Generator Diesel Fuel Tank: Types, Sizing, and Installation Guide

Introduction

A generator diesel fuel tank is an essential component in standby, prime, or continuous power systems, ensuring a reliable and uninterrupted fuel supply to diesel-powered generators. From hospitals and data centers to construction sites and remote facilities, selecting the right fuel tank is crucial for performance, safety, and compliance.

This guide explores types of generator diesel fuel tanks, sizing calculations, installation considerations, and maintenance tips to help you make an informed decision.

1. What Is a Generator Diesel Fuel Tank?

A generator diesel fuel tank is a specially designed container that stores diesel fuel for generators. These tanks can be integrated into the generator set (base tanks) or installed as external storage tanks to provide extended run time.

They are engineered to:

• Maintain fuel quality

• Prevent contamination

• Meet fire, environmental, and building code requirements

2. Types of Generator Diesel Fuel Tanks

2.1 Base-Mounted Fuel Tanks

• Installed directly beneath the generator set

• Typically provide 8 to 24 hours of run time

• Compact design, ideal for space-limited installations

2.2 Sub-Base Fuel Tanks

• Positioned between the generator frame and the skid

• Larger capacity than standard base tanks

• Suitable for medium to large commercial applications

2.3 Above-Ground Day Tanks

• Store fuel close to the generator for daily operations

• Paired with bulk storage tanks for automatic refilling

• Equipped with level sensors and alarms

2.4 Underground Bulk Fuel Tanks

• Large-capacity storage for multiple generators or extended run time

• Minimize above-ground space usage

• Require specialized installation and leak monitoring systems

3. Sizing a Generator Diesel Fuel Tank

Correct sizing depends on:

• Generator load (kW)

• Fuel consumption rate (liters or gallons per hour)

• Required run time before refueling

• Reserve margin for emergencies

Formula:
Tank Capacity = (Fuel Consumption Rate × Desired Run Time) + Safety Margin

Example:
A 200 kW generator consuming 12 GPH for 24 hours:
(12 × 24) + 10% safety margin = ~317 gallons

4. Material Options

5. Regulatory Compliance

When installing a generator diesel fuel tank, compliance with the following is essential:

• NFPA 30: Flammable and Combustible Liquids Code

• NFPA 110: Emergency and Standby Power Systems

• EPA SPCC (Spill Prevention, Control, and Countermeasure) regulations

• Local fire marshal and building code requirements

• UL 142 or UL 2085 certification for above-ground tanks

6. Installation Best Practices

• Install on a level, stable surface

• Ensure adequate ventilation for heat dissipation

• Provide secondary containment for spill prevention

• Use flexible fuel lines to reduce vibration stress

• Position tanks away from ignition sources

7. Maintenance Tips

• Inspect for leaks, corrosion, or loose fittings regularly

• Test fuel quality every 3–6 months

• Keep tank at ≥80% capacity to reduce condensation

• Clean sediment buildup and replace filters as needed

• Maintain an updated maintenance log for compliance audits

Conclusion

A generator diesel fuel tank is more than just a storage vessel—it’s a critical link in ensuring reliable backup or prime power. By choosing the right type, sizing it correctly, complying with regulations, and following maintenance best practices, you can maximize generator efficiency, reduce downtime, and ensure operational safety.