Dump truck and trailer cycle times, downtime and repair costs can escalate as you try to save a few dollars on tarp systems. There are also safety concerns with some of the less expensive hand tarps and manual systems. You don't want people crawling around the trucks. It is much safer to be able to tarp the load from ground level.
Purchase price is only part of the equation when selecting a tarp system. "The thing we see most often that lends itself to the contractor having problems is they opt for an inexpensive or price-based system," says Glenn Ray, vice president sales/market development, Pulltarps Mfg. "In the long run, it doesn't last."
For example, consider what typically happens when tarp laws become enforced in a certain region. "The operators go out and buy the cheapest thing they can get their hands on," says Ray. "In six months or a year, when it falls apart, they have resigned themselves to the fact that they are going to have to tarp. In the long run, you save money by buying good equipment. They are willing to make the investment at that point."
A range of choices/costs
The weakest link usually creates the most problems. "When you look at a dump truck or a dump trailer, the tarp system is probably the most fragile item that is on that body, other than a headlight or a windshield," says Ray.
But not all tarp systems are equal in terms of durability. "There are a variety of automated tarping systems that can range from $300 all of the way up to $3,000 for dump trucks," says Lenny Brescia, executive vice president and co-owner, Pioneer Cover-all. " An owner/operator has to consider the specific application to determine the specifications required of the system. There is a tarping system for every application."
The combination of tarping systems available is quite extensive. There are arm systems, pull-out systems, roll tarp systems and cable systems in manual or automatic configurations with several different power source options, including electric, hydraulic or air.
Cost depends on several variables. "The cable-type systems and arm-type systems are going to be pretty close to the same price," says Ray. "There are a lot of variations on that as far as the different options you can get with either system. A manual pull arm system or a pull-arm system is probably going to be 20% to 30% less than the electric arm. A plain manual pull-out system is going to be about 40% less than an electric arm."
The material to be hauled often determines which system will be most effective. "If you have heaped loads; haul construction debris or irregular material; have bodies that are real high, like belly dumps — then an arm system or a flip-type system is good for a lot of those applications," says Ray. "If you used a pull-out-style tarp or a cable style, the fabric is being drawn across the material and it could get torn. A flip or arm system lays the fabric down on top of what you are handling.
"But if you are just hauling dirt, soil or asphalt, as long as you are confident that nothing is real jagged, a pull-out system works well for shorter bodies and a cable system or electric arm system would be best for longer applications," he adds.
Ups and downs
of cable systems
Belly dump trailers and long-end dump trailers are great applications for cable systems. "The system collapses in an accordion style to the front or to the rear, allowing for a fully open container to be loaded," says Bob Nolan, sales, Shur-Co. "There are no bows or obstructions in the way to create the possibility of damage."
Depending upon the body design, they are also a good choice for some dump trucks. However, this is not the case for dump bodies with high bulkheads. "If you have a dump truck that has a high bulkhead, there is no way to get the tarp system out of the way of the loader," says Ray
There are exceptions. In the East, there is what is called a Pennsylvania-style dump body. "There is no bulkhead at the front to stop the tarp system and the cab shield is extended all the way over the cab," says Ray. "We have quite a few customers in the Midwest or East who have cable systems on their dump trucks because they can draw the cable system all the way up onto the cab shield at the front of the truck, where it is away from the loader."
There are downsides to some cable systems, such as twin cable setups. "If for any reason the cable slips on the pulley on one side — from the cable tension not being correct or from debris being on the top rail — the system gets out of time," says Ray. "The bows get out of square and it will jam up on you."
There are newer designs that solve this problem. "We make a single cable system," says Ray. Because the bows are connected to the same cable, they can't come out of time.
Adjusting the bows to keep the system in time is critical to most cable systems.
"We have a patented tension adjuster," says Shur-Co's Nolan. "It puts constant tension on the cable at all times. It requires maintenance, but it is a very foolproof and easy to adjust system. In the old days, you had to take the cables apart, slide them together and reconnect them. That part has been eliminated."
while saving time
Automatic tarping systems are becoming more popular. In some cases, this is due to liability issues. Drivers are simply not allowed out of the cab on some jobsites. "More people are interested in the electrical system primarily as a safety issue," says Nolan.
In addition, automatic tarping systems reduce cycle times. Consider the case of a manual tarp. You pull out of the jobsite next to a catwalk. You get out, pull out your tarp, get on the catwalk, throw the tarp on the load, spread it out, then bungee it down. This all takes time, which can be dramatically reduced by using a tarping system.
"We have customers telling us that they are getting two and sometimes three more loads in a day just because they can tarp quicker," says Ray. "Of course a Pulltarp is faster than tarping by hand. An electric system can even tarp on the fly."
Automatic tarp systems can be powered by electric motors, hydraulics or air. Brescia cites a couple reasons to consider air tarping systems over hydraulic or electric are that air is a renewable source of energy, it's free as opposed to buying hydraulic fluid. "It eliminates any stains from leaks and the mess that goes along with hydraulic fluid," says Brescia. "Compared to electric, there are no motors or solenoids to wear out."
Reliability has improved
Consider maintenance requirements when comparing tarps. Some bearings in tarp systems are maintenance free and stand up better to constant washing. "Sometimes the water has caustic soap in it. With some designs, that gets into the bearings and the bearings go away," says Ray.
Some pivot systems are also more tolerant to the construction environment. "We use reverse wound torsion springs for the pivot arms as opposed to a lot of the new spring systems that are more rigid," says Brescia. "A reverse wound torsion spring can actually take a hit. It is not so rigid that you can knock the whole thing out of whack. We do offer other spring options such as ribbon springs and underbody mounted springs. But I think the most durable is the reverse wound torsion spring that is mounted to the body."
Gear motors on automatic tarp systems can also influence reliability. "In the early days, there were not any purpose-made gear motors for tarp systems," says Ray. "They were adapted winch motors and things of that nature. Now there are purpose-made tarp motors that are very good."
But you still must exercise caution when selecting an electric-driven system. "The only thing to really watch out for is there are some very inexpensive tarp motors coming in from China that are copies of older designs," says Ray.
In general, you can now expect many years of service out of a quality tarp system. "A lot of it depends on the application and where it is used, but we feel that three to five years is a relatively good time for the tarp material to last," says Nolan.
"Basically each tarping company out there focuses on a little different market," says Brescia. For Pioneer Cover-all, this happens to be roll-off tarping systems. "That is 70% of our business."
Pioneer Cover-all's roll-off tarping system uses rack and pinion technology to deploy the pivot arm. "Rather than a cylinder pushing on a pivot arm, the cylinder actually pushes a rack against a pinion gear at the bottom of the pivot arm," Bescia explains. "The rack and pinion creates a mechanical advantage and eliminates the ‘free-fall' associated with conventional cylinder designs once the tarp arm reaches the 12 o'clock position."
This is important to reliability since the tarp and roller weigh about 90 lbs. "It doesn't sound like much, but when you are holding 90 lbs. out 12 ft. and try and lift it, trigonometry tells us it is over 1,000 lbs. It is like swinging 1,000 lbs. over each way," says Brescia. "If the driver isn't careful, they can self-destruct it." The rack and pinion simplifies deployment by the operator.
Select an appropriate material
The type of tarp for a particular application also has a major influence on reliability and performance.
"If you are hauling sand and aggregate where you can use a mesh tarp, then by all means a mesh tarp is better than a solid, vinyl tarp. Because it lets the air through and it does breathe, it doesn't blow around as much and it is just easier to handle," Ray points out. "If you are hauling construction demo or debris that is going to be sharp, or asphalt where you have to contain the heat, or anything that is sensitive to having water on it, then you are going to need a vinyl tarp."
For asphalt, the industry has gravitated to two types of tarps. "It is usually a 14-oz. vinyl that has a special urethane coating. Although asphalt is going to stick to anything, if it has a urethane coating, it does not build up as bad. It also holds up to the heat better," says Ray. "The other type is the 18-oz. vinyl. That is used on normal arm-type systems, as well as cable systems. It is just a heavier PVC-type vinyl."
Think application, not cost
Choosing the right combination can save you money. "Get the proper tarp system for the type of body you are using and the material you are hauling," advises Ray. "Get the proper fabric for what you will be hauling and invest in good equipment. It will serve you in the long run."
Ultimately, saving money on the purchase price is not necessarily the most cost- effective solution. "When you [buy on] price, at the end of the day, you get what you pay for," says Brescia.