TANK TRUCK safety remains a major concern for both National Tank Truck Carriers Inc (NTTC) and the Truck Trailer Manufacturers Association (TTMA). Currently, the two associations are working together on a safety videotape.
Areas to be covered in the videotape include general safety guidelines of working with cargo tanks, loading and unloading practices, hot temperature operations, cargo tank repairs, and internal inspections of lined tanks.
TTMA spokesman Ed Mansell, director of engineering at Polar Tank Trailer Inc, provided the update on the video project and other TTMA activities during the NTTC annual conference May 15-17 in Chicago, Illinois.
Among other activities, TTMA has taken a proactive stance in working on ASME Section XII with the American Society of Mechanical Engineers. The ASME program would cover all code tank trailers and calls for more detailed stress calculations, tank construction, and weld procedures.
These factors are tolerable, but ASME also is calling for third-party inspections of new construction and tank repairs. "At TTMA, we strongly object to this requirement," Mansell said. "We also object to the fact that no cargo tank engineers are on the ASME steering committee. We have proposed that TTMA assume ASME's role in creating standards for cargo tanks."
Rollover Study The association has responded to the University of Michigan Transportation Research Institute (UMTRI) study on the dynamics of cargo tank rollovers. Performed totally on computer, the study could have a major impact on tank design. Overturn guards would have to be stronger (also heavier) to meet the 10 g load determined in the study.
"We feel the study is lacking in several areas," Mansell said. "No physical testing was done. Assumptions about rollover did not represent what actually happens. Assumptions about energy absorption were ignored, and assumptions about rigidity of the ground were oversimplified."
Wetline rules are still under development at the Research and Special Programs Administration. They will be published as HM-213B, but no date has been announced. TTMA is working with the American Petroleum Institute on revisions to RP 1004, which covers bottom loading and vapor recovery for petroleum cargo tanks. TTMA also is working on recommended practices of its own for chemical vapor recovery and finite element analysis in cargo tank design. o