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Carrier training program helps raise awareness about cryogenic cargo tanks among enforcement, responder officials

Nov. 5, 2014
ALL TOO often, vapor released from tank trailers transporting liquefied nitrogen and other atmospheric gases is mistaken for smoke. This can result in an unnecessary call-out of emergency responders.

ALL TOO often, vapor released from tank trailers transporting liquefied nitrogen and other atmospheric gases is mistaken for smoke. This can result in an unnecessary call-out of emergency responders.

Liquefied atmospheric gases are vented as vapor as they warm up in cryogenic tank trailers. It is a normal occurrence in these highly specialized cargo tanks that are used to transport a wide range of cryogenic liquids, including argon, oxygen, and carbon dioxide. In addition to the atmospheric gases, cryogenic tank trailers are beginning to haul larger volumes of liquefied natural gas.

The lack of familiarity can lead to confusion when these vehicles are encountered, and not just for the general public. Of all the vehicles they encounter, commercial vehicle enforcement officials and emergency responders may be least familiar with the vehicles used to transport cryogenic products.

To address these concerns, Genox Transportation Inc, one of the largest cryogenic carriers in North America, recently organized a training program for the enforcement and responder community in Texas and Louisiana. Held in early September at the Genox Transportation headquarters terminal in La Porte, Texas, “Cryogenic Tanks: Construction, Inspection, and HM Response” was attended by approximately 130 enforcement and responder officials and Genox customers.

In a clear indication that the training program was needed, turnout exceeded expectations, according to Kevin Mathews, Genox Transportation president and chief executive officer. “We expected maybe 25 people when we began the planning process in June, but there is clearly a need for this information among enforcement officials and emergency responders,” he said. “We got a very favorable response from the people who attended the event, and we definitely will do it again. Since the program, we’ve gotten phone calls from a number of the participants wanting more information. That’s a good thing, because we want to avoid misunderstandings with our equipment and we want to ensure good communication.”

Kenneth P Utz, Genox Transportation vice-president of safety, added that the training program certainly filled an important need in the enforcement and responder community. “Our attendees were enthusiastic, and they had a lot of questions,” he said. “One of our objectives was to build relationships and lines of communication with the responder and enforcement community, and I think we did that. We want to work with these people.”

The one day program included a detailed review of the federal regulations that apply to cryogenic cargo tanks and presentations on the characteristics of liquefied gases. Various cryogenic trailers from the Genox Transportation fleet were on display, and attendees had plenty of time to take a close look at the equipment. They also had a chance to tour the WesMor Cryogenics LLC plant in La Porte, where cryogenic cargo tanks are manufactured and repaired.

Regulatory side

Sgt Charles Longfellow, Texas Department of Public Safety, opened the classroom phase of the program with a review of the key types of cryogenic cargo tanks used to transport liquefied gases. He explained that many of these products are transported in non-code tanks, while others must be carried in code tanks under federal regulations.

Non-code cryogenic cargo tanks are designed to handle atmospheric gases that are transported at a pressure of less than 25.3 psig, and the code cryogenic tanks are designed for pressure up to 500 psig. Inner product tanks can be constructed of aluminum or steel, and valves and piping must have collision protection. Tanks must have one or more pressure-relief valves. Cryogenic trailers typically last 30 to 40 years.

“These are very different animals, and many of you haven’t had much contact with them,” he said. “You need to become more knowledgeable about them. Non-code and code tanks used to transport cryogenic liquids look very similar. Both are insulated and are designed to carry liquefied gases that have been chilled to very low temperatures. However, the non-code tanks used to transport cryogenic atmospheric gases don’t have to meet the strict requirements set for cargo tanks like the MC338 that is used to transport hazardous materials, such as LNG (liquefied natural gas). We’re going to see a lot more of these MC338 code tank trailers on the road in the future as LNG becomes more widely used as a vehicle fuel.

“For enforcement officials and responders, it’s important to remember that placarding requirements are a key difference between code and non-code cryogenic cargo tanks. Placards are required on code tanks—like MC338s—that are transporting flammable cryogenic gases. Non-code tanks hauling atmospheric gases are exempt from the placarding requirements, but they will be labeled with the product name and/or product identification number. The only exception to the rule is non-code cryogenic tanks that are transporting liquefied oxygen, which must be placarded.

“It’s important for commercial vehicle inspectors and emergency responders to understand the differences and the sort of products that are transported in these tank trailers. Keep a current Emergency Response Guidebook readily available and know how to use it. When you need this book, you need it badly and right away.”

Texas Department of Public Safety Trooper Brad Gibson discussed how best to deal with cryogenic cargo tanks during roadside inspections. The number one rule is Safety First.

“If you think the trailer might be carrying hazmat, make sure the driver stops in a safe area,” Gibson said. “Approach the vehicle from the upwind side, but don’t overreact if you see that the trailer is just venting an atmospheric gas (such as nitrogen).

“Talk to the driver. Hazmat drivers are usually a cut above other truck drivers. They are smarter and better trained. They are masters at operating the equipment under their control.

“Ask whether the trailer is loaded or empty, and whether it is clean and purged. A cryogenic tank full of vapors can be considered to be clean. Check the shipping paper, which is to be within easy reach of the driver.”

Shipping document

The shipping document must contain a product identification number or description, proper shipping name, total quantity, and emergency contact information. For non-placarded shipments, the document does not need packaging details.

A hazmat registration document is required for hazmat in cargo tanks larger than 3,500 gallons. This doesn’t have to be the actual certificate issued by the US Department of Transportation. A hazmat safety permit will suffice.

During a walk-around inspection, the inspector needs to verify that the vehicle complies with federal marking and labeling requirements. “These details are contained in 49CFR173.320,” Gibson said. “You need to read that. Remember that non-code cryogenic tanks transporting atmospheric gases (with the exception of liquefied oxygen) are exempt from the hazmat placarding requirements. However, those tanks must have the name of the gas written on all four sides of the tank.”

Code tanks handling LNG or other flammable gases must be labeled for “One Way Travel Time,” which is the total number of hours the tank insulation can maintain the product before pressure buildup would cause product to vent.

Non-code cryogenic tanks are exempt from federally mandated testing and inspection and may not be labeled for those inspections. Both non-code and MC338 cryogenic tanks are exempt from internal visual inspections and leakage tests.

Keith Hall, vice-president of engineering at WesMor Cryogenics, a Trinity Cryogenics LLC Company, discussed the fundamentals of cryogenic products and transportation in a presentation entitled “Cryogenics 101.” He said the most important thing is to respect cryogenic products, but don’t fear them.

Cold demonstrations

Hall used a variety of demonstrations to ease concerns about the risks posed by cryogenic atmospheric gases. For instance he fed participants crackers that had been dipped in liquefied nitrogen. He had attendees wear caps that had been splashed with liquefied nitrogen.

Hall described the cargo tanks that transport the products as giant Thermos bottles that use vacuum and insulation to keep heat away from products, such as nitrogen that is transported at -320°F. LNG is transported at -258°F. Liquefied helium is the coldest at -425°F, and carbon dioxide must be in a pressure vessel (MC331) to remain liquefied.

“We ship these gases in cryogenic form because that is a more efficient, more compact means of transport,” Hall said. “The most important factor is to handle these products carefully and safely. An accidental release of these cryogenic products can cause serious injury, and possibly death.”

Emergency responders must wear the appropriate personal protective equipment when working around a cryogenic tank that may have a leak. At a minimum, this includes gloves and eye protection. Mathews says many shippers require Genox Transportation drivers to wear flame retardant clothing for additional protection.

Caution is needed when handling trailer equipment. Product hoses must be stowed properly, and hose caps must be securely attached. Make sure properly-rated safety valves are used to the trailer, because pipe ruptures can result from the wrong valves. Pressure-relief valves must be maintained for proper operation.

In the event of a spill or leak, it’s important to ensure that the site is properly ventilated. “A large concentration of these pure atmospheric gases will displace oxygen, which can be deadly for anyone without breathing protection,” Hall said. “If you are dealing with a liquefied oxygen trailer, you need to keep combustibles away from the site.”

Hall spent additional time on LNG and the trailers used to transport LNG. He pointed out that the product will not burn in pure liquid form. It will only burn when vaporized natural gas reaches a 5%-15% mix with air.

Initially heavier than air, LNG quickly warms up and becomes buoyant. This means spills will dissipate relatively quickly with no cleanup required. The same is true for other cryogenic gases.

While Genox Transportation took the lead in organizing the cryogenic transport training program they were supported by a number of other companies, including WesMor Cryogenics, Houston Freightliner, Great West Casualty Company, and Jerry Davis with BankcorpSouth Insurance Services Inc.   ♦

About the Author

Charles Wilson

Charles E. Wilson has spent 20 years covering the tank truck, tank container, and storage terminal industries throughout North, South, and Central America. He has been editor of Bulk Transporter since 1989. Prior to that, Wilson was managing editor of Bulk Transporter and Refrigerated Transporter and associate editor of Trailer/Body Builders. Before joining the three publications in Houston TX, he wrote for various food industry trade publications in other parts of the country. Wilson has a bachelor's degree in journalism from the University of Kansas and served three years in the U.S. Army.