Collapsible Petroleum Tanks:  

Past, Present, and Future

by Major John A. Leggieri and William Perdue

The Army provides bulk petroleum to all land-based forces in a theater of operations. Depending on the size of the operation, this may mean that several million gallons of fuel must be received and stored each day. To accomplish this task, Army petroleum units must be able to establish large fuel storage and dispensing systems quickly. The collapsible fabric petroleum tanks used by active and reserve component petroleum units to set up these systems are vital assets. Expired, defective, poorly stored, or inadequately maintained tanks negatively impact a petroleum unit's wartime readiness posture and adversely affect its ability to provide fuel storage. Conversely, well maintained, properly stored, and serviceable petroleum tanks provide fuel to fighting forces when and where they need it.

The life cycle, storage, and testing of petroleum tanks have been subjects of great debate in quartermaster circles over the past several years. Inspection procedures have been revised, and several initiatives are underway to improve the procurement, management, and use of collapsible tanks.

Past—High-Maintenance, Labor-Intensive

Collapsible fabric tanks have provided critical tactical bulk petroleum storage for military operations for over 50 years. Beginning in the 1940's with the 900- to 3,000-gallon pillow tanks, collapsible fabric tanks have evolved into the primary tactical fuel storage vessels now used by all of the military services.

Initially, fabric tanks were used to supplement large, bolted steel fuel storage tanks and to store small quantities of fuel in remote locations. Early collapsible tanks were made from thick, nitrile thermoset materials (synthetic rubber-like materials that do not soften when heated) that were heavy and required many soldiers and a lot of materials-handling equipment to deploy.

Technological advances in materials and fabrication techniques led to the manufacture of larger and lighter fabric tanks made from thinner thermoplastic urethanes. The new technologies permitted the development, manufacture, and fielding of collapsible tanks with a capacity of over 200,000 gallons. These tanks can be deployed rapidly and recovered using fewer personnel and less equipment. The success of the large-capacity collapsible tanks rendered the labor-intensive bolted steel tanks obsolete, and they were removed from the Army inventory.

Present—In Search of Storage Solutions

Today, a typical petroleum supply company is authorized over 100 10,000-, 20,000-, and 50,000-gallon collapsible tanks for its fuel storage and distribution mission. These tanks cost between $7,000 and $10,000 each, so the total value of the collapsible tanks in each petroleum unit's inventory ranges from $700,000 to over $1 million.

Many variables, such as storage location, environmental conditions, and storage container design, affect the storage and useful life of collapsible fuel tanks. Determining their shelf and service life, establishing procedures for their serviceability, and finding suitable storage options have proven extremely difficult.

In July 1996, the Army Aviation and Troop Command (ATCOM), the original program manager for petroleum and water tanks, issued a maintenance advisory message (MAM) that contained detailed guidance on extending the shelf life of collapsible fabric petroleum and water tanks. The MAM coded the tank storage life as extendible, provided each tank passed an elaborate examination. Test procedures required filling tanks to 80-percent capacity with water, waiting 24 hours, and then checking for leaks. If no leaks were found, the water could be emptied and the bag refolded and placed in storage.

The original procedures for this examination were cumbersome, time- and labor-intensive, and potentially hazardous to the tanks and the environment. Reserve petroleum units had a particularly hard time complying with the guidelines, because it was very difficult to complete the examination during a normal 2-day reserve drill period. Time and personnel constraints made testing all tanks in reserve component units impossible. These procedures also wasted water, contaminated petroleum tanks' interiors with water, and released tainted water into the environment when the tank was emptied.

Tank inspection criteria.

Tank inspection criteria.

Reserve component petroleum units presented their concerns about unrealistic test procedures to the Quartermaster General in May 1997. In response, the Petroleum Advisory Committee formed a subcommittee to examine the situation and recommend possible solutions. The study group, consisting of representatives from Active Army, Army Reserve, and Marine Corps organizations, tank manufacturers, coated-fabric manufacturers, and civilian technical personnel from the Army, Air Force, and Marine Corps, recommended suspension of the water test procedures in August 1997. The group's short- and long-term recommendations included leaving petroleum tanks in the original manufacturer's crates instead of removing them to perform test procedures, establishing a maximum time for depot and unit storage, creating limits on tank service life, and investigating technologies to extend service and shelf life further.

Based on the study group's recommendations, the Army Tank-automotive and Armaments Command (TACOM), the new program manager for petroleum and water tanks, published revised guidelines for shelf and service life of tanks in March 1998. TACOM's interim MAM rescinded the water test procedures and eliminated the ability to extend tank life. Instead, units were directed to inspect visually all tanks with a contract date of 1987 or earlier and those stored at the unit level for 5 years or more. The inspection criteria (see chart above) are still applicable and should be used to inspect petroleum tanks. TACOM further instructed units to conduct inspections at deployment or training sites if insufficient time or resources prevented them from doing so at their home station, as is the case for many reserve petroleum units.

Additional guidance in the message set rated fill capacities, established maximum wetted service life, and required record keeping at the unit level. TACOM directed that each tank be filled only to the capacity indicated in the chart above. The message defined a tank's "wetted service life" as beginning when a petroleum product was introduced into the tank. The maximum wetted service life of petroleum tanks was set at 3 years. It may be less than 3 years under some climatic conditions, such as extreme heat or cold, but will never exceed the 3-year limit. Tanks exceeding the 3-year service life limit must be discarded. Units also were instructed to maintain detailed historical records for all petroleum tanks on hand that included date of manufacture, date of receipt at the unit, and date of initial fill. The initial fill date must be marked permanently on each tank.

Tank rated capacity.
Tank rated capacity.

In addition to their concerns about unrealistic test procedures, Reserve units raised the issue of inadequate tank storage facilities to the U.S. Army Reserve Command (USARC), Fort McPherson, Georgia. Many tanks are stored outside with little or no protection from harsh weather except for their wooden shipping crates. Adequate storage facilities do not exist at the regional support command or unit level. Equipment concentration sites, which normally house reserve unit equipment, do not have the assets to store or properly care for the tanks.

Storage and maintenance of petroleum tanks are particularly challenging for reserve petroleum units organized under Logistics Unit Productivity System modification tables of organization and equipment (MTOE's). These units normally are authorized a large amount of equipment but few personnel. As an example, the 877th Quartermaster Company in Albuquerque, New Mexico, is authorized 111 collapsible fabric petroleum tanks but only 69 soldiers to maintain them. The ratio of 1.6 tanks per soldier makes it difficult to store, maintain, and use tanks properly during normal peacetime operations.

In response to the units' inquiries, the Office of the Deputy Chief of Staff for Logistics, USARC, placed collapsible fabric petroleum tanks on the command's intensively managed item list and directed a reserve-wide inventory of tanks to determine the magnitude of the problem. Data collected from the field confirmed that there was a problem. Reserve units reported having over 2,600 collapsible petroleum and water tanks on hand, with most of them stored under less than ideal conditions. A significant number of the tanks were at or near their expiration dates. Better storage solutions were required desperately.

USARC initiated research, which is still going on, into the feasibility of changing MTOE's of reserve petroleum units to reduce the number of tanks they are authorized while maintaining the current required levels. Efforts also were started to locate long-term storage facilities that could house tanks in a climate-controlled environment. Such facilities would store most of the reserve component petroleum tanks, leaving only a small number at the unit level. Turning in old tanks, replacing them, and then storing the new ones in the same locations makes no sense and will not remedy the storage problems. However, USARC still requires reserve petroleum units to dispose of old tanks, reorder new ones, and store them either at the unit's location or in a regional support command-run equipment concentration site.

Numerous lessons learned about the storage and service life of petroleum tanks were gleaned at Petroleum Exercises (POLEX's) '98 and '99 at Fort A.P. Hill, Virginia. During POLEX '98, several 50,000-gallon collapsible tanks that had been used to store fuel during a reserve unit's annual training in 1997 were unfolded and inspected. The tanks had been manufactured in the fall of 1987 and put into service in June 1997. In several cases, fuel left in a tank had leaked through its walls (see photo at right), primarily in areas where the tank had been folded for repacking after use. Such tanks were deemed unserviceable and marked for turn-in. The degradation of these tanks could be attributed in part to the age of their material but also to extended contact with fuel remaining in a tank during storage. This situation is hard to avoid because it is difficult to remove all residual fuel from the tank after use.

The tanks inspected during the petroleum exercises had been stored for over 5 years in an unprotected outdoor location in the original wooden packing crates constructed by the manufacturer. The crates had deteriorated to a point that most were unusable. Significant reconstruction of the crates was required before the tanks could be repacked and shipped back to home station.

Arrow points to wetted surface of tank showing fuel weeping from seams during storage. Arrow points to wetted surface of tank showing fuel weeping from seams during storage.

In June 1999, TACOM released a MAM that contained new guidance on collapsible fabric petroleum and water tank shelf and service life. The guidance, based on the results of tests conducted at Sierra Army Depot, California, during September and October 1998, set the depot shelf life of petroleum tanks at 12 years and defined depot storage conditions as a dry indoor environment. Tanks not stored under such conditions were given a shelf life of 5 years from date of receipt or 12 years from date of manufacture, whichever comes first.

The MAM reiterated the maximum 3-year wetted service life of petroleum tanks. Visual inspections are still the only way to ensure tank readiness for deployments. TACOM encourages the removal of serviceable components, such as valves and fittings, from tanks destined for salvage.

USARC recently approved inclusion of fabric, collapsible petroleum tanks in the Minimum Essential Equipment for Training (MEET) program. This allocates a small number of tanks to units for use in annual training petroleum missions. The rest will be housed in expanded equipment storage facilities at annual training locations or in long-term storage facilities at deployable equipment preparation sites. This decision means a reduced maintenance and storage burden for user units, more efficiently maintained tanks at expanded equipment storage facilities and deployable equipment preparation sites, and enhanced access to tanks for training and mobilization made possible by pre-positioning them near training sites and power-projection platforms.

USARC has located ample indoor, climate-controlled storage space in Ogden, Utah, that appears to be suitable for petroleum tank storage. Once the availability of that space is confirmed, the arduous task of moving tanks to that location will begin.

Future—A Revolution in Petroleum Logistics

New ideas, concepts, and technologies are bringing about a revolution in military logistics. Nowhere is this more evident than in the area of petroleum tanks. Collapsible tanks are, and will continue to be, the primary tactical fuel storage system of all military services.

Current initiatives to improve the storage and service life of collapsible tanks include reducing the quantity of tanks in petroleum units; adopting reusable, durable containers and improved smart-tank material; and reassigning tanks from class VII (major end items) to class II (durable items).

Reduced tank quantities. The requirement for increased quantities of fuel and simultaneous development of larger capacity collapsible tanks will allow the Army to reduce the total number of tanks authorized to each petroleum unit without reducing the unit's total storage capacity. Replacing 10,000-gallon tanks with 20,000-gallon tanks at the corps level and above will remove at least 24 tanks per company. This action will cut procurement costs, storage space requirements, and the amount of time spent inspecting tanks.

Tanks stored at unit level for more than 5 years or with a contract date of 1987 or earlier should be inspected visually. Tanks stored at unit level for more than 5 years or with a contract date of 1987 or earlier should be inspected visually.

Reusable containers. Current procurement specifications for all sizes of collapsible tanks require that a durable, reusable storage and shipping container be provided with each tank. These containers increase the initial cost of the tanks, but they produce cost savings and improve readiness by providing better protection. The fuel system supply point, the primary storage system that uses fabric tanks as components, also will be transported in standard 20-foot containers. The packing of the complete system in containers will help to increase the storage life of the collapsible tanks further.

Improved smart-tank material. Future tank material research will focus on developing a tank material that can store water or fuel better. Ideally, materials will be lighter, be able to sense the onset of material failure, and will improve tank storage and service life. These initiatives, if successful, will reduce procurement and logistics management costs, improve readiness, and diminish environmental hazards.

Transition from class VII to class II. Collapsible tanks are being reclassified from class VII, which includes major end items such as vehicles and major weapon systems, to class II, which includes durable equipment such as tents and tool sets. Replacement tanks no longer will be free-issue items to units. Tanks will be provided as part of the initial issue of a complete system, such as a fuel system supply point. Replacement tanks will have to be budgeted, requisitioned, and paid for by the using unit. This change will eliminate shortages, allow stockage of all sizes of tanks, and reduce order ship time. The transition will take effect in fiscal year 2002.

Collapsible tanks have stored fuel for warfighters successfully for several decades. The tanks have evolved into the single most effective tactical fuel storage system on the battlefield today. Their flexibility, limited transportation requirements, and low cost will continue to make fabric tanks an attractive bulk fuel storage alternative for many years. Recent initiatives and innovations have lessened the storage and service life difficulties and reduced storage-space dilemmas. The Army's continued quest for improved materials, lighter fabrics, and better manufacturing techniques ensures that its fuel storage systems will meet the needs of the combat soldier in the 21st century. ALOG

Major John A. Leggieri is a Congressional Fellow assigned to the office of Congressman John E. Sweeney in Washington, D.C. He is a graduate of the Mortuary Affairs Officer Basic Course, the Quartermaster Officer Advanced Course, the Army Logistics Management College's Logistics Executive Development Course, and the Army Command and General Staff College. He has a master's degree in education from the College of St. Rose in New York.

William Perdue is a logistics management specialist in the Directorate for Combat Developments-Quartermaster, Army Combined Arms Support Command, Fort Lee, Virginia. He has a bachelor's degree in engineering from Virginia Polytechnic Institute and State University and a master's degree in systems management from the University of Southern California.