They determine what kind of tank every liter of fuel you buy today comes out of.
1. It Started with “Leaking Steel Tanks”
Twenty years ago, most gas stations in China had single-wall steel tanks buried underground. Such tanks are simple and cheap, but have an unavoidable drawback: steel plates buried in damp soil for a long time suffer electrochemical corrosion, and after more than ten years of service they begin to develop pinholes and leaks. Once leaking, gasoline and diesel spread silently through groundwater, contaminating soil and drinking water sources – often discovered only years later.
The US learned this lesson as early as the 1970s.
In 1984 the US EPA (Environmental Protection Agency) designated underground storage tanks (USTs) as a priority pollution source and issued a series of regulations requiring “double-walled” tanks.
Against this background, UL (Underwriters Laboratories) developed two standards along two technical routes – UL 1316 and UL 1746 – which today are the industry-recognized product certification systems for replacing traditional single-wall steel tanks.
China’s tank replacement story begins in 2014–2015.
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From 2014, Sinopec and PetroChina began pilot tenders for SF (steel-fiberglass) double-wall tanks in some provinces as part of “green gas station” upgrade projects.
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On 16 April 2015, the State Council issued the Action Plan for Water Pollution Prevention and Control (the “Ten Water Measures”), explicitly requiring that “underground fuel tanks at gas stations be replaced with double-wall tanks or have anti-seepage pits installed by the end of 2017”.
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2015–2017 saw a nationwide peak in tank replacement. Sinopec, PetroChina, CNOOC and most private gas stations replaced single-wall steel tanks with SF double-wall tanks or FF (fiberglass-fiberglass) double-wall tanks within three years.
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By around 2018, the vast majority of buried fuel tanks in mainland China had completed this round of replacement.
And the core product certification standards for this “underground revolution” covering 100,000 gas stations were precisely UL 1316 and UL 1746.
2. UL 1316: The Rulebook for Fiberglass Tanks
Full title and positioning
UL 1316, Standard for Fibre Reinforced Underground Tanks for Flammable and Combustible Liquids, was first published in July 1983. It covers tanks made entirely of FRP (fiber-reinforced plastic, commonly called “fiberglass”).
In a nutshell: if both the inner and outer walls of a tank are fiberglass, UL 1316 applies – this is what China calls an FF double-wall tank.
The latest version is the 3rd edition (2018), reaffirmed in 2024 as ANSI/CAN/UL/ULC 1316,
a national standard jointly recognized by the US (ANSI, American National Standards Institute) and Canada (ULC, Underwriters Laboratories of Canada).
Core requirements
UL 1316 covers single-, double- and triple-wall fiberglass tanks. Typical tests include:
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Leakage Test – internal pressurization to check for leaks
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External Pressure Test (buckling test) – simulating soil and groundwater pressure to verify the tank will not buckle
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Lift Lug Test – verifying the pull-out strength of lifting points
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Fuel Compatibility Test – strength retention of tank materials after long-term immersion in E0–E100 (0–100% ethanol gasoline) and B0–B100 (0–100% biodiesel)
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Fuel immersion is the “toughest” part of the standard. Tanks must be immersed in test fuels for months and still retain sufficient mechanical properties afterwards – meaning the resin system must be carefully selected. Ordinary unsaturated polyester resin (UPR) will not pass; vinyl ester resin or specially modified terephthalic polyester resin is usually required.
3. UL 1746: The Rulebook for “Steel Tank + External Protective Layer”
Full title and positioning
UL 1746, Standard for External Corrosion Protection Systems for Steel Underground Storage Tanks, was first published in November 1989; the current mainstream version is the 3rd edition of 2007 (revised 2014).
Its logic is completely different – the inner tank is steel, with an additional anti-corrosion outer shell. So UL 1746 does not regulate the steel inner tank itself (that is UL 58’s job), only “the outer layer”. What China calls an SF double-wall tank corresponds to the UL 1746 system.
The four Parts of the standard
UL 1746 divides external corrosion protection into four technical routes:
Part III is overwhelmingly mainstream in China – a Q235-B steel inner tank, a spray-formed FRP outer layer, and an interstitial space of 0.1–3.5 mm between them for installing a leak detector, enabling 24-hour real-time monitoring.
Core tests
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Indentation Test – verifying the outer FRP layer’s resistance to mechanical damage
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Holiday Test – using high voltage to detect pinhole defects in the fiberglass layer, a key test every tank must pass before leaving the factory
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Solvent Immersion – long-term immersion in more than 20 solvents to verify strength retention
4. UL 1316 vs. UL 1746 at a Glance
5. Aligning Chinese and International Standards
The main national standard in use in China is GB/T 30040 Steel Double-Wall Fuel Storage Tanks, which drew heavily on UL 1746; GB/T 40909 Non-Metallic Double-Wall Underground Storage Tanks is benchmarked against UL 1316.
But to enter the centralized procurement systems of Sinopec and PetroChina, or to supply foreign brands (Shell, BP, TotalEnergies, etc.), a UL Listing remains the de facto “hard currency”. Corporate standards such as Sinopec’s Technical Requirements for SF Buried Double-Wall Fuel Tanks (2017 revision) correspond almost one-to-one with UL 1746 in tank structure, resin system and test items.
6. EVERBIZ: Twelve Years Supporting Double-Wall Tank Certification in China
We have specialized in double-wall fuel tank certification services for more than ten years, through the full cycle from Sinopec’s earliest SF tank pilot tenders in 2014 and the nationwide replacement peak in 2017 to today’s ongoing certification maintenance for existing tanks.
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Full support for UL 1316 / UL 1746 Listing – from resin system selection, process optimization and rehearsal of key tests to on-site factory audits by UL engineers (Initial Production Inspection) and final certification
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Combined testing to related standards – simultaneous certification to UL 58, UL 971, ULC-S603.1 and other related standards
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Benchmarking against Chinese standards – gap analysis between GB/T 30040, GB/T 40909 and UL standards, helping clients meet domestic and international markets with one production line
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Factory re-audits and annual maintenance (Follow-Up Service, FUS)
To date, EVERBIZ has completed more than 30 certification projects for SF and FF tanks, with clients including major Chinese manufacturers of fiberglass and steel double-wall tanks. We know the “tricks” for passing every test and have hit the “pitfalls” of every process route – experience you won’t find in books or on application forms, but which decides whether a certification project is completed on time or goes through three years of repeated corrections.
EVERBIZ Certification Services (Shanghai) Co., Ltd. (EVERBIZ) is a professional compliance service platform for testing, certification, consulting and training of medical products, dedicated to helping leading medical R&D companies at home and abroad improve their compliance capabilities and competitiveness. The company has offices and branches in Shanghai (China), Hong Kong, Munich (Germany), Salzburg (Austria), Thailand, Vietnam, Singapore and Malaysia, covering nearly 25 industries of compliance products (such as medical devices, new energy, household appliances, lighting, tools, laboratory instruments, machinery, in vitro diagnostics, wireless products and reagents).
Shanghai: Room 909, Building 1, Lane 111 Luxiang Road, Baoshan District, Shanghai, China; Germany: Landsberger Str. 155, 80687 München, Germany
Austria: Innsbrucker Bundesstraße 136/3, 5020 Salzburg, Austria
Hong Kong: Room A1, 11/F Winner Building, 36 Man Yue Street, Hung Hom, Kowloon, Hong Kong
Thailand: No. 850 Soi Lat Krabang 30/5, Lat Krabang Subdistrict, Bangkok 10520
