Dos & Donts for Domes and Housings
December 1, 2006
As security domes and video surveillance cameras in housings increase in number of installations and their sophistication and features grow, the installation becomes more complex. At the same time, customers are asking that they be less obtrusive.
A trend noted by Douglas Ringer, global product manager for Honeywell Video Systems, Louisville, Ky., is making PTZ domes more affordable.
“This is driving down the size and the feature sets,” he reports. “I think another drive coming is just making them simpler to install or less complicated to install, whether through better documentation or different ways of attaching the wiring.”
Ringer advises installers to terminate 485 data lines properly when putting in PTZ cameras.
“Are you doing daisy chain or home run wiring, because in our products you have to terminate if you’re doing home run wiring,” Ringer declares. “That’s a common problem we have.”
The complaint Ringer hears frequently is that the PTZ function on the domes is erratic, but the problem is caused by improper termination of the 485 data lines. “That’s 485 protocol,” he asserts. “In general, the termination must be done properly.”
How to correctly terminate the 485 data lines depends on the installation and the equipment used for it, Ringer maintains. Harry Ervin, technical support manager for Videotec Security Inc., Totowa, N.J., suggests a method.
“Some CCTV components have built-in terminations, some of which are switchable,” Ervin explains. “If you are using this equipment in series, you must switch off all terminations except the termination at the last piece of equipment in the cable run.”
KEEPING THEM COOLScott Watson, vice president of Videotec Security, advises not letting IP cameras in domes and housings get hotter than their operating limits. He estimates that analog cameras can operate at temperatures up to 122 degrees F, whereas IP cameras operate in a range from 100 to 110 degrees F, with 105 being average.
“What I’ve experienced and a lot of other manufacturers have experienced is that the cameras will randomly die on a hot day â€”they just stop working,” Watson maintains.
Agrees Ringer, “You start losing picture quality. The combination of air temperature and sun load can raise the temperature of domes beyond the point that the CCDs and camera blocks can give adequate pictures.”
Watson adds that the heat generated by the encoders required with IP cameras can make the situation worse. “The higher the wattage drawn by the camera, the higher the heat element is going to be inside the housing,” he explains. “In one cubic foot of air, a camera that draws 10 watts generates 12 to 14 degrees of heat.”
Adding additional heat to a high outside air temperature can exceed the operating temperature of an IP camera, Watson maintains.
“I do have to say that some of the newer cameras are addressing this problem as well, but most on the market still have the limited operating range and also draw more than their fair share of power,” he insists. “An analog camera draws 3 or 4 watts, but IP cameras draw 8, 10, or even 12 watts.”
The same can happen with megapixel cameras, which need elevated levels of processing power and hence electricity.
A tip Watson suggests to cool IP cameras in housings only is venting them with a fan through small holes in the front and back on which mesh filters must be changed. This makes the dust resistance designation of the housing invalid, but it can keep an IP camera cooler and working if high temperatures occur regularly.
Ringer says that venting the air inside a housing to the outside with a fan to cool it can remove the housing’s ability to keep dust out. Therefore, he recommends instead a sunshade to help keep the camera cool. “That’s one of the main reasons you have a sunshade on outdoor domes,” he notes.
He compares the shape of a sunshade to an umbrella or parasol used to keep the hot sun off a person. “It’s shaped exactly like the dome is; it’s just slightly larger, so you have an air gap,” he explains. “All the suppliers do theirs a little differently, but it’s all the same idea. It’s like a double wall in a thermos. It’s not sealed like a thermos is, but it’s the same idea â€” it’s an air gap for insulation.”
Ringer notes that condensation in outdoor domes can be a problem in certain regions. “Sometimes in warm and moist environments like Florida or Georgia, where you could have the temperature drop quickly, you could get condensation inside a dome,” he points out.
“Having a heater and blower inside a dome is a good idea,” he maintains. “It doesn’t cost that much more, but it could prevent your dome from getting fogged up. Then there is no way of getting it out short of getting up there and cleaning it, although this might be a fairly rare occurrence.”
Condensation sometimes is a problem when domes are received from a manufacturer located in a hot, moist environment, cautions Nick Rizzuto, product manager for CCTV cameras for Digimerge Technologies Inc., Markham, Ontario, Canada.
“A lot of times these are coming from Asia where there is a lot of humidity,” he points out. “When [the cameras] come here and the temperature is different, you’ll see some condensation building up in the production process. It’s extremely important to have a stable, dry product environment.” Rizzuto recommends putting desiccant-like packets of silica gel inside the product to absorb any moisture.
DONâ€™T FORGET ABOUT MAINTENANCEA frequently overlooked concern with dome cameras is their maintenance, points out Steve Surfaro, director strategic technical liaison, Panasonic Systems Solutions Co., Secaucus, N.J.
“One of the first things that you need to determine is a way to protect the dome after it is installed,” Surfaro declares. “A lot of installers put in these domes but then allow them to bake in the sun after a rain shower. Then the domes are permanently damaged with water spots.
“So if you take a little time to apply a light coating of some type of protectant that is compatible with the plastic material, this will help with water runoff and possible etching and water spotting on the dome itself,” he recommends. “Then you have to select the exact type of cleaner and polisher that are compatible with your acrylic or polycarbonate dome.”
Watson recommends choosing housings that open easily for maintenance, such as on one side. “With the side opening, you have access to it all the way around,” he points out. “That’s real important to the systems integrator because time is money.”
He also suggests using one-piece rubber gaskets for long-term durability instead of those made of foam and choosing housings with brass or stainless steel inset screws instead of screws that just go directly into the plastic housings so they can be opened as frequently as necessary.
With the large zoom lenses now available, housings may have to be fit to the lens rather than the camera, Watson notes. “We’ve had people that go and buy a camera, and we provide the housing based on the camera,” he remembers. “They want to put a huge lens on it, and then the lens does not fit anymore, so you have to be aware that the lens may be bigger than the camera.”
Gary Perlin, vice president of video products for Speco Technologies, Amityville, N.Y., reminds dealers and installers to be sure housings have rustproof hardware like hinges and locks on them. “You’d be surprised how many rust in a week,” he asserts. “The difference is negligible in cost, but you have to make sure it’s there. It’s no good if you save $2 on a housing not realizing it will rust in a week.”
WATCH THE WIRESAlways hide wires when possible, recommends Dan Scroggins, product sales manager â€” positioning systems for Pelco, Clovis, Calif. “What [installers] often try to do depending on the application is save labor or materials and leave some cabling exposed,” Scroggins notes. “That’s a huge mistake. If there’s ever an opportunity to conceal or protect cabling, that should always be taken.”
One good reason for concealing wires is to prevent them from being cut by people wanting to disrupt video surveillance, Watson says. Another reason Scroggins cites is in applications where domes or cameras in housings are mounted on hollow poles.
“When I was an integrator and I worked with our installation teams, CCTV installation 101 was to bring a carton of sealant and seal every pole that the cameras were mounted to,” Scroggins recalls. “Inside the pole, depending on where and how it’s mounted, condensation could develop and roll down the pole into the camera,” he explains. Although the camera may be sealed from the water, the water could coagulate or dam up in specific areas that might affect other components, he warns, such as an encoder or UTP transmitter.
“It’s just a good idea to seal the pole after the termination point,” he concludes. “Use a foam sealant that expands. Drill a hole 5 or 6 inches past the termination point, insert the foam sealant nozzle and fill it for 5 or 6 seconds. Let it expand and it creates a watertight seal.”
Another tip for dealers and integrators is to get involved in pole selection and choose poles for their effective projected area (EPA) characteristics. These determine how much a pole is swayed by wind and vibration, which affects the steadiness of the images obtained from a camera attached to it.
“Oftentimes what happens in an application where they know they will need poles is they’ll select the least expensive product that will do the job, and that often is not chosen for its EPA characteristics but for price,” Scroggins relates. “The result is your camera in 20 mph winds is moving all over the place and you can’t make head or tails of the video.
“If you add up the camera and EPA and estimated average wind load present in that area or climate throughout the year, you can estimate the vibration issues,” he recommends. “EPA is almost never taken into consideration and should always be.” Camera steadiness is critical if video analytics software is being applied to the images, he notes.
Handling wires is a major concern cited by Gareth McClean, director of research and development for Tyco Fire and Security’s American Dynamics video and CCTV product lines, San Diego.
“Being able to route wires easily through the housing and out is a big issue,” McClean notes. “The best designs out there have come up with ways to cleverly do that.”
Another tip Scroggins recommends for exterior domes that view areas with bright and low lighting at various times of day is using domes whose cameras have wide dynamic ranges that can show detail in what otherwise would be silhouettes and the glaring highlights called blooming.
Sidebar: TIP!Be sure to use the correct grade of coaxial cable for analog domes. “There’s different grades of coax cable depending on the distance and application,” says Douglas Ringer, global product manager for Honeywell Video Systems, Louisville, Ky.
Sidebar: TIP!For Internet protocol (IP) PTZ cameras, run extra power to them rather than relying on power over Ethernet (PoE) beyond certain distances, such as 200 feet. “You really can’t run a PTZ over Cat 5 exclusively because the power requirements won’t support full-size PTZ domes, at least not yet,” says Douglas Ringer global product manager for Honeywell Video Systems, Louisville, Ky., especially if heater or blowers are required in them for outdoor use.
Sidebar: Donâ€™t Lose FocusFocusing cameras in small domes can pose problems. “Everybody likes the smaller diameter domes, but they don’t realize the extra curvature actually creates an effect of adding another lens in front of the camera,” points out Steve Surfaro, director strategic technical liaison, Panasonic Systems Solutions Co., Secaucus, N.J. “The camera looks in focus with the dome off, and then looks out of focus with the dome on.”
Gareth McClean, director of research and development for Tyco Fire and Security’s American Dynamics video and CCTV product lines, San Diego, notes that some manufacturers produce domes carefully to minimize focus, color and light shifts. “We take quite a bit of pride to make sure our bubbles don’t impact the picture quality,” he maintains.
Some cameras have an automatic back-focus feature that allows for fine focusing after the dome is put on if the camera is focused roughly before dome placement. This also allows for night focusing under IR light, which frequently is different than under visible light.
Another solution for this problem suggested by Sara Scroggins, product sales manager – imaging systems for Pelco, Clovis, Calif., is using day/night cameras that have infrared (IR) focusing lenses.
“Traditional day/night cameras can’t focus IR and visible light at the same time,” she maintains.
IR light focuses on a plane behind the one on which visible light focuses, she explains. “An IR-corrected lens works like a contact lens,” she continues. “A plus or a minus with a corrective lens gives us a clear picture, and it does the same thing â€” it corrects for IR light.”
Making sure the focusing screws on the cameras in domes are tightened sufficiently is recommended by Scroggins. “Any vibration or movement of the housing will take it back out of focus, and in most cases that goes unnoticed until something happens,” she points out. “After the camera is installed, tighten the screws down and make sure the camera and lens module are tight where you need it.”
Nick Rizzuto, product manager for CCTV cameras for Digimerge Technologies Inc., Markham, Ontario, Canada, advises dealers to provide plenty of power for domes that use IR LEDs to light a scene at night. “The higher the number of LEDs or the intensity of the LEDs, the more current they draw,” he notes. “It’s absolutely critical that you use a power supply that exceeds the requirements of the device.”
McClean suggests using a handheld television monitor at a camera’s location to check its view through an output on the camera rather than constantly returning to a remote DVR or control room to inspect it. Once the view is perfected, the handheld monitor can be disconnected from the camera and from the installed wiring used to check the camera’s view back at the DVR or control room.
Gary Perlin, vice president of video products for Speco Technologies, Amityville, N.Y., points out that the video output for testing has an additional, unintended use. “We also find that a lot of people use that as a second video output,” he notes. “The main output goes to a DVR, and the second one goes to a second security office. It’s sort of like a built-in distribution amplifier. Although that was not the intention, it does work that way.”
Sidebar: TIP!Gary Perlin, vice president of video products for Speco Technologies, Amityville, N.Y., advises that screws used in a dome be self-retaining so they do not fall on the floor when the dome is opened for maintenance. Also, have a strap on the dome to keep it connected to its base if the dome’s interior needs to be accessed after installation, he adds.
Sidebar: Take the TestAlways test a system before installation, recommends David Craig, manager of technical services for Rainbow, Costa Mesa, Calif.
“It’s pretty rare for cameras to be bad out of the box,” Craig admits. “Many times when it does seem to happen, it’s the one where they’ve driven 300 miles out to the job site. It’s pretty straightforward to plug it in and make sure there’s a picture and get familiar with the equipment prior to installation so they can take care of any questions ahead of time.”
He also recommends checking with manufacturers when a job is being designed. “Another good thing is to use the manufacturer as a resource to call up and find out if their product will take care of the job and do what they need to do,” Craig advises. “Make sure you’re not combining different types of products that are not compatible.”
An example he cites is using infrared illumination with a color camera. Such illumination works best with a day/night camera that uses black-and-white at night and is infrared-sensitive.
Also, do not over-specify products. “Don’t spend more than you need to to get the results you need,” Craig recommends. “Salespeople don’t always like me to say that, but we find that a lot of customers will do a combination of low-cost minidomes indoors where lighting is not an issue and choose more advanced, high-end domes for tricky areas or outdoors.”
He also suggests using varifocal lenses instead of fixed ones so that a dome’s viewpoint can be widened or narrowed based on customer preference without moving the dome or housing itself.
Along with varifocal lenses, Gary Perlin, vice president of video products for Speco Technologies, Amityville, N.Y., recommends that autoirises be used indoors with a 12 VDC camera if fluorescent light is present to avoid color rolling.
“Any 12 VDC camera indoors under fluorescent lighting experiences color rolling,” he points out. “It will go from perfect color to a little red, then blue tint, then green and back to perfect, because a 12 VDC camera is not line-locked to the fluorescent lighting fixtures â€” it’s out of phase.
“Because fluorescent light is pulsing at 60 cycles and the camera is pulsing at 60 cycles, if you don’t use a 12 VDC line volt camera, they will not be in sync with each other,” Perlin explains. “But most people do not want to spend the extra dollars for that. An autoiris automatically corrects for it â€” it locks the camera shutter and overrides it.”
Sidebar: Donâ€™t Forget the HardwareJason Gonzalez, installation manager for IBT Video Systems Inc., Schererville, Ind., recommends being sure installers have the right hardware for a job.
“Use the right mounting hardware the first time so you don’t have to go back,” Gonzalez advises. He recommends dry wall anchors and toggle bolts as a strong, all-around fastener that can work in many types of material, such as concrete, dry wall, wood, particleboard, hollow poles, metal I-beams and anything else that can be penetrated, especially stucco.
“That is one of the materials that are harder to mount to,” he relates, adding that many car dealerships use it. “It’s a pain to mount if you don’t have the right hardware for it.”
He also recommends using special mountings for dome cameras. “There are mountings that give you the security of a dome camera but the angle of a bullet camera,” he notes, some of which are teardrop-shaped. “Just aesthetically, they look nicer than bullet cameras do. It looks very similar to an old-style lamppost.”
For vandal-proof domes in exterior locations, he recommends using dual-voltage AC or DC ones. “They can take a lot more if a lightning strike hits,” he maintains. “AC cameras hold up better than DC ones.”