Underground Fuel Tank Installation Requirements for Gas Stations: Complete UST Guide
News 2026年 8月 12日 33
Introduction
The underground fuel tank is one of the most important components of a modern gas station.
It is the foundation of the entire fuel storage and distribution system, connecting multiple critical components including:
- Submersible oil pump
- Underground fuel piping
- Vapor recovery systems
- Fuel level monitoring systems
- Leak detection systems
- Fuel dispensers
A properly designed underground fuel storage system helps improve:
- Fire safety
- Environmental protection
- Fuel supply reliability
- Equipment service life
- Daily operation efficiency
During gas station construction, the fuel tank installation process requires careful consideration of:
- Tank capacity
- Installation location
- Safety distance
- Anti-corrosion protection
- Leakage prevention
- Pump selection
- Piping layout
In China, underground fuel tank installation mainly follows GB 50156-2021 Technical Standard for Automobile Gas Filling Stations, CNG/LNG Stations and Hydrogen Refueling Stations.
However, different countries have different regulations. International projects should always follow local fire protection, environmental, and construction requirements.
This article explains the key points of underground fuel tank installation from an engineering perspective.
1.What Is an Underground Fuel Tank?
An underground fuel tank is a horizontal storage tank installed below ground level to store gasoline, diesel, and other petroleum products.
Unlike aboveground tanks, underground tanks provide several advantages:
- Save valuable station space
- Reduce exposure to external fire sources
- Reduce vehicle collision risks
- Improve overall station appearance
- Provide safer fuel storage conditions
A typical underground fuel storage system includes:
Underground Fuel Tank
↓
Tank Manhole
↓
Submersible oil pump
↓
Fuel Pipeline
↓
Fuel Dispenser
↓
Fuel Nozzle
The underground tank is not an independent component. It works as the core storage unit of the entire gas station fuel delivery system.
2.Common Underground Fuel Tank Capacities
The required fuel tank capacity depends on:
- Daily fuel sales
- Delivery frequency
- Station size
- Local regulations
- Available installation space
Common underground fuel tank capacities include:
| Tank Capacity | Typical Application |
|---|
| 10–20 m³ | Small fuel stations |
| 20–40 m³ | Standard urban stations |
| 40–60 m³ | Medium and large stations |
| 60 m³+ | Large commercial stations |
Common tank sizes:
- 20,000 liters
- 30,000 liters
- 40,000 liters
- 50,000 liters
- 60,000 liters
Example:
A medium-sized gas station may use:
| Fuel Type | Tank Configuration |
|---|
| Gasoline | 2 × 40 m³ |
| Diesel | 1 × 40 m³ |
Total storage capacity:
120,000 liters
The final tank configuration should be calculated according to actual fuel demand.
3. Types of Underground Fuel Tanks
3.1 Single-Wall Underground Fuel Tank
A single-wall tank uses one tank shell to contain fuel.
Advantages:
- Simple structure
- Lower initial investment
- Mature manufacturing technology
However, because there is only one containment layer, leakage monitoring becomes more important.
3.2 Double-Wall Underground Fuel Tank
A double-wall underground fuel tank consists of:
- Inner tank
- Outer protective layer
- Interstitial monitoring space
Structure:
Fuel Storage
↓
Inner Tank
↓
Leak Monitoring Space
↓
Outer Tank
Main advantages:
1. Better Leakage Protection
If the inner tank develops a leak, the outer layer provides secondary protection.
2. Environmental Protection
Reduces the risk of fuel entering soil and groundwater.
3. Easier Monitoring
The space between the two walls can be connected with leak detection equipment.
Modern gas stations increasingly use double-wall tanks because of stricter environmental requirements.
4. Underground Fuel Tank Installation Requirements
4.1 Underground Installation
For automobile gas stations, gasoline and diesel storage tanks are generally installed underground.
According to GB50156-2021, buried horizontal fuel tanks are considered a safer installation method because underground installation can reduce fire exposure and improve accident control.
The tank installation design should consider:
- Soil conditions
- Groundwater level
- Traffic load
- Maintenance access
- Surrounding structures
4.2 Tank Burial Depth Requirements
One of the most important installation parameters is the distance between the tank top and ground surface.
According to GB50156-2021:
Installation under non-traffic areas
Minimum cover thickness:
≥ 0.5 meters
Meaning:
The top of the tank should have at least 500 mm soil protection.
Installation under vehicle traffic areas
Tank top distance below concrete pavement:
≥ 0.9 meters
This provides protection against vehicle loads and allows sufficient installation space for tank accessories.
Backfill Requirements
Around underground steel tanks:
Backfill material should be:
Minimum thickness:
≥ 0.3 meters
The purpose is to prevent:
- Tank deformation
- Coating damage
- External corrosion
4.3 Anti-Floating Protection
In areas with:
- High groundwater levels
- Heavy rainfall
- Flood risks
underground tanks may experience upward buoyancy when empty.
If the tank moves upward, it may damage:
- Fuel pipelines
- Electrical connections
- Tank fittings
Therefore, anti-floating measures may be required.
Common solutions include:
- Concrete foundation
- Anchor straps
- Anti-floating structures
GB50156-2021 requires protection measures when underground tanks may float due to groundwater or rainwater.
5. Underground Fuel Tank Manhole System
The tank manhole is an important connection area installed above the underground fuel tank.
It provides access for:
- Submersible oil pump installation
- Fuel pipe connection
- Vapor recovery connection
- Liquid level monitoring
- Maintenance inspection
A typical tank manhole contains:
Tank Manhole
├── Submersible oil pump
├── Product Outlet
├── Vapor Recovery Connection
├── Level Sensor
└── Monitoring Equipment
It is important to understand:
Tank Manhole ≠ Fuel Dispenser Island
They have completely different functions.
Tank Manhole
Location:
Above the underground tank
Purpose:
Equipment installation and maintenance
Fuel Dispenser Island
Location:
Vehicle refueling area
Purpose:
Fuel dispensing operation
6. Submersible oil pump Connection
The underground fuel tank works together with a Submersible oil pump to deliver fuel to dispensers.
The fuel flow process:
Fuel Tank
↓
Submersible oil pump
↓
Underground Pipe
↓
Fuel Dispenser
↓
Fuel Nozzle
Common Submersible oil pump parameters:
| Parameter | Typical Range |
|---|
| Voltage | 220V / 380V |
| Power | 0.75kW–2.2kW |
| Flow Rate | 40–120 L/min |
| Installation Depth | 3–6 meters |
Pump selection depends on:
- Number of dispensers
- Fuel demand
- Pipe length
- Pressure loss
- Simultaneous fueling requirements
A larger pump is not always better.
The correct pump should match the complete fuel delivery system.
7. Fuel Tank Safety Monitoring System
Modern underground fuel tanks usually include monitoring systems.
Important functions include:
Fuel Level Monitoring
Measures:
- Current fuel volume
- Fuel consumption
- Abnormal changes
Leak Detection
Detects:
- Tank leakage
- Pipe leakage
- Abnormal fuel loss
According to GB50156-2021, stations equipped with vapor recovery systems should have fuel tank liquid level monitoring systems with high-level alarm functions.
For single-wall tanks, leakage detection capability is also required, with leakage detection resolution not greater than:
0.8 L/h
8. Overfill Prevention During Fuel Delivery
During tanker unloading, preventing fuel overflow is critical.
GB50156-2021 requires fuel tanks to have overfill prevention measures.
The typical control points are:
90% Tank Capacity
High-level alarm activated.
95% Tank Capacity
Automatic stopping of fuel filling.
Example:
For a:
50,000-liter fuel tank
Alarm point:
50,000 × 90%
= 45,000 liters
Automatic stop:
50,000 × 95%
= 47,500 liters
This helps prevent fuel overflow during unloading operations.
9. Underground Fuel Tank Anti-Corrosion Protection
Because underground tanks are exposed to:
- Soil moisture
- Groundwater
- Chemical conditions
corrosion protection is essential.
Common protection methods include:
- Anti-corrosion coating
- Corrosion-resistant materials
- Cathodic protection
- Proper installation procedures
For steel tanks, GB50156-2021 requires corrosion protection measures for external surfaces in contact with soil.
10. Complete Underground Fuel Storage System
A complete underground fuel storage system includes:
| Component | Function |
|---|
| Underground Fuel Tank | Stores fuel |
| Tank Manhole | Provides equipment access |
| Submersible oil pump | Transfers fuel |
| Fuel Pipeline | Delivers fuel |
| Vapor Recovery Pipe | Handles fuel vapor |
| Vent Pipe | Controls tank pressure |
| Leak Detection System | Detects leakage |
| Level Monitoring System | Measures fuel quantity |
| Emergency Shutdown System | Stops fuel supply |
All components must work together to achieve safe and efficient fuel delivery.
11. Common Installation Problems
Problem 1: Incorrect Tank Size Selection
Result:
- Insufficient storage capacity
- Increased delivery frequency
Solution:
Calculate based on actual fuel demand.
Problem 2: Poor Tank Location Planning
Result:
- Difficult maintenance
- Safety approval problems
Solution:
Consider the complete station layout before installation.
Problem 3: Incorrect Pump Selection
Result:
- Low fuel flow
- Unstable dispensing performance
Solution:
Match pump capacity with dispenser demand.
Problem 4: Ignoring Leak Detection
Result:
- Difficult leakage identification
- Environmental risks
Solution:
Install appropriate monitoring systems.
12. Underground Fuel Tank Installation Checklist
Before installation, confirm:
☐ Tank capacity
☐ Fuel type
☐ Tank structure
☐ Installation location
☐ Safety distance
☐ Burial depth
☐ Anti-floating measures
☐ Tank manhole configuration
☐ Submersible oil pump selection
☐ Fuel piping design
☐ Vapor recovery connection
☐ Leak detection system
☐ Corrosion protection
☐ Emergency shutdown system
Conclusion
The underground fuel tank is the foundation of every modern gas station fuel system.
A reliable underground storage solution requires more than selecting a tank. It requires correct integration between:
- Underground fuel tank
- Tank manhole
- Submersible oil pump
- Fuel piping
- Vapor recovery system
- Leak detection system
- Safety monitoring equipment
GB50156-2021 provides important technical guidance for gas station construction in China, while international projects must also follow local regulations.
For gas station owners and contractors, choosing an experienced equipment supplier can reduce installation risks and improve long-term system reliability.
A complete gas station solution is not only about supplying individual components — it is about ensuring that every part works together as one safe and efficient fuel delivery system.
