Everybody knows what a backup alarm sounds like – and that’s the problem.
Once a sound becomes commonplace, people tend to ignore it. On a busy construction site, multiple machines may be beeping simultaneously. Add engine noise, traffic, surveyors, supervisors and manual laborers on the ground and you have a recipe for chaos. Even the loudest audible alarm is just one of dozens of stimuli clamoring for everyone’s attention.
If this sounds like one of your jobsites, you may want to consider adding a rear-vision system to your machines and vehicles. Compared to audible alarms alone, these systems can vastly increase jobsite safety.
Prices range from around $350 for a single camera, cable and monitor to $1,000 and up for a ruggedized, top-of-the-line system. But over and over again, such systems have proven their financial value in preventing machine damage and reducing accidents. Just avoiding the downtime – not to mention the expense of repairing damaged machines or structures, increased insurance premiums, potential fines or lawsuits, and the costs and time associated with accident investigations – makes these systems a bargain if all they do is prevent one accident.
And in construction zones, accidents happen all too frequently. In it’s Building Safer Highway Workzones report, the National Institute for Occupational Safety and Health noted that among the 492 highway work zone deaths reported between 1992 and 1998, more workers were struck by a construction vehicle (154 fatalities) than by passing traffic (152 fatalities). And half the workers struck by construction vehicles were hit by vehicles backing up. That’s more than 12 backing fatalities a year in highway work zones – and it doesn’t include accidents at residential and commercial building sites, utility construction, land clearing and landscaping jobs, or mines and quarries.
To read the full text of Building Safer Highway Workzones, check out the website. For some sobering reading regarding how these kinds of accidents come about, NIOSH compiled a number of case histories at this site.
Rear-vision systems
Used in the mining industry for years, the most typical installation for a rear-vision system is to mount the camera on the rear axle or some protected spot on the rear of a large truck. They are typically wired to a monitor in the cab and can be triggered any number of ways – most often when the truck is put into reverse gear. When activated the camera gives the operator a wide-angle view of everything behind him.
But that’s just one of dozens of ways construction and mining companies are using these systems. Increasingly equipment owners are using these cameras to bring into view any number of a vehicle’s blind spots, says Jon Lovejoy, marketing director for Intec Video Systems. “Basically it gives you an eye wherever you need a view,” he says.
“It’s important to note that our mobile video systems are not only used for rear vision, but also for visibility all around the vehicle,” says Steve Sappol, an account executive with Safety Vision. “We use the term ‘enhanced mobile vision systems’ to incorporate rear-, side- and forward-facing cameras. Wherever a camera is pointed, the enhanced visibility reduces accidents and improves operator productivity.”
And video systems are hardly limited to trucks. On big excavators or shovels, equipment managers are mounting cameras on the counterweight and triggering them whenever the superstructure rotates, says Lovejoy. Excavators digging deep trenches also benefit from video systems. “Normally we have a wide-view camera to give you the largest view behind a vehicle,” Lovejoy says. “But we also have tight focus cameras to monitor specific functions. We’ve used one of those on a deep excavator application in combination with a light so that the operators can get a clear view of where the bucket is working 30 feet down in a trench – and they love it.”
Lovejoy notes he’s seen cameras mounted to give a view of a scraper blade or to monitor the activity of asphalt pavers, pavement striper machines and slurry seal equipment. In addition to these, Sappol cites video systems being used on milling machines, compactors, forklifts and crushers and belts.
Black and white or color
The video cameras and monitors can be either black and white or color, and each has a place in the construction environment. Black and white shows you the most detail in low light situations – dawn and dusk, during inclement weather or at night in work zones illuminated by tower lights.
Color systems show more detail in a busy environment. “In a waste hauling application, a transfer station or a landfill where trucks are constantly coming and dumping and you have people there sifting through it, color helps you recognize things much more quickly, Lovejoy says. “And on a lot of dozers and loaders we use the color system because of the tight range of maneuvering and the constantly changing background.”
Construction rugged
The NHTSA report cited in the box on page 48 estimated the cost for camera, monitor and hardware installed should run about $325. But Lovejoy says he’s concerned if a proposed rule to mandate rear-vision systems becomes law some people will buy the cheapest system available to meet the initial requirement and then not replace the camera when it fails.
The NHTSA report also raised questions as to whether such systems would be sufficiently rugged to withstand certain environments (primarily construction). But for the companies that sell into this market, that’s a non-issue. Construction-rugged cameras are housed in hardened enclosures and built with multiple redundant, water- and dust-proof seals.
“I’ve got a video of a pressure washer hose hitting right on the lens of a camera on a concrete truck and water sheeting off. But it’s built for that,” Lovejoy says. “We’ve had applications where the camera has outlasted the truck and was removed and installed on a new truck.”
“There’s no special challenge here,” Sappol says. “We have more than 1,000 systems installed on haul trucks. In this application our systems are mounted below the dump bed on the axle.” An optional camera cage protects the camera from damage. Sappol adds his company has more than 3,000 systems on rear-discharge mix trucks. “And conditions don’t get much dirtier than that,” he says.
Will rear-vision systems be mandated?
The National Highway Traffic Safety Administration published a notice of proposed rulemaking in the September 12 edition of the Federal Register that would, if enacted, require either a crossview mirror system or a rear-vision system on straight trucks with a gross vehicle weight between 10,000 and 26,000 pounds. A “straight truck” in this definition is a single-unit truck composed of an undetachable cab and body. Body types routinely incorporated as part of straight trucks include those with an enclosed box, flat bed, dump bed or bulk container, and special purpose equipment.
The proposed rule doesn’t cover off-road machines or equipment, however dump trucks, concrete mixers and tank trucks would fall under it. The period for public comments closed on November 14. NHTSA will deliberate on the comments and presumably announce its decision sometime this year. For more on the proposed rulemaking visit this site. Click on the September 12 edition of the Federal Register and scroll down to the NHTSA section.
ETECTION PLUS AUTOMATIC BREAKING
Although non-video rear object detection systems that use radar or sonar to alert the driver to unseen objects in a truck’s blind spots were not included in the list of NHTSA’s proposed recommendations, they have been used in the trucking industry for decades.
One recent and innovative new product that caught our eye in this category and that may appeal to the construction equipment market is the Mico Object Detection and Brake Interlock System. It uses pulsed radar sensors and will visibly and audibly warn the operator when an object comes within 26 feet (adjustable). And at a predetermined distance the Mico system will automatically apply the vehicle’s brakes, bringing it to a complete stop until the vehicle is switched out of reverse or a momentary release switch is pressed.
The system is actually a joint effort combining Mico’s 691 brake lock system and an object detection sensor from manufacturer Preco. The system is designed for applications involving refueling vehicles, delivery vans, forklifts, boom trucks, aerial lifts and most highway trucks that are converted to construction use, says Josh Peters, marketing manager of Mico. The system is designed for hydraulic brakes, but an air brake version is due out in the first quarter of this year. Sensors are typically mounted on the bumper, about 30 inches up. The sensor housing is ABS plastic around aluminum and has been tested to SAE’s 1455 standard, which includes pressure washing, gravel bombardment and other physical abuse.
“We had been watching the sensor technology for a long time,” says Terry Bangert, engineering designer. “It went from infra-red to ultrasonic to radar to pulsed radar. When Preco came out with the pulse radar, we knew we had the right thing. It’s impervious to mud, snow, ice, sun glare and wind. It’s extremely reliable because it’s looking for mass.”
Installed prices for the Mico system come in higher than rear-vision systems, ranging from $1,500 to $2,000, but Peters says the value here is in the addition of the automatic braking function and the state-of-the-art sensor.
