TRFLEX® -REFOR Flexible storage berm with reinforced tubular structure


Storage tank for oil-filled electrical transformers

The standard TRFLEX® REFOR range of ultra-strong flexible retention tanks has been designed for long-term storage of your oil-filled electrical transformers up to 200,000 litres under conditions of high mechanical stress. With its structure of galvanised brackets reinforced by a tubular metal structure, our unique process of double ultrasonic welding of ultra-reinforced 1670 DTEX two-way internal weave tarpaulin and double PVC induction with UV protection at over 1450 g/m² has made TRFLEX REFOR one of the leading references on the European market.




How can you create a simple, fast, and effective temporary storage area for short to medium periods for your oil-filled power transformers?  SANERGRID’s TRFLEX-REFOR range is the answer to this problem, thanks to the design of its flexible retention bins and their very high technical characteristics, capable of withstanding lorries, cranes, shifting beams and other mechanical stresses associated with handling power transformers.


The TRFLEX REFOR range is made up of 3 distinctive elements:


Extensive feedback on TRFLEX technology

SANERGRID’s TRFLEX REFOR flexible tarpaulin for transformer storage is the direct result of extensive experience in dealing with oil spills and managing hydrocarbon pollution on the high seas. SANERGRID has reengineered this ultra-strong tarpaulin, which is mechanically and chemically resistant and treated against ultraviolet rays, to adapt perfectly to the constraints associated with the storage of electrical transformers.

  • Reinforced PVC tarpaulin with double internal weft in high-tenacity 1670 DTEX polyester for improved mechanical resistance to tearing, perforation, cutting and tearing.
  • Tarpaulin covered with a double-sided vinyl (PVC) resistant to hydrocarbons and ultraviolet rays with a total weight of over 1450g/m² for enhanced resistance to abrasion, sunlight, and hydrocarbons.
  • Unlike traditional tarpaulins on the market, the double-sided induction process provides double retention security: in the event of a non-through cut on one side, the opposite wall continues to act as retention.
  • All our welds are made using a unique double-sided ultrasonic welding process, which makes the welds extremely robust and guarantees that the TRFLEX flexible containers® are completely watertight.


Structure to hold the tarpaulin in place with brackets 100 mm to 500 mm high

  • TRFLEX REFOR tarpaulin sleeves are welded all around the trough in our factories. These sleeves can be fitted with feet to support the vertical walls. For the TRFLEX REFOR range, this angled metal structure is made of hot-dip galvanised steel as standard. Aluminium or stainless steel can be supplied on request.
  • All our TRFLEX range of retaining structures have been sized and tested by our factory to maintain their retention integrity up to 120% of their communicated nominal volume.
  • The TRFLEX-REFOR range has a double tubular structure in hot-dip galvanised steel, providing high mechanical strength. For more corrosive conditions, a 316L stainless steel passage is available.


Protection against abrasion, puncturing and cuts

The TRFLEX ECO, ECO+ and REFOR ranges are supplied with 2 layers of GEOGRID™ protective geotextile, a special anti-abrasion material made of polypropylene reinforced with polyester.

  • One covering 110% of the surface of the planter, to be placed under the planter to protect it from uneven ground and, above all, to make it easier to fit the tarpaulin without slipping.
  • The other 50% of the surface of the tray to be placed in the tray, to protect against scratches and punctures when the equipment is installed.
  • Finally, for simple on-site repair, all our TRFLEX® ECO, ECO+, MAINTENANCE, ECO-TRUCK™ and REFOR tanks come with a tarpaulin repair kit with patch and glue in the event of punctures or tears of less than 10 cm.


Please note: all our low rainwater drainage points are between 30 and 50 mm from the ground by default. It is normal to have a residual level of water in the tanks. We recommend raising your water-sensitive equipment several centimetres above ground level using planks, wooden wedges, or concrete joists. For specific low point requirements, please contact us.

Accessories and options

The TRFLEX range also includes several accessories to suit your needs:

  • Anti-hydrocarbon cartridges Kit PETRO PIT PVC and KIT PIPE PVC, when the tank is used outdoors to allow continuous drainage of rainwater.
  • Additional protective geotextile layers GEOGRID™
  • Steel load distribution plates.
  • Transport and storage bag.
  • Stackable hard cases for secure storage and transport of your TRFLEX products.
  • ECOROLL™ anti-puncture treads for heavy machinery.
  • Prefabricated concrete beams to raise your machine by a few centimetres if the equipment cannot withstand exposure to water
  • Ballast bags for ballasting bins in windy areas or if there is a significant delay between the deployment of the bin and the installation of the equipment to be stored in the bin.
  • CAMFLEX™ communications hoses to enable several TRFLEX® to communicate with each other


We have a range of different references depending on the constraints to which your flexible retention system is exposed and your temporary storage requirements:

  • For temporary retention with lower mechanical stresses, short durations, and frequent reuse with a lighter tarpaulin: TRFLEX-ECO™ range.
  • For temporary retention with higher mechanical stress, short to medium durations and frequent reuse with a heavier tarpaulin: TRFLEX-ECO+™ range.
  • For storing your HGVs and tankers or rolling heavy machinery in the bin with special bearing races: TRFLEX-TRUCK™ range
  • For the storage of machinery containing hydrocarbons with an anti-slip maintenance surface: TRFLEX-MAINTENANCE™ range.


For permanent or semi-permanent storage, we recommend the TRT and TRT MODULO ranges, as well as concrete pits fitted with our SKID PIPE, STORM BARRIER and PETRO BARRIER PUMP drainage systems.

Technical data

Additional information

Conditions of use

indoor, outside



Type of bin


Use and maintenance

Before installing the berm:

  • Make sure that the ground surface is smooth, flat, clean, and large enough to accommodate the flexible drip tray with the transformer, to avoid pinching and pressure points.
  • It is advisable to add at least one layer of geotextile before unfolding the tarpaulin (supplied as standard).
  • If the bins are stored outside, they must be emptied regularly, and not handled with water inside.


Installing the berm:

  • Unfold the flexible bund at the desired storage location onto the layer of geotextile supplied with the bund.
  • Place your equipment on the geotextile previously installed at the support points, or on the runways/load distribution plates to avoid punching.
  • Unfold the sides of the tray and insert the brackets into the welded sleeves around the edges.
  • Secure or weight the tray to the ground to prevent tearing and lifting during windy periods if you do not place the equipment in the tray within a few moments of placing the tray.



Regular visual inspection of the equipment should cover the following points:

  • Tightness at wall penetrations, accessories and/or plugs correctly screwed in.
  • Integrity of the walls of the bin, no deformation or damage (knocks, impacts, cuts, tears, cracks, etc.).
  • Check that rainwater is flowing properly through the filters: if they are clogged, clean the pre-filters, or change the filters if they are saturated or have exceeded their recommended service life.
  • It is essential to carry out a visual inspection after each period of strong winds.
  • The frequency of these checks depends on the constraints of each site, depending on its degree of corrosion, dirtiness, presence of organic matter, etc.


Refer to the user manual for further details.

Failure to comply with good practice in use and failure to deal with anomalies and defects in the field are the responsibility of the owner of the equipment.

Additional information

Storage facilities for high-voltage substations in contact with polluting products must comply with the standards and laws in force.


The road transport structures used comply with the recommendations for the transport of dangerous goods, as set out in the ADR.


Regarding retention and the risk of soil pollution, our tanks comply with European standards:

  • NF C13-100 and NF C13-200, which prevent the risk of overcurrent and earthing problems. They protect people from direct or indirect contact with conductors, and electrical installations from the risks of fire, short circuits, and lightning.
  • NF EN 61936-1, relating to the design and installation of electrical installations, which requires a watertight retention tank representing 100% of the volume of oil used.


Rainwater drainage and hydrocarbon pollution:

Thanks to the SPI anti-hydrocarbon water filter system, the tank is empty of water most of the time and ready to receive hydrocarbons. In compliance with the French Water Act (decree 77-254), the water discharged from the tanks is not contaminated with more than 5 ppm of hydrocarbons, in accordance with standard EN 858-1 (“light liquid separation installations”).

SPI® filters are regularly tested in independent laboratories: please refer to the SPI® range.


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