes. Domes and enclosures have become less obtrusive, more stylish and indestructible as the technology has advanced.
Sometimes the best protection for a CCTV camera is not necessarily a hardware solution. The most reliable, cost-effective, vandal-resistant schemes can be covert by design. Thoughtful camera positioning can produce the same results as a dome or other enclosure with less risk, and a CCTV system that cannot be seen has a better chance of solving crimes and surviving assaults. "The best defense against vandalism or theft is always covert," says Dennis Dill of Cohu Inc.'s Electronics Division, a San Diego-based CCTV manufacturer.
Covert cameras can be disguised as smoke detectors, fire sprinklers, junction boxes and even wall clocks. The most popular for general-purpose applications, however, are dome systems. Domes or heavy duty enclosure installations for pan/tilt/zoom systems are almost indestructible.
Stronger Than Dirt
Domes and enclosures are engineered to bring together the elements needed for CCTV into one small environmentally sealed unit. Advances in material strength have enabled stronger and/or thicker dome bubble materials, protective metal bubble cages and the use of strong, lightweight polycarbonates and metals in the dome housings themselves. Tamper-proof screws and fittings are now standard, as are electronic alarms to keep units from being destroyed or stolen. Bulletproof glass is also an option. Although the dome or enclosure lens has gotten thicker, it does not affect the image. "Achieving the desired optical performance of a bubble requires a delicate balance of materials with the desired molecular weight, tensile strength and optical properties that will provide the appropriate impact resistance while minimizing aberrations and distortions," says Ed Hamilton, senior product line manager for San Diego-based American Dynamics, a unit of the Tyco Safety Products Division.
"The type of material and manufacturing process employed to produce the 'bubble' or 'dome' in a dome camera has a definite effect on picture quality, particularly in the areas of light transmission and image distortion," warns Frank Abram of Panasonic Security Systems, Secaucus, N.J.
With recently discovered materials, domes and enclosures are lighter in weight and able to withstand greater impact. "The material being used, and how the dome is made are both very important," says John Ellenberger of Pelco, Clovis, Calif. "For many years, acrylic was the only material used for domes because of its superior optical clarity. As injection molding technology advanced, the stronger polycarbonate material was introduced into the market, which is by far the best choice."
What should a customer look for in a good CCTV vandal proof or reinforced product? There are several significant criteria for evaluation of integrated units. "First and foremost are camera performance and features," Abram says. "When evaluating dome cameras with pan/tilt/zoom lens capabilities, other factors are more mechanical in nature ¡ª pan/tilt, speed and focal range, durability ¡ª but these are equally important in the overall evaluation."
When building a surveillance system indoors or outdoors, or when an older system is updated, there are important factors to consider when choosing a ruggedized solution. Are the protective materials indeed strong enough and do they need to be bulletproof? The best advice is to stick with products that conform to measurable standards. For example, the bubble in a ruggedized housing from American Dynamics "exceeds ANSI Z-87.1 impact safety standards," meaning it can withstand the impact of a 1/4-inch steel ball at 150 feet-per-second without cracking or breaking. There are other considerations ¡ª are there interchangeable parts if the housing or domes were ever damaged, or does the entire housing have to be replaced? When the dome or enclosure and the CCTV camera are totally integrated, it is virtualy impossible to merely replace the outer extremities of the unit.
Perhaps the most important consideration is performance. Is the camera effective when the protective components are added? If the answer is no, then it's time to reconsider. "It's also worth noting that vandal-proof differs from vandal-resistant," Hamilton explains. "There are some bulletproof housings on the market, but these are specialized products that use unique parts that are not interchangeable with existing equipment. Typical vandal-resistant enclosures use similar, if not identical, products to the mainstream product line."
There have been a few cases when the thieves have gone after the CCTV cameras ¡ª rather than what they were protecting. One of the most common protection solutions to ensure a camera is not tampered with or stolen is a simple jumper wire placed between two normally unused contacts. The continuity through these two contacts is remotely monitored via the signal cable. If someone tries to remove the unit or cut the cable, the continuity is broken and triggers an alarm. The camera does not even need to be operating for this method to be effective.
There are other ways, too. Some products, for example, employ a low-pressure detection system on environmental [outdoor] cameras, which can also be used as a vandal-resistant feature providing an alarm output as soon as the camera housing is breached.
On the Job
The need to better protect a CCTV system from being destroyed comes from both the increasing sophistication and cost of the cameras and from thieves who try to destroy the domes and enclosures that are capturing their crimes.
Heavy-duty and ruggedized domes and enclosures protect CCTV cameras so that security professionals using PTZ lens capabilities can do their job. They protect a CCTV investment and blend into the overall decor, enabling users to do more with less. With good planning and camera-site selection, a rock-solid dome or enclosure can also help to reduce the total number of cameras in an overall surveillance system.
"Vandal-proof cameras will continue to benefit from other general advancements in video surveillance technology," Abram says. "I would also expect that prices will continue to fall as demand for these products continues to rise. This will increase competition further and provide for an even higher level of manufacturing efficiencies."