Adding Armor to Security Systems
Editor / Provider: a&s International | Updated: 7/27/2011 | Article type: Tech Corner
As video surveillance systems find their way into new markets and applications, it is important to protect increasingly sophisticated cameras from not only good old vandalism, but also harsh weather conditions and environments.
Weather and environmental stress that can disrupt service in the surveillance system must be evaluated and accounted for. Enclosures are to cameras what shells are to turtles, except much more durable and versatile. Different environments will require different considerations, as one will definitely not fit all.
Recent trends in camera enclosures include smaller form factors, customized designs, increased tolerance to extreme temperatures and more offerings that include both the camera and lens, said Barry Lawson, Global Marketing Manager for Schneider Electric. “Advanced materials, such as plastics that are resistant to any type of challenging environment, are being used in camera enclosures.”
Developments in camera housings are leading to new, cost-effective, indoor plastic camera enclosures and vandal-resistant aluminum and polycarbonate outdoor camera enclosures,Marketing and Product Management for Arecont Vision. “Also becoming more available are all-in-one designs that include the camera, mounting hardware and IP66 enclosure. In general, cameras are reducing in size yet provide higher resolutions.”
Fine-tuning materials to eliminate any form of rust or oxidation on the exterior of the housing ensures longevity of the housing itself, as well as its aesthetics, said William Ferris, Engineering Department of Dotworkz Systems. “In addition, the use of different types of vandaland gunshot-resistant materials in outdoor housings allows for more design flexibility." Cameras of all types can be placed closer to the action, without the risk of damage.
Some types of housings see new developments more rapidly than others, but it has more to do with the standards than anything else, said Kostas Mellos, Commercial Leader for Video and Transmission, Interlogix (a UTC Fire & Security company). “Explosion-proof housings that are intrinsically safe against sparks are governed by specific NEMA and UL conditions. They must adhere to the conditions specified and do not see rapid changes.”
There are mainly three types of housings targeted for adverse environments, Mellos said. “There are ones that withstand atmospheric conditions, such as extreme heat and cold; explosion-proof; and pressurized bubbles.” As environmental conditions vary widely from project to project, the characteristics of the site must be accounted for differently and accordingly.
For example, electronics have specified operating temperatures; when mounting an outdoor, vandalproof dome camera outside a building in a very cold region, you must have at least heaters in there to ensure the electronics do not malfunction, Mellos continued. “Plastics have come a long way and some can deal with this type of environment, but you still can't use them in explosion-proof settings. They simply do not conform to the specifications that are needed.”
For projects that face corrosion and extreme conditions, the enclosure can deteriorate quickly and cause the camera view to be compromised, the housing mounts to be altered or the wires to be exposed, said Lem Blanco, Engineering Manager at CPS Security. “All these may lead to countless issues, such as falling housings or loss of video.”
Natural factors, such as insect infestation, temperature and climate, salt, humidity and wind, must be evaluated, Blanco continued. “For example, airports need to address the constant jarring movements caused by landing planes, while oceanfront projects such as seaports must factor sea breeze and salt water into the equation.”
Protecting the inside of the housing is just as important, through added pressure using dry nitrogen or other types of gas, Mellos said. “When the inside pressure is greater than the outside pressure, outside elements can't enter the inside, effectively protecting it from harm.”
Cable management is another issue. How the housing manages the cables that come out of the camera or heater is critical in some cases. In the UL standard for explosionproof environments, a certain type of conduit is required to avoid any risk of sparks within that space.
System requirements such as power supply also need to be examined. For truly extreme locations, directly powering camera housings ensures that the cameras are set up for long-term reliability, Ferris said. “PoE injectors can create a point of failure in the long term. Furthermore, many professionalgrade brands of video hardware have higher power requirements than PoE can provide. For example, a high-end extreme cold weather system can easily require 65 watts just for the heating system, exceeding current PoE limits.”
Products that incorporate heaters/ blowers or IR illuminators currently require separate auxiliary AC or DC power sources, but there are companies developing technology to support power for these accessories via PoE, Calderon said. “Gaskets and fillings are provided to facilitate proper installation and protection from outside elements. When properly installed, they maintain protection for the auxiliary power wiring as well as the PoE/ data cable.”
Maintenance should not be overlooked, either. For a high-performance, 360-degree, HD camera housing that oversees high-value assets, performance can quickly deteriorate due t o dus t and salt buildup on the lower lens.
Commonly it only takes a few weeks before cleaning maintenance is required, Ferris said. “Properly scheduling maintenance and purchasing the needed cleaning tools are often overlooked. Products designed to safely clean all shapes of exterior lenses and camera housings from ground level are available.”
The biggest issue for pressurized housings, or housings that are intrinsically safe such as explosionproof housings, is maintenance. A pressurized dome in an environment with a lot of dust will need the typical cleaning, wiping down and pressure cleaning as any other appliance, Mellos said. “However, the internals do not necessarily need maintenance. If it's pressurized, the camera tends to be more stable than its non-pressurized counterparts since no outside elements can find their way into the components. If there is something wrong with the camera, or if you need to do something to the camera itself, you need to depressurize the housing, which is not a big deal, but you need to have the proper tools.”
Frequent maintenance is necessary for really adverse environments. For mills or furnaces, it is very possible that the cameras themselves will not last long, due to the sheer heat generated, no matter how much you try to cool the housing, Mellos said. Factors to keep in mind differ per location or need, Blanco added, but one thing to always be on the lookout for is quality.
IP66 rating is the typical, minimum standard, and yet not all housings are IP66-rated, Calderon said. “Many outdoor housings are IP65-rated or even offer no IP rating. In addition, many lower-end housings and integrated cameras are offered without integrated accessories such as wall mounts, pendants, corner mounts or pole mounts.”
Buyers should be wary of self-certified products offered by obscure manufacturers, said C.C. Yu, Senior Sales Manager for Unitechno. “Certification by independent laboratories ensures that a product meets its claimed specifications. An official report of the details of the testing procedures and results can be provided upon request for additional peace of mind.”
“IP66 is what you normally need for outdoor settings; IP67 is what is required of pressurized PTZ domes. There are multiple standards for hazardous locations,” Mellos said. Other standards include the NEMA and UL. Moving devices, such as PTZ, usually adhere to these standards as they are common in hazardous environments such as mills or oil-processing facilities, Mellos said.
An integrator should not feel the need to beta-test an IP66 housing unless they question the quality of the installation, Calderon said. “When subjected to an environment appropriate to the IP rating and properly installed, long-term reliability of the housing seals and materials should not be an issue. Performance will be equal to any equivalent IP-rated product on the market.
If bought from a reputable manufacturer, additional testing should not be necessary as the product will generally perform as specified, Mellos agreed. “There may be some bench testing, but it is more about understanding how the units are installed rather than testing the units themselves for performance.” Testing equipment is generally too expensive and not necessary for system integrators and installers. Some manufacturers have testing chambers in their own laboratories, Ferris said. “Manufacturers may be willing to provide a live demo or live camera uplink so that their customers can see these systems in action.” The customer can see how the units perform in extreme hot or cold chambers, as well as pressure, explosion and corrosion chambers.
An average warranty should cover two to three years, Mellos said. “However, in very adverse environments, such as a watercooled housing installed in a furnace, a one-year warranty can be appropriate.”
“Housings of higher quality come with more parts for added durability and to keep them intact, which is important for long-term use,” Blanco said.
The devil is always in the details. “Most low-end products look good on paper, since product specs are often written by marketing teams. However, many unforeseen problems can arise in the long run. Higher-end products tend to be built better and engineered with real-world factors in mind so that known and common problems are avoided,” Ferris said.
For example, most low-end housings allow insects to nest the warm camera units, causing the camera view to be compromised within three months of the installation, Ferris added. “Similar issues can be seen when water leaks inside and freezes or causes rust and induces condensation.”
Housing costs reflect the materials and manufacturing processes used, as well as what accessories are provided, Yu said. “Die casting is a more complicated and expensive process compared to extrusion and greatly affects the unit price.”
Some products have model names such as “arctic” or “cooled,” but these can be misleading, Ferris cautioned. “If they have not been properly tested by the manufacturer or verified to adhere to standards via independent bodies, buyers may end up with a product that does not meet their expectations.”
Brand names are important, but specifications must also be carefully evaluated, Mellos said. “A housing must be installed in the environment it's specified for. For places where temperature is a problem, the customer should ask the manufacturer what the tolerated range is and what happens if exceeded.”
RIGHT PLACE, RIGHT TIME
Camera housings must be used in the exact environment they were meant for and according to the specified parameters, Lawson said. “Items like lens charts and site surveys are invaluable.”
For example, a few years ago in the Middle East, there was a project that specified plastic housings with a metal sun shield, Mellos said. “In the very hot months, the housings quickly deformed. Although the damage was minimal, the housings had to be changed.” The problem is not necessarily always the quality, but rather the wrong specification or installation.
Proper installation ensures the housing performs as expected. After taking the housing off for maintenance, it is necessary to confirm the unit is installed properly with special attention to the gasket, Calderon said. “If a wall mount is placed over a masonry seam, there will be obvious water ingress into the housing.”
Specifications cover installation practices as well, Mellos added. “You must adhere to the whole thing to ensure expected performance.” Since cameras are the most critical components in a surveillance system, it makes sense to protect those investments; proper housings are a small price to pay to avoid future headaches