Generator Fuel Tanks — Base, Belly & Day Tanks
A generator fuel tank is the dedicated diesel storage that keeps a standby generator running through a power outage. Neftgen designs and manufactures generator fuel tanks in every configuration a project needs — sub-base (belly) tanks that sit under the genset, day tanks that feed the engine, and bulk storage tanks that supply the whole system.
- Sub-base / belly tanks (integral generator base tank)
- Generator day tanks (engine-mounted supply)
- Bulk diesel storage tanks
- Fuel-polishing and transfer ready
Every generator fuel tank is built to order — sized to the generator rating and the required autonomy, in single-wall or double-wall (self-bunded) form, for indoor plant rooms or outdoor installation. Tanks ship with the fittings, gauges and alarms needed to connect straight to the generator fuel system.
Advantages of Neftgen Generator Fuel Tanks
Neftgen generator fuel tanks are engineered for mission-critical standby power, where a fuel-supply failure means a failed generator start. Unlike a generic storage tank, our tanks are purpose-built for diesel generator duty:
- Double-wall (self-bunded) design — no civil bund required
- Interstitial leak detection for early warning
- Steel construction to EN 12285-2 / UL-142
- Level transmitters with high-high and low-low alarms
- BMS-ready volt-free contacts and Modbus signals
- Sized to the exact generator kVA and autonomy
- Free Maintenance
Each tank is manufactured to the project’s storage conditions — indoor or outdoor, aboveground, single or double wall — and to the fuel handled (diesel, gas oil, MGO or light fuel oil).
Because the tank, transfer set and instrumentation are engineered together, the complete generator fuel system starts reliably and runs for the full specified autonomy.
- Any capacity — day tanks to bulk storage
- Full-drainage, easy-clean tank design
- Superior sealing and quick site installation
- Rated for indoor plant rooms or outdoor sites
- Lower installed cost than a bunded concrete pit
- Fast and easy installation
Diesel & Fuel-Oil Storage for Standby Generators
Neftgen supplies base (belly) tanks, day tanks and bulk diesel storage tanks for standby and prime generators. Diesel, gas oil, MGO and light fuel oil are stored safely in single- or double-wall steel tanks, sized from the generator’s fuel consumption and the required back-up runtime — from a few hours for commercial buildings to 24–96 hours for Tier IV data centers.
Product Benefits
- Engineered specifically for diesel generator duty
- Double-wall option with interstitial leak detection
- Corrosion-protected steel for a long service life
- Leak-tight, pressure-tested construction
- Delivered with gauges, alarms and fittings ready to connect
- It is possible to produce designs of complex structures
Tank Capacities
Standard generator day tanks run from 200 to 5,000 litres; bulk and base tanks are built to any capacity the project requires. Net volume is sized as fuel consumption (L/h) × required autonomy (h), with a design margin for expansion and fill setpoint. Send us the generator kVA and the required back-up hours and we will size the tank for you.
Available Tank Configurations
- Single Wall or Double Wall (self-bunded)
- Indoor or Outdoor installation
- Horizontal, Vertical or sub-base
Data Center & Critical-Facility Applications
Neftgen generator fuel tanks protect the standby power that keeps critical facilities online — data centers, hospitals, airports, ports, telecom sites and industrial plants. Every design follows the availability targets the facility is built to.
Tanks are installed indoors in generator plant rooms or outdoors alongside the genset, as single- or double-wall units matched to the fuel type and site conditions. Double-wall (self-bunded) tanks need no concrete bund and cut installation cost and footprint.
Steel construction with corrosion protection to ISO 12944 (C4 / C5-M) gives a long service life indoors or outdoors. Interstitial leak detection on double-wall tanks warns of any breach before fuel can reach the environment.
Neftgen’s engineering team sizes each tank, transfer set and control system to the generator and the applicable standards (EN 12285-2, UL-142, NFPA 30 and NFPA 110). Contact us with your project details for a complete design.
Single-Wall & Double-Wall Steel Fuel Tanks
Steel Tank Construction
Steel Shell & Welding
Tanks are fabricated from certified structural steel plate with fully welded, pressure-tested seams. Wall thickness is selected for the tank capacity and installation, and every tank is leak-tested before dispatch.
Corrosion Protection & Coating
Internal and external surfaces are shot-blasted and coated to ISO 12944 C4 or C5-M, matched to indoor or outdoor exposure, for decades of corrosion-free service. Warning signs and labelling are applied as required.
Level Instrumentation & Gauging
Each tank carries a level transmitter plus high-high and low-low level switches — the high-high alarm warns of overfill and the low-low alarm gives the generator a pre-alarm and load-shed warning. A mechanical contents gauge is fitted for local reading.
Leak Detection
On double-wall tanks the interstitial space between the two shells is continuously monitored, so any leak in the primary containment is detected early — before fuel can escape and before the secondary containment is compromised.
Painting & Marking
The outer surface of the tank is painted to the project requirements, and any requested warning signs and labelling are applied. The static and dynamic calculations required for the tank are performed by the Neftgen design team.
Double-Wall (Self-Bunded) Construction
Because diesel is valuable and a spill can contaminate the environment, generator fuel tanks for critical sites are built double-wall, with a leak-detection system between the two walls to prevent pollution and the heavy cost of any clean-up.
A double-wall (self-bunded) tank is built as two steel shells with a monitored gap between them. The inner shell holds the fuel; the outer shell provides secondary containment, so no separate concrete bund is needed on site.
Accessories & Equipment
Generator Fuel Tanks — FAQ
Common questions about generator fuel tanks — faq from Neftgen.