NTTC Cargo Repair Seminar Covers Variety of Industry Topics

Feb. 1, 1999
The annual NTTC Cargo Maintenance Seminar produced several issues to be addressed by the tank truck industry, but the possibility of a new rule that would

The annual NTTC Cargo Maintenance Seminar produced several issues to be addressed by the tank truck industry, but the possibility of a new rule that would add third-party inspectors garnered special interest. That was one of many technical topics covered during the October 19-21 meeting in Chicago, Illinois.

John Cannon, vice-president of Brenner Tank Inc, presented information about a possible new rule regarding third-party inspection of cargo tank repairs that could cost the industry $4 million annually.

"The third-party inspector or authorized inspector would be any inspector currently commissioned by the National Board of Boiler and Pressure Vessel Inspectors and employed by an authorized inspection agency," he said. An agency is defined as any jurisdiction that has adopted and administers the ASME code, or an insurance company licensed to underwrite boiler and pressure vessel insurance. A state or province could have its own agency.

Third-party inspectors may be required because Department of Transportation (DOT) officials are concerned that some repair facilities are not following their own published quality assurance manuals in repair of DOT specification cargo tanks.

"The question is, how many repair shops are falling short," said Cannon. "If a widespread problem is found, government and industry should work together to create a solution. If a widespread problem is not found, those repair shops that are causing the problem should be dealt with."

However, if a third-party rule is implemented, costs for repairs are expected to increase significantly. He listed the following reasons: -Efficiency lost by time spent waiting for inspector. -Inspection fees of $500 per unit. -Inspector travel fees. -Administrative fees in inspector coordination and paperwork.

The implementation would be further complicated by the time required to qualify new inspectors and the availability of the few already meeting the requirements.

"Will this type of mandate reduce substandard repairs?" he asked. "Do the potential benefits outweigh the known costs?

"We as an industry must be prepared to propose alternatives and work together with government to promote the safe transportation of hazardous materials."

Another subject discussed at the meeting involves a study by the Federal Highway Administration (FHWA). The FHWA has contracted for two engineering studies to be performed related to cargo tank construction, said Pat O'Brien of E D Etnyre & Co. The first study is to produce a method by which FHWA engineers can determine whether a cargo tank complies with structural integrity, and the second is to analyze stresses experienced by various accident damage protection devices.

O'Brien serves as chairman of the Truck Trailer Manufacturers Association (TTMA) Tank Conference Engineering Committee, which has designated the two issues as top priorities for the committee's oversight. He also discussed other concerns involving tank manufacturing regulations.

"The two engineering studies are underway, but not yet completed," he said. "What we have found is that the FHWA has used the preliminary results of these studies in an audit of at least one cargo tank manufacturer. We think the methods used by FHWA are inappropriate, incomplete, and unverified. The FHWA is not applying these new informal rules uniformly and the new criteria have not been published."

Another issue has arisen involving maintenance of rear underride guards. A proposed rule would require carriers to maintain the guards so that the dimensional requirements and certification label remain in compliance.

"The dimensions required are pretty straightforward," he said. "The problem arises when someone has to make a judgment on how much of a beating a guard can endure in normal service and still be in compliance. From a strictly engineering analysis, it is hard to defend a guard with any permanent deformation. From a practical standpoint, it must be expected that some deformation will occur over years of service."

Rear underride guards aren't the only safety devices receiving scrutiny. The use of conspicuity tape has a new regulatory twist. A proposal would require the retrofit of old trailers. "This is, of course, an expense that will fall directly on carriers, and is an important concern for maintenance personnel," he said.

Ed Mansel of Polar Tank Trailer Inc said carriers should be familiar with DOT requirements concerning cargo tank modifications, repairing, and rebarreling. Understanding the contents of 49CFR Part 180.413 is necessary to meet the rules and to ensure that the work being conducted complies, he said.

Modification is defined as any change to the original design that affects structural integrity or product retention. There are two categories of modification: welding to the cargo tank wall and welding that does not involve the cargo tank wall.

Rebarreling means replacing more than 50% of the combined shell and head material of the cargo tank. Replacement of the barrel means to replace an existing tank on a motor vehicle chassis with a new tank.

Modifying a tank calls for DOT-certified facilities and periodic updating and renewal of registration. A certified design engineer must verify rebarreling, stretching, and modification. "The work must be in compliance," he said. "Have the original manufacturer approve the work, if necessary, and always request documentation."

The engineer will require detailed information to plan the work, meeting with the carrier to learn what the modifications are designed to do. Mansel recommended a schematic drawing for planning and conducting the work. "In addition, a brief description should be stated on the schematic," he said.

The end user and shop have to certify that the barrel structure meets requirements. Nameplates must be properly affixed adjacent to the original, and certification documents must be available.

All tractors manufactured after March 1, 1997, are required to provide a continuous power supply to the trailer whenever the ignition is in the on position, said Jack Rademacher of Brenner Tank Inc. "As the trailers are required to be manufactured with ABS so, too, is the ABS required to have a continuous power circuit to the tractor.

"The trailers are also required to be supplied back-up power from the stop lamp circuit," he said.

The connector that is used exclusively, SAE J560, is the industry standard electrical connector. The number seven pin on this connector was typically not used by about 85% of the fleets. The remaining 15% used the pin to power auxiliary equipment such as lift axles and backup lights. The seventh pin is now the designated ABS continuous power supply.

The ISO3731 is the newest connector. It is the Truck Manufacturers Association (TMA) and TTMA recommended connector for auxiliary power requirements. The pin configuration is the same as the SAE J560 except that pin number one, the ground, has a female terminal. The SAE J560 has a male ground terminal.

"To maintain interchangeability within the fleet, TMA and TTMA have designated the SAE J560 connector to carry the ABS continuous power across the number seven pin," he said.

New tractors are being built with the number seven pin hot, so connecting a new tractor to an old trailer would automatically power any auxiliary equipment on that circuit. Because of the conflict with the present equipment, many fleets have been ordering or modifying the new equipment to conform with their old equipment. "There is nothing wrong with that," he pointed out.

However, if a company purchases a trailer manufactured after March 1998 with a nonstandard wiring scheme, the trailer electrical configuration is not likely to match an owner/operator or lease tractor.

"If the hired tractor is a post-March of 1997 tractor, the trailer auxiliary equipment will be constantly powered," Rademacher said. "The backup lights will be on or the lift axle will be raised."

Unplugging the backup lights to bypass the system risks detection and fines, he noted.

"If you are not currently conforming to the industry standard electrical scheme, you really have no choice but to convert," he said. "Manage your chaos. The long-term goal must be to plan an organized conversion of your fleet to the new industry standard."

Beginning March 1, 2001, all newly manufactured trailers will be required to have a system linked to a tractor-mounted monitor that will indicate when there is an ABS failure.

Because of the endless system monitoring that is possible between the tractor and trailer, such as tire pressure sensing, brake drum temperature, and backup lights, TMA and TTMA have endorsed multiplexing to communicate the ABS malfunction signal and any other unit signals.

Multiplexing is a method by which numerous signals can be sent across a single line. PLC4Trucks, developed by a manufacturing consortium, is the system selected by TMA and TTMA.

"The most universally intelligent spot on the trailer currently is the ABS electronic control module (ECU), and it is the most likely place to embed the PLC4Trucks system," he said. "And since the PLC4Trucks will be embedded into the ABS electronic control module, TMA and TTMA have agreed to send the multiplexing communication through the number seven pin, which is the ABS continuous power."