By Ed Ritchie
source: gradingandexcavation.com March 31, 2014
Worker safety is gaining more attention from state and federal agencies as road construction continues to grow in response to needed highway infrastructure repair. Overall, according to the US Bureau of Labor Statistics, fatal work injuries in the private construction sector increased 5% in 2012. And when it comes to the leading cause of highway construction worker injuries and fatalities, the US Federal Highway Administration’s statistics identify “contact with construction vehicles, objects, and equipment.” But these injuries and deaths are preventable through good practices and use of the proper safety equipment. Moreover, such practices can also prevent costly work interruptions, and even costlier insurance claims and regulatory agency penalties. So let’s take a look at some measures for staying safe.
To start with the obvious, many injuries from contact with vehicle equipment can be avoided by using high-visibility apparel, according to Sally Boven, chief executive officer of Reflective Apparel Factory in Marietta, GA. “Most excavators and road builders know they’re supposed to be in high-visibility apparel, but they ask about which of the two classes they need to satisfy,” says Boven. “It starts with Class 2 which is a certain number of square inches of reflective material that has to wrap all the way around 360 degrees and include the shoulder area. It’s typically a sleeveless safety vest. Next, there is Class 3, which requires more reflective and more fluorescent material so that you can differentiate a worker’s limbs to show movement. That’s where you get into having a vest or jacket with sleeves. Most people say when you’re working at night it’s absolutely Class 3. There are certain states and groups that have decided that workers in road building should always wear Class 3 apparel so they don’t have to worry about making the wrong decision.”
So the easiest and safest solution is to always choose Class 3, but getting workers to wear their equipment can be a problem if it’s uncomfortable or a nuisance, notes Sally Baldwin, transportation safety manager for employee safety, at the Tennessee Department of Transportation. “We’ve done all the research,” says Baldwin, “and found the best available safety vest, hardhat, reflective nightwear, and lighting. But we know that if it’s not comfortable, the workers won’t wear it. If a safety vest is just plastic, it’s like spending the summer in a garbage can liner, and in the winter it’s just as uncomfortable, so workers don’t want to wear them. It’s the same with hardhats. You can get a cheap one, but if it’s not comfortable it’s not going to stay on their heads. So it may cost a little more to get something that’s adjustable and something that actually works, but it’s comfortable enough that it becomes a habit and the workers forget that they have it on.”
Speaking of summer heat, even though we’re talking about safety at night, many workers can find themselves working from day to night, and heat exhaustion during the day needs to be prevented. Part of the answer is in protecting exposed skin areas, according to Boven. “Obviously, in the summer, when it’s really hot and a worker has spent many hours surrounded by hot blacktop, there are heatstroke issues and other issues. Of course, common sense defaults to a short-sleeved T-shirt but it’s actually better to have a long-sleeved T-shirt made out of the right kind of microfiber, because it’s cooler and reflects that heat and keeps us from getting sunburned.”
Now that we’ve discussed the task of keeping workers highly visible, the next step is to make sure your heavy equipment operators have all the tools possible to avoid injuring their co-workers. So let’s look at the latest developments in video and proximity warning systems. Operating heavy equipment is a constant challenge due to the vehicles’ blind spots, and night work doesn’t make it any easier. But a good video camera system is just like having an extra set of eyes on those blind spots, according to Bob DeFazio, vice president of sales at Intec Video Systems, Belle Vernon, PA. “Our cameras are designed and developed to be mounted in just about any location where a blind spot is a concern to the operator or crew,” says DeFazio. “Ultimately, it depends on the application, but in construction the rear blind spot is always significant. As you get into larger equipment, you’ll also have blind spots in front, and to the right on larger articulated trucks and equipment, so front right side and rear viewing are typically a priority.”
Those blind spots can slow down operations for drivers, and DeFazio notes that cameras give contractors better productivity because operators have clear visibility around the machine and can maneuver safely and quickly without having to walk around the vehicle, as they would do without a camera. “It also gives the operator a better sense of security and makes their job easier and less stressful because they can see what’s going on,” says DeFazio.
Also important is the camera’s angle of view for providing the vehicle operator with a wide zone of visibility, adds Ken Breegle, tech support manager. “The angle of view has a lot to do with what an operator sees,” he says, “and our angle view is extremely wide at 165 degrees diagonal, 125 degrees horizontal, and 100 degrees vertical. These cameras are built for mining and heavy-duty applications and to handle the vibration and abuse in all different types of climates and environmental conditions. Vibration is a really big challenge in the construction industry, and our cameras are designed to withstand a force of 9 g at 2,000 times per minute. The displays can handle 4.5 g at 2,000 times per minute.”
With so much to watch for in terms of the front of the vehicle, the mirrors, and the blind spots displayed by camera views on the vehicle’s monitor, operators have a lot visual information to keep track of, and that can lead to fatigue. For vehicles with limited interior space, Brigade Electronics, of Palmerton, PA, offers a mirror monitor for small cabs, particularly those with rear visibility limited by obtrusive bodywork panels, absent rear windows, and solid bulkheads. By replacing the original interior mirror with the monitor, a compact camera at the back of the vehicle displays rear visibility for safer maneuvering. The display delivers a clear, mirror-image picture and resembles the existing mirror. Brigade also manufactures Backscan, an ultrasonic sensor for vehicles maneuvering in tight spaces and congested areas. A three-stage audible and optional visual warning informs the driver of the distance between the vehicle and the obstacle, minimizing vehicle damage and collisions with people.
Audible alert systems can add another layer of safety by “seeing” through conditions of visual impairment, such as heavy rain or fog. These warning systems use radar or other forms of object detection, so they see through bad weather, while avoiding the addition of visual clutter in a cab. That’s where a sophisticated proximity warning system can help, explains Peter Evans, vice president of sales and marketing for Preco Electronics Inc., of Boise, ID. “Contractors buy different technologies, and the biggest problem is that the dashboard is cluttered,” Evans says, “especially in the retrofit world. So it ends up causing more distractions rather than improving safety. But we use standard communications protocols and communications so they can have our radar information on top of existing displays. So it makes it a good safety tool without adding to the distractions.”
With fewer visual distractions, proximity sensors can cover more viewpoints and offer a variety of sensitivity options. “It depends on the industry,” adds Evans, “but in the mining industry, we offer 360-degree coverage for their trucks, because whether it’s night and day or bad weather or fog or rain, there are blind spots that need many sensors, so you have a good warning system that surpasses your visibility.”
Preco offers a variety of systems designed for the industries they serve, and Evans notes that he would suggest different detection zones depending on the use at a construction site or at a mining site. “We offer sensors with different shapes and distances of detection zones and lengths and widths, because the idea is to find the proper area of detection. Then a customer gets the alerts needed without becoming bothersome and annoying. If you put a 20-foot detection zone on a truck that’s operating in roadside construction, the driver will hear that warning constantly because it’s so close to other equipment. But if you take it down to 15 feet and adjust the audible alert, you can operate safely and efficiently.”
Radar technology isn’t the only choice in proximity sensor systems. They are also available with IFR (infrared) technology and automatic braking. For example, Global Sensor Systems Inc., of Mississauga, ON, offers the Global Search-Eye Sensor System, incorporating infrared technology for vehicles to prevent backing accidents. “Drivers can be legitimately distracted and miss an opportunity to prevent a backing accident,” says Ray Glenn, president of Global Sensor Systems. “But this is an active system with automatic braking, so no driver participation is needed to stop the vehicle.” Global’s infrared sensor technology is not heat sensitive or activated by motion. It uses active modulation and reacts to any object hot or cold, moving or stationary, at a predetermined protected area behind the vehicle.
Another approach to proximity warning technology is the Armour System from Scan-Link Technologies, of Ancaster, ON, which uses RFID (radio-frequency identification) to detect people and objects that are too close to a heavy vehicle. For workers, wearing the Armour-equipped safety vest and hardhat allows detection by the Armour antenna mounted on equipment. This alerts operators to people in the blind spot of the equipment. In addition to detecting people, RFID obstacle detection technology is capable of alerting the operator of the vehicle when they are approaching specially marked inanimate objects, and it’s suitable for marking the position of such forms of static infrastructure as pipes, vents, transformers, and open pits. Scan-Link also offers its Safe-Zone Sentinel to determine that all members of a group of people are accounted for within a small zone or region located close to the Sentinel.
Although cameras and proximity sensors help operators with their blind spots, they still need good illumination for the view from the front windshield, and extra lighting with directional controls can help. For example, Golight Inc., of Culbertson, NE, offers searchlights and spotlights with 370-degree rotation and 135-degree tilt capabilities. These create a sphere of coverage that reaches extreme angles and are easily controlled with a wireless remote for operations from up to 100 feet away.
But how much do you need? According to Golight, candlepower is not a valid measurement for rating any type of light output or brightness. Instead, peak beam intensity, which is rated in candelas, is now part of the official ANSI accredited “FL1 Standard” which measures the true intensity of a spotlight beam. The higher the candela number, the higher the spotlight beam intensity, and the higher the target illuminating capability, the farther the beam distance. For comparison, the average automobile halogen headlights on bright are rated at 100,000 candelas. Golight models range from 200,000 to 650,000 candelas.
We’ve discussed a variety of measures to help a contractor’s crew work safely, but what about the general public that drives on roads under construction? Unfortunately, night driving accounts for a large percentage of vehicle accidents, and road construction crews should make sure they have the highest visi-bility possible to alert the public to construction hazards. Moreover, construction sites need to be protected from drivers that lose control of their vehicles in construction zones. Such traffic control devices and crash attenuation products as those offered by TrafFix Devices Inc., of San Clemente, CA, can provide substantial protection. The company’s impact attenuator, also known as a crash attenuator, is a device intended to reduce damage to vehicles, structures, and most importantly, motorists, workers, and bystanders from an automobile collision. Impact attenuators are designed to absorb the energy of the colliding vehicle, and even redirect the vehicle away from a hazard, roadway machinery, and workers. Impact attenuators are typically placed in front of guardrails, Jersey barriers, overpass supports, and construction work zones.
For vehicles that are prone to collisions from oncoming vehicles, TrafFix notes that work zone regulations specify a minimum safety distance between the vehicle, with an attached truck-mounted attenuator (TMA), and the work zone. A TMA is extremely important when working in mobile work zones, especially if the truck’s parking brake is not engaged. Also, TMAs have the added benefit of absorbing most, of the energy from the impacting vehicle, resulting in little or no damage to the truck.
We have reviewed a wide variety of products to improve safety for road construction during night hours, but benefits of these products depend upon sound safety practices by the employees that use them. To that end, it’s worth noting that safety training courses are available from many state and federal resources, plus a variety of private enterprises. In fact, some enterprises have a vested interest in helping contractors operate their equipment safely, such as Sunbelt Rentals, based in Fort Mill, SC. Sunbelt has courses for trainers, plus heavy-equipment operator training, scaffold safety, and excavation training.
Ultimately, safety for road construction workers during night hours is a critical concern for contractors. Accidents are destructive to lives and property, and costly, so it’s important to supply workers with the proper equipment, and the proper training in its operations and usage.