Used Tube Trailers for Sale

It's a road trailer carrying a group of large high-pressure cylinders ("tubes") joined by a manifold. It hauls bulk compressed gas such as helium, hydrogen, nitrogen or natural gas from a fill plant to a customer site. Layouts range from under ten large tubes to several dozen smaller ones. Steel tubes are often rated around 2,400 psi, and higher-pressure designs are offered.

Sources: 49 CFR 173.301 · FIBA tube trailers · FIBA DOT tubes · 49 CFR 178.37

Steel tubes (DOT-3AAX, 3T) are heavy, so a steel trailer hits the road weight limit carrying less gas. One manufacturer says its Type 4 composite tubes weigh about 75% less than steel and carry more than twice the hydrogen per trip. Composite systems also run higher pressures, commonly about 3,600–7,500 psi. Most composite tubes in U.S. service run under a PHMSA special permit rather than a standard DOT spec.

Sources: Hexagon Purus · Luxfer · PHMSA DOT-SP 14951 · PHMSA DOT-SP 21935

A MEGC (multiple-element gas container) is a set of pressure receptacles of the same design, joined by a manifold and mounted in a structural frame. The receptacles are seamless steel or composite, built to ISO standards. It moves on a chassis or intermodally like a container, and carries a metal plate showing its approval number, test pressure, number of receptacles, water capacity and inspection dates.

Source: 49 CFR 178.75

Check the requalification dates stamped on every tube. DOT-3AAX and 3T tubes must be requalified every 5 years, and an overdue tube can't legally be filled and shipped, so a set of overdue tubes is a rehab job, not a ready delivery asset. Then check the tube markings, valves and manifold, the trailer's annual inspection status (brakes, suspension, frame, tires), and the gas the tubes have been in.

Sources: 49 CFR 180.209 · 49 CFR 173.301 · 49 CFR 396.17

The original markings show the spec and service pressure (e.g. "DOT-3AAX2400"), a serial number, the maker's symbol, and the inspector's mark with the original test month and year. Each retest adds the requalifier's ID around the test date. A "+" mark on a steel tube allows filling up to 10% over service pressure, in hydrogen service among other cases. Composite tubes are marked with their special-permit number and working pressure.

Sources: 49 CFR 178.35 · 49 CFR 180.213 · FIBA — fill pressure in hydrogen service · PHMSA DOT-SP 14951

Yes. Under the special permits we reviewed, composite tubes may not be used past 15 years from manufacture. An approved life-extension program can stretch that to 30 years based on test data. They're requalified every 5 years by hydraulic proof test or acoustic emission testing, plus visual inspection, and a copy of the permit must ride on each vehicle hauling them.

Sources: PHMSA DOT-SP 14951 · PHMSA DOT-SP 21935

Get the tube markings and manufacture dates, the latest requalification records, and the trailer title and chassis documents. For composite tubes, get the special permit too. Ask for the gas service history. Whether a trailer can change gas service depends on the manufacturer, so contact them before switching. Some tubes aren't suited to every gas; for example, UN tubes need an "H" stamp for hydrogen.

Sources: 49 CFR 180.213 · PHMSA DOT-SP 14951 · FIBA — hydrogen service

A steel tube is condemned if it leaks through the wall, shows cracks, or its permanent expansion is more than 10% of total expansion at retest. Condemned tubes are stamped and can't be refilled. Under the composite permit we reviewed, a tube that's been in a fire may not return to service. The chassis also needs a periodic inspection at least every 12 months.

Sources: 49 CFR 180.205 · PHMSA DOT-SP 14951 · 49 CFR 396.17