EN 45545-7: Fire Safety for Flammable Liquid & Gas Installations (Fuel, LPG, Hydraulics)

EN 45545-7 is the specific part of the European Fire Safety Standard dedicated to Flammable Liquid and Gas Installations. While Part 2 focuses on interior materials, Part 7 focuses on the fuel itself. It establishes the mandatory design rules for installations containing Diesel, LPG (Liquefied Petroleum Gas), CNG, or Flammable Hydraulic Fluids.

The primary engineering goal is “Segregation”: ensuring that leaked fuel never comes into contact with an ignition source (like a hot exhaust pipe or electrical spark) and preventing the accumulation of explosive vapors in confined spaces.

1. Core Principles: Leakage and Containment

Pipelines carrying flammable liquids are the arteries of a combustion train. EN 45545-7 mandates strict construction protocols to prevent catastrophic failures:

• Routing: Fuel lines must not pass through passenger areas or driver cabs. If they must pass through high-risk zones, they must be “Double-Walled” (pipe-in-pipe).
• Draining: Any leakage must be gravity-fed to the ground (trackbed) without touching hot surfaces like bogies or braking resistors.
• Shut-off Valves: Automatic isolation valves must be installed directly at the tank outlet. In case of a crash or fire detection, these valves must close instantly to stop the fuel supply.

2. Requirements by Installation Type

Different fluids pose different risks. Diesel is heavy and pools; LPG is volatile and expands. The standard tailors its requirements accordingly:

3. LPG Safety (Dining Cars)

For trains equipped with gas-powered kitchens, EN 45545-7 imposes rigorous ventilation rules. Since LPG is heavier than air, it sinks. Therefore, storage compartments must have low-level ventilation openings to prevent gas pockets from forming at the floor level, creating a potential bomb.

4. Pressure and Tightness Testing

Before entering service, all flammable liquid installations must undergo Hydrostatic Pressure Testing (typically 1.5x working pressure) to verify joint integrity. Furthermore, pipework must be flexibly mounted to withstand the continuous vibration of the railway environment without fatigue cracking.