FRP Double-wall Underground Fuel-tank

FRP DW storage tanks are produced by A&Z Company under OKET Group, A&Z Specializing in the design, production, sales, service and information integration of new composite material liquid storage system related business, the main products is FRP double-wall tanks for gas stations and Phoenix lining system.   Due to the high-tech, high quality, and good on-site services, the products have a leading share in the double-wall fuel storage tank market and have become a veritable industry leader. A&Z has 4 plants in HeiBei, SiChuan, XinJiang and JiangXi province of China. With strong production and manufacturing capabilities, it is currently the world's leading DW manufacturer.




A&Z's advanced 3DFF® double-wall tank technology is exclusively introduced from ZCL Canada, which is the world's largest manufacturer of FRP composite storage tanks.  A&Z is the first Chinese company to obtain UL certification for FRP double-wall tanks.

Origin of technology: ZCL, a Showcor company with a long history of over 40 years of product design and manufacturing, is a leading global designer and manufacturer of underground and aboveground storage tanks with 12 direct manufacturing companies and several licensed manufacturers around the world. In North America, ZCL has two plants in Canada, with nearly 90% of all underground tanks in Canada using ZCL branded 3DFF® double tanks, and four plants in the US, with over 50% of all underground tanks in the US using Xerxes branded 3DFF®double tanks. The market share in the whole North America is over 60%. International famous oil marketing companies such as Shell, BP, ExxonMobil, Dardor, etc. are all customers of 3DFF® double-wall tanks.

【Market share】No. 1 Leader supplier in the market of China


FRP DW Storage Tanks, Product Features and Benefits


(1) Corrosion Resistance and Fuel Compatibility

●External corrosion protection will always be a concern, but, with the widely use of ethanol-blended gasoline (E10, E15, E85), biodiesel fuels and ultra-low sulfur diesel (ULSD), the focus has shifted to internal corrosion protection. These new biofuels are creating increasing incidents of aggressive microbial-induced corrosion (MIC) of metal components in fueling systems. Fiberglass tanks are not affected to internal corrosion caused by MIC. Neither do they rust externally due to corrosive soil environments.

●In addition to creating corrosive conditions in tanks, new ethanol-blended fuels today also raise questions regarding compatibility of the stored fuel with tank materials. OKet double-wall fiberglass tanks are not only warranted for the full range of ethanol-blended gasoline, they are also UL-tested and UL-listed as compatible with 0-100 percent ethanol storage. This is a very clear difference from steel storage tanks.


(2) Structurally strong

●Integral Rib – Ribs are an important design element of any fiberglass underground tanks. Therefore, the rib form and how it connected to the tank, or tank itself, is an important consideration for designers and customers as they compare products. In our design, with its consistent, high-profile rib structure, ribs are connected directly to the tank shell – not as a secondary step in the process. This increases the overall strength of the tank and results in a structurally superior product.

●Parabeam® 3D Construction – As part of our history of continuous improvement, ZCL and A&Z introduced Parabeam, an unique and patented three-dimensional glass fabric, into its underground tank design. Parabeam enhances overall structural integrity by creating a bond between the primary and secondary tank walls, while providing a free-flowing interstitial space for monitoring.


(3) Buried directly under the lanes

Buried directly under the lanes due to integrally Constructed Ribs with ultra strong and robust.


(4) Full tank monitoring and Compatible with a variety of leak monitoring methods

A&Z's FRP DW Tanks are compatible with a variety of leak monitoring methods and sensors, including liquid media leak detection sensors, or pressure or vacuum sensors, or wall-to-wall sensors. 

●Hydrostatic monitoring system (liquid media leak detection ) is an active leak detection system, the interstitial space and a connected reservoir is full of salty water, then Hydrostatic monitoring system can identify the leakage on outer shell or inner shell.

●Pressure or vacuum, Using the annular space formed by the double-layer tank wall gap, we inflate it to form positive pressure, or pump it to form negative pressure. Operates through the vent and monitoring holes. Leak monitoring is based on pressure changes over a certain period of time.


(5) Easy to install

●Pre-cast Concrete Tank Anchors

●Prevent uplift at full flood conditions

●Buried directly under the lanes due to integrally Constructed Ribs with ultra strong and robust

●Lightweight, easy to install, safe and convenient


(6) Maintenance-Free and warranty 30 years with UL certificate

●Many manufacturers of steel tanks have reduced their warranty from 30 years to 10 years, and have emphasized that requires on going maintenance and removal of water bottoms as a condition of warranty coverage. The presence of water in the bottom of fuel tanks is a common condition. Maintenance to frequently remove it can be expensive over both the short-term and long-term life of a tank. A&Z offers a 30-year warranty with no limiting condition regarding water-bottom monitoring and removal.

●Tank Design Code: UL1316. A&Z has passed the strict UL certification, each FRP DW tank produced has a unique certification label issued by UL, which is the same as the production number, traceable to all information on each tank through the UL number. UL certification need to carry out corresponding production management and file management in accordance with UL specifications. A&Z's UL certification system ensures product traceability to true and accurate information. An example of UL Lable is shown below: