Identify and isolate fuel systems in modes of transport

Control Measure Knowledge

This control measure relates to the fuel being used to power a mode of transport. Any fuel that is being carried as cargo should be dealt with as a hazardous material.

Due to the hazards presented by electrical systems and fuel in modes of transport, it is essential to:

  • Seek advice or assistance if appropriate, such as from:
    • Tactical adviser (TacAd)
    • Transport industry specialist
    • Hazard identification software
    • Responsible person
  • Identify the type of fuels used
  • Control ignition sources
  • Select appropriate firefighting media
  • Isolate power sources and fuel supplies; this may require activating emergency or fuel isolation switches
  • Locate fuel tanks and supply lines when stabilising and carrying out space creation activities
  • Control fuel leaks

If there is a risk of ignition, it may be appropriate to set up firefighting equipment around the scene of the incident. It may also be appropriate to apply foam blanketing.

For investigation purposes, it is important to document at the earliest opportunity any actions taken to isolate or control the fuel system.


For generic isolation of railways and electric powered rail vehicles refer to Transport – Establish proportionate control over the railway.

In the absence of third and fourth rails and overhead line equipment systems, rail vehicles will be self-powered, usually by diesel.

Diesel rail vehicles may operate independently of any electrical power supply being available to the rail track or overhead catenary.

Diesel rail vehicles may carry in excess of 8,000 litres of fuel, which can be isolated with emergency shut-off buttons located near to the fuel tanks, often under the carriage.

Steam engines are fuelled by coal, which means that isolating fuel can be easily achieved as this is normally fed manually. However, the steam will continue to be generated as the coal will burn for some time.


The location of fuel tanks vary depending on the type and model of road vehicle. Locations can include:

  • Under the floor of the boot
  • Within the boot
  • Behind the rear seat, within a rear wheel well
  • Under the vehicle, between the axles
  • Between the front seats

Fuel tanks may or may not be vented to the outside. They can be constructed of metal, plastic or Kevlar to prevent rupturing during a collision.

Most road vehicles use electric fuel pumps to transfer the fuel from the tank to the engine intake system. These fuel pumps can continue to supply fuel under pressure following a collision or during a fire. Some manufacturers include an emergency shut-off switch that interrupts the electrical supply to the pump in a collision.

Most road vehicles use two fuel lines to transfer fuel between the fuel tank and the engine. One line transfers the fuel from the fuel tank to the engine, while the other line is used to return unused fuel back to the tank. Hard fuel lines are commonly steel pipe, but may be made of aluminium. Due to the natural movement of vehicles, they have a flexible joint at the engine and tank.

Some road vehicles use fuel additives to increase horsepower from the engine. Additives can be a small amount of flammable liquid, referred to as an octane booster, which is added to the fuel tank.

There are also nitrous oxide systems (NOS) installed to induce nitrous oxide directly into an engine. A NOS has a cylinder containing pressurised liquid nitrous oxide, often located in the boot, which is connected to the engine with delivery hoses. Personnel need to approach NOS with caution as while most correctly installed systems can be isolated by isolating the battery or turning the cylinder off, some may not have this feature leading to an uncontrolled release.

Some vehicles may have additional fuel filler inlets for diesel exhaust fluid (DEF), which may be confused with an liquid petroleum gas (LPG) inlet. Personnel should familiarise themselves with the types of filler caps on road vehicles to assist with identifying the fuels used.

Road vehicles can be powered by alternative fuels. This includes electric, hybrid electric, hydrogen or LPG. For more information refer to Transport – Alternative fuel vehicles.


Fuel tanks are generally located at the rear of small and medium sized vessels, such as narrowboats and yachts, which are normally isolated by removing ignition keys and isolating batteries as fuel is normally delivered to the engine by an electrical pump. However, in large vessels there are requirements for fuel and lubricant tanks, which are spread all over the vessel’s structure.

There are various types and size of fuel and lubrication tanks in vessels, including:

  • Bunker tanks, also referred to as main fuel tanks
  • Settling tanks
  • Service tanks
  • Overflow tanks
  • Emergency generator diesel oil tank
  • Lubricating oil tanks

Isolation of these tanks can be difficult and complicated and therefore requires specialist advice and assistance.

For more information refer to Transport – Safe system of work: Non-fire incidents involving vessels.


For information relating to aircraft fuel systems refer to Transport – Safe system of work: Aircraft incidents.

Strategic Actions

Tactical Actions