Hauling Heat: Louisiana Fleet Claims Hottest Cargo

t’s safe to say that just about everything in Louisiana is hot: the jambalaya, the weather, the jazz. It turns out some of the trucks are pretty hot, too, and we’re not talking about paint jobs and chrome.

We’re talking temperature.

Just ask John N. John III, vice president and co-owner with his brothers of John N. John Truck Line. At 500 degrees Fahrenheit, he said, “our tank trailers have the highest temperature rating in the country.”

In contrast to a barrel of milk, which must be refrigerated en route to its distributor, polypropylene has to simmer, or it, too, will spoil.

“We deliver the product at the temperature it is ordered,” said William John, another co-owner and director of maintenance for the interstate fleet.

Used widely in the roofing industry and as an adhesive, polypropylene offers some unusual challenges to the transporter. Since it starts to solidify at 345 degrees, the substance is maintained at 380 degrees for the entire trip. That means loading at extreme temperature, transporting over the road at extreme temperature and off-loading at extreme temperature.

The perfect job in a Louisiana summer.

Of course, refrigerated tank trailers were invented long ago to transport that load of milk. But when the Johns moved into the narrow niche market of hauling polypropylene two decades ago, the shipper told them to keep the cargo hot all the way across the country or it would turn into a worthless lump of residue.

Clearly, that couldn’t be done with an ordinary

anker. When the Johns discovered there was no suitable equipment readily available, they were forced to come up with their own trailer design.

They went through quite a few tankers before they got it right. “We learned by trial and error, because those were the first bulk shipments we did,” said Joseph John, vice president and co-owner.

Today, the carrier starts with a 42-foot Fruehauf model with a basic barrel, certified for 500 degrees, atop a chassis. The electrical heating system, insulation pack and outer shell are added, a process that takes four to five weeks. All the work is done at the carrier’s retrofit facility here.

The result is John N. John’s own “EH” Series tank trailer, with 7,000-gallon capacity.

The carrier design has a thermostatically controlled heating system wrapping around the underbelly and sides of the trailer for maximum effect. A 25-horsepower diesel generator provides the juice. A mainstay of the design is the heated unloading valve, which prevents coagulation in the unloading line.

oused in what looks like a large shoe box, the valve is operated by a handle designed to prevent any contact with the scalding cargo.

Normal unloading time of an EH trailer is one hour, but a plugged valve “can mess up your day,” said Steve Courville, the company’s chief executive officer. “You can spend 8 to 10 hours unplugging it.” An entire load once had to be returned because goo set up in the out-take.

“In the past, the first thing we would have to do is go to a steaming facility to have the valve unplugged,” William John said. With the electrically heated valve, “we’re in and we’re out.”

The company sought the help of the Louisiana Productivity Center in developing the trailer’s heating and insulation. The center, located at the University of Southwestern Louisiana in Lafayette, a few miles down Interstate 49 from Crowley, helps businesses boost productivity by recommending technical solutions. With the center’s help, a team was assembled to study the challenges of hauling polypropylene.

“When William came to us, he was looking for an insulation package that was not only lightweight but very precise,” said Ted Kozman, director of the center. “The first thing we did was work with NASA people to see what they used, and then we put together various practical and theoretical models.”

Before building a full-size prototype, the team experimented with a variety of models, including one called King Tut, a tank one foot in diameter and two feet long. They wrapped Tut first in ordinary wool insulation and then tried other materials. Boiling water was poured into the tank, and the researchers measured how long it took for the water to reach room temperature — generally about 40 hours, as it turned out. It didn’t stay warm enough long enough.

Then Johns latched onto a derivative of the space shuttle’s insulation. An air-blown polymer material, it resembles household fiberglass insulation but has only half the weight and far greater heat-retaining capacity.

Bill John said temperature loss in the series EH trailer has been measured at 1 degree per hour when the vehicle is traveling at 55 mph in zero-degree weather. “On a typical 48-hour trip, we may lose two degrees from the point of origin to the final destination; five degrees at the most. If we load at 380 degrees, we might unload at 375.”

As assiduously as the company controls the temperature, it also monitors the residue in its tankers. As heat is lost, a solid buildup known as a “heel” develops on the bottom of the tank.

Too much heel is called “phantom freight,” beef taking up space inside the tank. Before the Johns’ design was perfected, a three- to four-foot-wide heel was not uncommon. Today, the average is down to one inch, which presents no problem to top-loading. Tolerating a minimum heel cuts down on the need to clean the tank between loads.

The need to go to all this trouble makes the high-temperature market “less competitive than dry freight,” said John N. John III. “A few people have tried it but backed away from it,” Mr. Courville said. “People just don’t want to fool with it. There’s a lot of one-way freight, and the people who come to us know we have the equipment to do it.”

The key to remaining a leader in its niche is to “personalize the service,” Bill John said. “We have been going up against the big boys for a long time, and I love it.” Despite the wave of consolidation in the trucking industry, he said, there will always be room for a small trucking company.

“Big companies consolidate because they can’t offer the same level of service as the smaller ones, so they just buy the company,” he said. “Most bulk carriers start off by hauling something like vanilla type products and then move into the difficult stuff. We started with the most difficult, and the rest has been a piece of cake.”