The Flexible Shipping Alternative


At least one day a week, trucks arrive at Bigler Specialty Oils in Houston to pick up products. But instead of forklifts bringing on scores of 55-gallon drums or 250-gallon tote bins, these intermodal containers will get fitted with a liner and then a huge red bag. Hooked up to a hose and pump – whoosh! – the polyethylene pouch is filled with fluid until it plumps up like a giant pillow. As rigid bulkheads protect the bag from pinching, the fittings are carefully stowed and the doors closed firmly. The truck pulls away, and the entire 20-foot container, packing over 6,000 gallons of base oil, white oil or ink oil, heads to a ship bound for a foreign port.

Supervising the whole process is a specialist from Environmental Packaging Technologies, one of a number of global companies that supply the bulk packaging and expertise needed to fill flexitanks or flexibags. Its common today for the leading flexitank suppliers to have a representative on site for each lading, users say; not only does this assure the packages reliability but it can also ease insurance costs for the shipment.

Dan Schramm, president of Bigler Specialty Oils, is an avid user of this bulk option. In my mind, the flexibag is the transportation package of the future, he enthused. We even upgraded our truck racks and built new ones to handle them, and we can load them now with the same ease and time as a tank truck.

Bigler processes, blends and markets specialty oils, most of it sold on contract. Especially were seeing demand for using flexibags southward, into South America, where the market is building. Older producers do not seem thrilled about them, or set up to handle them, but were located on the Houston Ship Channel, and its ideal for us. In all, the flexibag is still relatively small volume, but its gaining a foothold, and is part of our differentiation, Schramm added.

Shane Sims, vice president of manufacturing and technical at EPT in Houston, sees more lube oils heading from Houston to Central and South America in flexitanks. He says flexitanks today haul vegetable oils from Asia, bulk chemicals from Europe, and oceans of wine from Argentina, South Africa and Australia. The bags themselves usually are made of low-or high-density polyethylene, and constructed either in a single thick layer, or as multiple thinner layers.

Sims makes a strong economic case for this package option: The volume that will fit in an intermodal container with a flexibag is about 15 percent greater than with IBCs, and 40 percent greater than with drums. Its much faster to fill one flexitank than an equivalent volume into drums, of course. And for the customer, discharge is very easy; they just hook up a hose to the fitting, which is standard, and pump the material out. The single-use plastic bag is easy for most customers to recycle once its empty, too.

Handle with Care

But another shipper in the Houston area, who regularly sends flexitanks of specialty lubricants to South America, says that not every customer is ready to love the bags. Some customers are still skeptical – they want drums, confided this executive, who asked not to be identified. Theyre in hilly areas, where the cargo is going to be going up and down. They have concerns with the total weight, and worry about ruptures, as well as traction on the roads. In South America, trucks have to go up a lot of hills, and weight can be an issue. If a tote bin fails, youve lost 200 to 300 gallons. But youre looking at 6,000 gallons lost if one bag is compromised. Its a live cargo – 20 metric tons of liquid.

Theres quite a bit more to using a flexitank than just putting a giant baggie of oil into a trailer, slamming the doors shut and dropping it onto a ship. Shippers, haulers and users all warn that punctures and damage from poorly constructed flexitanks can flush away the cost advantages in an instant. The containers must be designed, manufactured and handled with appropriate care.

For example, EPTs system (trademarked as Big Red Flexitank) is engineered to avoid shifting or tipping of the load in transit. The bulkhead system helps to hold the dynamic forces while airbags fill the unused space inside the container, to keep the load rigid. Properly filled, the EPT bag will carry about 6,400 gallons, and can move on all intermodal options – truck, rail and ship.

EPTs Big Red system is pretty lightweight, coming in at about 350 pounds for the total system, so you can really max out on the product weight-wise, pointed out Sims. With base oils youre usually looking at about 46,000 to 48,000 pounds per container.

The trick, he said, is to prepare the shipment so there is no way this liquid can move or shift. The railroads frowned on flexitanks early on because theyd seen a lot of problems. We have the only rail-approved bulkhead, and we always take those back. For customers who get a lot of shipments in our tanks, we might have a trailer on their site to collect my parts for return. EPT recently passed stringent impact tests for railroad carriage – a flexitank first – and now we expect to see more activity on the rails in the U.S.

Only non-hazardous goods may be filled in flexitanks, shippers emphasize. Sizes usually are optimized to take advantage of a standard 20-foot intermodal shipping container. The maximum allowable weight is about 24,000 kilograms of product with a specific gravity of 1 or lower.

A Crowded Field

Many companies offer flexitanks, and even more make just the bags, so experienced shippers advise careful vetting of vendors: their manufacturing quality, service, technical support, costs (smaller suppliers may not be cheaper), years in business and reliability. Inferior bags abound, cautioned Sims, and there are at least 35 manufacturers in China that can make you all the cheap bags you want. EPT had its bags made in China for a while, but last year transferred manufacturing to the United States, resulting in tighter quality control. It also reaped a cost savings of 25 to 30 percent, helping it to stay competitive.

EPT estimates that flexitanks now are a $400 million-plus business worldwide, and says it holds about a 10 percent share of that. Among its customers are ExxonMobil, Georgia Pacific, Gavilon (formerly ConAgra), and many others. Other leading flexitank logistics companies are Trans Ocean Distribution, Braid Logistics and Hoyer Global Transport.

One important group that has worked to improve flexitanks is the Container Owners Association (COA), which represents companies that own and lease the freight containers. Through the 1990s, its members grew increasingly unhappy with problems they were seeing – unstable loads; bulging of side walls from surge forces; permanently distorted containers; leaks that dripped onto other containers stowed below; insurance losses. The chorus of negatives kept getting louder.

With no standards in place, by the mid-2000s several shipping lines and railroads had banned all flexitanks outright. But in 2006, logistics companies, flexibag suppliers, ship owners and container fleets persuaded the COA to form a working group to write rules to tame the flexitank fray. Its Code of Practice for Flexitanks was published last year to great approval, and took effect in January. The 24-page Code is online at

Also, North of England P&I Association, a marine liability insurer in Newcastle, England, last year published a fact-filled guide to using flexitanks in intermodal containers. NEPIAs guide explains the factors that can cause flexibag damage and leakage. It also includes a useful checklist of questions to ask when considering carriage via flexitank. Youll find the four-page guide online at under Loss Prevention Briefings.

Flexitank success begins with the intermodal container, both of these documents stress. Before the flexibag is installed, the container should be inspected for debris or sharp spots. This is because when the cranes drop it onto the ocean vessel or a truck or the ground, theyll drop it hard – and all the liquid will want to go somewhere. If the bag and container are not properly fitted, it can fail. If there are splinters, nails or protruding screws, youll get a puncture, or chaffing against the bag.

Across the U.S.?

A spotless container also is critical to the customer, echoed Biglers Schramm. Perception is key. If Im shipping a white oil, and theres dirt on the drum, the customer is going to reject it. Same thing with the flexibag – if theres an oil stain on the outside of the bag, even if its from another shipment, that can create a problem.

To his surprise, Schramm is not seeing much flexitank use in the United States yet. Maybe the reason is that many in the oil segment are already invested in appropriate tank sizes, and theres good truck availability.

A more recent flexitank convert, Jayna Mull, vice president of lubricant toll blender and packager ZXP Technologies in Highland, Texas, thinks that may be changing. The concept is great, and the freight cost is terrific, she said. ZXP uses Hoyer Global Transport as its principal flexitank supplier. They bring in the entire thing, and supervise the loading here. Directions are pasted on the side of the container. We can ship about 6,000 gallons, while an ISO tank usually holds about 4,000.

ZXP has been shipping in flexibags actively for about six months, Mull said, always without incident. She expects to step up the use of the package even more. We looked at the cost of shipping one to the West Coast – its always a struggle to get product to the West Coast by truck and rail – and I found I can send a flexibag by container ship to Long Beach in California cheaper than to truck it there. A ship does take a little longer; it may take 12 to 14 days to send via rail, and going by ship adds another four or five days to that, up to 21 days in all. So it just takes planning.

It also requires a couple more steps at the customers end than an ISO tank or a tank truck, EPTs Sims said. You do have to take the flexitank down and roll it up. But you dont have to wash it out like you do with drums and totes. And youre not handling 80 drums at both ends, which have to be individually filled and then discharged.

The flexibag companies have made significant moves to improve the quality and service and support, which was needed to overcome the doubts, Schramm commented. At one time, you had to be able to prepare yourself emotionally for a flexibag tear or puncture. Then there was an industry shake-out, and the survivors really stepped up, and took responsibility – they still do. They have improved their manufacturing processes, too.

So will the container of the future live down its spotty past? Seriously consider it – have an open mind, ZXPs Mull said. It takes a while to get past the fact that Im putting my precious motor oil into a big bag. Three years ago we wouldnt even be having this conversation, but theyve really improved.

Related Topics

Flexi Tanks    Packaging    Packaging Containers