In the case of Vulcan Materials, cameras are constantly exposed to water. "If you take a typical driver, let's say he averages four loads a day," says Ed Luce, ready-mix manager, Western Division. After each load, the truck is thoroughly washed down. "Four loads a day over the term of a year, is a lot of... exposure for the cameras."
The cameras must be able to live in this environment. "I don't have time for our shop personnel to go out there and continually service or replace cameras. We have enough things to concentrate on other than the cameras," Luce states. So durability is a huge issue.
"All of our cameras are weatherproof, and we utilize a threaded O-ring sealed connector where the camera attaches to the video cable," notes Safety Vision's Tom Clark. "There are other ones on the market that are like a snap-type connector. That is susceptible to moisture or corrosion."
Shock and vibration resistance are also critical. Clark recommends looking for a high shock and vibration rating. For instance, LCD monitors are generally more rugged that CRT monitors. "With an LCD monitor, all of the transistors and capacitors are surface mounted to the board itself," he explains. "So in a high vibration application, an LCD will outperform a CRT for reliability over time."